The Experts below are selected from a list of 11358 Experts worldwide ranked by ideXlab platform
Eckhard Mandelkow - One of the best experts on this subject based on the ideXlab platform.
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cell cycle dependent phosphorylation and microtubule binding of tau protein stably transfected into chinese hamster ovary cells
Molecular Biology of the Cell, 1995Co-Authors: Ute Preuss, F Doring, Susanne Illenberger, Eckhard MandelkowAbstract:Tau protein, a neuronal microtubule-associated protein, is phosphorylated in situ and hyperphosphorylated when aggregated into the paired helical filaments of Alzheimer's disease. To study the phosphorylation of tau protein in vivo, we have stably transfected htau40, the largest human tau isoform, into Chinese hamster ovary cells. The distribution and phosphorylation of tau was monitored by gel shift, Autoradiography, immunofluorescence, and immunoblotting, using the antibodies Tau-1, AT8, AT180, and PHF-1, which are sensitive to the phosphorylation of Ser202, Thr205, Thr231, Ser235, Ser396, and Ser404 and are used in the diagnosis of Alzheimer tau. In interphase cells, tau becomes phosphorylated to some extent, partly at these sites; most of the tau is associated with microtubules. In mitosis, the above Ser/Thr-Pro sites become almost completely phosphorylated, causing a pronounced shift in M(r) and an antibody reactivity similar to that of Alzheimer tau. Moreover, a substantial fraction of tau is found in the cytoplasm detached from microtubules. Autoradiographs of metabolically labeled Chinese hamster ovary cells in interphase and mitosis confirmed that tau protein is more highly phosphorylated during mitosis. The understanding of tau phosphorylation under physiological conditions might help elucidate possible mechanisms for the hyperphosphorylation in Alzheimer's disease.
Walter E. Stumpf - One of the best experts on this subject based on the ideXlab platform.
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whole body and microscopic Autoradiography to determine tissue distribution of biopharmaceuticals target discoveries with receptor micro Autoradiography engendered new concepts and therapies for vitamin d
Advanced Drug Delivery Reviews, 2013Co-Authors: Walter E. StumpfAbstract:Abstract Information about the distribution of biopharmaceuticals is basic for understanding their actions. Tissue and cellular localization is a key to function. Autoradiography with radiolabeled compounds has provided valuable information with both low resolution whole-body macro-Autoradiography and high resolution microscopic Autoradiography (micro-Autoradiography). Whole-body macro-Autoradiography is a uniform and expedient single method approach, providing convenient dose- and time-related overviews with data similar to those obtained with conventional bioassays – and therefore widely used. However, whole-body macro-Autoradiography, like common bioassays, has limitations. High specificity-low capacity sites of binding and deposition frequently remain unrecognized. Lack of cellular resolution can cause false negatives and provide misleading results (e.g., false blood–brain barrier). For micro-Autoradiography, different methods are advertised in the literature. Most of them are, however, unsuited for drug localization because of inadequate resolution and frequent artifacts. Most drugs interact with their receptors non-covalently by weak electrostatic forces. Therefore, translocation and loss can occur during tissue preparation. This has complicated the use of micro-Autoradiography. Receptor micro-Autoradiography has overcome these complications and is a method of choice. It has been validated through several diffusible compounds with known localization, extensively applied. It has contributed numerous discoveries, followed by new concepts and therapies. Pictorial evidence in this review indicates that cellular information is essential, a ‘sine qua non’ for meaningful drug distribution studies. High resolution cellular microscopic information obtained from Autoradiography requires tissue dissection and the necessary precautions for preserving pristine in vivo drug deposition. Receptor micro-Autoradiography fulfils these requirements. It reveals crucial information at the subcellular level that cannot currently be obtained with any other type of Autoradiography or spectrometric imaging.
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In Vivo Dose-related Receptor Binding of the Vitamin D Analogue [3H]-1,25-dihydroxy-22-oxavitamin D3 (OCT) in Rat Parathyroid, Kidney Distal and Proximal Tubules, Duodenum, and Skin, Studied by Quantitative Receptor Autoradiography
Journal of Histochemistry and Cytochemistry, 1998Co-Authors: Nobuo Koike, Naohiko Hayakawa, Kenji Kumaki, Walter E. StumpfAbstract:: 1,25-Dihydroxy-22-oxavitamin D3 (OCT) is a new synthetic analogue of 1,25(OH)2D3 with a low calcemic effect. This study utilized quantitative receptor Autoradiography to determine the dose-related receptor binding and saturation among the vitamin D target cells: parathyroid chief cells, kidney distal and proximal tubule epithelium, duodenal absorptive epithelium, and epidermal keratinocytes. Rats were injected with 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, or 16.0 microgram/kg bw of [26-3H]-OCT and sacrificed 1 hr afterwards. Then Autoradiographs were prepared under identical conditions. In these target cells, nuclear uptake of radioactivity increased with dose and then achieved a plateau. However, their saturation doses showed differences: parathyroid chief cells 1-2 microgram duodenal absorptive epithelium, distal tubule epithelium, and epidermal keratinocytes 4-6 microgram proximal tubule epithelium 8 microgram (per kg bw). In contrast, in nontarget cells, such as liver and duodenal smooth muscle, radioactivity did not concentrate in the nuclei but increased in the cytoplasm with dose, without plateauing. These results provide the first information on the relative saturabilities of various target cell populations with a vitamin D ligand. Parathyroid chief cells required the relatively lowest receptor saturation dose. This suggests a high sensitivity and response to OCT treatment with related therapeutic potential for the regulation of parathyroid function.
Ute Preuss - One of the best experts on this subject based on the ideXlab platform.
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cell cycle dependent phosphorylation and microtubule binding of tau protein stably transfected into chinese hamster ovary cells
Molecular Biology of the Cell, 1995Co-Authors: Ute Preuss, F Doring, Susanne Illenberger, Eckhard MandelkowAbstract:Tau protein, a neuronal microtubule-associated protein, is phosphorylated in situ and hyperphosphorylated when aggregated into the paired helical filaments of Alzheimer's disease. To study the phosphorylation of tau protein in vivo, we have stably transfected htau40, the largest human tau isoform, into Chinese hamster ovary cells. The distribution and phosphorylation of tau was monitored by gel shift, Autoradiography, immunofluorescence, and immunoblotting, using the antibodies Tau-1, AT8, AT180, and PHF-1, which are sensitive to the phosphorylation of Ser202, Thr205, Thr231, Ser235, Ser396, and Ser404 and are used in the diagnosis of Alzheimer tau. In interphase cells, tau becomes phosphorylated to some extent, partly at these sites; most of the tau is associated with microtubules. In mitosis, the above Ser/Thr-Pro sites become almost completely phosphorylated, causing a pronounced shift in M(r) and an antibody reactivity similar to that of Alzheimer tau. Moreover, a substantial fraction of tau is found in the cytoplasm detached from microtubules. Autoradiographs of metabolically labeled Chinese hamster ovary cells in interphase and mitosis confirmed that tau protein is more highly phosphorylated during mitosis. The understanding of tau phosphorylation under physiological conditions might help elucidate possible mechanisms for the hyperphosphorylation in Alzheimer's disease.
Jean-jacques Dreifuss - One of the best experts on this subject based on the ideXlab platform.
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Oxytocin Excites Neurons Located in the Ventromedial Nucleus of the Guinea‐Pig Hypothalamus
Journal of neuroendocrinology, 1991Co-Authors: Kiyotoshi Inenaga, H. Karman, Hiroshi Yamashita, Eliane Tribollet, Mario Raggenbass, Jean-jacques DreifussAbstract:Abstract The area of the ventromedial nucleus of the hypothalamus in the guinea-pig was shown in Autoradiographs to contain high affinity binding sites for oxytocin. In order to ascertain whether these sites may represent neuronal receptors, single-cell extracellular recordings were obtained from ventromedial neurons in coronal slices of the hypothalamus of adult guinea-pigs. Oxytocin applied in the nanomolar range excited about half of the neurons tested; none were inhibited. The response to the peptide was reversible and concentration-dependent. It was exerted directly since it persisted under the condition of synaptic isolation. Moreover, the effect was specific since it could be mimicked by a selective oxytocin agonist and since vasopressin was usually at least 10-fold weaker than oxytocin. These findings suggest that the binding sites for oxytocin detected by light microscopic Autoradiography in the guinea-pig hypothalamic ventromedial nucleus represent functional receptors.
F Doring - One of the best experts on this subject based on the ideXlab platform.
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cell cycle dependent phosphorylation and microtubule binding of tau protein stably transfected into chinese hamster ovary cells
Molecular Biology of the Cell, 1995Co-Authors: Ute Preuss, F Doring, Susanne Illenberger, Eckhard MandelkowAbstract:Tau protein, a neuronal microtubule-associated protein, is phosphorylated in situ and hyperphosphorylated when aggregated into the paired helical filaments of Alzheimer's disease. To study the phosphorylation of tau protein in vivo, we have stably transfected htau40, the largest human tau isoform, into Chinese hamster ovary cells. The distribution and phosphorylation of tau was monitored by gel shift, Autoradiography, immunofluorescence, and immunoblotting, using the antibodies Tau-1, AT8, AT180, and PHF-1, which are sensitive to the phosphorylation of Ser202, Thr205, Thr231, Ser235, Ser396, and Ser404 and are used in the diagnosis of Alzheimer tau. In interphase cells, tau becomes phosphorylated to some extent, partly at these sites; most of the tau is associated with microtubules. In mitosis, the above Ser/Thr-Pro sites become almost completely phosphorylated, causing a pronounced shift in M(r) and an antibody reactivity similar to that of Alzheimer tau. Moreover, a substantial fraction of tau is found in the cytoplasm detached from microtubules. Autoradiographs of metabolically labeled Chinese hamster ovary cells in interphase and mitosis confirmed that tau protein is more highly phosphorylated during mitosis. The understanding of tau phosphorylation under physiological conditions might help elucidate possible mechanisms for the hyperphosphorylation in Alzheimer's disease.