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Search Results: 1 - 10 of 210790 matches for " Amy L. Weaver "
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Prognostic Value of Complete Blood Count and Electrolyte Panel during Emergency Department Evaluation for Acute Ischemic Stroke
Latha Ganti,Rachel M. Gilmore,Amy L. Weaver,Robert D. Brown Jr.
ISRN Stroke , 2013, DOI: 10.1155/2013/974236
Abstract: Objective. To determine whether routine laboratory parameters are predictors of early mortality after acute ischemic stroke (AIS). Methods. The cohort consisted of 522 consecutive patients with AIS presenting to the emergency department (ED) at a tertiary referral center during a 27-month period, residing within the surrounding ten counties. Serum laboratory values were obtained for all patients and categorized according to whether the levels were low, normal, or high. These laboratory results were evaluated as potential predictors of 90-day mortality using Cox proportional hazards models. The associations were summarized by calculating risk ratios (RRs) and 95% confidence intervals (CI). Results. The presence of elevated white blood cell count (RR 2.2, 95% CI 1.5–3.4), low bicarbonate (RR 4.2, 95% CI 2.6–6.7), low calcium (RR 2.9, 95% CI 1.4–5.9), and high glucose (RR 1.3, 95% 1.1–1.6) were each univariately associated with significantly higher mortality within the first 90 days. Based on fitting a multivariate Cox regression model, elevated white blood cell count, low bicarbonate, and high glucose were each identified as being jointly associated with early mortality ( ). Conclusion. Early leukocytosis, acidosis, and hyperglycemia and hypocalcemia in AIS appear to be associated with early mortality. Whether addressing these factors will impact survival remains to be investigated. 1. Introduction For patients who present with chief complaint of acute ischemic stroke, the American Stroke Association recommends a set of diagnostic studies [1] to be done at presentation, with the intent of optimizing and expediting the care of these patients. From the Emergency Physicians’ perspective many tests are simply part of a routine battery, often without direct impact on emergency department (ED) management, diagnostic or prognostic value. In this study, we sought to determine whether the routine complete blood count (CBC) and electrolyte panel include any components that are markers of early mortality in acute ischemic stroke. Specifically, the parameters of interest were those obtained as part of routine clinical investigation. 2. Methods 2.1. Study Design This study was an observational study using a consecutive sample of local residents presenting to the ED with acute ischemic stroke (AIS). The primary outcome measure was death at 90 days. This study was approved by the Mayo Clinic Institutional Review Board. 2.2. Study Population and Setting This study was conducted at the Saint Marys Hospital, a tertiary referral academic medical center with an annual ED
New Alternately Colored FRET Sensors for Simultaneous Monitoring of Zn2+ in Multiple Cellular Locations
Jose G. Miranda, Amanda L. Weaver, Yan Qin, J. Genevieve Park, Caitlin I. Stoddard, Michael Z. Lin, Amy E. Palmer
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0049371
Abstract: Genetically encoded sensors based on fluorescence resonance energy transfer (FRET) are powerful tools for reporting on ions, molecules and biochemical reactions in living cells. Here we describe the development of new sensors for Zn2+based on alternate FRET-pairs that do not involve the traditional CFP and YFP. Zn2+ is an essential micronutrient and plays fundamental roles in cell biology. Consequently there is a pressing need for robust sensors to monitor Zn2+ levels and dynamics in cells with high spatial and temporal resolution. Here we develop a suite of sensors using alternate FRET pairs, including tSapphire/TagRFP, tSapphire/mKO, Clover/mRuby2, mOrange2/mCherry, and mOrange2/mKATE. These sensors were targeted to both the nucleus and cytosol and characterized and validated in living cells. Sensors based on the new FRET pair Clover/mRuby2 displayed a higher dynamic range and better signal-to-noise ratio than the remaining sensors tested and were optimal for monitoring changes in cytosolic and nuclear Zn2+. Using a green-red sensor targeted to the nucleus and cyan-yellow sensor targeted to either the ER, Golgi, or mitochondria, we were able to monitor Zn2+ uptake simultaneously in two compartments, revealing that nuclear Zn2+ rises quickly, whereas the ER, Golgi, and mitochondria all sequester Zn2+ more slowly and with a delay of 600–700 sec. Lastly, these studies provide the first glimpse of nuclear Zn2+ and reveal that nuclear Zn2+ is buffered at a higher level than cytosolic Zn2+.
The impact of blood pressure hemodynamics in acute ischemic stroke: a prospective cohort study
Latha Stead, Sailaja Enduri, M Fernanda Bellolio, Anunaya R Jain, Lekshmi Vaidyanathan, Rachel M Gilmore, Rahul Kashyap, Amy L Weaver, Robert D Brown
International Journal of Emergency Medicine , 2012, DOI: 10.1186/1865-1380-5-3
Abstract: The study cohort consisted of 189 patients who presented to our emergency department with ischemic stroke of less than 24 hours onset who had hemodynamic parameters recorded and available for review. Blood pressure (BP) was non-invasively measured at 5 minute intervals for the length of the patient's emergency department stay. Systolic BP (sBP) and diastolic BP (dBP) were measured for each patient and a differential (the maximum minus the minimum BP) calculated. Three outcomes were studied: stroke severity, disability at hospital discharge, and death at 90 days. Statistical tests used included Spearman correlations (for stroke severity), Wilcoxon test (for disability) and Cox models (for death).Larger differentials of either dBP (p = 0.003) or sBP (p < 0.001) were significantly associated with more severe strokes. A greater dBP (p = 0.019) or sBP (p = 0.036) differential was associated with a significantly worse functional outcome at hospital discharge. Those patients with larger differentials of either dBP (p = 0.008) or sBP (0.007) were also significantly more likely to be dead at 90 days, independently of the basal BP.A large differential in either systolic or diastolic blood pressure within 24 hours of symptom onset in acute ischemic stroke appears to be associated with more severe strokes, worse functional outcome and early deathStroke is associated with a high mortality and significant long-term functional disability. Of the 15 million patients affected by stroke worldwide yearly, the World Health Organization reports almost a third of these patients die, and another third are permanently disabled. Hypertension accounts for nearly 12.7 million strokes worldwide [1].Close to 80% of acute ischemic stroke (AIS) patients have an elevated blood pressure [2]. The elevation of blood pressure (BP) post-AIS has a multitude of causes, ranging from chronic hypertension and sympathetic stress response to stroke-related pathology itself [3]. Previous studies have shown tha
Human Calmodulin-Like Protein CALML3: A Novel Marker for Normal Oral Squamous Mucosa That Is Downregulated in Malignant Transformation
Michael D. Brooks,Richard D. Bennett,Amy L. Weaver,Thomas J. Sebo,Steven E. Eckert,Emanuel E. Strehler,Alan B. Carr
International Journal of Dentistry , 2013, DOI: 10.1155/2013/592843
Abstract: Oral cancer is often diagnosed only at advanced stages due to a lack of reliable disease markers. The purpose of this study was to determine if the epithelial-specific human calmodulin-like protein (CALML3) could be used as marker for the various phases of oral tumor progression. Immunohistochemical analysis using an affinity-purified CALML3 antibody was performed on biopsy-confirmed oral tissue samples representing these phases. A total of 90 tissue specimens were derived from 52 patients. Each specimen was analyzed in the superficial and basal mucosal cell layers for overall staining and staining of cellular subcompartments. CALML3 was strongly expressed in benign oral mucosal cells with downregulation of expression as squamous cells progress to invasive carcinoma. Based on the Cochran-Armitage test for trend, expression in the nucleus and at the cytoplasmic membrane significantly decreased with increasing disease severity. Chi-square test showed that benign tissue specimens had significantly more expression compared to dysplasia/CIS and invasive specimens. Dysplasia/CIS tissue had significantly more expression than invasive tissue. We conclude that CALML3 is expressed in benign oral mucosal cells with a statistically significant trend in downregulation as tumorigenesis occurs. CALML3 may thus be a sensitive new marker for oral cancer screening. 1. Introduction Approximately 30,000 new cases of cancer in the oral cavity and oropharynx are diagnosed in the United States each year, corresponding to about 3% of all malignant tumors. Although visibly detectable due to the accessibility of the oral cavity, oral cancer has a high morbidity and mortality because it is typically at an advanced stage when it is finally clinically visible. Accordingly, the five-year survival rate for all stages combined is only 51%. Of the cancers involving the oral cavity and oropharynx, more than 90% are squamous cell carcinomas [1–3]. Up to 40% of those diagnosed with squamous cell carcinoma will develop a metastatic tumor or a second primary tumor to a nearby organ at a later time. Early diagnosis of oral and oropharyngeal squamous cell carcinoma is crucial for a more favorable prognosis. The oral cavity and oropharynx are easily accessible for routine screening for squamous cell carcinoma, but reliable detection in early stages will require robust markers that are easy to assay. Methods for testing oral epithelial cells for malignancy traditionally involve an invasive and often painful biopsy. Whether as a diagnostic tool or prognostic marker, the potential to develop a
Identification of N-acetylglucosaminyltranferase-IV as a modifier of Epstein-Barr virus BZLF1 activity  [PDF]
Amy L. Adamson
Open Journal of Genetics (OJGen) , 2013, DOI: 10.4236/ojgen.2013.31001
Abstract:

Epstein-Barr virus is a prevalent human herpesvirus, with about 95% of the world’s adult population positive for anti-EBV antigen antibodies. After the initial infection and production of new virus particles, the virus may enter a latent state within a subset of cells, and therefore can remain within the host indefinitely. Epstein-Barr virus contributes to a variety of diseases, including many types of cancers. We have created a model system in Drosophila melanogaster to study the effect of expression of the Epstein-Barr virus protein BZLF1, and to identify cellular proteins that mediate BZLF1 activity. Here we present the results of a genetic screen that determined that the Drosophila melanogaster CG9384 gene (an N-acetylglucosaminyl-transferase) is a significant modulator of BZLF1 activity and EBV early lytic replication.

Cystathionine Beta-Synthase (CBS) Contributes to Advanced Ovarian Cancer Progression and Drug Resistance
Sanjib Bhattacharyya, Sounik Saha, Karuna Giri, Ian R. Lanza, K. Sreekumar Nair, Nicholas B. Jennings, Cristian Rodriguez-Aguayo, Gabriel Lopez-Berestein, Eati Basal, Amy L. Weaver, Daniel W. Visscher, William Cliby, Anil K. Sood, Resham Bhattacharya, Priyabrata Mukherjee
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079167
Abstract: Background Epithelial ovarian cancer is the leading cause of gynecologic cancer deaths. Most patients respond initially to platinum-based chemotherapy after surgical debulking, however relapse is very common and ultimately platinum resistance emerges. Understanding the mechanism of tumor growth, metastasis and drug resistant relapse will profoundly impact the therapeutic management of ovarian cancer. Methods/Principal Findings Using patient tissue microarray (TMA), in vitro and in vivo studies we report a role of of cystathionine-beta-synthase (CBS), a sulfur metabolism enzyme in ovarian carcinoma. We report here that the expression of cystathionine-beta-synthase (CBS), a sulfur metabolism enzyme, is common in primary serous ovarian carcinoma. The in vitro effects of CBS silencing can be reversed by exogenous supplementation with the GSH and H2S producing chemical Na2S. Silencing CBS in a cisplatin resistant orthotopic model in vivo by nanoliposomal delivery of CBS siRNA inhibits tumor growth, reduces nodule formation and sensitizes ovarian cancer cells to cisplatin. The effects were further corroborated by immunohistochemistry that demonstrates a reduction of H&E, Ki-67 and CD31 positive cells in si-RNA treated as compared to scrambled-RNA treated animals. Furthermore, CBS also regulates bioenergetics of ovarian cancer cells by regulating mitochondrial ROS production, oxygen consumption and ATP generation. This study reports an important role of CBS in promoting ovarian tumor growth and maintaining drug resistant phenotype by controlling cellular redox behavior and regulating mitochondrial bioenergetics. Conclusion The present investigation highlights CBS as a potential therapeutic target in relapsed and platinum resistant ovarian cancer.
An ultrasound elastography method for examining the anterior cruciate ligament  [PDF]
Amy L. Cochran, Yingxin Gao
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.58A2004
Abstract:

We introduce an ultrasound elastography method for examining the ACL. It consisted of imaging the distal ACL while applying a drawer test and analyzing the resulting displacement and strain maps, where a map refers to how a variable is distributed spatially throughout an image. Our method was applied to healthy knees of cadaveric sheep to determine whether 1) our method can consistently generate displacements and strain maps in healthy ACLs; 2) displacement and strain maps are repeatable; and 3) healthy ACLs experience similar maps. We found that our method could consistently provide displacements and strain maps of the distal ACL region. Moreover, these ACLs experienced displacement and strain maps that were positively-correlated between trials, knees, and specimens. This correlation was statistically significant between pairs of trials and between left and right knees (p < 0.05). These results suggest that the maps are indeed repeatable and similar for healthy ACLs.

A chronology of hurricane induced changes in puerto rico?s lower montane rain forest
Weaver,Peter L;
Interciencia , 2002,
Abstract: ridges in the lower montane rain forests of puerto rico and the lesser antilles from st. kitts to grenada are dominated by tabonuco (dacryodes excelsa vahl), a long-lived tree adapted to recurrent hurricanes. the oldest tabonuco trees in puerto rico appear to survive 500 to 600yrs in forests that periodically (perhaps every 50 to 60yrs) lose nearly one-fifth of their biomass. post hurricane-recovery, characterized by greater rates of stem ingrowth and mortality, showed an immediate and abundant regeneration of yagrumo hembra (cecropia schreberiana mig.) along with numerous small- to medium-sized species in forest openings. stem density, species numbers, and the rate of biomass accumulation are at a maximum 15yrs after the hurricane; about 50yrs later, most of the secondary species associated with past forest disturbance have disappeared and the rate of biomass accumulation becomes asymptotic
On the retrieval of attenuation from the azimuthally averaged coherency of a diffuse field
Richard L. Weaver
Physics , 2012,
Abstract: It has been suggested that seismic attenuation \alpha can be inferred from comparisons of empirical coherencies (the cross spectra of pre-whitened ambient seismic noise records) with attenuated Bessel functions Jo(\omega r/c) exp(-\alpha r). Analysis shows here, however, that coherency depends strongly on the directionality of ambient noise intensity. Even if coherency is azimuthally averaged, the suggested attenuation dependence exp(-\alpha r) does not apply. Indeed in highly directional noise fields, coherency is independent of attenuation. It is also argued that spatial and azimuthal averages of coherency can incur phase cancellations related to variations in wavespeed that may mimic factors like exp(-\alpha r). Inference of attenuation from comparison of empirical coherencies to Jo(\omega r/c) exp(-\alpha r) is problematic.
Generalized Berry Conjecture and mode correlations in chaotic plates
Alexei Akolzin,Richard L. Weaver
Physics , 2004, DOI: 10.1103/PhysRevE.70.046212
Abstract: We consider a modification of the Berry Conjecture for eigenmode statistics in wave-bearing systems. The eigenmode correlator is conjectured to be proportional to the imaginary part of the Green's function. The generalization is applicable not only to scalar waves in the interior of homogeneous isotropic systems where the correlator is a Bessel function, but to arbitrary points of heterogeneous systems as well. In view of recent experimental measurements, expressions for the intensity correlator in chaotic plates are derived.
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