36 results on '"McCoy MR"'
Search Results
2. Travelers checks for official travel
- Author
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McCoy, Mr
- Subjects
MONEY ,TRAVEL PAY - Published
- 1987
3. Angiographic and artefact-free computed tomography imaging of experimental aneurysms embolised with hydrogel filaments.
- Author
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McCoy MR, Cruise GM, Killer M, McCoy, Mark R, Cruise, Gregory M, and Killer, Monika
- Abstract
Objectives: We compared experimental rabbit carotid bifurcation aneurysms embolised with platinum coils or hydrogel filaments by using digital subtraction angiography (DSA) and computed tomography angiography (CTA).Methods: Embolisation was performed using platinum coils (n = 2), hydrogel filaments loaded with iodine (n = 3) and hydrogel filaments loaded with barium sulphate (n = 3). In one case, a stent was deployed in the parent vessel to determine the effect of hydrogel filaments on stent visualisation. DSA evaluations occurred immediately post-treatment. CTA evaluations occurred at 0-13 weeks post-treatment. The DSA and CTA images were evaluated for the lack of artefacts and the visibilities of the embolic mass, individual coils and residual flow in the aneurysm sac and neck.Results: The DSA results were largely concordant among the three groups. The embolic masses were readily evident with some individual coils being distinguished. In the aneurysms embolised with hydrogel filaments, visualisation of the individual coils, residual flow and stent with minor or no artefacts was possible using CTA. On the other hand, the beam hardening artefacts precluded analysis of aneurysms embolised with platinum coils.Conclusion: CTA-compatible embolic devices could have wide applications in diverse locations throughout the vasculature, particularly in combination with stents or stent grafts. [ABSTRACT FROM AUTHOR]- Published
- 2010
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4. The Generation of a Nanobody-Based ELISA for Human Microsomal Epoxide Hydrolase.
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He Q, McCoy MR, Qi M, Morisseau C, Yang H, Xu C, Shey R, Goodman MC, Zhao S, and Hammock BD
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- Humans, Enzyme-Linked Immunosorbent Assay, Antibodies, Epoxy Compounds, Epoxide Hydrolases metabolism, Single-Domain Antibodies
- Abstract
A microsomal epoxide hydrolase (mEH) metabolizes in vivo in both xenobiotic and endogenous epoxides associated with signaling function. Findings in patients suggest that mEH might be a biomarker for several diseases, including metastatic cancer and viral hepatitis. To easily quantify mEH, nanobodies specific to the human mEH were isolated from a phage library of llama VHHs. Four unique clones were obtained and used for developing ELISAs. Three formats of double antibody sandwich assays were investigated using different detection strategies. Using PolyHRP, the signal was strongly amplified, yielding a 22-fold lower LOD (12 pg mL
-1 ) than the 'conventional'. To further validate the performance of the immunoassays, human tissue samples were analyzed by nanobody-based ELISAs and compared to the enzyme activities ( R2 > 0.95). The results demonstrate that these nanobodies are powerful tools for the quantification of human mEH and could eventually result in a bedside assay.- Published
- 2023
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5. Mix-and-Read Nanobody-Based Sandwich Homogeneous Split-Luciferase Assay for the Rapid Detection of Human Soluble Epoxide Hydrolase.
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He Q, McCoy MR, Yang H, Lin M, Cui X, Zhao S, Morisseau C, Li D, and Hammock BD
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- Luciferases analysis, Humans, Epoxide Hydrolases metabolism, Time Factors, Solubility, Calibration, Animals, Mice, Rats, Single-Domain Antibodies immunology
- Abstract
The soluble epoxide hydrolase (sEH) is possibly both a marker for and target of numerous diseases. Herein, we describe a homogeneous mix-and-read assay for the detection of human sEH based on using split-luciferase detection coupled with anti-sEH nanobodies. Selective anti-sEH nanobodies were individually fused with NanoLuc Binary Technology (NanoBiT), which consists of a large and small portion of NanoLuc (LgBiT and SmBiT, respectively). Different orientations of the LgBiT and SmBiT-nanobody fusions were expressed and investigated for their ability to reform the active NanoLuc in the presence of the sEH. After optimization, the linear range of the assay could reach 3 orders of magnitude with a limit of detection (LOD) of 1.4 ng/mL. The assay has a high sensitivity to human sEH and reached a similar detection limit to our previously reported conventional nanobody-based ELISA. The procedure of the assay was faster (30 min total) and easy to operate, providing a more flexible and simple way to monitor human sEH levels in biological samples. In general, the immunoassay proposed here offers a more efficient detection and quantification approach that can be easily adapted to numerous macromolecules.
- Published
- 2023
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6. Pesticide Residues in Vegetables and Fruits from Farmer Markets and Associated Dietary Risks.
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El-Sheikh EA, Ramadan MM, El-Sobki AE, Shalaby AA, McCoy MR, Hamed IA, Ashour MB, and Hammock BD
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- Humans, Vegetables chemistry, Fruit chemistry, Chromatography, Liquid methods, Tandem Mass Spectrometry methods, Farmers, Food Contamination analysis, Pesticide Residues analysis, Pesticides analysis
- Abstract
The use of pesticides leads to an increase in agricultural production but also causes harmful effects on human health when excessively used. For safe consumption, pesticide residues should be below the maximum residual limits (MRLs). In this study, the residual levels of pesticides in vegetables and fruits collected from farmers' markets in Sharkia Governorate, Egypt were investigated using LC-MS/MS and GC-MS/MS. A total number of 40 pesticides were detected in the tested vegetable and fruit samples. Insecticides were the highest group in detection frequency with 85% and 69% appearance in vegetables and fruits, respectively. Cucumber and apple samples were found to have the highest number of pesticide residues. The mean residue levels ranged from 7 to 951 µg kg
-1 (in vegetable samples) and from 8 to 775 µg kg-1 (in fruit samples). It was found that 35 (40.7%) out of 86 pesticide residues detected in vegetables and 35 (38.9%) out of 90 pesticide residues detected in fruits exceeded MRLs. Results for lambda-cyhalothrin, fipronil, dimothoate, and omethoate in spinach, zucchini, kaki, and strawberry, respectively, can cause acute or chronic risks when consumed at 0.1 and 0.2 kg day-1 . Therefore, it is necessary for food safety and security to continuously monitor pesticide residues in fruits and vegetables in markets.- Published
- 2022
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7. Generation of bioluminescent enzyme immunoassay for ferritin by single-chain variable fragment and its NanoLuc luciferase fusion.
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He Q, Yang L, Lin M, Yang H, Cui X, McCoy MR, Hammock BD, Fang Y, and Zhao S
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- Enzyme-Linked Immunosorbent Assay, Ferritins, Immunoassay, Immunoenzyme Techniques, Luciferases genetics, Peptide Library, Single-Chain Antibodies
- Abstract
Ferritin, widely present in liver and spleen tissue, is considered as a serological biomarker for liver diseases and cancers. The detection of ferritin may be an important tool in health diagnosis. In this study, 14 non-immunized chicken spleens were utilized to construct a single-chain fragment (scFv) phage library. After 4 rounds of panning, 7 unique clones were obtained. The optimal clone was further screened and combined with NanoLuc luciferase (Nluc) as a dual functional immunoprobe to bioluminescent enzyme immunoassay (BLEIA), which was twice as sensitive as its parental scFv-based double-sandwich enzyme-linked immunoassay (ds-ELISA). The cross-reactivity analysis revealed that the proposed methods were highly selective and suitable for clinical detection. To further verify the performance of the immunoassays, serum samples were tested by the proposed methods and a commercial ELISA kit, and there was a good correlation between the results. These results suggested that scFv fused with Nluc might be a powerful dual functional tool for rapid, practically reliable, and highly sensitive ferritin detection., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2022
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8. Molecular analysis of the effects of steroid hormones on mouse meiotic prophase I progression.
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Burks DM, McCoy MR, Dutta S, Mark-Kappeler CJ, Hoyer PB, and Pepling ME
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- Animals, Cell Cycle Proteins genetics, Cell Cycle Proteins metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Female, Fetus, Gene Expression Regulation, Developmental drug effects, Granulosa Cells metabolism, Mice, Inbred C57BL, Oocytes cytology, Oocytes metabolism, Organ Culture Techniques, Ovary embryology, Ovary metabolism, Pachytene Stage drug effects, Pregnancy, RNA-Binding Proteins genetics, RNA-Binding Proteins metabolism, Estradiol pharmacology, Meiotic Prophase I drug effects, Oocytes drug effects, Ovary drug effects, Progesterone pharmacology
- Abstract
Background: Infertility is linked to depletion of the primordial follicle pool consisting of individual oocytes arrested at the diplotene stage of meiotic prophase I surrounded by granulosa cells. Primordial germ cells, the oocyte precursors, begin to differentiate during embryonic development. These cells migrate to the genital ridge and begin mitotic divisions, remaining connected, through incomplete cytokinesis, in clusters of synchronously dividing oogonia known as germ cell cysts. Subsequently, they enter meiosis, become oocytes and progress through prophase I to the diplotene stage. The cysts break apart, allowing individual oocytes to be surrounded by a layer of granulosa cells, forming primordial follicles each containing a diplotene arrested oocyte. A large number of oocytes are lost coincident with cyst breakdown, and may be important for quality control of primordial follicle formation. Exposure of developing ovaries to exogenous hormones can disrupt cyst breakdown and follicle formation, but it is unclear if hormones affect progression of oocytes through prophase I of meiosis., Methods: Fetal ovaries were treated in organ culture with estradiol, progesterone, or both hormones, labeled for MSY2 or Synaptonemal complex protein 3 (SYCP3) using whole mount immunocytochemistry and examined by confocal microscopy. Meiotic prophase I progression was also followed using the meiotic surface spread technique., Results: MSY2 expression in oocytes was reduced by progesterone but not estradiol or the hormone combination. However, while MSY2 expression was upregulated during development it was not a precise marker for the diplotene stage. We also followed meiotic prophase I progression using antibodies against SYCP3 using two different methods, and found that the percent of oocytes at the pachytene stage peaked at postnatal day 1. Finally, estradiol and progesterone treatment together but not either alone in organ culture increased the percent of oocytes at the pachytene stage., Conclusions: We set out to examine the effects of hormones on prophase I progression and found that while MSY2 expression was reduced by progesterone, MSY2 was not a precise diplotene stage marker. Using antibodies against SYCP3 to identify pachytene stage oocytes we found that progesterone and estradiol together delayed progression of oocytes through prophase I.
- Published
- 2019
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9. Neuroimaging alterations related to status epilepticus in an adult population: Definition of MRI findings and clinical-EEG correlation.
- Author
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Giovannini G, Kuchukhidze G, McCoy MR, Meletti S, and Trinka E
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- Brain diagnostic imaging, Brain physiopathology, Correlation of Data, Female, Follow-Up Studies, Humans, Image Processing, Computer-Assisted, Male, Middle Aged, Retrospective Studies, Time Factors, Electroencephalography, Magnetic Resonance Imaging, Status Epilepticus diagnostic imaging, Status Epilepticus physiopathology
- Abstract
Magnetic resonance imaging (MRI) provides an opportunity for identifying peri-ictal MRI abnormalities (PMAs) related to status epilepticus (SE). Extremely variable MRI alterations have been reported previously during or after SE, mainly in small selected populations. In a retrospective monocentric study, we analyzed brain MRI changes observed in the ictal/postictal periods of SE in an adult population. We included all consecutive patients observed in a 5-year period with an electroclinical diagnosis of SE and an MRI performed within 30 days from the beginning of SE. We identified 277 patients. Among them, 32 (12%) showed PMAs related to SE. The duration of SE was strongly associated with MRI alterations, showing a mean duration of 6 days vs 2 days (P = .011) in the group with and without MRI alterations, respectively. Focal electroencephalography (EEG) abnormalities (P = .00003) and in particular, lateralized periodic discharges (LPDs) (P < .0001) were strongly associated with PMAs. MRI alterations were unilateral (23 patients, 72%), located in multiple brain structures (19 patients, 59%), and involving mesiotemporal structures (17 patients, 53%). Sixteen patients (50%) had good spatial correspondence between cortical PMAs and the focal EEG pattern; 12 patients (38%) with focal EEG pattern showed cortical PMAs plus MRI signal changes also involving subcortical structures. A follow-up MRI was available for 14 of 32 patients (44%): 10 patients presented a disappearance of PMAs, whereas in 4, PMAs were still present. This study demonstrates that a long duration SE and the presence of certain EEG patterns (LPDs) are associated with the occurrence of PMAs. A good spatial concordance was observed between cortical PMA location and the EEG focus., (© 2018 The Authors. Epilepsia published by Wiley Periodicals, Inc. on behalf of International League Against Epilepsy.)
- Published
- 2018
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10. Safety and Efficacy of Rose Bengal Derivatives for Glial Scar Ablation in Chronic Spinal Cord Injury.
- Author
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Patil N, Truong V, Holmberg MH, Lavoie NS, McCoy MR, Dutton JR, Holmberg EG, and Parr AM
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- Animals, Chronic Disease, Nerve Regeneration drug effects, Neuroglia pathology, Rats, Rats, Long-Evans, Recovery of Function drug effects, Cicatrix pathology, Fluorescent Dyes pharmacology, Phototherapy methods, Rose Bengal pharmacology, Spinal Cord Injuries pathology
- Abstract
There are no effective therapies available currently to ameliorate loss of function for patients with spinal cord injuries (SCIs). In addition, proposed treatments that demonstrated functional recovery in animal models of acute SCI have failed almost invariably when applied to chronic injury models. Glial scar formation in chronic injury is a likely contributor to limitation on regeneration. We have removed existing scar tissue in chronically contused rat spinal cord using a rose Bengal-based photo ablation approach. In this study, we compared two chemically modified rose bengal derivatives to unmodified rose bengal, both confirming and expanding on our previously published report. Rats were treated with unmodified rose bengal (RB1) or rose bengal modified with hydrocarbon (RB2) or polyethylene glycol (RB3), to determine the effects on scar components and spared tissue post-treatment. Our results showed that RB1 was more efficacious than RB2, while still maintaining minimal collateral effects on spared tissue. RB3 was not taken up by the cells, likely because of its size, and therefore had no effect. Treatment with RB1 also resulted in an increase in serotonin eight days post-treatment in chronically injured spinal cords. Thus, we suggest that unmodified rose Bengal is a potent candidate agent for the development of a therapeutic strategy for scar ablation in chronic SCI.
- Published
- 2018
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11. Fatal Necrotizing Encephalopathy after Treatment with Nivolumab for Squamous Non-Small Cell Lung Cancer: Case Report and Review of the Literature.
- Author
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Leitinger M, Varosanec MV, Pikija S, Wass RE, Bandke D, Weis S, Studnicka M, Grinzinger S, McCoy MR, Hauer L, and Sellner J
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- Aged, Brain diagnostic imaging, Brain drug effects, Brain pathology, Brain Diseases diagnostic imaging, Brain Diseases pathology, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung pathology, Fatal Outcome, Female, Humans, Lung Neoplasms diagnostic imaging, Lung Neoplasms drug therapy, Lung Neoplasms pathology, Antineoplastic Agents, Immunological adverse effects, Brain Diseases chemically induced, Nivolumab adverse effects
- Abstract
Immune checkpoint inhibitors are antibodies, which enhance cellular and humoral immune responses and are approved for the treatment of various tumors. Immune-related adverse events (irAE) involving different organs and systems are, however, among the side-effects. Recent reports of severe persistent neurological deficits and even fatal cases underpin the need for better understanding of the exact pathomechanisms of central nervous system (CNS) toxicity. To our knowledge, we report the first biopsy-proven case of fatal necrotizing encephalopathy after treatment with nivolumab. Nivolumab targets the immune-check point inhibitor programmed cell death-1 and was used for squamous non-small cell lung cancer. Partly reversible neurologic and psychiatric symptoms and unremarkable brain magnetic resonance imaging (MRI) were observed after the first course. Neurological symptoms progressed and recurrent seizures developed after the second course. Brain MRI disclosed multiple edematous and confluent supra- and infratentorial lesions, partly with contrast-enhancement. We excluded autoimmune and paraneoplastic causes and performed ancillary investigations to rule out common and opportunistic infections. Eventually, postmortem histopathological analysis of the brain revealed a necrotizing process, which contrasts previous cases reporting parenchymal immune cell infiltration or demyelination. Appropriate diagnostic pathways and treatment algorithms need to be implemented for the work-up of CNS toxicity and irAEs related to immune checkpoint inhibitor treatment.
- Published
- 2018
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12. Sigmoid Sinus Characteristics Correlate with Early Clinical and Imaging Surrogates in Anterior Circulation Ischemic Stroke.
- Author
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Pikija S, Magdic J, Liebeskind DS, Karamyan A, Bubel N, McCoy MR, and Sellner J
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- Aged, Aged, 80 and over, Brain Ischemia diagnostic imaging, Brain Ischemia drug therapy, Cerebrovascular Circulation drug effects, Female, Humans, Male, Middle Aged, Stroke diagnostic imaging, Stroke drug therapy, Thrombolytic Therapy methods, Treatment Outcome, Brain Ischemia pathology, Infarction, Middle Cerebral Artery therapy, Stroke pathology
- Abstract
Cerebral venous outflow may play a decisive role in acute ischemic stroke. Here, we assessed the relation of cerebral sinus vein characteristics with clinical and imaging surrogates of early outcome in acute ischemic stroke. We evaluated cerebral vein characteristics in 212 patients with the middle cerebral artery (MCA) occlusive stroke confirmed by CT angiography CTA within 6 h from symptom onset. Readout parameters included volume and density of the sigmoid sinus (SS) and density of the superior sagittal sinus (SupSagS). These were correlated with early clinical outcome defined as hospital death (HD), final infarct volume (FIV), and National Institute of Health Stroke Scale (NIHSS) at discharge. We found a correlation for the volume of the right SS and the FIV when the M1 segment of the MCA of either side was occluded (p = 0.002, Rho = 0.206, n = 134). A decrease in SS density was more pronounced in the subgroup with unfavorable outcome (NIHSS > 15 + HD) but only when the left hemisphere was affected (p = 0.026, n = 101). On stepwise logistic regression analysis, adjusted for on-admission NIHSS, age at presentation, and FIV, smaller SS volume was independently associated with lower odds for hospital death (n = 183, OR 0.13, 95 % CI 0.02-0.94, p = 0.043). A larger right SS and a decrease in density increase the risk of unfavorable early clinical and imaging outcome in AIS. This finding of an outflow pattern independent of the stroke site implicates an involvement of the cerebral venous drainage system in the pathophysiology of ischemic stroke.
- Published
- 2017
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13. Proximal flow to middle cerebral artery is associated with higher thrombus density in terminal internal carotid artery occlusion.
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Pikija S, Magdic J, Killer-Oberpfalzer M, Florea C, Hauer L, Novak HF, McCoy MR, and Sellner J
- Abstract
Proximal collaterals may determine the composition of occluding thrombi in acute ischemic stroke (AIS) in addition to source, hematocrit, time, and medication. Here, we performed a retrospective study of 39 consecutive patients with radiological evidence of I-, L-, and T-type terminal internal carotid artery occlusion. Middle cerebral artery (MCA) thrombus density was assessed on noncontrast enhanced CT and proximal collaterals on CT angiography. In patients with presence of proximal collaterals to the MCA we detected more hyperdense clots ( P = 0.003) and a higher frequency of leptomeningeal collaterals ( P = 0.008). We expand the spectrum of factors that potentially determine clot perviousness and evolution of ischemic stroke.
- Published
- 2017
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14. Delayed Hospital Presentation and Neuroimaging in Non-surgical Spinal Cord Infarction.
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Pikija S, Mutzenbach JS, Kunz AB, Nardone R, Leis S, Deak I, McCoy MR, Trinka E, and Sellner J
- Abstract
Background: Lack of timely recognition and neuroimaging may be a barrier to reperfusion efforts in acute spinal cord infarction., Methods: We performed a retrospective study of patients diagnosed with acute non-surgical spinal cord infarction at our tertiary academic center from 2001 to 2015. We studied parameters associated with time from symptom onset to initial hospital presentation and magnetic resonance imaging (MRI) of the spinal cord., Results: We identified 39 patients among whom anterior spinal artery syndrome was the most frequent presentation (87.2%) and atherosclerosis the most common etiology (56.4%). Nearly, half of the patients presented to the emergency department on the same day of symptom onset (48.7%) but only nine (23.1%) within the first 6 h. Average time from symptom onset to spinal cord MRI was 3.2 days. We could not identify clinical, radiological, or outcome patterns associated with early vs. delayed presentation and imaging., Discussion: Our study found a time lag from symptom onset to hospital presentation and spinal cord MRI in patients with acute spinal cord infarction. These findings point at low clinical suspicion of spinal cord syndromes and limited recognition as a potentially treatable medical emergency.
- Published
- 2017
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15. Extensive pneumatized air cells causing susceptibility artifacts in the petrosus part of the ICA.
- Author
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McCoy MR, Broussalis E, Killer M, Steinbacher J, and Klausner F
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- Adult, Aged, Aged, 80 and over, Air, Female, Humans, Imaging, Three-Dimensional methods, Male, Middle Aged, Reproducibility of Results, Sensitivity and Specificity, Artifacts, Carotid Artery Diseases diagnostic imaging, Carotid Artery, Internal diagnostic imaging, Diagnostic Errors prevention & control, Magnetic Resonance Angiography methods, Petrous Bone diagnostic imaging
- Abstract
Introduction: 3D-Time-of-flight magnetic-resonance-angiography (TOF MRA) is an established method in vessel analysis. However, many artifacts that occur may lead to a false diagnosis. This retrospective study evaluates the coherence of MR artifacts to extensive pneumatized air cells surrounding the internal carotid artery (ICA) in the petrosus part of the temporal bone., Materials and Methods: Patients who received 3D-TOF MRA and multidetector helical computed tomography (CT) angiography were registered from April 2012 to April 2013. Of these patients, both ICAs in the petrosus part were analyzed. Vertical maximum intensity projection (MIP) artifacts were graduated as normal, mild to moderate, and severe artifacts. The distinction of the vertical part of the pneumatized air cells was also categorized in three groups, regarding the circumference of the ICA in pneumatization ≤ 90°, between 90° and 180°, and ≥ 180°., Results: A total of 203 vessels were collected for analysis. The more extensive the pneumatized air cells were present, the more band-like artifacts and pseudostenosis at the vertical portion of the petrosus part of the ICA were registered., Conclusion: Careful examination of the source images and evaluation of the size of the pneumatized air cells with CT scan are essential to avoid false positive diagnosis in the distal petrosus part of the ICA.
- Published
- 2017
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16. Fibrinogen consumption is related to intracranial clot burden in acute ischemic stroke: a retrospective hyperdense artery study.
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Pikija S, Trkulja V, Mutzenbach JS, McCoy MR, Ganger P, and Sellner J
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- Adult, Aged, Aged, 80 and over, Female, Hospital Mortality, Humans, Male, Middle Aged, Multivariate Analysis, Patient Admission, Retrospective Studies, Treatment Outcome, Young Adult, Brain Ischemia complications, Brain Ischemia metabolism, Fibrinogen metabolism, Intracranial Thrombosis complications, Intracranial Thrombosis metabolism, Stroke complications, Stroke metabolism
- Abstract
Background: Understanding the underlying mechanism of thrombus formation and its components is critical for effective prevention and treatment of ischemic stroke. The generation of thrombotic clots requires conversion of soluble fibrinogen to an insoluble fibrin network. Quantitative features of intracranial clots causing acute ischemic stroke can be studied on non-contrast enhanced CT (NECT). Here, we evaluated on-admission fibrinogen and clot burden in relation to stroke severity, final infarct volume and in-hospital mortality., Methods: We included 132 consecutive patients with ischemic stroke and presence of hyperdense artery sign admitted within 6 h from symptom onset. Radiological parameters including clot area (corresponding to clot burden) and final infarct volume were manually determined on NECT. National Institute of Health Stroke Scale (NIHSS) was used to quantify disease severity and short-term outcome., Results: Median patient age was 77, 58 % were women, and 63 % had an occlusion of the proximal middle cerebral artery segment. Thrombolysis was performed in 60 % and thrombectomy in 44 %. We identified several independent associations. Higher fibrinogen levels on admission were associated with smaller clot burden (p = 0.033) and lower NIHSS on admission (p = 0.022). Patients with lower fibrinogen had a higher clot burden (p = 0.028) and greater final infarct volume (p = 0.003). Higher fibrinogen was associated with a lower risk of in-hospital death or NIHSS score >15 if discharged alive (p = 0.028)., Conclusions: Our study suggests that intracranial clot burden in acute ischemic stroke is associated with fibrinogen consumption, and shows a complex relationship with disease severity, infarct size and in-hospital survival.
- Published
- 2016
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17. Antiplatelet Usage Impacts Clot Density in Acute Anterior Circulation Ischemic Stroke.
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Pikija S, Magdic J, Lukic A, Schreiber C, Mutzenbach JS, McCoy MR, and Sellner J
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- Aged, Aged, 80 and over, Blood Platelets pathology, Erythrocyte Count, Female, Humans, Male, Multivariate Analysis, Retrospective Studies, Stroke drug therapy, Tomography, X-Ray Computed, Platelet Aggregation Inhibitors therapeutic use, Stroke pathology
- Abstract
We explored whether clot density in middle cerebral artery (MCA) occlusion is related to clinical variables, stroke etiology, blood constituents, and prestroke medication. We performed a retrospective chart review of patients with acute ischemic stroke of the anterior circulation admitted to two Central European stroke centers. The acquisition of non-contrast enhanced CT (NECT) and CT angiography (CTA) within 4.5 h of symptom onset was obligatory. We assessed the site of MCA occlusion as well as density, area, and length of the clot in 150 patients. The Hounsfield unit values for the clot were divided with contralateral MCA segment to yield relative Hounsfield Unit ratio (rHU). The site of the vessel occlusion (M1 vs. M2) and antiplatelet usage, but not stroke etiology, significantly influenced rHU. We found an inverse correlation of rHU with erythrocyte count (p < 0.001). The multivariate analysis revealed that a higher rHU (i.e., clot being more hyperdense) was more likely with the use of antiplatelets (OR 4.24, CI 1.10-16.31, p = 0.036). Erythrocyte (OR 0.18, CI 0.05-0.55, p = 0.003), and thrombocyte counts (OR 0.99, CI 0.98-0.99, p = 0.029) were associated with odds for more hypodense clots (lower rHU). Our study disclosed that antiplatelet therapy impacts the composition of intracranial clots of the anterior circulation., Competing Interests: The authors declare no conflicts of interest.
- Published
- 2016
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18. Behavioral assessment of NIH Swiss mice acutely intoxicated with tetramethylenedisulfotetramine.
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Flannery BM, Silverman JL, Bruun DA, Puhger KR, McCoy MR, Hammock BD, Crawley JN, and Lein PJ
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- Adaptation, Ocular drug effects, Animals, Anxiety drug therapy, Cognition Disorders chemically induced, Diazepam therapeutic use, Dose-Response Relationship, Drug, Exploratory Behavior drug effects, GABA Modulators therapeutic use, Male, Maze Learning drug effects, Mice, Mice, Inbred Strains, Neurotoxicity Syndromes drug therapy, Recognition, Psychology drug effects, Seizures chemically induced, Time Factors, Anxiety chemically induced, Behavior, Animal drug effects, Bridged-Ring Compounds toxicity, Convulsants toxicity, Neurotoxicity Syndromes etiology, Neurotoxicity Syndromes physiopathology
- Abstract
Tetramethylenedisulfotetramine (TETS) is a potent convulsant poison that is thought to trigger seizures by inhibiting the function of the type A gamma-aminobutyric acid receptor (GABAAR). Acute intoxication with TETS can cause vomiting, convulsions, status epilepticus (SE) and even death. Clinical case reports indicate that individuals who survive poisoning may exhibit long-term neuropsychological issues and cognitive deficits. Therefore, the objective of this research was to determine whether a recently described mouse model of acute TETS intoxication exhibits persistent behavioral deficits. Young adult male NIH Swiss mice received a seizure-inducing dose of TETS (0.15mg/kg, ip) and then were rescued from lethality by administration of diazepam (5mg/kg, ip) approximately 20min post-TETS-exposure. TETS-intoxicated mice typically exhibited 2 clonic seizures prior to administration of diazepam with no subsequent seizures post-diazepam injection as assessed using behavioral criteria. Seizures lasted an average of 72s. Locomotor activity, anxiety-like and depression-relevant behaviors and cognition were assessed at 1week, 1month and 2months post-TETS exposure using open field, elevated-plus maze, light↔dark transitions, tail suspension, forced swim and novel object recognition tasks. Interestingly, preliminary validation tests indicated that NIH Swiss mice do not respond to the shock in fear conditioning tasks. Subsequent evaluation of hot plate and tail flick nociception tasks revealed that this strain exhibits significantly decreased pain sensitivity relative to age- and sex-matched C57BL/6J mice, which displayed normal contextual fear conditioning. NIH Swiss mice acutely intoxicated with TETS exhibited no significant anxiety-related, depression-relevant, learning or memory deficits relative to vehicle controls at any of the time points assessed with the exception of significantly increased locomotor activity at 2months post-TETS intoxication. The general absence of long-term behavioral deficits in TETS-intoxicated mice on these six assays suggests that the neurobehavioral consequences of TETS exposure described in human survivors of acute TETS intoxication are likely due to sustained seizure activity, rather than a direct effect of the chemical itself. Future research efforts are directed toward developing an animal model that better recapitulates the SE and seizure duration reported in humans acutely intoxicated with TETS., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2015
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19. The efficacy of dexamethasone on reduction in the reoperation rate of chronic subdural hematoma--the DRESH study: straightforward study protocol for a randomized controlled trial.
- Author
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Emich S, Richling B, McCoy MR, Al-Schameri RA, Ling F, Sun L, Wang Y, and Hitzl W
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- Adult, Austria, China, Clinical Protocols, Dexamethasone adverse effects, Double-Blind Method, Drug Administration Schedule, Glucocorticoids adverse effects, Hematoma, Subdural, Chronic diagnosis, Humans, Reoperation, Secondary Prevention, Time Factors, Treatment Outcome, Dexamethasone administration & dosage, Glucocorticoids administration & dosage, Hematoma, Subdural, Chronic drug therapy, Hematoma, Subdural, Chronic surgery, Research Design
- Abstract
Background: Chronic subdural hematoma (cSDH) is a common neurosurgical disease. It is often considered to be a rather benign entity. In spite of well established surgical procedures cSDH is complicated by a recurrence rate up to 30%. Since glucocorticoids have been used for treatment of cSDH in 1962 their role is still discussed controversially in lack of evident data. On the basis of the ascertained inflammation cycle in cSDH dexamethasone will be an ideal substance for a short lasting, concomitant treatment protocol., Objective: to test the efficacy of dexamethasone on reduction inthe reoperation rate of cSDH., Methods/design: The study is designed as a double-blind randomized placebo-controlled trial 820 patients who are operated for cSDH and from the age of 25 years are included after obtaining informed consent. They are randomized for administration of dexamethasone (16-16-12-12-8-4 mg/d) or placebo (maltodextrin) during the first 48 hours after surgery. The type I error is 5% and the type II error is 20%. The primary endpoint is the reoperation within 12 weeks postoperative., Discussion: This study tests whether dexamethasone administered over 6 days is a safe and potent agent in relapse prevention for evacuated cSDH., Trial Registration: EudraCT 201100354442.
- Published
- 2014
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20. Indirect homologous competitive enzyme-linked immunosorbent assay for the detection of a class of glycosylated dihydrochalcones.
- Author
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Ranganathan A, Paradise GA, Hansen CA, McCoy MR, Gee SJ, Zhong P, Chang D, and Hammock BD
- Subjects
- Animals, Antibodies immunology, Antibody Specificity, Female, Fermentation, Flavanones immunology, Glucosides immunology, Haptens chemistry, Haptens immunology, Immune Sera biosynthesis, Immunization, Phloretin analysis, Phloretin immunology, Rabbits, Serum Albumin, Bovine immunology, Taste, Enzyme-Linked Immunosorbent Assay methods, Flavanones analysis, Glucosides analysis, Phloretin analogs & derivatives
- Abstract
Hesperetin dihydrochalcone 4'-glucoside, 1, and phloretin 4'-glucoside, 2, belong to a family of dihydrochalcone glycosides that exhibit flavorant properties. In this study was developed a competitive, indirect homologous ELISA for the detection of targets 1 and 2 in fermentation media. Immunogen and coating antigen were prepared by conjugating hapten, 4-(3-oxo-3-(2,6-dihydroxy-4-glucoside phenyl)propyl) benzoic acid, to thyroglobulin and bovine serum albumin, respectively. Antibodies raised in rabbits M6122, M6123, and M6124 and the coating antigen were screened and characterized to determine their optimum concentrations. The optimized ELISA, developed with antibody M6122, gave IC50 values of 27.8 and 21.8 ng/mL for 1 and 2, respectively. Selectivity of the assay was assessed by measuring cross-reactivity of antibody M6122 to related congeners such as aglycones and the 2'-glycosides of hesperetin dihydrochalcone, 5 and phloretin, 6. Antibody M6122 showed very low recognition of 5 and virtually no recognition of the aglycones and 6.
- Published
- 2013
- Full Text
- View/download PDF
21. Electroejaculation of chimeric rats.
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McCoy MR, Montonye D, and Bryda EC
- Subjects
- Anesthetics, Inhalation administration & dosage, Animals, Isoflurane administration & dosage, Rats, Semen Analysis, Chimera physiology, Ejaculation, Electric Stimulation methods, Semen physiology, Specimen Handling methods
- Abstract
With the advent of genetic engineering of rodents came the need to assess fertility and germline competency, especially in chimeric rodents generated using embryonic stem cells. Traditional methods rely on natural mating and progeny testing, which is time- and cost-intensive. Electroejaculation is a faster method of collecting sperm for genetic analysis and offers the additional benefit of using fewer animals. This column describes a refined electroejaculation technique for chimeric rats using light gas anesthesia and a custom-made platform for sperm collection.
- Published
- 2013
- Full Text
- View/download PDF
22. Aqueductal flow of cerebrospinal fluid (CSF) and anatomical configuration of the cerebral aqueduct (AC) in patients with communicating hydrocephalus--the trumpet sign.
- Author
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McCoy MR, Klausner F, Weymayr F, Georg L, Broussalis E, Golaszewski SM, Emich S, Steinbacher J, and Al-Shameri AR
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Retrospective Studies, Cerebral Aqueduct, Hydrocephalus cerebrospinal fluid, Magnetic Resonance Imaging methods
- Abstract
Purpose: We explore the relationship of aqueductal flow of cerebrospinal fluid (CSF) and the changes of the anatomical configuration of the cerebral aqueduct (AC) in patients with communicating hydrocephalus (CH) in a routine MRI setting., Methods/patients: We performed a retrospective evaluation of different anatomical configurations of the AC on midsaggital MRI images in 43 patients (medial age 67 years, median 68 years, range from 14 to 85, 25 women) with suspected communicating hydrocephalus and compared the anatomical form of the AC on the sagittal sequences with MRI CSF flow data. The measured acqueductal cross sectional area was correlated (Pearson's correlation coefficient, which is a measure of the linear dependence between two variables, is 0.747. From 0.7 to 1 correlation is strong, from 0.7 to 0.5 moderate correlation, from 0.5 to 0.3 weak correlation, and 0.3 to 0 means no correlation) with MRI CSF flow data based on phase contrast measurements., Results: Two independent neuroradiologists were blinded to the patients' diagnosis. In 53% (Rater I) and 67% (Rater II) the anatomical appearance of the AC on sagittal MRI was tubular shaped and in 47% (Rater I) and 33% (Rater II) trumpet shaped. Highly elevated CSF flow correlated with a dilated and trumpet shaped AC lumen area., Conclusion: The anatomical morphology of the AC in midsagittal MRI sequences may be a significant diagnostic sign for suspected communicating hydrocephalus, already discernible on routine MRI scans; consequently, this may also be a sensitive method of supporting the clinical diagnosis of communicating hydrocephalus and moreover supports patients' selection for further CSF flow measurements., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
23. Correction to isolation of alpaca antihapten heavy chain single domain antibodies for development of sensitive immunoassay.
- Author
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Kim HJ, McCoy MR, Majkova Z, Dechant JE, Gee SJ, Tabares-da Rosa S, González-Sapienza GG, and Hammock BD
- Published
- 2012
- Full Text
- View/download PDF
24. The role of MRI in spinal stab wounds compared with intraoperative findings.
- Author
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Emich S, Weymayr F, Steinbacher J, and McCoy MR
- Subjects
- Adult, Brown-Sequard Syndrome diagnostic imaging, Brown-Sequard Syndrome etiology, Humans, Male, Radiography, Spinal Cord Injuries complications, Spinal Cord Injuries diagnostic imaging, Wounds, Stab complications, Wounds, Stab diagnostic imaging, Brown-Sequard Syndrome pathology, Spinal Cord Injuries pathology, Wounds, Stab pathology
- Abstract
Introduction: Spinal stab wound injuries are quite rare and only few patients have been reported on the basis of MRI scan., Methods: A 25-year-old man was stabbed at C1/2 and had an incomplete Brown-Sequard syndrome. He underwent surgical exploration because of CSF leakage on the fourth day., Results: After a follow-up period of 32 months, he was left with a remaining loss of the proprioception of the right foot. We show detailed CT and MR images with the focus on the lesions of the dura and myelon and compared them with intraoperative images. In addition, we contrast our findings with a review of literature published over the last three decades., Conclusion: MRI gives the most detailed view of soft tissue lesions in SSWs and is in accordance with our intraoperative findings.
- Published
- 2012
- Full Text
- View/download PDF
25. Monitoring of total type ii pyrethroid pesticides in citrus oils and water by converting to a common product 3-phenoxybenzoic acid.
- Author
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McCoy MR, Yang Z, Fu X, Ahn KC, Gee SJ, Bom DC, Zhong P, Chang D, and Hammock BD
- Subjects
- Benzoates analysis, Chromatography, Liquid, Immunoassay, Insecticides chemistry, Pyrethrins chemistry, Tandem Mass Spectrometry methods, Benzoates chemistry, Citrus chemistry, Insecticides analysis, Plant Oils chemistry, Pyrethrins analysis, Water analysis
- Abstract
Pyrethroids are a class of insecticides that are becoming increasingly popular in agricultural and home use applications. Sensitive assays for pyrethroid insecticides in complex matrices are difficult with both instrumental and immunochemical methods. Environmental analysis of the pyrethroids by immunoassay requires either knowing which pyrethroids contaminate the source or the use of nonspecific antibodies with cross-reactivities to a class of compounds. We describe an alternative method that converts the type II pyrethroids to a common chemical product, 3-phenoxybenzoic acid (3-PBA), prior to analysis. This method is much more sensitive than detecting the parent compound, and it is much easier to detect a single compound rather than an entire class of compounds. This is useful in screening for pyrethroids as a class or in situations where a single type of pyrethroid is used. We demonstrated this technique in both citrus oils and environmental water samples with conversion rates of the pyrethroid to 3-PBA that range from 45 to 75% and methods that require no extraction steps for either the immunoassay or the liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. Limits of detection for this technique applied to orange oil are 5 nM, 2 μM, and 0.8 μM when detected by LC-MS/MS, gas chromatography-mass spectrometry, and immunoassay, respectively. The limit of detection for pyrethroids in water when detected by immunoassay was 2 nM.
- Published
- 2012
- Full Text
- View/download PDF
26. Characterization of seizures induced by acute and repeated exposure to tetramethylenedisulfotetramine.
- Author
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Zolkowska D, Banks CN, Dhir A, Inceoglu B, Sanborn JR, McCoy MR, Bruun DA, Hammock BD, Lein PJ, and Rogawski MA
- Subjects
- Animals, Astrocytes drug effects, Astrocytes metabolism, Calcium-Binding Proteins metabolism, Cerebral Cortex drug effects, Cerebral Cortex metabolism, Extremities, Glial Fibrillary Acidic Protein metabolism, Gliosis chemically induced, Gliosis metabolism, Hippocampus drug effects, Hippocampus metabolism, Male, Mice, Microfilament Proteins metabolism, Microglia drug effects, Microglia metabolism, Pentylenetetrazole pharmacology, Picrotoxin adverse effects, Rats, Rats, Sprague-Dawley, Bridged-Ring Compounds toxicity, Convulsants toxicity, Seizures chemically induced, Seizures metabolism
- Abstract
Tetramethylenedisulfotetramine (tetramine; TETS) is a potent convulsant poison that is considered to be a chemical threat agent. To provide a basis for the investigation of antidotes for TETS-induced seizures, we characterized the convulsant activity of TETS in mice and rats when administered by the intraperitoneal, intravenous, oral, and intraventricular routes as a single acute dose and with repeated sublethal doses. In mice, parenteral and oral TETS caused immobility, myoclonic body jerks, clonic seizures of the forelimbs and/or hindlimbs, tonic seizures, and death. The CD₅₀ values for clonic and tonic seizures after oral administration were 0.11 and 0.22 mg/kg, respectively. Intraventricular administration of TETS (5-100 μg) in rats also caused clonic-tonic seizures and death. In mice, repeated sublethal doses of TETS at intervals of 2, 24, and 48 h failed to result in the development of persistent enhanced seizure responsivity ("kindling") as was observed with repeated pentylenetetrazol treatment. In mice, sublethal doses of TETS that produced clonic seizures did not cause observable structural brain damage as assessed with routine histology and Fluoro-Jade B staining 7 days after treatment. However, 1 to 3 days after a single convulsant dose of TETS the expression of glial fibrillary acidic protein, an astrocyte marker, and ionized calcium binding adaptor molecule 1, a microglia marker, were markedly increased in cortex and hippocampus. Although TETS doses that are compatible with survival are not associated with overt evidence of cellular injury or neurodegeneration, there is transient reactive astrocytosis and microglial activation, indicating that brain inflammatory responses are provoked.
- Published
- 2012
- Full Text
- View/download PDF
27. Isolation of alpaca anti-hapten heavy chain single domain antibodies for development of sensitive immunoassay.
- Author
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Kim HJ, McCoy MR, Majkova Z, Dechant JE, Gee SJ, Tabares-da Rosa S, González-Sapienza GG, and Hammock BD
- Subjects
- Animals, Antibodies, Anti-Idiotypic immunology, Antibodies, Anti-Idiotypic urine, Cross Reactions, Enzyme-Linked Immunosorbent Assay, Humans, Immunoassay, Male, Peptide Library, Pyrethrins immunology, Recombinant Proteins immunology, Single-Chain Antibodies immunology, Single-Chain Antibodies urine, Antibodies, Anti-Idiotypic isolation & purification, Benzoates immunology, Camelids, New World immunology, Haptens immunology, Immunoglobulin Heavy Chains immunology, Single-Chain Antibodies isolation & purification
- Abstract
Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain (VHH). Although conventional antibodies dominate current assay development, recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. We expressed VHHs from an immunized alpaca and developed a VHH-based immunoassay using 3-phenoxybenzoic acid (3-PBA), a major metabolite of pyrethroid insecticides as a model system. A phage VHH library was constructed, and seven VHH clones were selected by competitive binding with 3-PBA. The best immunoassay developed with one of these VHHs showed an IC(50) of 1.4 ng/mL (limit of detection (LOD) = 0.1 ng/mL). These parameters were further improved by using the phage borne VHH, IC(50) = 0.1 ng/mL and LOD = 0.01 ng/mL. Both assays showed a similar tolerance to methanol and dimethylsulfoxide up to 50% in assay buffer. The assay was highly specific to 3-PBA and its 4-hydroxylated derivative, 4-hydroxy 3-PBA, (150% cross reactivity) with negligible cross reactivity with other tested structural analogues, and the recovery from spiked urine sample ranged from 80 to 112%. In conclusion, a highly specific and sensitive VHH for 3-PBA was developed using sequences from immunized alpaca and phage display technology for antibody selection.
- Published
- 2012
- Full Text
- View/download PDF
28. Treatment of vertebral artery origin stenosis with a Pharos stent device: a single center experience.
- Author
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Broussalis E, Kunz AB, Luthringshausen G, Klein S, McCoy MR, Trinka E, and Killer-Oberpfalzer M
- Subjects
- Aged, Aged, 80 and over, Cerebral Angiography, Female, Follow-Up Studies, Humans, Male, Middle Aged, Severity of Illness Index, Treatment Outcome, Vertebrobasilar Insufficiency diagnostic imaging, Cerebral Revascularization instrumentation, Cerebral Revascularization methods, Stents, Vertebrobasilar Insufficiency therapy
- Abstract
Atherosclerotic stenosis of vertebral artery (VA) origin exceeding 70% severity accounts for one third of all vertebrobasilar strokes. For a period of one year the results of endovascular treatment of VA stenosis with the new Pharos stent device were assessed.Twenty-two patients with symptomatic VA stenosis were treated with the Pharos stent. Clinical status and stenosis grade were documented before treatment and 24 hours, one, three and twelve months after treatment via ultrasound and magnetic resonance tomography.All procedures proved to be technically successful without the occurrence of intra-procedural complications. During the observation period of more than one year, 55% of patients were documented with a mean stenosis degree of 60%: two (10%) of these patients showed a residual stenosis after angioplasty and nine patients (45%) an in-stent restenosis, whereas only two patients were documented with a hemodynamically relevant in-stent restenosis of 80%. These two patients were retreated with balloon dilatation. None of the patients showed neurological deterioration or new abnormalities at magnetic resonance tomography examination. Neither VA occlusion nor restenosis of the contralateral VA negatively affected the clinical outcome. An in-stent restenosis was developed by more female than male patients.VA origin stenting with the Pharos stent device is an effective treatment of stenosis. The good clinical results compared to the high restenosis rates have to be examined in further studies. Pin particular, it has to be determined whether the Pharos stent allows the vessel time for collateralization, whether double antiplatelet treatment prevents recurrent cerebrovascular events or whether merely the low restenosis degree is causative for the clinical outcome.
- Published
- 2011
- Full Text
- View/download PDF
29. MR imaging of hydrogel filament embolic devices loaded with superparamagnetic iron oxide or gadolinium.
- Author
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Killer M, Keeley EM, Cruise GM, Schmitt A, and McCoy MR
- Subjects
- Animals, Barium Sulfate administration & dosage, Barium Sulfate chemistry, Contrast Media, Hydrogel, Polyethylene Glycol Dimethacrylate chemistry, Rabbits, Treatment Outcome, Embolization, Therapeutic instrumentation, Ferric Compounds, Gadolinium, Hydrogel, Polyethylene Glycol Dimethacrylate administration & dosage, Intracranial Aneurysm therapy, Magnetic Resonance Angiography
- Abstract
Introduction: We evaluated hydrogel filaments loaded with barium sulphate and either gadolinium or superparamagnetic iron oxide (SPIO) in an effort to develop an embolic material that is visible with fluoroscopic and magnetic resonance imaging., Methods: Hydrogel filaments were prepared with gadolinium and iron concentrations ranging from 1,500 to 7,500 and 500 to 2,500 ppm, respectively. The filaments were encased in agar and imaged using an MR scanner. Embolisation of eight aneurysms (seven bifurcation, one sidewall) in seven rabbits was performed using hydrogel filaments loaded with gadolinium (n = 4) or SPIO (n = 4). Angiographic evaluations occurred immediately post-treatment and at 13 weeks. Magnetic resonance angiography (MRA) evaluations occurred immediately post-treatment or 13 weeks post-treatment., Results: Based on the in vitro results, we selected 4,500 and 2,000 ppm for gadolinium and iron loadings, respectively, for the in vivo experiments. Loading the filaments with gadolinium or SPIO did not affect the angiographic results, as embolic masses were readily evident with some distinguishing of individual filaments. In MRA, the hydrogel filaments loaded with SPIO were hypointense, and the hydrogel filaments loaded with Gd were hyperintense. The hyperintensity of the Gd-loaded filaments confounded the ability to distinguish between flow and the embolic devices. The hypointensity of the hydrogel filaments loaded with SPIO provided sufficient contrast between the embolic devices and the blood flow to allow of aneurysm occlusion evaluation using MRA., Conclusion: Based on these results, we are focusing on loading hydrogel filaments with SPIO in an effort to provide adequate visualisation for use in MR-guided interventions.
- Published
- 2011
- Full Text
- View/download PDF
30. Use of CT angiography in comparison with other imaging techniques for the determination of embolus and remnant size in experimental aneurysms embolized with hydrogel filaments.
- Author
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Killer M, McCoy MR, Vestal MC, Weitgasser L, and Cruise GM
- Subjects
- Animals, Equipment Design, Equipment Failure Analysis, Female, Hydrogels, Intracranial Aneurysm complications, Intracranial Embolism etiology, Intracranial Embolism prevention & control, Male, Materials Testing, Rabbits, Reproducibility of Results, Sensitivity and Specificity, Stents, Treatment Outcome, Cerebral Angiography methods, Embolization, Therapeutic instrumentation, Intracranial Aneurysm diagnostic imaging, Intracranial Aneurysm surgery, Intracranial Embolism diagnostic imaging
- Abstract
Background and Purpose: Beam-hardening artifacts in CTA can be greatly reduced by using metal-free coils for aneurysm embolization. We compared the embolic masses and remnants of experimental rabbit aneurysms coiled with hydrogel filaments by using DSA, CTA and histology., Materials and Methods: Embolization of 12 rabbit bifurcation aneurysms was performed with detachable hydrogel filaments. Six aneurysms were embolized as completely as possible, and 6 aneurysms were embolized incompletely to intentionally leave remnants. Three aneurysms in each group underwent follow-up at 4 and 13 weeks. DSA, MRA, and CTA were performed immediately before sacrifice. The harvested aneurysms were evaluated histologically. For each imaging technique, the areas of the embolic mass and remnant were determined by using image analysis. Results were compared by using paired t tests., Results: CTAs were suitable for quantification of the embolus and remnant areas because only small streaking artifacts were evident. The areas of the embolus were larger on CTA compared with DSA and histologic sections. The areas of the remnant were larger on CTA and MRA compared with DSA and histologic sections. Like DSA and MRA, CTA was suitable for determining whether aneurysm retreatment was necessary, provided that loops of hydrogel filaments were not present in the parent artery., Conclusions: We demonstrated that CTA is a technique with potential for surveillance of aneurysms treated with hydrogel filaments. Additional work is required to determine the accuracy of the technique compared with currently accepted imaging modalities of DSA and MRA.
- Published
- 2011
- Full Text
- View/download PDF
31. Immunoassays and biosensors for monitoring environmental and human exposure to pyrethroid insecticides.
- Author
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Ahn KC, Kim HJ, McCoy MR, Gee SJ, and Hammock BD
- Subjects
- Antibodies, Body Fluids chemistry, Humans, Pesticide Residues analysis, Biosensing Techniques, Environmental Exposure analysis, Immunoassay methods, Insecticides analysis, Pyrethrins analysis
- Abstract
This paper describes some of the early work on pyrethroid insecticides in the Casida laboratory and briefly reviews the development and application of immunochemical approaches for the detection of pyrethroid insecticides and their metabolites for monitoring environmental and human exposure. Multiple technologies can be combined to enhance the sensitivity and speed of immunochemical analysis. The pyrethroid assays are used to illustrate the use of some of these immunoreagents such as antibodies, competitive mimics, and novel binding agents such as phage-displayed peptides. The paper also illustrates reporters such as fluorescent dyes, chemiluminescent compounds, and luminescent lanthanide nanoparticles, as well as the application of magnetic separation, and automatic instrumental systems, biosensors, and novel immunological technologies. These new technologies alone and in combination result in an improved ability to both determine if effective levels of pyrethroids are being used in the field and evaluate possible contamination.
- Published
- 2011
- Full Text
- View/download PDF
32. Angiographic and histologic comparison of experimental aneurysms embolized with hydrogel filaments.
- Author
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Killer M, Kallmes DF, McCoy MR, Ding YH, Shum JC, and Cruise GM
- Subjects
- Angiography, Animals, Humans, Rabbits, Treatment Outcome, Disease Models, Animal, Embolization, Therapeutic methods, Hemostatics therapeutic use, Hydrogels therapeutic use, Intracranial Aneurysm diagnosis, Intracranial Aneurysm therapy
- Abstract
Background and Purpose: The embolization of aneurysms with hydrogel filaments allow postprocedural CT and MR imaging studies without artifacts. We compared the performance of 3 hydrogel filament formulations in rabbit experimental aneurysms by using angiography and histologic samples., Materials and Methods: Embolization of 35 rabbit elastase or bifurcation aneurysms was performed with 3 different formulations of detachable hydrogel filaments, including 1) polyethylene glycol opacified with aromatic iodine (PEG-I; n = 12), 2) polyethylene glycol opacified with barium sulfate (PEG-B; n = 12), or 3) polypropylene glycol opacified with barium sulfate (PPG-B; n = 11). Follow-up angiography was performed before the rabbits were killed at 2 (n = 7), 6 (n = 9), 10 (n = 8), or 26 (n = 11) weeks. Angiographic occlusion was scored according to the Raymond scale, and interval changes were assessed. The harvested aneurysms were evaluated on histologic examination. From the sections, we determined the percentage of the sac excluded from the vasculature and occupied by embolic devices by using image analysis. We compared results using the analysis of variance/t test or chi(2) test., Results: The mean number of devices used to treat aneurysms in the PPG-B group was significantly greater than that used for the other 2 groups, though aneurysm volumes were similar among groups. Compared with immediate posttreatment occlusion scores, mean angiographic occlusion at follow-up was increased for all 3 hydrogel filament groups. On histologic examination, thrombus organization, neointima formation, and inflammation were similar to that observed in rabbit experimental aneurysms with other embolic devices containing platinum coils., Conclusions: The embolization of experimental aneurysms with hydrogel filaments resulted in durable angiographic and histologic occlusion from 2 to 26 weeks. With improvements, hydrogel filaments free from metallic coils show promise for endovascular use.
- Published
- 2009
- Full Text
- View/download PDF
33. Engineered antibody fragments with infinite affinity as reporter genes for PET imaging.
- Author
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Wei LH, Olafsen T, Radu C, Hildebrandt IJ, McCoy MR, Phelps ME, Meares C, Wu AM, Czernin J, and Weber WA
- Subjects
- Animals, Antibodies, Monoclonal genetics, Antibodies, Monoclonal immunology, Antibodies, Monoclonal metabolism, Base Sequence, Cell Line, Tumor, Feasibility Studies, Gene Expression Regulation, Neoplastic, Heterocyclic Compounds, 1-Ring chemistry, Heterocyclic Compounds, 1-Ring metabolism, Heterocyclic Compounds, 1-Ring pharmacokinetics, Humans, Immunoglobulin Fragments metabolism, Mice, Neoplasms diagnostic imaging, Neoplasms genetics, Neoplasms metabolism, Protein Engineering, Substrate Specificity, Tissue Distribution, Yttrium chemistry, Antibody Affinity, Genes, Reporter, Immunoglobulin Fragments genetics, Immunoglobulin Fragments immunology, Positron-Emission Tomography methods
- Abstract
Unlabelled: Reporter gene imaging has great potential for many clinical applications including the tracking of transplanted cells and monitoring of gene therapy. However, currently available reporter gene-reporter probe combinations have significant limitations with the biodistribution of the reporter probe and the specificity and immunogenicity of the reporter gene. The objective of the present study was to evaluate a new approach for reporter gene imaging based on cell surface expression of antibody fragments that can irreversibly bind to radiometal chelates., Methods: We developed a new reporter gene, designated 1,4,7,10-tetraazacyclodocecane-N,N',N'',N'''-tetraacetic acid (DOTA) antibody reporter 1 (DAbR1), which consists of the single-chain Fv (scFv) fragment of the anti-Y-DOTA antibody 2D12.5/G54C fused to the human T cell CD4 transmembrane domain. The corresponding reporter probe is yttrium-(S)-2-(4-acrylamidobenzyl)-DOTA (*Y-AABD), a DOTA complex that binds irreversibly to a cysteine residue in the 2D12.5/G54C antibody. U-87 glioma cells were stably transfected with a DAbR1 expression vector. Binding of *Y-AABD to transfected and wild-type cells was studied in vitro and in vivo., Results: Flow cytometry revealed high expression of the DAbR1 protein on the cell surface of tumor cells. Uptake of 90Y-AABD in DAbR1-expressing human U-87 glioma xenografts was 6.2 (+/-1.3) percentage injected dose per gram (%ID/g) at 1 h and 4.9 (+/-0.62) %ID/g at 24 h after injection. The corresponding tumor-to-plasma ratios were 45:1 and 428:1, respectively. Uptake by U-87 tumors without the DAbR1 gene was 0.16 (+/-0.02) %ID/g at 1 h and 0.05 (+/-0.03) %ID/g at 24 h. PET images in mice with 86Y-AABD demonstrated intense uptake in DAbR1-positive tumors and low background activity in the liver., Conclusion: These findings indicate that cell surface expression of radiometal chelate binding antibodies such as 2D12.5/G54C is a promising strategy for reporter gene imaging.
- Published
- 2008
- Full Text
- View/download PDF
34. Cysteinylated protein as reactive disulfide: an alternative route to affinity labeling.
- Author
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Miao Z, McCoy MR, Singh DD, Barrios B, Hsu OL, Cheal SM, and Meares CF
- Subjects
- Animals, Binding Sites, Immunoglobulin Fab Fragments chemistry, Ligands, Models, Molecular, Protein Structure, Tertiary, Sensitivity and Specificity, Sulfhydryl Compounds chemistry, Affinity Labels chemistry, Cysteine chemistry, Disulfides chemistry
- Abstract
Engineering the permanent formation of a receptor-ligand complex has a number of promising applications in chemistry, biology, and medicine. Antibodies and other proteins can be excellent receptors for synthetic ligands such as probes or drugs. Because proteins possess an array of nucleophilic sites, the placement of an electrophile on the synthetic ligand to react with a nucleophile on the macromolecule is a standard practice. Previously, we have used the site-directed incorporation of cysteine nucleophiles at the periphery of an antibody's binding site, paired with the chemical design of weakly electrophilic ligands, to produce receptor-ligand pairs that conjugate specifically and permanently (Corneillie et al. (2004) Bioconjugate Chem. 15, 1392-1402 and references therein). After protein expression in Drosophila S2 cells, we found, as is frequently observed, that the engineered cysteine was reversibly blocked by disulfide linkage to a cysteine monomer (cysteinylated). Removal of the cysteine monomer requires some care because of the need to preserve other disulfide linkages in the protein. Here, we report that cysteinylation can be used to advantage by treating the cysteine monomer as a leaving group and the protein disulfide as an electrophile with special affinity for thiols. Two ligands bearing thiol side chains were synthesized and incubated with the cysteinylated antibody Fab fragment 2D12.5 G54C, with the finding that both ligands become covalently attached within a few minutes under physiological conditions. The attachment is robust even in the presence of excess thiol reagents. This rapid, specific conjugation is particularly interesting for biomedical applications.
- Published
- 2008
- Full Text
- View/download PDF
35. Evaluating an internet weight loss program for diabetes prevention.
- Author
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McCoy MR, Couch D, Duncan ND, and Lynch GS
- Subjects
- Adult, Aged, Diet, Exercise, Female, Health Status Indicators, Humans, Male, Middle Aged, Program Evaluation, Diabetes Mellitus prevention & control, Internet, Weight Loss
- Abstract
Being overweight or obese is a major risk factor for developing type 2 diabetes but weight loss through lifestyle interventions can markedly reduce its incidence. The Internet provides an opportunity for the development and implementation of lifestyle intervention programs that promote self-managed behavioural change. We developed an online weight loss program emphasizing physical activity and dietary modifications and conducted a short-term qualitative evaluation of it, examining participant recruitment from the general public, website usage and satisfaction and use of self-reported health risk appraisal records. From a total of 808 registered participants who accessed the online services, 683 (84.5%) completed at least one online health risk appraisal and of those, 464 (68%) people (364 female, aged 19-70 years; 100 male, aged 20-71 years) enrolled in the weight loss program. The program was met with a high level of satisfaction by participants, with 56% of feedback respondents agreeing that the program helped them achieve their goals. The program home page, the principal arrival destination of participants, was viewed an average of 29 times per participant, suggesting that the website's services were used with a high frequency. These preliminary findings indicate that the general public will use an Internet-based weight loss program that involves physical activity and dietary behavioural interventions. Whether Internet delivery of these interventions can significantly reduce the risk for developing type 2 diabetes is worthy of further investigation. The findings have relevance for development of health promotion policies and practices.
- Published
- 2005
- Full Text
- View/download PDF
36. Gas chromatographic quantification of fatty acid methyl esters: flame ionization detection vs. electron impact mass spectrometry.
- Author
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Dodds ED, McCoy MR, Rea LD, and Kennish JM
- Subjects
- Calibration, Chromatography, Gas, Fatty Acids chemistry, Flame Ionization, Mass Spectrometry, Sensitivity and Specificity, Fatty Acids analysis
- Abstract
The determination of FAME by GC is among the most commonplace analyses in lipid research. Quantification of FAME by GC with FID has been effectively performed for some time, whereas detection with MS has been used chiefly for qualitative analysis of FAME. Nonetheless, the sensitivity and selectivity of MS methods advocate a quantitative role for GC-MS in FAME analysis-an approach that would be particularly advantageous for FAME determination in complex biological samples, where spectrometric confirmation of analytes is advisable. To assess the utility of GC-MS methods for FAME quantification, a comparative study of GC-FID and GC-MS methods has been conducted. FAME in prepared solutions as well as a biological standard reference material were analyzed by GC-FID and GC-MS methods using both ion trap and quadrupole MS systems. Quantification by MS, based on total ion counts and processing of selected ions, was investigated for FAME ionized by electron impact. Instrument precision, detection limits, calibration behavior, and response factors were investigated for each approach, and quantitative results obtained by each technique were compared. Although there were a number of characteristic differences between the MS methods and FID with respect to FAME analysis, the quantitative performance of GC-MS compared satisfactorily with that of GC-FID. The capacity to combine spectrometric examination and quantitative determination advances GC-MS as a powerful alternative to GC-FID for FAME analysis.
- Published
- 2005
- Full Text
- View/download PDF
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