12 results on '"Reick M"'
Search Results
2. Accurate IVIM model-based liver lesion characterisation can be achieved with only three b-value DWI
- Author
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Mürtz, P., Sprinkart, A. M., Reick, M., Pieper, C. C., Schievelkamp, A.-H., König, R., Schild, H. H., Willinek, W. A., and Kukuk, G. M.
- Published
- 2018
- Full Text
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3. Correction to: Is liver lesion characterisation by simplified IVIM DWI also feasible at 3.0 T?
- Author
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Mürtz, Petra, Pieper, C. C., Reick, M., Sprinkart, A. M., Schild, H. H., Willinek, W. A., and Kukuk, G. M.
- Published
- 2019
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4. Comparative functional characterization and in vitro immunological cross-reactivity studies on Daboia russelii and Craspedocephalus malabaricus venom.
- Author
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Rajan K, Alangode A, Menon JC, Raveendran D, Nair SS, Reick M, Nair BG, Reick M, and Vanuopadath M
- Subjects
- Animals, Enzyme-Linked Immunosorbent Assay, Hyaluronoglucosaminidase, Daboia, Snake Bites immunology, Snake Bites drug therapy, Species Specificity, Cross Reactions, Antivenins immunology, Viper Venoms immunology, Phospholipases A2 immunology, Viperidae, L-Amino Acid Oxidase immunology
- Abstract
Background: Snake venom is a complex mixture of organic and inorganic constituents, including proteins and peptides. Several studies showed that antivenom efficacy differs due to intra- and inter-species venom variation., Methods: In the current study, comparative functional characterization of major enzymatic proteins present in Craspedocephalus malabaricus and Daboia russelii venom was investigated through various in vitro and immunological cross-reactivity assays., Results: The enzymatic assays revealed that hyaluronidase and phospholipase A2 activities were markedly higher in D. russelii. By contrast, fibrinogenolytic, fibrin clotting and L-amino acid oxidase activities were higher in C. malabaricus venom. ELISA results suggested that all the antivenoms had lower binding potential towards C. malabaricus venom. For D. russelii venom, the endpoint titration value was observed at 1:72 900 for all the antivenoms. In the case of C. malabaricus venom, the endpoint titration value was 1:2700, except for Biological E (1:8100). All these results, along with the avidity assays, indicate the strength of venom-antivenom interactions. Similarly, the western blot results suggest that all the antivenoms showed varied efficacies in binding and detecting the venom antigenic epitopes in both species., Conclusions: The results highlight the need for species-specific antivenom to better manage snakebite victims., (© The Author(s) 2024. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.)
- Published
- 2024
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5. Sodium oleate, arachidonate, and linoleate enhance fibrinogenolysis by Russell's viper venom proteinases and inhibit FXIIIa; a role for phospholipase A 2 in venom induced consumption coagulopathy.
- Author
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Alangode A, Reick M, and Reick M
- Subjects
- Animals, Antivenins, Arachidonic Acid, Blood Coagulation Disorders, Disseminated Intravascular Coagulation, Endopeptidases, Linoleic Acid, Metalloproteases, Oleic Acid, Factor XIIIa antagonists & inhibitors, Peptide Hydrolases, Phospholipases A2 metabolism, Daboia, Viper Venoms
- Abstract
Life-threatening symptoms produced by Russell's viper (RV, Daboia russelii) envenomation result largely from venom induced consumption coagulopathy (VICC). VICC is thought to be mediated to a large degree by venom serine and metalloproteinases, as well as by snake venom phospholipase A
2 (svPLA2 ), the most abundant constituent of RV venom (RVV). The observation that the phenolic lipid anacardic acid markedly enhances proteolytic degradation of fibrinogen by RVV proteinases led us to characterize the chemical basis of this phenomenon with results indicating that svPLA2 products may be major contributors to VICC. RESULTS: Of the chemical analogs tested, the anionic detergents sodium dodecyl sulfate, sodium deoxycholate, N-lauryl sodium sarcosine, and the sodium salts of the fatty acids arachidonic, oleic and to a lesser extend linoleic acid were able to enhance fibrinogenolysis by RVV proteinases. Enhanced Fibrinogenolysis (EF) was observed with various venom size exclusion fractions containing different proteinases, and also with trypsin, indicating that conformational changes of the substrate and increased accessibility of otherwise cryptic cleavage sites are likely to be responsible for EF. In addition to enhancing fibrinogenolysis, sodium arachidonate and oleate were found to partially inhibit thrombin induced, factor XIIIa (FXIIIa) mediated ligation of fibrin chains. In clotting experiments with fresh blood RVV was found to disrupt normal coagulation, leading to small, partial clot formation, whereas RVV pretreated with the PLA2 inhibitor Varespladib induced rapid and complete clot formation (after 5 min) compared to blood alone. CONCLUSION: The observations that fatty acid anions and anionic detergents induce conformational changes that render fibrin(ogen) more susceptible to proteolysis by RVV proteinases and that RVV-PLA2 activity (which produces FFA) is required to render blood incoagulable in clotting experiments with RVV indicate a mechanism by which the activity of highly abundant RVV-PLA2 promotes degradation and depletion of fibrin(ogen) resulting in incoagulable blood seen following RVV envenomation (VICC)., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2020
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6. Altered patterns of sleep and behavioral adaptability in NPAS2-deficient mice.
- Author
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Dudley CA, Erbel-Sieler C, Estill SJ, Reick M, Franken P, Pitts S, and McKnight SL
- Subjects
- Animals, Basic Helix-Loop-Helix Transcription Factors, Behavior, Animal, Body Weight, CLOCK Proteins, Crosses, Genetic, Darkness, Eating, Electroencephalography, Electromyography, Female, Food, Gene Targeting, Light, Male, Mice, Mice, Inbred C57BL, Nerve Tissue Proteins genetics, Prosencephalon physiology, Suprachiasmatic Nucleus physiology, Trans-Activators genetics, Trans-Activators physiology, Transcription Factors genetics, Adaptation, Physiological, Biological Clocks physiology, Circadian Rhythm physiology, Motor Activity, Nerve Tissue Proteins physiology, Sleep, Transcription Factors physiology
- Abstract
Animal behavior is synchronized to the 24-hour light:dark (LD) cycle by regulatory programs that produce circadian fluctuations in gene expression throughout the body. In mammals, the transcription factor CLOCK controls circadian oscillation in the suprachiasmatic nucleus of the brain; its paralog, neuronal PAS domain protein 2 (NPAS2), performs a similar function in other forebrain sites. To investigate the role of NPAS2 in behavioral manifestations of circadian rhythm, we studied locomotor activity, sleep patterns, and adaptability to both light- and restricted food-driven entrainment in NPAS2-deficient mice. Our results indicate that NPAS2 plays a substantive role in maintaining circadian behaviors in normal LD and feeding conditions and that NPAS2 is critical for adaptability to food restriction.
- Published
- 2003
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7. Characterization of U2AF(6), a splicing factor related to U2AF(35).
- Author
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Shepard J, Reick M, Olson S, and Graveley BR
- Subjects
- Amino Acid Sequence, Animals, Cell Fractionation, Cloning, Molecular, HeLa Cells, Humans, Immunohistochemistry, Mice, Molecular Sequence Data, Protein Binding, Protein Structure, Tertiary, Protein Subunits, RNA Splice Sites genetics, Ribonucleoproteins chemistry, Ribonucleoproteins genetics, Ribonucleoproteins isolation & purification, Sequence Alignment, Splicing Factor U2AF, Tissue Distribution, Nuclear Proteins, RNA Splicing physiology, Ribonucleoproteins metabolism
- Abstract
The essential splicing factor U2AF (U2 auxiliary factor) is a heterodimer composed of 65-kDa (U2AF(65)) and 35-kDa (U2AF(35)) subunits. U2AF(35) has multiple functions in pre-mRNA splicing. First, U2AF(35) has been shown to function by directly interacting with the AG at the 3' splice site. Second, U2AF(35) is thought to play a role in the recruitment of U2AF(65) by serine-arginine-rich (SR) proteins in enhancer-dependent splicing. It has been proposed that the physical interaction between the arginine-serine-rich (RS) domain of U2AF(35) and SR proteins is important for this activity. However, other data suggest that this may not be the case. Here, we report the identification of a mammalian gene that encodes a 26-kDa protein bearing strong sequence similarity to U2AF(35), designated U2AF(26). The N-terminal 187 amino acids of U2AF(35) and U2AF(26) are nearly identical. However, the C-terminal domain of U2AF(26) lacks many characteristics of the U2AF(35) RS domain and, therefore, might be incapable of interacting with SR proteins. We show that U2AF(26) can associate with U2AF(65) and can functionally substitute for U2AF(35) in both constitutive and enhancer-dependent splicing, demonstrating that the RS domain of the small U2AF subunit is not required for splicing enhancer function. Finally, we show that U2AF(26) functions by enhancing the binding of U2AF(65) to weak 3' splice sites. These studies identify U2AF(26) as a mammalian splicing factor and demonstrate that distinct U2AF complexes can participate in pre-mRNA splicing. Based on its sequence and functional similarity to U2AF(35), U2AF(26) may play a role in regulating alternative splicing.
- Published
- 2002
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8. Metabolism and the control of circadian rhythms.
- Author
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Rutter J, Reick M, and McKnight SL
- Subjects
- Animals, Basic Helix-Loop-Helix Transcription Factors, Brain cytology, Brain physiology, CLOCK Proteins, Cells, Cultured, Cryptochromes, Eye Proteins genetics, Eye Proteins metabolism, Flavoproteins genetics, Flavoproteins metabolism, Glucose metabolism, Humans, Liver physiology, Nerve Tissue Proteins genetics, Nerve Tissue Proteins metabolism, Neurons metabolism, Oxidation-Reduction, Period Circadian Proteins, Receptors, G-Protein-Coupled, Suprachiasmatic Nucleus metabolism, Trans-Activators genetics, Trans-Activators metabolism, Transcription Factors genetics, Transcription Factors metabolism, Biological Clocks physiology, Circadian Rhythm physiology, Drosophila Proteins, Photoreceptor Cells, Invertebrate
- Abstract
The core apparatus that regulates circadian rhythm has been extensively studied over the past five years. A looming question remains, however, regarding how this apparatus is adjusted to maintain coordination between physiology and the changing environment. The diversity of stimuli and input pathways that gain access to the circadian clock are summarized. Cellular metabolic states could serve to link physiologic perception of the environment to the circadian oscillatory apparatus. A simple model, integrating biochemical, cellular, and physiologic data, is presented to account for the connection of cellular metabolism and circadian rhythm.
- Published
- 2002
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9. NPAS2: an analog of clock operative in the mammalian forebrain.
- Author
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Reick M, Garcia JA, Dudley C, and McKnight SL
- Subjects
- ARNTL Transcription Factors, Amino Acid Sequence, Animals, Basic Helix-Loop-Helix Transcription Factors, Blotting, Northern, CLOCK Proteins, Cell Cycle Proteins, Cell Line, Cloning, Molecular, Cryptochromes, Darkness, Dimerization, Ecdysterone pharmacology, Flavoproteins genetics, Flavoproteins metabolism, Gene Expression Regulation, Humans, In Situ Hybridization, Light, Mice, Mice, Inbred Strains, Molecular Sequence Data, Nerve Tissue Proteins chemistry, Nerve Tissue Proteins genetics, Nuclear Proteins genetics, Nuclear Proteins metabolism, Oligonucleotide Array Sequence Analysis, Period Circadian Proteins, Receptors, G-Protein-Coupled, Trans-Activators chemistry, Trans-Activators metabolism, Transcription Factors chemistry, Transcription Factors genetics, Transfection, Tumor Cells, Cultured, Biological Clocks physiology, Circadian Rhythm physiology, Drosophila Proteins, Ecdysterone analogs & derivatives, Eye Proteins, Nerve Tissue Proteins metabolism, Photoreceptor Cells, Invertebrate, Prosencephalon metabolism, Transcription Factors metabolism
- Abstract
Neuronal PAS domain protein 2 (NPAS2) is a transcription factor expressed primarily in the mammalian forebrain. NPAS2 is highly related in primary amino acid sequence to Clock, a transcription factor expressed in the suprachiasmatic nucleus that heterodimerizes with BMAL1 and regulates circadian rhythm. To investigate the biological role of NPAS2, we prepared a neuroblastoma cell line capable of conditional induction of the NPAS2:BMAL1 heterodimer and identified putative target genes by representational difference analysis, DNA microarrays, and Northern blotting. Coinduction of NPAS2 and BMAL1 activated transcription of the endogenous Per1, Per2, and Cry1 genes, which encode negatively activating components of the circadian regulatory apparatus, and repressed transcription of the endogenous BMAL1 gene. Analysis of the frontal cortex of wild-type mice kept in a 24-hour light-dark cycle revealed that Per1, Per2, and Cry1 mRNA levels were elevated during darkness and reduced during light, whereas BMAL1 mRNA displayed the opposite pattern. In situ hybridization assays of mice kept in constant darkness revealed that Per2 mRNA abundance did not oscillate as a function of the circadian cycle in NPAS2-deficient mice. Thus, NPAS2 likely functions as part of a molecular clock operative in the mammalian forebrain.
- Published
- 2001
- Full Text
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10. Regulation of clock and NPAS2 DNA binding by the redox state of NAD cofactors.
- Author
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Rutter J, Reick M, Wu LC, and McKnight SL
- Subjects
- ARNTL Transcription Factors, Animals, Aryl Hydrocarbon Receptor Nuclear Translocator, Basic Helix-Loop-Helix Transcription Factors, Biological Clocks, CLOCK Proteins, Cell Line, Circadian Rhythm, Dimerization, Helix-Loop-Helix Motifs, Humans, L-Lactate Dehydrogenase genetics, L-Lactate Dehydrogenase metabolism, Mice, NAD pharmacology, NADP pharmacology, Nerve Tissue Proteins chemistry, Oxidation-Reduction, Recombinant Proteins metabolism, Trans-Activators chemistry, Transcription Factors chemistry, DNA metabolism, DNA-Binding Proteins, NAD metabolism, NADP metabolism, Nerve Tissue Proteins metabolism, Receptors, Aryl Hydrocarbon, Trans-Activators metabolism, Transcription Factors metabolism
- Abstract
Clock:BMAL1 and NPAS2:BMAL1 are heterodimeric transcription factors that control gene expression as a function of the light-dark cycle. Although built to fluctuate at or near a 24-hour cycle, the clock can be entrained by light, activity, or food. Here we show that the DNA-binding activity of the Clock:BMAL1 and NPAS2:BMAL1 heterodimers is regulated by the redox state of nicotinamide adenine dinucleotide (NAD) cofactors in a purified system. The reduced forms of the redox cofactors, NAD(H) and NADP(H), strongly enhance DNA binding of the Clock:BMAL1 and NPAS2:BMAL1 heterodimers, whereas the oxidized forms inhibit. These observations raise the possibility that food, neuronal activity, or both may entrain the circadian clock by direct modulation of cellular redox state.
- Published
- 2001
- Full Text
- View/download PDF
11. Impaired cued and contextual memory in NPAS2-deficient mice.
- Author
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Garcia JA, Zhang D, Estill SJ, Michnoff C, Rutter J, Reick M, Scott K, Diaz-Arrastia R, and McKnight SL
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- Animals, Avoidance Learning, Basic Helix-Loop-Helix Transcription Factors, Behavior, Animal, Brain metabolism, Conditioning, Psychological, Cues, Fear, Gene Targeting, Helix-Loop-Helix Motifs, Limbic System metabolism, Limbic System physiology, Male, Mice, Nerve Tissue Proteins chemistry, Nerve Tissue Proteins genetics, Prosencephalon metabolism, Prosencephalon physiology, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins metabolism, Touch, Transcription Factors chemistry, Transcription Factors genetics, Transcriptional Activation, Transfection, beta-Galactosidase metabolism, Brain physiology, Learning physiology, Memory physiology, Nerve Tissue Proteins physiology, Transcription Factors physiology
- Abstract
Neuronal PAS domain protein 2 (NPAS2) is a basic helix-loop-helix (bHLH) PAS domain transcription factor expressed in multiple regions of the vertebrate brain. Targeted insertion of a beta-galactosidase reporter gene (lacZ) resulted in the production of an NPAS2-lacZ fusion protein and an altered form of NPAS2 lacking the bHLH domain. The neuroanatomical expression pattern of NPAS2-lacZ was temporally and spatially coincident with formation of the mature frontal association/limbic forebrain pathway. NPAS2-deficient mice were subjected to a series of behavioral tests and were found to exhibit deficits in the long-term memory arm of the cued and contextual fear task. Thus, NPAS2 may serve a dedicated regulatory role in the acquisition of specific types of memory.
- Published
- 2000
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12. Down-regulation of nuclear aryl hydrocarbon receptor DNA-binding and transactivation functions: requirement for a labile or inducible factor.
- Author
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Reick M, Robertson RW, Pasco DS, and Fagan JB
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- Animals, Base Sequence, Binding Sites, Cell Line, Cell Nucleus metabolism, Down-Regulation, Gene Expression Regulation, Enzymologic, In Vitro Techniques, Mice, Molecular Sequence Data, Nuclear Proteins metabolism, Oligodeoxyribonucleotides chemistry, Rats, Transcription, Genetic, DNA-Binding Proteins metabolism, Receptors, Aryl Hydrocarbon metabolism, Transcriptional Activation
- Abstract
Aryl hydrocarbons (AHs) such as 2,3,7,8-tetrachlorodibenzo-p-dioxin and benzo[a]pyrene activate the sequence-specific DNA-binding activity of the AH receptor. In the rat hepatocyte-derived cell line LCS7, DNA-binding activity peaked after 30 min and was then down-regulated, reaching negligible levels by 2 h. Down-regulation could be blocked, and DNA-binding activity maintained at maximum for many hours by inhibiting protein or RNA synthesis, implying that down-regulation is a mediated process requiring a labile or inducible protein. CYP1A1 transcription and in vivo DNA-protein interactions at xenobiotic response elements were down-regulated in parallel with DNA-binding activity in nuclear extracts, and these changes could also be blocked by inhibitors of protein synthesis. The correlation between AH receptor DNA-binding activity, intensity of in vivo footprints at xenobiotic response elements, and CYP1A1 transcription rate implies that down-regulation of AH receptor DNA-binding activity is important in regulating CYP1A1 transcription and that receptor is required continuously to maintain transcription. This correlation extends to the murine hepatoma cell line Hepa-1c1c7, in which slower kinetics of activation and down-regulation of CYP1A1 transcription paralleled slower activation and down-regulation of AH receptor DNA-binding activity. The difference in kinetics between cell lines also implies that AH receptor DNA-binding activity is modulated by a mechanism that may be influenced by cell-specific regulatory pathways. The above observations in conjunction with mixing experiments and comparisons of cytoplasmic and nuclear extracts indicate that down-regulation of AH receptor DNA-binding activity is probably due either to degradation or to conversion of the receptor to form that is inactive in both DNA binding and transactivation.
- Published
- 1994
- Full Text
- View/download PDF
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