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  • 1985-1989  (23)
  • Cell & Developmental Biology  (22)
  • Autoradiography
  • 1
    ISSN: 1432-0878
    Schlagwort(e): LH-cells ; Prolactin cells ; Immunocytochemistry ; Estrogen ; Autoradiography ; Guinea pig ; Hamster ; Gerbil
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Nuclear uptake and retention of3H-estradiol by luteinizing hormone (LH) and prolactin (PRL) cells was examined in three species of rodents (guinea pigs, hamsters and gerbils) using the combined techniques of immunocyto-chemistry and autoradiography. Castrated animals were injected with3H-estradiol and decapitated 1.5 h later. The pituitary glands were processed for thaw-mount autoradiography followed by conventional immunocytochemical staining for LH and PRL.3H-estradiol accumulated in more than 80% of the anterior pituitary cells in the gerbils, while only 33 and 22% of the cells accumulated3H-estradiol in the hamsters and guinea pigs, respectively. A varying percentage of immunoreactive LH and PRL cells in all three species were found also to contain binding sites for estradiol. Some LH and PRL cells in hamsters and guinea pigs and only some in PRL cells of gerbils were found to be devoid of grains. Quantitative analysis revealed that the number of grains per nucleus differed considerably from cell to cell. LH cells of guinea pigs accumulated much larger amounts of3H-estradiol than did the PRL cells, while the LH cells in the hamsters and gerbils accumulated only slightly more3H-estradiol than the PRL cells. These results confirm the previous observations in rats and baboons that demonstrated tremendous species differences in percentage of cells in the anterior pituitary gland that accumulated3H-estradiol. Also, these data suggest that there are functionally heterogeneous cell types among the LH and PRL cells in hamsters, guinea pigs and gerbils as has been previously demonstrated in rats and baboons.
    Materialart: Digitale Medien
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  • 2
    ISSN: 0886-1544
    Schlagwort(e): nuclear migration ; microtubules ; F-actin ; root hairs ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A prominent feature of tip growth in filamentous plant cells is that the nucleus often migrates in step with the tip as it extends. We have studied this long-recognized but unexplained relationship in root hairs of the legume Vicia hirsuta by a variety of microscopic techniques. Using rhodaminyl lysine phallotoxin, and antitubulin antibodies, root hairs are shown to contain axial bundles of F-actin and a complex microtubular system. To the basal side of the nucleus the microtubules are cortical and net axial but in the region between nucleus and tip the arrangement is more complicated. Electron microscopic thin sections demonstrate that internal bundles of microtubles exist in addition to the plasma membrane-associated kind. Computerized deblurring of through-focal series of antitubulin stained hairs clarifies the three-dimensional organization: bundles of endoplasmic microtubules progress from the nuclear region toward the apical dome where they can be seen to fountain out upon the cortex.The relationship between nucleus and tip can be uncoupled with antimicrotubule herbicides. Time lapse video microscopy shows that these agents cause the nucleus to migrate toward the base. This contrary migration can be inhibited by adding cytochalasin D, which fragments the F-actin bundles.It is concluded that microtubules connect the nucleus to the tip but that F-actin is involved in basipetal migration as is known to occur when symbiotic bacteria uncouple the nucleus from the tip.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 28 (1985), S. 171-182 
    ISSN: 0730-2312
    Schlagwort(e): insulin receptor ; tyrosine phosphorylation ; serine kinases ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Insulin causes rapid phosphorylation of the β subunit (Mr = 95,000) of its receptor in broken cell preparations. This occurs on tyrosine residues and is due to activation of a protein kinase which is contained in the receptor itself. In the intact cell, insulin also stimulates the phosphorylation of the receptor and other cellular proteins on serine and threonine residues. In an attempt to find a protein that might link the receptor tyrosine kinase to these serine/threonine phosphorylation reactions, we have studied the interaction of a partially purified preparation of insulin receptor with purified preparations of serine/threoine kinases known to phosphorylate glycogen synthase. No insulin-dependent phosphorylation was ob served when casein kinases I and II, phosphorylase kinase, or glycogen synthase kinase 3 was incubated in vitro with the insulin receptor. These kinases also failed to phosphorylate the receptor. By contrast, the insulin receptor kinase catalyzed the phosphorylation of the calmodulin-dependent kinase and addition of insulin in vitro resulted in a 40% increase in this phosphorylation. In the presence of calmodulin-dependent kinase and the insulin receptor kinase, insulin also stimulated the phosphorylation of calmodulin. Phosphoamino acid analysis showed an increase of phosphotyrosine content in both calmodulin and calmodulindependent protein kinase. These data suggest that the insulin receptor kinase may interact directly and specifically with the calmodulin-dependent kinase and calmodulin. Further studies will be required to determine if these phosphorylations modify the action of these regulatory proteins.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 39 (1989), S. 293-304 
    ISSN: 0730-2312
    Schlagwort(e): retinoic acid ; transcriptional control ; antiproliteratiory differentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Retinoids (structural and functional analogs of vitamin A) are potent antiproliferative agents whose mode of action is poorly understood. It has been suggested that the molecular events that underscore their action involve alterations in gene expression, but no gene has yet been shown to be directly regulated by these molecules. Several years ago, we found that retinoic acid caused an accumulation of the enzyme tissue transglutaminase in murine peritoneal macrophages and in human promyelocytic leukemia (HL-60) cells. We now report that this induction is caused by an increase in the mRNA for this enzyme. Retinoic acid is the only mediator of this induction, since its effects do not depend on the presence of serum proteins. The induction of tissue transglutaminase mRNA is not due to an increase in its stability but to an increase in the relative transcription rate of its gene. We present a model to correlate the retinoid induction of tissue transglutaminase with retinoid effects on cellular growth and differentiation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 214 (1986), S. 32-40 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Bone cells obtained by digestion of fetal mouse or chicken calvaria were tested for their ability to form or resorb bone in vitro. The isolated cells were precultured for 6 days and subsequently cocultured for 11 days with periosteum-free noninvaded fetal mouse long bone rudiments. Bone formation and resorption during coculture were evaluated by histology and 45Ca release from prelabeled bones. The calvarial origin of cells in cocultures was traced by labeling the cells with 3H-thymidine before coculture, followed by autoradiography.Many osteoblasts and osteoclasts as well as fibroblasts developed from mouse periosteal cells released late in the sequential digestion procedure and previously denoted as “osteoblastlike” (BL). No or few osteoblasts and osteoclasts but many fibroblasts developed from early released cell fractions that have previously been denoted as “osteoclastlike” (CL).Only osteoblasts and fibroblasts but not osteoclasts developed from chicken calvarial cell fractions. The osteoblasts developed primarily from cell fractions from the inner layer of the periosteum, previously denoted as “osteoblastlike” (OB). Cells obtained from the outer layer of the periosteum (PF) gave rise mainly to fibroblasts.These studies show that osteoblast and osteoclast precursor cells are maintained in monolayer cultures of periosteal cell fractions. However, sequential digestion of mouse calvaria does not lead to separation of the two types of bone cells. Rather, osteoclast and osteoblast precursors are released jointly, from the periosteal cell layers closest to the bone surface. In the chicken cell fractions osteoclast precursors are absent after preculture, resulting in a more homogeneous population of osteoblast and fibroblast but not osteoclast precursors.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 217 (1987), S. 328-338 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Architectural arrangement, ultrastructure, and selected histochemical properties of the newt (Notophthalmus viridescens) liver were examined. Although hematopoietic tissue (1-4 cells thick) invested the liver, direct vascular communication between this tissue and hepatic parenchyma was not observed. The liver was intensely positive when stained with Oil-red-O and periodic acid-Schiff reagent and connective tissue was limited to large vascular channels and the capsule. A distinctive polarity was observed in the hepatic vascular system when lobes were viewed in cross section. Dorsally, portal venules accompanied arterioles and branches of the biliary system, while tributaries of hepatic veins were observed ventrally. Following perfusion fixation, hepatocytes appeared as sheets of cells 1-5 cells thick; however, lobules as defined in adult mammalian liver were absent. Hepatocytes contained abundant smooth endoplasmic reticulum, mitochondria, electron-dense lysosomes, patches of granular endoplasmic reticulum, and lipid droplets. Continuous endothelial cells lined sinusoids and exhibited fenestrae organized into structures similar to sieve plates observed in mammalian liver. Variable numbers of melanin-containing macrophages and subendothelial macrophages were observed; however, Kupffer cells and lipid containing perisinusoidal fat-storing cells were not seen. Patterns of reaction product for glucose-6-phosphatase (G-6-Pase), glucose-6-phosphate dehydrogenase (G-6-PDH), and succinic dehydrogenase (SDH) were localized in the newt liver. All enzymes exhibited a uniform distribution pattern; however, small punctate regions of intensely positive G-6-PDH cells were noted within hepatic parenchyma. Cells comprising the hematopoietic tissue were intensely positive for G-6-Pase, G-6-PHD, and negative for SDH.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 220 (1988), S. 442-445 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: There exists a sexual dimorphism in the occurrence of meningiomas. Biochemical binding assays conducted on samples of meningiomas have indicated a high incidence of progesterone and androgen receptors in these tumors. However, similar studies have been very controversial as to the existence of estrogen receptors in these tumors. The present study was conducted to determine whether the normal leptomenix contains estrogen and androgen receptors in a primate model, namely the baboon. Three male and three female baboons were injected with either 3H-dihydrotestosterone (3H-DHT) or 3H-estradiol. One animal from each group received 3H-steroid + 100-fold unlabeled corresponding steroid to serve as control. One hour after injection of the 3H-steroids the animals were sacrificed. Their brains were removed and processed for autoradiography. Nuclear uptake and retention of 3H-DHT and/or one of its metabolites was found in 25-50% of the cells in pieces of the arachnoid adhering to the brain, cells of the glial membrane, cells in large fiber bundles, presumably oligodendroglia, and cells lining the Virchow-Robins spaces. No such localization was found with 3H-estradiol. This study provides the first anatomical evidence for the presence of androgen receptors in the normal leptomenix and glial cells of the baboon. These findings are discussed in relation to the possible clinical significance of the use of steroids to modulat the growth of meningiomas.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 221 (1988), S. 619-634 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The intrahepatic biliary system was studied in the rainbow trout (Salmo gairdneri), a teleost known to form liver neoplasms after exposure to various carcinogens. Normal adults (N = 25) were examined using light microscopic, enzyme histochemical, and transmission and scanning electron microscopic methods. In light micrographs, longitudinal arrays of hepatocytes appeared as double rows incompletely divided by elongated darkly stained cells. Electron micrographs showed tubules of five to nine pyramidally shaped hepatocytes with their apices directed toward a central biliary passageway and their bases directed toward sinusoids. Sequentially, beginning with hepatocytes, biliary passageways included canaliculi, preductules, ductules, and ducts. Canaliculi were short and joined transitional passageways (preductules) formed by junctional complexes between plasma membranes of hepatocytes and small, electron-dense cells with a high nuclear to cytoplasmic ratio. Ductules, completely lined by biliary epithelial cells, occupied central regions of hepatic tubules. Relatively elongated, ductular cells were intimately associated with surrounding hepatocytes, separated from them by only a thin extracellular space devoid of a basal lamina. Epithelium of bile ducts included cuboidal through mucus-laden columnar cells, surrounded by basal lamina and, in larger ducts, by fibroblasts, smooth muscle cells, and a capillary plexus. Bile ducts and hepatic arterioles, but not venules, were distributed together. The ultrastructure of biliary epithelium, periductular, and periductal cells is presented.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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  • 9
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The sex differential in coronary heart disease is well documented but poorly understood. Previous studies have demonstrated receptors for dihydrotestosterone (DHT) in the myocardium and smooth muscle cells of arteries from a number of species. In this autoradiographic study, we further investigated and characterized the in vivo uptake and retention of the androgen binding in the male baboon. Adult castrated male baboons were injected with 1 μg/kg bw 3H-testosterone; 1 hr after the injection, the animals were rapidly exsanguinated while under anesthesia. The heart and arterial system were removed and processed for autoradiography. As a negative control, one animal received both 3H-testosterone and 100-fold unlabeled testosterone. For positive controls, the pituitary gland, prostate, seminal vesicles, and other tissues were also removed and processed for autoradiography. In contrast to our previous finding with 3H-DHT, no nuclear uptake and retention of 3H-steroid was found in any of the cells in either the heart or the arterial system. In the positive control tissues, pituitary gland, prostate, seminal vesicles, and others, a very distinct nuclear uptake and retention of 3H-steroid was observed, which was completely inhibited by the simultaneous injection of 100-fold unlabeled testosterone. In the binding study, Scatchard analysis of the cytosol prepared from a 17-year-old female baboon demonstrated levels of androgen receptor (as determined by the use of radiolabeled R1881) comparable to that found in young adults. The results of these studies suggest that, in contrast to the generally accepted hypotheses, (1) circulating DHT, not testosterone, is the androgenic hormone that interacts with the cardiovascular tissue of the baboon and (2) there are separate receptors for testosterone and DHT in different tissues rather than a single receptor capable of binding both steroids.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 214 (1986), S. 418-423 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Osteoclast progenitors are seeded via the blood stream in the mesenchyme surrounding embryonic long bone models long before the appearance of multinucleated osteoclasts. The proliferation and differentiation of these progenitors in embryonic mouse metatarsal bones was studied with acid phosphatase (AcP) histochemistry and 3H-thymidine autoradiography.In vivo, tartrate-resistant, acid phosphatase-positive, mononuclear cells appear in the periosteum (AcPP-P cells) at the age of 17 days (after conception). On day 18, AcP-positive, multinucleated osteoclasts invade the bone rudiment and start resorbing the calcified cartilage matrix, resulting in the formation of the marrow cavity.The kinetics of osteoclast formation in vitro was studied in metatarsal bones of embryonic mice of different ages cultured in the continuous presence of 3H-thymi-dine. In young bones (15 days), mainly proliferating, 3H-thymidine-incorporating progenitors gave rise to AcPP-P cell and osteoclast formation. In older bones (16 and 17 days) osteoclasts were progressively more derived from postmitotic, unlabeled precursors. Irradiation of the metatarsal bones with a radiation dose of 5.0 Gy prior to culture resulted in a selective elimination of the proliferating progenitors, whereas the contribution of postmitotic precursors in AcPP-P cell and osteoclast formation remained unchanged. The results demonstrate that in the periosteum of embryonic metatarsal bones a shift occurs from a population composed of proliferating osteoclast progenitors (15 days) to a population composed of postmitotic precursors (17 days) before multinucleated osteoclasts are formed (18 days). Obviously, postmitotic AcP-negative precursors, already present in 16-day-old bones, differentiate into precursors characterized by tartrate-resistant AcP activity, the preosteoclasts (17 days), which in their turn fuse into osteoclasts.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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