36 results on '"McAvoy E"'
Search Results
2. Minimizing Honey Bee Exposure to Pesticides
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Vu, Amy T., primary, Ellis, J. D., primary, Klopchin, J., primary, Buss, E., primary, Diepenbrock, L., primary, Fishel, F. M., primary, Kern, W. H., primary, Mannion, C., primary, McAvoy, E., primary, Osborne, L. S., primary, Rogers, M., primary, Sanford, M., primary, Smith, H., primary, Stanford, B. S., primary, Stansly, P., primary, Stelinski, L., primary, and Webb, S., primary
- Published
- 2021
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3. DETECTION AND CHARACTERIZATION OF TOMATO VIRUSES: A CASE STUDY OF EMERGING TOSPOVIRUSES IN FLORIDA
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Adkins, S., primary, Webster, C.G., additional, Mellinger, H.C., additional, Frantz, G., additional, Turechek, W.W., additional, McAvoy, E., additional, Reitz, S.R., additional, and Funderburk, J.E., additional
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- 2015
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4. GREENHOUSE VEGETABLES IN FLORIDA'S MILD WINTER CLIMATE - 2004 UPDATE
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Tyson, R.V., primary, Hochmuth, R.C., additional, Lamb, E.M., additional, McAvoy, E., additional, Olczyk, T., additional, and Lamberts, M., additional
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- 2004
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5. Photoisomerization of sterically hindered merocyanine dyes
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Benniston, Andrew C., primary, Harriman, Anthony, additional, and McAvoy, e, additional
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- 1997
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6. Papillomavirus E7 protein binding to the retinoblastoma protein is not required for viral induction of warts
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Defeo-Jones, D, primary, Vuocolo, G A, additional, Haskell, K M, additional, Hanobik, M G, additional, Kiefer, D M, additional, McAvoy, E M, additional, Ivey-Hoyle, M, additional, Brandsma, J L, additional, Oliff, A, additional, and Jones, R E, additional
- Published
- 1993
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7. Human papillomavirus type 16 E7 protein inhibits DNA binding by the retinoblastoma gene product
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Stirdivant, S M, primary, Huber, H E, additional, Patrick, D R, additional, Defeo-Jones, D, additional, McAvoy, E M, additional, Garsky, V M, additional, Oliff, A, additional, and Heimbrook, D C, additional
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- 1992
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8. Lovastatin selectively inhibits ras activation of the 12-O-tetradecanoylphorbol-13-acetate response element in mammalian cells
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Defeo-Jones, D, primary, McAvoy, E M, additional, Jones, R E, additional, Vuocolo, G A, additional, Haskell, K M, additional, Wegrzyn, R J, additional, and Oliff, A, additional
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- 1991
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9. Protein kinase C phosphorylates P-glycoprotein in multidrug resistant human KB carcinoma cells.
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Chambers, T C, primary, McAvoy, E M, additional, Jacobs, J W, additional, and Eilon, G, additional
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- 1990
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10. Dynamic Analysis with Latent Constructs.
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Kellstedt, Paul, McAvoy, E., and Stimson, James A.
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- 1993
11. Renal sugar transport in the winter flounder. III. Two glucose transport systems
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Kleinzeller, A., primary, Dubyak, G. R., additional, Griffin, P. M., additional, McAvoy, E. M., additional, Mullin, J. M., additional, and Rittmaster, R., additional
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- 1977
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12. Using metagenomic analyses to estimate the consequences of enrichment bias for pathogen detection
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Pettengill James B, McAvoy Eugene, White James R, Allard Marc, Brown Eric, and Ottesen Andrea
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Enrichment bias ,Metagenomics ,Pathogen ,Taxonomy ,Medicine ,Biology (General) ,QH301-705.5 ,Science (General) ,Q1-390 - Abstract
Abstract Background Enriching environmental samples to increase the probability of detection has been standard practice throughout the history of microbiology. However, by its very nature, the process of enrichment creates a biased sample that may have unintended consequences for surveillance or resolving a pathogenic outbreak. With the advent of next-generation sequencing and metagenomic approaches, the possibility now exists to quantify enrichment bias at an unprecedented taxonomic breadth. Findings We investigated differences in taxonomic profiles of three enriched and unenriched tomato phyllosphere samples taken from three different tomato fields (n = 18). 16S rRNA gene meteganomes were created for each of the 18 samples using 454/Roche’s pyrosequencing platform, resulting in a total of 165,259 sequences. Significantly different taxonomic profiles and abundances at a number of taxonomic levels were observed between the two treatments. Although as many as 28 putative Salmonella sequences were detected in enriched samples, there was no significant difference in the abundance of Salmonella between enriched and unenriched treatments. Conclusions Our results illustrate that the process of enriching greatly alters the taxonomic profile of an environmental sample beyond that of the target organism. We also found evidence suggesting that enrichment may not increase the probability of detecting a target. In conclusion, our results further emphasize the need to develop metagenomics as a validated culture independent method for pathogen detection.
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- 2012
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13. Photoisomerization of sterically hindered merocyanine dyes.
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C. Benniston, Andrew, Harriman, Anthony, and McAvoy, e
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- 1997
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14. Urine drug testing in the context of opioid analgesic prescribing for chronic pain: a content analysis of U.S. state laws in 2022.
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Andraka-Christou B, McAvoy E, Gordon AJ, Ohama M, Brach M, Taylor EA, Vaiana M, Saloner B, and Stein BD
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- Humans, Analgesics, Opioid therapeutic use, Substance Abuse Detection methods, Pain Management, Chronic Pain drug therapy, Substance-Related Disorders
- Abstract
Background: In response to the opioid crisis, U.S. states have passed laws requiring urine drug testing (UDT) when opioid analgesics are prescribed for chronic pain. We sought to identify state law UDT requirements., Methods: We searched NexisUni legal database using terms related to UDT, chronic pain, and opioids. We included laws effective during spring 2022 that required UDT when opioids were prescribed for chronic pain. We performed deductive content analysis, coding laws for mandated UDT frequency, type of clinician and type of payer to whom the law applied, and circumstances under which UDT was mandated., Results: We found 32 laws across 13 states that met our inclusion criteria. UDT requirements varied substantially by state, including with regard to the type of clinician to whom the law applied, the mandated frequency of UDT (eg, at initiation/assessment, at least annually, more than once per year), and the circumstances in which UDT was mandated (eg, patient had substance use disorder; dosage/day threshold)., Discussion: Relatively few states have UDT mandates associated with prescribing opioids as chronic pain treatment. When developing policy indicators for empirical studies, researchers evaluating how UDT policy affects health outcomes must consider the complexity and lack of uniformity of UDT requirements. In addition, even if states mandate UDT, it is unclear whether clinicians understand the best way to use the test results., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2023
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15. Systematic Identification and Categorization of Opioid Prescribing and Dispensing Policies in 16 States and Washington, DC.
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Andraka-Christou B, McAvoy E, Ohama M, Smart R, Vaiana ME, Taylor E, and Stein BD
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- Humans, United States, District of Columbia, Practice Patterns, Physicians', Policy, Analgesics, Opioid therapeutic use, Prescription Drug Monitoring Programs
- Abstract
Objectives: State policies can impact opioid prescribing or dispensing. Some state opioid policies have been widely examined in empirical studies, including prescription drug monitoring programs and pain clinic licensure requirements. Other relevant policies might exist that have received limited attention. Our objective was to identify and categorize a wide range of state policies that could affect opioid prescribing/dispensing., Methods: We used stratified random sampling to select 16 states and Washington, DC, for our sample. We collected state regulations and statutes effective during 2020 from each jurisdiction, using search terms related to opioids, pain management, and prescribing/dispensing. We then conducted qualitative template analysis of the data to identify and categorize policy categories., Results: We identified three dimensions of opioid prescribing/dispensing laws: the prescribing/dispensing rule, its applicability, and its disciplinary consequences. Policy categories of prescribing/dispensing rules included clinic licensure, staff credentials, evaluating the appropriateness of opioids, limiting the initiation of opioids, preventing the diversion or misuse of opioids, and enhancing patient safety. Policy categories related to applicability of the law included the pain type, substance type, practitioner, setting, payer, and prescribing situation. The disciplinary consequences dimension included specific consequences and inspection processes., Discussion: Policy categories within each dimension of opioid prescribing/dispensing laws could become a foundation for creating variables to support empirical analyses of policy effects, improving operationalization of policies in empirical studies, and helping to disentangle the effects of multiple state laws enacted at similar times to address the opioid crisis. Several of the policy categories we identified have been underexplored in previous empirical studies., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2023
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16. Synergistic interactions between detritivores disappear under reduced rainfall.
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Joly FX, McAvoy E, and Subke JA
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- Animals, Climate Change, Forests, Plant Leaves, Soil, Arthropods, Ecosystem
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Understanding the consequences of altered rainfall patterns on litter decomposition is critical to predicting the feedback effect of climate change on atmospheric CO
2 concentrations. Although their effect on microbial decomposition has received considerable attention, their effect on litter fragmentation by detritivores, the other dominant decomposition pathway, remains largely unexplored. Particularly, it remains unclear how different detritivore species and their interactions respond to changes in rainfall quantity and frequency. To fill this knowledge gap, we determined the contribution to litter decomposition of two detritivore species (millipede and isopod), separately and in combination, under contrasting rainfall quantity and frequency in a temperate forest. Although halving rainfall quantity and frequency decreased topsoil moisture by 7.8 and 13.1%, respectively, neither millipede- nor isopod-driven decomposition were affected by these changes. In contrast, decomposition driven by both detritivore species in combination was 65.5% higher than expected based on monospecific treatments under high rainfall quantity, but unchanged or even lower under low rainfall quantity. This indicates that although detritivore activity is relatively insensitive to changes in rainfall patterns, large synergistic interactions between detritivore species may disappear under future rainfall patterns. Incorporating interspecific interactions between decomposers thus seems critical to evaluate the sensitivity of decomposition to altered rainfall patterns., (© 2021 The Authors. Ecology published by Wiley Periodicals LLC on behalf of Ecological Society of America.)- Published
- 2021
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17. Extending julius seizure, a bang-sensitive gene, as a model for studying epileptogenesis: Cold shock, and a new insertional mutation.
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Dean D, Weinstein H, Amin S, Karno B, McAvoy E, Hoy R, Recknagel A, Jarvis C, and Deitcher D
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- Aminopeptidases, Animals, Cell Body metabolism, Cold Temperature, Drosophila melanogaster, Epilepsy physiopathology, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, Humans, Neurons metabolism, Disease Models, Animal, Drosophila Proteins genetics, Epilepsy genetics, Membrane Proteins genetics
- Abstract
The bang-sensitive (BS) mutants of Drosophila are an important model for studying epilepsy. We recently identified a novel BS locus, julius seizure (jus), encoding a protein containing two transmembrane domains and an extracellular cysteine-rich loop. We also determined that jus
sda iso7.8 , a previously identified BS mutation, is an allele of jus by recombination, deficiency mapping, complementation testing, and genetic rescue. RNAi knockdown revealed that jus expression is important in cholinergic neurons and that the critical stage of jus expression is the mid-pupa. Finally, we found that a functional, GFP-tagged genomic construct of jus is expressed mostly in axons of the neck connectives and of the thoracic abdominal ganglia. In this Extra View article, we show that a MiMiC GFP-tagged Jus is localized to the same nervous system regions as the GFP-tagged genomic construct, but its expression is mostly confined to cell bodies and it causes bang-sensitivity. The MiMiC GFP-tag lies in the extracellular loop while the genomic construct is tagged at the C-terminus. This suggests that the alternate position of the GFP tag may disrupt Jus protein function by altering its subcellular localization and/or stability. We also show that a small subset of jus-expressing neurons are responsible for the BS phenotype. Finally, extending the utility of the BS seizure model, we show that jus mutants exhibit cold-sensitive paralysis and are partially sensitive to strobe-induced seizures.- Published
- 2018
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18. Super-resolution structure of DNA significantly differs in buccal cells of controls and Alzheimer's patients.
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Garcia A, Huang D, Righolt A, Righolt C, Kalaw MC, Mathur S, McAvoy E, Anderson J, Luedke A, Itorralba J, and Mai S
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- Aged, Aged, 80 and over, Case-Control Studies, Cell Nucleus chemistry, Chromatin isolation & purification, Chromatin Assembly and Disassembly, DNA isolation & purification, Female, Humans, Imaging, Three-Dimensional, Male, Microscopy methods, Middle Aged, Mouth Mucosa chemistry, Nucleic Acid Conformation, Severity of Illness Index, Alzheimer Disease genetics, Alzheimer Disease pathology, Cell Nucleus ultrastructure, Chromatin genetics, Chromatin ultrastructure, DNA genetics, DNA ultrastructure, Mouth Mucosa ultrastructure
- Abstract
The advent of super-resolution microscopy allowed for new insights into cellular and physiological processes of normal and diseased cells. In this study, we report for the first time on the super-resolved DNA structure of buccal cells from patients with Alzheimer's disease (AD) versus age- and gender-matched healthy, non-caregiver controls. In this super-resolution study cohort of 74 participants, buccal cells were collected and their spatial DNA organization in the nucleus examined by 3D Structured Illumination Microscopy (3D-SIM). Quantitation of the super-resolution DNA structure revealed that the nuclear super-resolution DNA structure of individuals with AD significantly differs from that of their controls (p < 0.05) with an overall increase in the measured DNA-free/poor spaces. This represents a significant increase in the interchromatin compartment. We also find that the DNA structure of AD significantly differs in mild, moderate, and severe disease with respect to the DNA-containing and DNA-free/poor spaces. We conclude that whole genome remodeling is a feature of buccal cells in AD., (© 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.)
- Published
- 2017
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19. Quantitative 3D Telomeric Imaging of Buccal Cells Reveals Alzheimer's Disease-Specific Signatures.
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Garcia A, Mathur S, Kalaw MC, McAvoy E, Anderson J, Luedke A, Itorralba J, and Mai S
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- Aged, Aged, 80 and over, Analysis of Variance, Case-Control Studies, Female, Humans, Male, Psychiatric Status Rating Scales, Telomere ultrastructure, Alzheimer Disease pathology, Imaging, Three-Dimensional methods, Mouth Mucosa pathology, Optical Imaging methods, Telomere pathology
- Abstract
This study validates and expands on our previous work that assessed three-dimensional (3D) nuclear telomere profiling in buccal cells of Alzheimer's disease (AD) patients and non-AD controls (Mathur et al., J Alzheimers Dis 39, 35-48, 2014). While the previous study used age- and gender-matched caregiver controls, the current study consented a new cohort of 44 age- and gender-matched healthy non-caregiver controls and 44 AD study participants. 3D telomeric profiles of buccal cells of AD patients and their non-AD controls were examined with participant information blinded to the analysis. In agreement with our previous study, we demonstrate that 3D telomeric profiles allow for the distinction between AD and non-AD individuals. This validation cohort provides an indication that the total number of 3D telomeric signals and their telomere lengths may be a suitable biomarker to differentiate between AD and non-AD and between mild, moderate, and severe AD. Further studies with larger sample sizes are required to move this technology further toward the clinic.
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- 2017
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20. Emergence of Groundnut ringspot virus and Tomato chlorotic spot virus in Vegetables in Florida and the Southeastern United States.
- Author
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Webster CG, Frantz G, Reitz SR, Funderburk JE, Mellinger HC, McAvoy E, Turechek WW, Marshall SH, Tantiwanich Y, McGrath MT, Daughtrey ML, and Adkins S
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- Animals, Florida, Thysanoptera virology, Tospovirus genetics, Plant Diseases virology, Tospovirus isolation & purification, Vegetables virology
- Abstract
Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus (TCSV) are two emerging tospoviruses in Florida. In a survey of the southeastern United States, GRSV and TCSV were frequently detected in solanaceous crops and weeds with tospovirus-like symptoms in south Florida, and occurred sympatrically with Tomato spotted wilt virus (TSWV) in tomato and pepper in south Florida. TSWV was the only tospovirus detected in other survey locations, with the exceptions of GRSV from tomato (Solanum lycopersicum) in South Carolina and New York, both of which are first reports. Impatiens (Impatiens walleriana) and lettuce (Lactuca sativa) were the only non-solanaceous GRSV and/or TCSV hosts identified in experimental host range studies. Little genetic diversity was observed in GRSV and TCSV sequences, likely due to the recent introductions of both viruses. All GRSV isolates characterized were reassortants with the TCSV M RNA. In laboratory transmission studies, Frankliniella schultzei was a more efficient vector of GRSV than F. occidentalis. TCSV was acquired more efficiently than GRSV by F. occidentalis but upon acquisition, transmission frequencies were similar. Further spread of GRSV and TCSV in the United States is possible and detection of mixed infections highlights the opportunity for additional reassortment of tospovirus genomic RNAs.
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- 2015
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21. Three-dimensional quantitative imaging of telomeres in buccal cells identifies mild, moderate, and severe Alzheimer's disease patients.
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Mathur S, Glogowska A, McAvoy E, Righolt C, Rutherford J, Willing C, Banik U, Ruthirakuhan M, Mai S, and Garcia A
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- Aged, Alzheimer Disease classification, Female, Humans, Imaging, Three-Dimensional, In Situ Hybridization, Fluorescence, Interphase genetics, Male, Reference Values, Alzheimer Disease genetics, Alzheimer Disease pathology, Genomic Instability genetics, Mouth Mucosa pathology, Telomere ultrastructure
- Abstract
Using three-dimensional (3D) telomeric analysis of buccal cells of 82 Alzheimer's disease (AD) patients and cognitively normal age and gender-matched controls, we have for the first time examined changes in the 3D nuclear telomeric architecture of buccal cells among levels of AD severity based on five 3D parameters: i) telomere length, ii) telomere number, iii) telomere aggregation, iv) nuclear volume, and v) a/c ratio, a measure of spatial telomere distribution. Our data indicate that matched controls have significantly different 3D telomere profiles compared to mild, moderate, and severe AD patients (p < 0.0001). Distinct profiles were also evident for each AD severity group. An increase in telomere number and aggregation concomitant with a decrease in telomere length from normal to severe AD defines the individual stages of the disease (p < 0.0001).
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- 2014
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22. Divergent roles of Toll-like receptor 2 in response to lipoteichoic acid and Staphylococcus aureus in vivo.
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Gillrie MR, Zbytnuik L, McAvoy E, Kapadia R, Lee K, Waterhouse CC, Davis SP, Muruve DA, Kubes P, and Ho M
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- Animals, Endothelial Cells immunology, Enzyme-Linked Immunosorbent Assay, Humans, Interferon-gamma immunology, Mice, Mice, Inbred C57BL, Mice, Knockout, Staphylococcus aureus immunology, Toll-Like Receptor 2 deficiency, Transplantation Chimera, Chemotaxis, Leukocyte immunology, Lipopolysaccharides immunology, Staphylococcal Infections immunology, Teichoic Acids immunology, Toll-Like Receptor 2 immunology
- Abstract
The response of leukocytes to lipoteichoic acid (LTA), a TLR2-dependent major cell wall component of Staphylococcus aureus, is linked to the outcome of an infection. In this study we investigated the role of nonhematopoietic TLR2 in response to LTA and S. aureus by creating bone marrow chimeras. Significant leukocyte recruitment in response to LTA required IFN-gamma priming in WT C57BL/6 and TLR2(-/-)-->WT mice, but was not observed in TLR2(-/-) or WT-->TLR2(-/-) animals. LTA also induced a proinflammatory response in IFN-gamma primed primary human microvascular endothelial cells leading to leukocyte recruitment in vitro. When mice were infected with S. aureus, the most profound elevation of TNF-alpha and IL-6 was seen in TLR2(-/-) and TLR2(-/-)-->WT mice. TLR2(-/-), but not chimeric mice, demonstrated increased IL-17, blood leukocytosis and pulmonary neutrophilia compared to WT mice. Collectively, the results suggest an essential role for IFN-gamma and nonhematopoietic TLR2 for leukocyte recruitment in response to LTA. In contrast, TLR2 on both hematopoietic and nonhematopoietic cells appears to orchestrate an inhibitory response to S. aureus such that in complete TLR2 deficiency, there is an exaggerated proinflammatory response and/or skewing of the immune response towards a Th17 phenotype that may contribute to the decreased survival of TLR2(-/-) mice.
- Published
- 2010
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23. Platelet TLR4 activates neutrophil extracellular traps to ensnare bacteria in septic blood.
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Clark SR, Ma AC, Tavener SA, McDonald B, Goodarzi Z, Kelly MM, Patel KD, Chakrabarti S, McAvoy E, Sinclair GD, Keys EM, Allen-Vercoe E, Devinney R, Doig CJ, Green FH, and Kubes P
- Subjects
- Alanine Transaminase blood, Animals, Epithelium pathology, Humans, Lipopolysaccharides metabolism, Liver metabolism, Mice, Neutrophils enzymology, Sepsis immunology, Bacteria immunology, Blood Platelets immunology, Neutrophils immunology, Sepsis microbiology, Sepsis physiopathology, Toll-Like Receptor 4 metabolism
- Abstract
It has been known for many years that neutrophils and platelets participate in the pathogenesis of severe sepsis, but the inter-relationship between these players is completely unknown. We report several cellular events that led to enhanced trapping of bacteria in blood vessels: platelet TLR4 detected TLR4 ligands in blood and induced platelet binding to adherent neutrophils. This led to robust neutrophil activation and formation of neutrophil extracellular traps (NETs). Plasma from severely septic humans also induced TLR4-dependent platelet-neutrophil interactions, leading to the production of NETs. The NETs retained their integrity under flow conditions and ensnared bacteria within the vasculature. The entire event occurred primarily in the liver sinusoids and pulmonary capillaries, where NETs have the greatest capacity for bacterial trapping. We propose that platelet TLR4 is a threshold switch for this new bacterial trapping mechanism in severe sepsis.
- Published
- 2007
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24. Tumor cell sensitization to apoptotic stimuli by selective inhibition of specific Akt/PKB family members.
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DeFeo-Jones D, Barnett SF, Fu S, Hancock PJ, Haskell KM, Leander KR, McAvoy E, Robinson RG, Duggan ME, Lindsley CW, Zhao Z, Huber HE, and Jones RE
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- 3-Phosphoinositide-Dependent Protein Kinases, Antibiotics, Antineoplastic pharmacology, Caspase 3, Caspases metabolism, Chromones pharmacology, Drug Resistance, Neoplasm drug effects, Enzyme Activation, Humans, Morpholines pharmacology, Protein Isoforms chemistry, Protein Isoforms pharmacology, Protein Serine-Threonine Kinases physiology, Proto-Oncogene Proteins physiology, Proto-Oncogene Proteins c-akt, Sirolimus pharmacology, Tumor Cells, Cultured, Apoptosis physiology, Neoplasms enzymology, Protein Kinase Inhibitors chemistry, Protein Kinase Inhibitors pharmacology, Protein Serine-Threonine Kinases antagonists & inhibitors, Proto-Oncogene Proteins antagonists & inhibitors
- Abstract
Recent studies indicate that dysregulation of the Akt/PKB family of serine/threonine kinases is a prominent feature of many human cancers. The Akt/PKB family is composed of three members termed Akt1/PKBalpha, Akt2/PKBbeta, and Akt3/PKBgamma. It is currently not known to what extent there is functional overlap between these family members. We have recently identified small molecule inhibitors of Akt. These compounds have pleckstrin homology domain-dependent, isozyme-specific activity. In this report, we present data showing the relative contribution that inhibition of the different isozymes has on the apoptotic response of tumor cells to a variety of chemotherapies. In multiple cell backgrounds, maximal induction of caspase-3 activity is achieved when both Akt1 and Akt2 are inhibited. This induction is not reversed by overexpression of functionally active Akt3. The level of caspase-3 activation achieved under these conditions is equivalent to that observed with the phosphatidylinositol-3-kinase inhibitor LY294002. We also show that in different tumor cell backgrounds inhibition of mammalian target of rapamycin, a downstream substrate of Akt, is less effective in inducing caspase-3 activity than inhibition of Akt1 and Akt2. This shows that the survival phenotype conferred by Akt can be mediated by signaling pathways independent of mammalian target of rapamycin in some tumor cell backgrounds. Finally, we show that inhibition of both Akt1 and Akt2 selectively sensitizes tumor cells, but not normal cells, to apoptotic stimuli.
- Published
- 2005
25. A prostate-specific antigen (PSA)-activated vinblastine prodrug selectively kills PSA-secreting cells in vivo.
- Author
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DeFeo-Jones D, Brady SF, Feng DM, Wong BK, Bolyar T, Haskell K, Kiefer DM, Leander K, McAvoy E, Lumma P, Pawluczyk JM, Wai J, Motzel SL, Keenan K, Van Zwieten M, Lin JH, Garsky VM, Freidinger R, Oliff A, and Jones RE
- Subjects
- Animals, Antineoplastic Agents therapeutic use, Antineoplastic Agents, Phytogenic metabolism, Dogs, Doxorubicin therapeutic use, Humans, Male, Mice, Mice, Nude, Models, Chemical, Neoplasm Transplantation, Prodrugs metabolism, Prostatic Neoplasms pathology, Species Specificity, Tissue Distribution, Tumor Cells, Cultured, Vinblastine metabolism, Antineoplastic Agents, Phytogenic therapeutic use, Prodrugs therapeutic use, Prostate-Specific Antigen metabolism, Prostatic Neoplasms therapy, Vinblastine therapeutic use
- Abstract
Currently, there is no therapy for men with androgen-refractory prostate cancer that substantially extends survival. This report characterizes by in vitro and in vivo techniques a new chemotherapeutic that is composed of desacetyl-vinblastine covalently linked to a peptide that contains a peptide bond that can be hydrolyzed by prostate-specific antigen (PSA). This compound (referred to as vinblastine-conjugate) is minimally toxic to cells in culture which do not express PSA. In the presence of PSA, the peptide moiety is hydrolyzed, generating several highly toxic metabolites that contain vinblastine. Animals bearing PSA-positive human prostate tumors that were treated with the vinblastine-conjugate experienced a >99% reduction in PSA serum level. In contrast, animals bearing PSA-positive human prostate tumors treated with the cytotoxic metabolites derived from the PSA hydrolysis of the vinblastine-conjugate showed a nonsignificant change in both PSA and tumor weight values. The cell killing activity of the vinblastine-conjugate is PSA dependent because animals bearing non-PSA-producing human tumor xenografts had a nonsignificant increase in tumor weight after vinblastine-conjugate treatment. Exploratory efficacy/toxicity studies in LNCaP tumor-bearing nude mice were conducted with animals treated for 5 consecutive days with various doses of either the vinblastine-conjugate or a PSA-generated toxic metabolite (desacetyl-vinblastine). The desacetyl-vinblastine treatment resulted in 10-70% mortality with a very slight effect on tumor growth. In contrast, vinblastine-conjugate treatments resulted in no mortality, good to excellent antitumor efficacy, very slight to slight peripheral neuropathy and myelopathy, and slight to severe testicular degeneration. Similar treatment of beagle dogs with the vinblastine-conjugate showed even less toxicity. These data support the use of the PSA-hydrolyzable vinblastine-conjugate as an experimental therapy for prostate cancer in man.
- Published
- 2002
26. A peptide-doxorubicin 'prodrug' activated by prostate-specific antigen selectively kills prostate tumor cells positive for prostate-specific antigen in vivo.
- Author
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DeFeo-Jones D, Garsky VM, Wong BK, Feng DM, Bolyar T, Haskell K, Kiefer DM, Leander K, McAvoy E, Lumma P, Wai J, Senderak ET, Motzel SL, Keenan K, Van Zwieten M, Lin JH, Freidinger R, Huff J, Oliff A, and Jones RE
- Subjects
- Animals, Doxorubicin pharmacokinetics, Humans, Male, Mice, Mice, Nude, Oligopeptides pharmacokinetics, Prodrugs pharmacokinetics, Prostate-Specific Antigen analysis, Prostate-Specific Antigen blood, Tissue Distribution, Tumor Cells, Cultured, Xenograft Model Antitumor Assays, Doxorubicin analogs & derivatives, Doxorubicin therapeutic use, Oligopeptides therapeutic use, Prodrugs therapeutic use, Prostate-Specific Antigen physiology, Prostatic Neoplasms drug therapy, Prostatic Neoplasms pathology
- Abstract
We covalently linked doxorubicin with a peptide that is hydrolyzable by prostate-specific antigen. In the presence of prostate tumor cells secreting prostate-specific antigen, the peptide moiety of this conjugate, L-377,202, was hydrolyzed, resulting in the release of leucine-doxorubicin and doxorubicin, which are both very cytotoxic to cancer cells. However, L-377,202 was much less cytotoxic than conventional doxorubicin to cells in culture that do not secrete prostate-specific antigen. L-377,202 was approximately 15 times more effective than was conventional doxorubicin at inhibiting the growth of human prostate cancer tumors in nude mice when both drugs were used at their maximally tolerated doses. Nude mice inoculated with human prostate tumor cells secreting prostate-specific antigen showed considerable reductions in tumor burden with minimal total body weight loss when treated with L-377, 202. This improvement in therapeutic index correlated with the selective localization of leucine-doxorubicin and free doxorubicin in tissues secreting prostate-specific antigen after exposure to L-377,202.
- Published
- 2000
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27. Novel inhibitors of the nuclear factor of activated T cells (NFAT)-mediated transcription of beta-galactosidase: potential immunosuppressive and antiinflammatory agents.
- Author
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Michne WF, Schroeder JD, Guiles JW, Treasurywala AM, Weigelt CA, Stansberry MF, McAvoy E, Shah CR, Baine Y, and Sawutz DG
- Subjects
- Anti-Inflammatory Agents, Non-Steroidal chemistry, Cell Line, Humans, Immunosuppressive Agents chemistry, Magnetic Resonance Spectroscopy, NFATC Transcription Factors, Anti-Inflammatory Agents, Non-Steroidal pharmacology, DNA-Binding Proteins antagonists & inhibitors, Immunosuppressive Agents pharmacology, Nuclear Proteins, Transcription Factors antagonists & inhibitors, Transcription, Genetic drug effects, beta-Galactosidase genetics
- Abstract
The preparation of a series of quinazoline-2,4-diones, 1-3, and pyrrolo[3,4-d]pyrimidine-2,4-diones, 4-8 is described. A small number of quinazolinedione analogs were identified from random screening to possess low micromolar (1.3-4.4 microM) potency in the nuclear factor of activated T cells-1-regulated beta-galactosidase expression assay. An expanded analog search resulted in identifying pyrrolopyrimidinedione 4b which is 5-10-fold (0.26 microM) more potent than the quinazolinediones. Replacement of the benzyl group with naphthyl led to greater potency and conformationally restricted analogs 4u-w. The naphthyl and acenaphthyl analogs are 10-100 times more potent inhibitors of beta-galactosidase expression than 4b. Binding affinity data for displacement of radiolabeled 4s from Jurkat cell membranes reflected an excellent correlation with the IC50 value for inhibition of beta-galactosidase activity. These products, whose structure-activity relationships are discussed, are of interest as potential agents for preventing interleukin-2 gene transcription.
- Published
- 1995
- Full Text
- View/download PDF
28. Polarity of transport of 2-deoxy-D-glucose and D-glucose by cultured renal epithelia (LLC-PK1).
- Author
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Miller JH, Mullin JM, McAvoy E, and Kleinzeller A
- Subjects
- Animals, Biological Transport drug effects, Cells, Cultured, Cytochalasin B pharmacology, Epithelial Cells, Epithelium metabolism, Glucose Transporter Type 1, Insulin pharmacology, Kidney cytology, Monosaccharide Transport Proteins metabolism, Phloretin pharmacology, Phlorhizin pharmacology, Swine, Deoxyglucose metabolism, Glucose metabolism, Kidney metabolism
- Abstract
At least two types of glucose transporter exist in cultured renal epithelial cells, a Na(+)-glucose cotransporter (SGLT), capable of interacting with D-glucose but not 2-deoxy-D-glucose (2dglc) and a facilitated transporter (GLUT) capable of interacting with both D-glucose and 2dglc. In order to examine the polarity of transport in cultured renal epithelia, 2dglc and D-glucose uptakes were measured in confluent cultures of LLC-PK1 cells grown on collagen-coated filters that permitted access of medium to both sides of the monolayer. The rates of basolateral uptake of both 1 mM glucose (Km 3.6 mM) and 1 mM 2dglc (Km 1.5 mM) were greater than apical uptake rates and the (apical-to-basolateral)/(basolateral-to-apical) flux ratio was high for glucose (9.4) and low for 2dglc (0.8), thus, confirming the lack of interaction of 2dglc with the apical SGLT. Specific glucose transport inhibitor studies using phlorizin, phloretin and cytochalasin B confirmed the polarised distribution of SGLT and GLUT in LLC-PK1 cells. Basolateral sugar uptake could be altered by addition of insulin (1 mU/ml) which increased 2dglc uptake by 72% and glucose uptake by 50% and by addition of 20 mM glucose to the medium during cell culture which decreased 2dglc uptake capacity at confluence by 30%. During growth to confluence, 2dglc uptake increased to a maximum, then decreased at the time of confluence, coincident with a rise in uptake capacity for alpha-methyl-D-glucoside, a hexose that interacts only with the apical SGLT. It was concluded that the non-metabolisable sugar 2dglc was a useful, specific probe for GLUT in LLC-PK1 cells and that GLUT was localised at the basolateral membrane after confluence.
- Published
- 1992
- Full Text
- View/download PDF
29. Mammalian cell lines engineered to identify inhibitors of specific signal transduction pathways.
- Author
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Jones RE, Defeo-Jones D, McAvoy EM, Vuocolo GA, Wegrzyn RJ, Haskell KM, and Oliff A
- Subjects
- 1-Methyl-3-isobutylxanthine pharmacology, Alkaline Phosphatase metabolism, Animals, Base Sequence, Cell Line, Clone Cells, Colforsin pharmacology, Female, Humans, Isoenzymes metabolism, Mice, Molecular Sequence Data, Placenta enzymology, Platelet-Derived Growth Factor pharmacology, Pregnancy, Tetradecanoylphorbol Acetate pharmacology, Transfection, Alkaline Phosphatase genetics, Isoenzymes genetics, Signal Transduction drug effects, Transcription, Genetic drug effects
- Abstract
A variety of signal transduction pathways contribute to the regulation of transcription in mammalian cells. Several of these pathways ultimately rely upon the interaction of transcription factors with genetic sequences termed response elements in the promoter regions of some genes. The biochemical mechanisms that control the levels and state of activation of transcription factors are poorly understood. However, specific phosphorylation events mediated by protein kinase C, growth factor receptor-linked tyrosine kinases, and protein kinase A clearly participate in the regulation of these signal transduction pathways. To understand the relationship between activation and/or inhibition of these pathways and regulation of gene expression controlled by specific response elements, cell lines were prepared containing the TPA response element (TRE), serum response element (SRE), or cyclic AMP response element (CRE) fused to a gene encoding a secretable form of alkaline phosphatase (SEAP). These TRE-SEAP, SRE-SEAP, and CRE-SEAP cells exhibit dramatic increases in alkaline phosphatase (AP) activity following exposure to TPA, PDGF, or forskolin. Down regulation of protein kinase C or inhibition of tyrosine kinase activity blocked the stimulation of AP activity caused by TPA or PDGF. These cell lines can be used to characterize existing inhibitors, and to identify new agents that affect specific signal transduction pathways in mammalian cells.
- Published
- 1991
30. Transport and phosphorylation of D-galactose in renal cortical cells.
- Author
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Kleinzeller A and McAvoy EM
- Subjects
- Animals, Biological Transport, Active, Hydrogen-Ion Concentration, In Vitro Techniques, Kidney Cortex drug effects, Kinetics, Lithium pharmacology, Models, Biological, Phlorhizin pharmacology, Rabbits, Sodium pharmacology, Zinc pharmacology, Galactose metabolism, Hexosephosphates biosynthesis, Kidney Cortex metabolism
- Abstract
An improved analytical procedure for the extraction and determination of total, free and phosphorylated tissue sugar is described. This method, employing ZnSO4 plus Ba(OH)2 for the precipitation of sugar phosphates, yields values identical with those obtained by the more laborious separation of free and phosphorylated sugar by ion-exchange chromatography. Erroneous values for free sugar due to the action of a Zn2+ -activated phosphatase and/or the lability to acids of some sugar phosphates, are avoided. Using this technique for the sudy of transport and phosphorylation of D-galactose in rabbit renal cortical slices and tissue extracts, it was found: 1. The cellular uptake of D-galactose was associated with the appearance of both free and phosphorylated sugar whether or not external Na+ was present. At 1 mM sugar, galactose was accumulated in the cells against a modest concentration gradient of 1.445 +/- 0.097 (n = 17). Galactose phosphate appeared in the cells considerably faster than free sugar under conditions of net uptake as well as of steady-state exchange (pulse-labelling). 2. Increasing saline pH (6-8) increased the cellular levels of sugar phosphate without affecting the steady-state values of free sugar. With tissue extracts, increasing pH also stimulated the activity of galactokinase and the dephosphorylation of galactose 1-phosphate by a Zn2+ -activated phosphatase. 3. 0.5 mM phlorizin inhibited the tissue uptake of galactose and its subsequent oxidation to CO2 only to a minor degree (30 and 10%, respectively). The absence of external Na+ further depressed the phlorizin effect. Preincubation of the tissue with phlorizin and subsequent washing in part abolished the inhibitory effect. The data suggest that a major portion of the galactose uptake by the tissue proceeds by a mechanism with a low affinity for phlorizin. 4. Efflux studies showed that the wash-out of free galactose from slices was associated with a net decrease of both free and phosphorylated tissue sugar. 5. The above results suggest the possibility that phosphorylation may represent a step in the Na+ -independent, phloretin-sensitive transfer of D-galactose across the antiluminal cell membrane. The participation of intracellular galactokinase and a Zn2+ -activated alkaline phosphatase in the maintenance of the steady state of free and phosphorylated galactose in the cells has been demonstrated.
- Published
- 1976
- Full Text
- View/download PDF
31. Glucose transport and metabolism in rat renal proximal tubules: multicomponent effects of insulin.
- Author
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Kleinzeller A and McAvoy EM
- Subjects
- Alloxan pharmacology, Animals, Biological Transport drug effects, Gluconeogenesis, In Vitro Techniques, Kidney Tubules, Proximal drug effects, Kinetics, Lactates metabolism, Lactic Acid, Male, Oxidation-Reduction, Phlorhizin pharmacology, Rats, Rats, Inbred Strains, Sodium metabolism, Streptozocin pharmacology, Glucose metabolism, Insulin pharmacology, Kidney Tubules, Proximal metabolism
- Abstract
Glucose transport and metabolism, and the effect of insulin thereon, was studied using suspensions of rat renal tubules enriched in the proximal component. [U-14C]Glucose oxidation is a saturable process (Km 3.1 +/- 0.2 mM; Vmax 14 +/- 0.2 mumole 14CO2 formed/g tissue protein per h). Glucose oxidation and [14C]lactate formation from glucose are inhibited in part by phlorizin and phloretin: the data suggest that the rate-limiting entry of glucose into the cell metabolic pool occurs by both the Na-glucose cotransport system (at the brush border) and the equilibrating, phloretin-sensitive system (at the basal-lateral membrane). Raising external glucose from 5 to 30 mM markedly increases aerobic and anaerobic lactate formation. Gluconeogenesis from lactate is not affected by variations of glucose concentrations. 24 h after streptozotocin administration, aerobic lactate formation is enhanced, as is the uptake of methyl alpha-D-glucoside by the tubules, while anaerobic glycolysis is depressed. Streptozotocin treatment (ST) increases both the Km and Vmax of glucose oxidation; gluconeogenesis and lactate oxidation are not affected. The effect of streptozotocin treatment on lactate formation are abolished by 1 mU/ml insulin. Streptozotocin treatment increases tissue hexokinase activity, decreases glucose-6-phosphatase, but has no significant effect on fructose-1,6-diphosphatase; phosphoenolpyruvate carboxykinase and pyruvate dehydrogenase. The data demonstrate fast streptozotocin-induced changes in cellular enzymes of carbohydrate metabolism. The enhancing effect of streptozotocin on methyl alpha-glucoside uptake is transient: 8 days after administration of the agent, no significant difference from controls is found. It is concluded that under the given experimental conditions insulin enhances the equilibrating glucose entry by the phloretin-sensitive pathway at the basal-lateral membrane, and transiently inhibits the Na-glucose cotransport system.
- Published
- 1986
- Full Text
- View/download PDF
32. Transport and phosphorylation of 2-deoxy-D-galactase in renal cortical cells.
- Author
-
Kleinzeller A and McAvoy EM
- Subjects
- Animals, Biological Transport, Active, Galactose metabolism, Hydrogen-Ion Concentration, In Vitro Techniques, Kinetics, Rabbits, Structure-Activity Relationship, Deoxy Sugars metabolism, Hexosephosphates biosynthesis, Kidney Cortex metabolism
- Abstract
The transport and phosphorylation of 2-deoxy-D-[3H]galactose in rabbit renal cortical cells was studied. 1. The uptake of 2-deoxy-galactose by cortical slices is associated with an appearance of both free and phosphorylated sugar in the cells. At 1 mM external sugar the cells establish a steady-state gradient of free 2-deoxy-galactose of 3.97 +/- 0.15 (23 animals). 2. The acid-labile sugar phosphate accumulated in the tissue has been identified by a combination of paper and radio-chromatography, as well as on the basis of some of its chemical properties, as 2-deoxy-D-galactose 1-phosphate. Ice-cold trichloroacetic acid produces a decomposition of this compound. 3. Increasing external pH (6-8) brings about a decrease in the steady-state levels of both free and phosphorylated sugar in slices. On the other hand, increasing pH activates the phosphorylation of 2-deoxy-D-galactose by a crude kinase in a tissue extract. 4. Sugar phosphate accumulated in the cells is dephosphorylated by the action of a Zn2+ -activated phosphatase. 5. The efflux of 2-deoxy-D-galactose from the cells is rather slow compared with that found for D-galactose. The efflux is associated with some dephosphorylation of cellular sugar phosphate, and some loss of 2-deoxy-galactose phosphate into the wash-out medium takes place. 6. An inhibition analysis of the uptake of 2-deoxy-D-galactose by the slices indicates that the transport site is shared by D-galactose. The following points of interaction between the sugar molecule and the carrier are identified: C1-OH, C3-OH and C4-OH (both axial) and C6-OH. A (pyranose) ring structure is also essential. A close packing between the substrate and the carrier in the vicinity of C2 is indicated. 7. The data suggest that the above transport system is localized predominantly at the antiluminal (basolateral) face of the renal tubular cells. While the detailed mechanism of the actual transport step (i.e. active transport of the free sugar, or by the action of a phosphotransferase) is still unclear, the data present evidence that both galactokinase and a Zn2+ -activated phosphatase participate in the maintenance of an intracellular steady state of the transported sugar.
- Published
- 1976
- Full Text
- View/download PDF
33. The phlorizin effect on the transport of sugars at the antiluminal face of teased flounder tubules.
- Author
-
Kleinzeller A, Dubyak G, Mullin JF, and McAvoy EM
- Subjects
- Animals, Biological Transport, Active drug effects, Deoxyglucose metabolism, Glucose metabolism, Hexoses metabolism, In Vitro Techniques, Mannose metabolism, Methylglucosides metabolism, Rabbits, Fishes metabolism, Kidney Tubules metabolism, Phlorhizin pharmacology
- Abstract
The effect of phlorizin on the uptake of sugars by teased renal tubules of the flounder (Pseudopleuronectes americanus) and slices of rabbit kidney cortex was investigated: 1. Increasing concentrations (0.05-0.5 mM) of phlorizin inhibited the uptake of D-glucose at the antiluminal face of the tubular cells by affecting primarily the cellular levels of glucose phosphates, whereas the levels of free glucose remained constant. This result suggests the possibility that the actual transport step is associated with sugar phosphorylation. 2. As opposed to the high affinity of phlorizin for the Na+-dependent active transport system for methyl-alpha-D-glucoside in flounder and rabbit kidney, the carrier shared by glucose, 2-deoxyglucose and mannose at the antiluminal face of tubular cells displays a low affinity for the inhibitor. It is suggested that glucose and its C2-analogs enter the renal tubular cells at the antiluminal face by a phosphorylating pathway which has a low affinity for phlorizin, and mix readily with the metabolic pool. This transport pathway serves the nutritional requirements of the cells.
- Published
- 1977
- Full Text
- View/download PDF
34. The structural requirement for C1-OH for the active transport of D-mannose and 2-deoxy-D-hexoses by renal tubular cells.
- Author
-
Kleinzeller A, Tam I, Kanter RK, and McAvoy EM
- Subjects
- Animals, Biological Transport, Active, Carbon Radioisotopes, Deoxyglucose metabolism, Galactose metabolism, Lithium pharmacology, Methylgalactosides metabolism, Methylglucosides metabolism, Methylglycosides metabolism, Molecular Conformation, Ouabain pharmacology, Phlorhizin pharmacology, Rabbits, Sodium pharmacology, Sorbitol analogs & derivatives, Sorbitol metabolism, Time Factors, Tritium, Deoxy Sugars metabolism, Kidney Cortex metabolism, Mannose metabolism
- Published
- 1974
- Full Text
- View/download PDF
35. Active renal hexose transport. Structural requirements.
- Author
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Kleinzeller A, McAvoy EM, and McKibbin RD
- Subjects
- Animals, Biological Transport, Active drug effects, Dinitrophenols pharmacology, Galactose analogs & derivatives, Galactose metabolism, Glucose analogs & derivatives, Glucose metabolism, Ouabain pharmacology, Phlorhizin pharmacology, Rabbits, Structure-Activity Relationship, Hexoses metabolism, Kidney Cortex metabolism, Methylgalactosides metabolism, Methylglycosides metabolism
- Abstract
The active transport of methyl beta-D-galactoside and some other analogs of D-glucose and D-galactose was studied in slices of rabbit and renal cortex. 1. The non-metabolizable methyl beta-D-galactoside accumulates in renal cortical cells against its concentration gradient. At 1 mM substrate concentration (O2, 35 degrees C, 60 min incubation) the gradient was 2.36 +/- 0.11 S.E. (n = 33). The Kt was 1.50 +/- 0.02 mM. The active transport of the substrate was inhibited by dinitrophenol, phlorizin, absence of Na+ and by ouabain. This inhibition was incomplete, suggesting that the sugar may enter the cells by two separate pathways, only one of which was coupled to the down-hill electrochemical Na gradient. 2. The structural requirements for the interaction between substrate and the carrier were defined: (a) by testing the transport behavior of some analogs (1,5-anhydro-D-glucitol; methyl beta-thio-D-galadtoside; 3-deoxy-D-glucose; 4-deoxy-D-glucose; 5-thio-D-glucose; 6-deoxy-D-glucose and methyl-alpha-6-deoxy-D-glucoside); and (b) by inhibition analysis of methyl beta-D-galactoside transport. The role of each hydroxyl of the sugar molecule was tested by using a total of 41 analogs modified on each C by replacing -OH by -H, -O-CH3, -F and in some instances also by -SH. 3. The carrier is shared by D-glucose, D-galactose and their methyl glycosides. A pyranose ring is mandatory. The D-glucoconfiguration is preferred for the interaction with the carrier. 4. Replacement of -OH by -H or -S practically abolished (on C1, C2, C3) or greatly reduced (on C4) the affinity of the analog for the carrier. This was also confirmed by demonstrating that 1-deoxy-, and 3-deoxy-glucose and the thio-galactoside were not actively transported and their entry into the cells was not markedly affected by phlorizin, dinitrophenol, ouabain or absence of Na+. 4-Deoxy-D-glucose was taken up and its transport was inhibited by agents affecting the transport of methyl beta-D-galactoside. 5. Replacement of -OH by -F did not abolish the affinity of the analogs for the carrier, indicating hydrogen bonding between the carrier and the oxygens at C1, C2, C3, and C4. 6. 5-Thio-D-glucose was not transported against its concentration gradient and also poorly interacted with the carrier as shown by inhibition analysis. Hydrogen bonding between the carrier and the pyranose ring oxygen is suggested. 7. 6-Deoxyglucose is a potent inhibitor of methyl beta-D-galactoside transport although it is not actively taken up by the tissue. It is concluded that a hydroxyl at C6 is required for transport, but is not mandatory for an interaction with the carrier. However, 6-deoxy-D-galactose was ineffective as inhibitor. 8. The specificity of the carrier involved in the renal active transport of D-glucose, D-galactose and their methyl glycosides resembles qualitatively, and mostly also quantitatively that described for intestinal transport of these sugars.
- Published
- 1980
- Full Text
- View/download PDF
36. Sugar transport across the peritubular face of renal cells of the flounder.
- Author
-
Kleinzeller A and McAvoy EM
- Subjects
- Animals, Biological Transport, Active, Galactose metabolism, Glucose metabolism, Glucose pharmacology, Glycosides metabolism, Kidney Tubules drug effects, Ouabain pharmacology, Phlorhizin pharmacology, Carbohydrate Metabolism, Fishes physiology, Kidney Tubules metabolism
- Abstract
The transport of some sugars at the antiluminal face of renal cells was studied using teased tubules of flounder (Pseudopleuronectes americanus). The analytical procedure allowed the determination of both free and total (free plus phosphorylated) tissue sugars. The inulin space of the preparation was 0.333 +/- 0.017 kg/kg wet wt (7 animals, 33 analyses). The nonmetabolizable alpha-methyl-D-glucoside entered the cells by a carrier-mediated (phloridzin-sensitive), ouabain-insensitive process. The steady-state tissue/medium ratio was systematically below that for diffusion equilibrium. D-Glucose was a poor inhibitor of alpha-methyl-glucoside transport, D-galactose was ineffective. The phloridzin-sensitive transport processes of 2-deoxy-D-glucose,D-galactose,and 2-deoxy-D-galactose were associated with considerable phosphorylation. Kinetic evidence suggested that these sugars were transported in free form and subsequently were phosphorylated. 2-Deoxy-D-glucose accumulated in the cells against a slight concentration gradient. This transport was greatly inhibited by D-glucose, whereas alpha-methyl-glucoside and also D-galactose and its 2-deoxy-derivative were ineffective. D-Galactose and 2-deoxy-D-galactose mutually competed for transport; D-glucose, 2-deoxy-D-glucose, and alpha-methyl-D-glucoside were ineffective. Studies using various sugars as inhibitors suggest the presence of three carrier-mediated pathways of sugar transport at the antiluminal cell face of the flounder renal tubule: the pathway of alpha-methyl-D-glucoside (not shared by D-glucose); the pathway commonly shared by 2-deoxy-D-glucose and D-glucose; the pathway shared by D-galactose and 2-deoxy-D-galactose.
- Published
- 1973
- Full Text
- View/download PDF
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