765 research outputs found

    The Role of Autophagy During Myocardial Ischemia/Reperfusion Injury

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    Autophagy is a housekeeping process to remove damaged cytoplasmic constituents. However, a debate persists on whether autophagy is beneficial or detrimental when an ischemic/reperfusion (I/R) insult occurs in the heart. This study tested the effects of autophagy enhancers (e.g. rapamycin and trehalose) and autophagy inhibitor (e.g. 3-methyladenine) on heart function and infarct size after global I (30 minutes) and R (45 minutes) when given prior to ischemia (pre-treatment) or at the beginning of reperfusion (post-treatment). We found that Rapamycin (25nM) pre-treatment and post-treatment significantly restored final left ventricular developed pressure (LVDP) to 75.4±9.1% and 60±5% of initial baseline respectively (both n=5, p\u3c0.05), compared to I/R group (n=9) that recovered to 35±5.5% of initial baseline. Likewise, trehalose (5mM) pre-treatment and post-treatment also significantly restored final LVDP to 61.4±3.7% (n=6) and 69.1±2.7% (n=5) of initial baseline respectively, compared to I/R group. However, 3-methyladenine (1mM) pre-treatment (n=6) and post-treatment (n=5) showed similar reduction in final LVDP to 24.7±9.1% and 33.4±12.8 % of initial baseline respectively, as I/R group. Moreover, infarction percentage was significantly reduced by rapamycin pre-treatment and post-treatment (14 ± 2.8% and 21.4 ± 5.3%, respectively; both p\u3c0.05); and trehalose pre-treatment and post-treatment (19.2 ± 3% and 15.2% ± 3, respectively; both p\u3c0.05), but not by 3-methyladenine pre-treatment and post-treatment (26±2% and 28±4.1%, respectively) when compared to I/R group (38.6±4.3%). The data suggests that autophagy enhancement before ischemia or at reperfusion is beneficial for reducing I/R injury

    Signs of a vector's adaptive choice: on the evasion of infectious hosts and parasite-induced mortality

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    Laboratory and field experiments have demonstrated in many cases that malaria vectors do not feed randomly, but show important preferences either for infected or non-infected hosts. These preferences are likely in part shaped by the costs imposed by the parasites on both their vertebrate and dipteran hosts. However, the effect of changes in vector behaviour on actual parasite transmission remains a debated issue. We used the natural associations between a malaria-like parasite Polychromophilus murinus, the bat fly Nycteribia kolenatii and a vertebrate host the Daubenton's bat Myotis daubentonii to test the vector's feeding preference based on the host's infection status using two different approaches: 1) controlled behavioural assays in the laboratory where bat flies could choose between a pair of hosts; 2) natural bat fly abundance data from wild-caught bats, serving as an approximation of realised feeding preference of the bat flies. Hosts with the fewest infectious stages of the parasite were most attractive to the bat flies that did switch in the behavioural assay. In line with the hypothesis of costs imposed by parasites on their vectors, bat flies carrying parasites had higher mortality. However, in wild populations, bat flies were found feeding more based on the bat's body condition, rather than its infection level. Though the absolute frequency of host switches performed by the bat flies during the assays was low, in the context of potential parasite transmission they were extremely high. The decreased survival of infected bat flies suggests that the preference for less infected hosts is an adaptive trait. Nonetheless, other ecological processes ultimately determine the vector's biting rate and thus transmission. Inherent vector preferences therefore play only a marginal role in parasite transmission in the field. The ecological processes rather than preferences per se need to be identified for successful epidemiological predictions

    Iatrogenic Spinal Cord Injury Resulting From Cervical Spine Surgery.

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    STUDY DESIGN: Retrospective cohort study of prospectively collected data. OBJECTIVE: To examine the incidence of iatrogenic spinal cord injury following elective cervical spine surgery. METHODS: A retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network was conducted. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were reviewed to identify occurrence of iatrogenic spinal cord injury. RESULTS: In total, 3 cases of iatrogenic spinal cord injury following cervical spine surgery were identified. Institutional incidence rates ranged from 0.0% to 0.24%. Of the 3 patients with quadriplegia, one underwent anterior-only surgery with 2-level cervical corpectomy, one underwent anterior surgery with corpectomy in addition to posterior surgery, and one underwent posterior decompression and fusion surgery alone. One patient had complete neurologic recovery, one partially recovered, and one did not recover motor function. CONCLUSION: Iatrogenic spinal cord injury following cervical spine surgery is a rare and devastating adverse event. No standard protocol exists that can guarantee prevention of this complication, and there is a lack of consensus regarding evaluation and treatment when it does occur. Emergent imaging with magnetic resonance imaging or computed tomography myelography to evaluate for compressive etiology or malpositioned instrumentation and avoidance of hypotension should be performed in cases of intraoperative and postoperative spinal cord injury

    Optimizing patient care and outcomes through the congenital heart center of the 21st century

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    Pediatric cardiovascular services are responding to the dynamic changes in the medical environment, including the business of medicine. The opportunity to advance our pediatric cardiology field through collaboration is now realized, permitting us to define meaningful quality metrics and establish national benchmarks through multicenter efforts. In March 2016, the American College of Cardiology hosted the first Adult Congenital/Pediatric Cardiology Section Congenital Heart Community Day. This was an open participation meeting for clinicians, administrators, patients/parents to propose metrics that optimize patient care and outcomes for a stateĂą ofĂą theĂą art congenital heart center of the 21st century. Care center collaboration helps overcome the barrier of relative small volumes at any given program. Patients and families have become active collaborative partners with care centers in the definition of acute and longitudinal outcomes and our quality metrics. Understanding programmatic metrics that create an environment to provide outstanding congenital heart care will allow centers to improve their structure, processes and ultimately outcomes, leading to an increasing number of centers that provide excellent care. This manuscript provides background, as well listing of proposed specialty domain quality metrics for centers, and thus serves as an updated baseline for the ongoing dynamic process of optimizing care and realizing patient value.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143653/1/chd12575_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143653/2/chd12575.pd

    Geophysical Well-Log Measurements in Three Drill Holes at Salt Valley, Utah

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    Three exploratory drill holes were drilled at Salt Valley, Utah, to study the geologic, physical, geochemical, and hydrologic properties of the evaporite sequence in the Permian Paradox Member of the Hermosa Formation. The results of these studies will be used to help to determine the suitability of salt deposits in the Paradox basin as a storage medium for radioactive waste material

    Clinical features of the pathogenic m.5540G>A mitochondrial transfer RNA tryptophan gene mutation

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    AbstractMitochondrial DNA disease is one of the most common groups of inherited neuromuscular disorders and frequently associated with marked phenotypic and genotypic heterogeneity. We describe an adult patient who initially presented with childhood-onset ataxia without a family history and an unremarkable diagnostic muscle biopsy. Subsequent multi-system manifestations included basal ganglia calcification, proteinuria, cataract and retinitis pigmentosa, prompting a repeat muscle biopsy that showed features consistent with mitochondrial myopathy 13 years later. She had a stroke with restricted diffusion change in the basal ganglia and internal capsule at age 44 years. Molecular genetic testing identified a previously-reported pathogenic, heteroplasmic mutation in the mitochondrial-encoded transfer RNA tryptophan (MT-TW) gene which based on family studies was likely to have arisen de novo in our patient. Interestingly, we documented an increase in the mutant mtDNA heteroplasmy level in her second biopsy (72% compared to 56%), reflecting the progression of clinical disease

    Multi-Messenger Gravitational Wave Searches with Pulsar Timing Arrays: Application to 3C66B Using the NANOGrav 11-year Data Set

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    When galaxies merge, the supermassive black holes in their centers may form binaries and, during the process of merger, emit low-frequency gravitational radiation in the process. In this paper we consider the galaxy 3C66B, which was used as the target of the first multi-messenger search for gravitational waves. Due to the observed periodicities present in the photometric and astrometric data of the source of the source, it has been theorized to contain a supermassive black hole binary. Its apparent 1.05-year orbital period would place the gravitational wave emission directly in the pulsar timing band. Since the first pulsar timing array study of 3C66B, revised models of the source have been published, and timing array sensitivities and techniques have improved dramatically. With these advances, we further constrain the chirp mass of the potential supermassive black hole binary in 3C66B to less than (1.65±0.02)×109 M⊙(1.65\pm0.02) \times 10^9~{M_\odot} using data from the NANOGrav 11-year data set. This upper limit provides a factor of 1.6 improvement over previous limits, and a factor of 4.3 over the first search done. Nevertheless, the most recent orbital model for the source is still consistent with our limit from pulsar timing array data. In addition, we are able to quantify the improvement made by the inclusion of source properties gleaned from electromagnetic data to `blind' pulsar timing array searches. With these methods, it is apparent that it is not necessary to obtain exact a priori knowledge of the period of a binary to gain meaningful astrophysical inferences.Comment: 14 pages, 6 figures. Accepted by Ap

    Enhanced sphingosine-1-phosphate receptor 2 expression underlies female CNS autoimmunity susceptibility

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    Multiple sclerosis (MS) is an inflammatory disease of the CNS that is characterized by BBB dysfunction and has a much higher incidence in females. Compared with other strains of mice, EAE in the SJL mouse strain models multiple features of MS, including an enhanced sensitivity of female mice to disease; however, the molecular mechanisms that underlie the sex- and strain-dependent differences in disease susceptibility have not been described. We identified sphingosine-1-phosphate receptor 2 (S1PR2) as a sex- and strain-specific, disease-modifying molecule that regulates BBB permeability by destabilizing adherens junctions. S1PR2 expression was increased in disease-susceptible regions of the CNS of both female SJL EAE mice and female patients with MS compared with their male counterparts. Pharmacological blockade or lack of S1PR2 signaling decreased EAE disease severity as the result of enhanced endothelial barrier function. Enhanced S1PR2 signaling in an in vitro BBB model altered adherens junction formation via activation of Rho/ROCK, CDC42, and caveolin endocytosis-dependent pathways, resulting in loss of apicobasal polarity and relocation of abluminal CXCL12 to vessel lumina. Furthermore, S1PR2-dependent BBB disruption and CXCL12 relocation were observed in vivo. These results identify a link between S1PR2 signaling and BBB polarity and implicate S1PR2 in sex-specific patterns of disease during CNS autoimmunity
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