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  • 1990-1994  (1.609)
  • 1975-1979  (862)
  • 1890-1899
  • 1992  (1.609)
  • 1978  (862)
  • Analytical Chemistry and Spectroscopy  (2.256)
  • Ultrastructure  (215)
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  • 1990-1994  (1.609)
  • 1975-1979  (862)
  • 1890-1899
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    TNF induces cytoplasmic vesicles in actinomycin D-treated K 562 cells (1992)
    Springer
    Annals of hematology 65 (1992), S. 50-52 
    Details
    ISSN: 1432-0584
    Schlagwort(e): TNF ; K 562 ; Leukemia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report here that tumor necrosis factor alpha (TNF) induces peculiar cytoplasmic vesicles in the human erythromyeloid leukemia cell line K 562, sensitized to the cytotoxic action of TNF by a treatment with the inhibitor of transcription actinomycin D. These vesicles are well delineated ultrastructurally. The formation of these vesicles is characteristic for the combination of actinomycin D with TNF and precedes the changes of apoptosis and cellular disintegration. These vesicles correspond to an intermediate step in the cytotoxicity caused by TNF and may indicate that reactive metabolites are involved in the mechanism of action of TNF.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01715127
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  • 2
    Digitale Medien
    Digitale Medien
    In vitro formation of mineralized nodules by periodontal ligament cells from the rat (1992)
    Springer
    Calcified tissue international 50 (1992), S. 459-467 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Periodontal ligament fibroblast ; Mineralized nodule ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The purposes of this study were to determine whether periodontal ligament (PDL) cells are capable of producing mineralized nodules in vitro and to analyze ultrastructural features of the nodules. Rat PDL cells were obtained from coagulum in the socket at 2 days after tooth extraction and cultured at confluence in standard medium containing Dulbecco's Modified Eagle's Medium supplemented with 10% FBS and antibiotics. To test mineralized nodule formation, cells were further cultured for an additional 3 weeks in the standard medium containing (1) ascorbic acid (50 μg/ml) and sodium β-glycerophosphate (10 mM), (2) ascorbic acid, sodium β-glycerophosphate, and dexamethasone (5 μM), or (3) ascorbic acid alone. Cells were then fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4, and prepared for light and electron microscopy. Threedimensional nodules containing mineralized matrices were formed only when the cells were cultured in the presence of ascorbic acid and dexamethasone. They were composed of multilayered fibroblasts (up to 13 layers), and highly organized collagen fibrils with 64 nm cross-banding patterns between the cell layers. The fibroblasts in the nodules exhibited an elongated shape with a high degree of cytoplasmic polarity throughout the nodule, and have the morphological features of PDL fibroblasts as seen in vivo. Mineral deposition with needle-like crystals was initiated on collagen fibrils located in intercellular spaces of the upper cell layers and became increasingly heavier towards the bottom half of the nodules. X-ray microanalysis and electron diffraction analysis confirmed that mineral deposition contained calcium and phosphate in the form of immature hydroxyapatite. These nodules contained neither osteoblasts nor osteocytes, and have their own morphological organization and characteristics which differ from those formed by bone cells in culture. Therefore, these data suggest that PDL cells are capable of forming mineralized tissue in vitro with the morphological characteristics different from bone mineralized nodules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296778
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  • 3
    Digitale Medien
    Digitale Medien
    Ultrastructure and cytochemistry of circulating erythrocytes during the annual cycle of Rana esculenta L. (1992)
    Springer
    Comparative clinical pathology 2 (1992), S. 166-169 
    Details
    ISSN: 1433-2981
    Schlagwort(e): Erythrocytes ; Flow cytometry ; Frog hibernation ; Image analysis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Morphometrical (image analysis of cell and nuclear shape factor), morphological (electron microscopy) and cytochemical (acridine orange fluoro-chromasia and propidium iodide-DNA flow cytometry) features of circulating red blood cells were investigated during two periods of the annual cycle of Rana esculenta: the active phase (July) and the underground hibernating phase (January). The results showed that the hibernating phase is marked by more homogeneity of the red cells, both at nuclear (strongly condensed chromatin) and cytoplasmic level (loss of intact organelles and acridine orange fluorochromasia). The almost complete disappearance of the ‘immature’ erythrocytes from the circulation, during the hibernating phase, should be related to a decrease of haemopoietic activity and to an increase of life span accompanied by uncommon storage in different organs both at vascular and intracellular level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00426172
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  • 4
    Digitale Medien
    Digitale Medien
    Eccrine gland involvement in Krabbe's disease (1992)
    Springer
    Virchows Archiv 421 (1992), S. 351-354 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Krabbe's disease ; Eccrine gland storage ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Lysosomal storage inclusions were observed in skin eccrine gland secretory and myoepithelial cells in three cases of Krabbe's disease. In addition to storage there were numerous degenerative changes, occasionally resulting in cell necrosis. These findings suggest a generalized nature of the storage process in this lysosomal enzymopathy and point to high galactocerebroside turnover in eccrine gland epithelium. This knowledge may be of value in the biopsy diagnosis of Krabbe's disease.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01660983
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  • 5
    Digitale Medien
    Digitale Medien
    Multicystic mesothelial proliferation (1992)
    Springer
    Virchows Archiv 421 (1992), S. 379-385 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Multicystic mesothelial proliferation ; Immunohistochemistry ; Ultrastructure ; DNA analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We investigated the clinicopathological findings in five cases of multicystic mesothelial proliferation (MMP). All masses consisted of multiloculated cysts attached to pelvic organs and sometimes growing into the upper abdominal cavity. The cystic spaces were lined by flattened or cuboidal cells. The stroma showed fibrosis, oedema and chronic inflammation. Immunohistochemistry revealed strong positive staining for cytokeratin and epithelial membrane antigen, and focal positivity for vimentin and carcinoembryonic antigen. The endothelial markers were negative. Electron microscopy showed abundant surface microvilli and well-developed basal lamina. DNA analysis identified euploid cell populations in all cases. All but one case had a previous history of abdominal surgery. Despite the worrying appearance the clinical outcome was favourable in all cases; there was one recurrence. Clinical and pathological data support the hypothesis that MMP represent a reactive mesothelial proliferation and not a neoplastic process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606909
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  • 6
    Digitale Medien
    Digitale Medien
    Immunopathological study of eosinophils in eosinophilic granuloma of bone: Evidence for release of three cationic proteins and subsequent uptake in macrophages (1992)
    Springer
    Virchows Archiv 421 (1992), S. 255-261 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Eosinophilic granuloma of bone ; Eosinophil granule proteins ; Immunostaining ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Eosinophils from two patients with eosinophilic granuloma of bone (EGB) were studied by combined immunohistochemical and immuno-ultrastructural methods with antibodies directed against three eosinophil granule proteins: major basic protein, eosinophil cationic protein, and eosinophil peroxidase. Immunohistostaining showed the presence and distribution of large numbers of eosinophils in the granuloma. Immuno-ultrastructural methods showed alterations of eosinophil fine structure associated with some steps in the release of granule proteins. No granule extrusion was seen, but rather cationic proteins diffused within cytoplasmic tubulo-vesicular structures. Furthermore, the three granule proteins were found within phagolysosomes of surrounding macrophages, suggesting an interaction between eosinophils and phagocytic cells at the destructive stage of EGB.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01611183
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  • 7
    Digitale Medien
    Digitale Medien
    Small cell carcinoma of the ovary: An immunohistochemical and ultrastructural study with a review of the literature (1992)
    Springer
    Virchows Archiv 421 (1992), S. 263-270 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Small cell carcinoma ; Ovary ; Immunohistochemistry ; Ultrastructure ; Literature review
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This is an immunohistochemical and ultrastructural study of two small cell carcinomas of the ovary with a review of the literature. These cases showed a dimorphic population of small and large cells sharply demarcated from each other. Cytokeratin 18 and vimentin were mainly expressed in the large tumour cells, some of which also stained for alpha-smooth muscle actin. Periodic-acid-Schiff-positive, alpha-1-antitrypsin-positive hyaline globules were present in one case. Ultrastructural findings included filamentous nucleolonema as well as evidence of smooth muscle differentiation. Some of these observations have not been previously reported. Certain of the above features seem to support a germ cell origin of small cell carcinoma, but they cannot be considered specific for germ cell neoplasms. Thus, small cell carcinoma of the ovary cannot be classified into one of the known categories of ovarian tumours at the present time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01611184
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  • 8
    Digitale Medien
    Digitale Medien
    Immunohistochemical and ultrastructural studies of intraluminal crystalloids in human prostatic carcinomas (1992)
    Springer
    Virchows Archiv 421 (1992), S. 421-425 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Crystalloid ; Prostatic cancer ; Epithelial membrane antigen ; Phosphotungstic acid hematoxylin stain ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Intraluminal crystalloids (ICr) observed in 19 cases of incidental or invasive human prostatic carcinoma (PCa) and in a case of benign prostatic hyperplasia were examined extensively by immunohistochemistry and electron microscopy. They were brilliantly eosinophilic with haematoxylin and eosin, manifesting needlelike, triangular, rectangular, hexagonal and irregular lump-like in shape. They were strongly positive, dark blue, with phosphotungstic acid -haematoxylin (PTAH) stain in all cases examined. Among the human antibodies tested, epithelial membrane antigen (EMA) gave specifically positive immunostainability with ICr in all cases. Annual ring-like lamellar or concentric structures were detected by electron microscopy. Positive staining of ICr with PTAH and anti-EMA antibody is very useful as a diagnostic marker for PCa in human prostatic tissues.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606915
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  • 9
    Digitale Medien
    Digitale Medien
    Ultrastructural observations on cytotoxic effector cells infiltrating pancreatic islets of low-dose streptozocin treated mice (1992)
    Springer
    Virchows Archiv 420 (1992), S. 5-10 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Islets of Langerhans ; Monocytic phagocytes ; Streptozocin ; Type 1 diabetes ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The aim of this study was to observe the ultrastructural events, during the onset of diabetes mellitus in the low-dose streptozocin (LDS)-treated mouse model with emphasis on the infiltrating elements. Forty male C57 BL/6J mice were given 40 mg/streptozocin on 5 consecutive days and killed 5, 6, 7, 8, 9, 10, 15, and 18 days after the first injection. Results demonstrated that islet infiltration occurring in LDS-treated mice is characterized by a very early pre-infiltration state in which mononuclear phagocytes in islet capillary vessels were considerably increased in number. A new histopathological time sequence for the early insulitis is described, in which attraction of blood mononuclear phagocytes into the islet capillary lumen is the first step. During the successive stage, occurring on days 6–8 we observed that mononuclear phagocytes migrate through capillary and venule walls into the islet parenchyma, where they differentiate into tissue macrophages. It was only later (step 3) that these macrophages acquired novel properties, typical of their “activated state” and started to phagocytose islet beta-cell debris. These data suggest that during the pre-infiltration and early insulitis the mononuclear phagocyte system plays a key role in the onset of LDS diabetes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01605977
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  • 10
    Digitale Medien
    Digitale Medien
    Malignant rhabdoid tumour of the uterus: an immunohistochemical and ultrastructural study (1992)
    Springer
    Virchows Archiv 420 (1992), S. 459-462 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Malignant rhabdoid tumour ; Uterus ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Malignant rhabdoid tumours (MRTs) are highly aggressive neoplasms which most frequently occur in the kidney of young children. Several cases of primary MRT occurring in extra-renal sites have been reported, particularly in the soft tissues. We report a case of primary MRT of the uterus, a very rare site for this neoplasm, with morphological, immunohistochemical and ultrastructural features corresponding to restrictive morphological criteria for MRT. The possible differential diagnoses were considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600519
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  • 11
    Digitale Medien
    Digitale Medien
    Effects of combined renovascular hypertension and diabetes mellitus on myocardial cells, non-vascular interstitium and capillaries: a stereological study on rat hearts (1992)
    Springer
    Virchows Archiv 420 (1992), S. 499-506 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Diabetes mellitus ; Renovascular hypertension ; Myocardium ; Stereology ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of combined renovascular hypertension and diabetes mellitus on the rat heart were investigated in order to detect possible synergistic effects of the two conditions. Hypertensive diabetic and hypertensive non-diabetic animals were compared to diabetic and non-diabetic controls. Hypertension was established for 12 weeks by a surgical stenosis of the left renal artery; diabetes mellitus was maintained for 8 weeks by a single intraperitoneal injection of 60 mg/kg streptozotocin. Light microscopic stereology did not reveal significant divergences between diabetic hypertensives and non-diabetic hypertensives. Hypertension induced a focal perivascular and interstitial fibrosis with increased volume densities of non-vascular interstitium and fibrosis (P〈0.001). Capillary density (QA) was decreased in transverse sections (P〈0.01) and increased in longitudinal sections (P〈0.01). This indicates a three-dimensional remodelling of the capillary bed with an increased number of obliquely running capillaries. At least the length density (LV) of capillaries (mm/mm3) tends to be normalized in long-term renovascular hypertension. At the ultrastructural level, a synergism of hypertension and diabetes mellitus was observed: the volume ratio of mitochondria to myofibrils was significantly decreased in hypertensive diabetics, but not in non-diabetic hypertensives or in diabetics. This may enhance the risk of cardiac deterioration. We conclude that the primary target of the synergistic damage in hypertensive diabetic heart muscle disease is the myocardial cell and not the cardiac interstitium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600254
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  • 12
    Digitale Medien
    Digitale Medien
    Cytoskeletal filaments in the smooth muscle cells of uterine leiomyomata and myometrium: An ultrastructural and immunohistochemical analysis (1992)
    Springer
    Virchows Archiv 420 (1992), S. 51-58 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Leiomyoma ; Myometrium ; Cytoskeleton ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The filamentous components of the cytoskeleton in smooth muscle cells of leiomyomata and normal myometrium were studied by immunohistochemistry and electron microscopy. Fourteen patients hysterectomised for non-malignant disease provided leiomyomata of conventional histological type and histologically normal myometrium: four samples of fetal myometrium were studied by immunohistochemistry alone. All samples of leiomyoma and myometrium were strongly positive for α-smooth muscle actin and desmin, the latter often as paranuclear columns or granules. Vimentin was also stained in most samples but less intensely, while cytokeratin stained in about half the samples with an intensity comparable to that of vimentin. By electron microscopy, myofilaments with focal densities were abundant in both normal myometrium and leiomyomata. Intermediate filaments corresponding to the desmin and vimentin demonstrated by immunohistochemistry were also recognised in a variety of architectural arrangements. At one extreme, comparatively small numbers of filaments were loosely distributed around membranous organelles; at the other, filaments formed conspicuous aggregates, largely excluding other organelles and corresponding to the paranuclear granules seen by immunohistochemistry. A comparison of these findings with those of the literature and comments on the possible significance and origin of these aggregates are provided.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01605984
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  • 13
    Digitale Medien
    Digitale Medien
    Granular cell tumour of the breast (1992)
    Springer
    Virchows Archiv 420 (1992), S. 219-226 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Breast ; Granular cell tumour ; Mammography ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Eight cases of benign granular cell tumour of the breast are reported. Seven patients were women and one was male. The age at the time of the excision ranged from 17 to 73 (average 40.1) years. All tumours were positive for S-100 protein and negative for keratin, myoglobin and gross cystic disease fluid protein. In two cases ultrastructural studies revealed findings identical to those in the previously reported cases of granular cell tumours. None of these cases were diagnosed preoperatively. In six cases the clinical and mammographic findings, and in one case the frozen section, led to an erroneous diagnosis of malignancy. The clinico-pathological features of the cases are delineated in order to draw attention to a benign condition which closely simulates malignancy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600274
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  • 14
    Digitale Medien
    Digitale Medien
    Ultrastructural anomalies in the fetal small intestine indicate that fetal swallowing is important for normal development: an experimental study (1992)
    Springer
    Virchows Archiv 420 (1992), S. 305-312 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Fetus ; Small intestine ; Ultrastructure ; Malnutrition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fetal swallowing is established early in development and if fetal ingestion is prevented, the gastrointestinal (GI) tract fails to grow normally. In this article we describe the ultrastructural features of GI tissues developing in the absence of swallowing, in the fetal sheep. We have noted a number of defects in enterocyte morphology. These include abnormal or absence of microvilli, inappropriate cell extrusion, glycogen accumulation and altered lysosomal morphology. Many of these changes resemble those seen in malnourished infants. It is possible that fetal ingestion provides a significant source of nutrients, ensuring adequate GI tract growth in utero, in addition to specific growth factors which may be present in ingested fluid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600209
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  • 15
    Digitale Medien
    Digitale Medien
    A histopathological and ultrastructural study of eccrine porocarcinoma with special reference to its subtypes (1992)
    Springer
    Virchows Archiv 420 (1992), S. 395-401 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Eccrine porocarcinoma ; Ultrastructure ; Giant cell ; Elastic fibre ; Globular filamentous body
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Five cases of eccrine porocarcinoma were studied by light and electron microscopy. Histopathologically, these could be classified into two types; the common and the giant cell type. The common type was characterized by almost uniform medium-sized cuboidal tumour cells and a formation of well-developed intracytoplasmic lumina. A broad diversity of histopathological and ultrastructural features was seen in these tumours. The tumours of the giant cell type consisted of mononu-clear polygonal cells and bizarre giant cells. This type was considered to be an undifferentiated form of porocarcinoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600510
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  • 16
    Digitale Medien
    Digitale Medien
    Ultrastructural identification of neurofibrillary tangles in the spinal cords in Guamanian amyotrophic lateral sclerosis and parkinsonism-dementia complex on Guam (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 277-282 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Spinal cord neurofibrillary tangles ; Parkinsonism-dementia complex on Guam ; Guamanian amyotrophic lateral sclerosis ; Ultrastructure ; Immunoelectron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The immunohistochemical and ultrastructural characteristics of spinal cord neurofibrillary tangles (NFTs) were examined in Guamanian amyotrophic lateral sclerosis and in parkinisonism-dementia complex on Guam. The spinal cord NFTs reacted with antibodies to tau protein (tau-2), ubiqitin and paired helical filaments (PHFs). Ultrastructurally, the components of the NFTs were seen as randomly arranged fibrils which were often associated with osmiophilic granules; small bundle-like arrangements were also occasionally observed. Individual NFT fibrils appeared as straight fibrils with a diameter of approximately 15 nm and constricted fibrils with a periodicity of approximately 80 nm. Ultrastructural microscopic examination of specimens stained by the modified Bielschowsky method and with the antibodies revealed silver particles and the products of the tau, ubiquitin and PHF immunoreactions on the NFT fibrils. This is the first demonstration of the fine structure of the spinal cord NFTs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296790
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  • 17
    Digitale Medien
    Digitale Medien
    Immunocytochemical and ultrastructural studies of eosinophilic granular bodies in astrocytic tumors (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 408-414 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Eosinophilic granular body ; Astrocytoma ; Ultrastructure ; Immunocytochemistry ; αB-crystallin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Eosinophilic granular bodies (EGBs) are studied immunocytochemically and ultrastructurally in a case of low-grade and a case of high-grade astrocytoma. EGBs are recognized as brightly eosinophilic round bodies of variable size in hematoxylin and eosin-stained sections. Immunocytochemically some EGBs are positive for antibodies raised against αB-crystallin, ubiquitin and glial fibrillary acidic protein with the staining patterns for each being different from one another. Ultrastructurally EGBs consist of membrane-bound round body of various diameter ranging from 50 nm to 20 μm. Small EGBs contain electron-dense homogeneous material with occasional myelin figures, while large EGBs contain small EGB-like structures within electron-dense homogeneous material or loose granular profiles. Our studies demonstrate (1) ultrastructural variety of EGB; (2) and αB-crystallin epitope in EGB; and (3) the presence of EGB in high-grade as well as low-grade astrocytoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00713533
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  • 18
    Digitale Medien
    Digitale Medien
    Ultrastructural studies of the cells forming amyloid in the cortical vessel wall in Alzheimer's disease (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 117-127 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer disease ; Amyloid angiopathy ; Pericytes ; Microglia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural studies of serial sections of the vessels with amyloid deposits in the brain cortex of patients with Alzheimer's disease showed that cells in the position of pericytes — perivascular cells - and perivascular microglial cells are producers of amyloid fibrils in the vascular wall. Three types of changes from normal are distinguishable in the vessel wall: (1) semicircular or circular thickening of vascular wall containing a large amount of amorphous material and various number of amyloid fibrils, (2) tuberous amyloid deposits containing both amorphous material and amyloid fibrils, some of the fibrils being arranged in strata and others arranged radially, and (3) amyloid star composed of a predominantly radial arrangement of bundles of amyloid fibrils and a less prominent amorphous component. A mixture of amorphous material and amyloid fibrils is present in cell membrane envaginations of perivascular cells, and occasionally perivascular microglial cells. Bundles of amyloid fibrils are found in altered cisternae of the endoplasmic reticulum and in the channels confluent with the infoldings of the plasma membrane of perivascular microglial cells. The amyloid deposition in the wall of the vessel causes degeneration of endothelial cells and the reduction of, and in some vessels obliteration of, the vessel lumen. In areas affected by amyloid angiopathy, extensive degeneration both of the neuropil and of neurons was observed. These changes were accompanied by astrogliosis. This study demonstrates similarities in amyloid formation in amyloid angiopathy and in β-amyloid plaques in the neuropil and suggests that cells of the mononuclear phagocyte system of the brain (perivascular cells and perivascular microglia) are engaged in amyloid fibril formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00311383
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  • 19
    Digitale Medien
    Digitale Medien
    Ultrastructural and immunohistochemical studies on ballooned cortical neurons in Creutzfeldt-Jakob disease: expression of αB-crystallin, ubiquitin and stress-response protein 27 (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 443-448 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Creutzfeldt-Jakob disease ; Ballooned neurons ; Ultrastructure ; αB-Crystallin ; Stress-response proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This report concerns ultrastructural and immunohistochemical studies on ballooned neurons of ten patients with Creutzfeldt-Jakob disease (CJD). While abundant ballooned neurons and severe white matter degeneration was seen in six Japanese cases, only occasional ballooned neurons and no white matter degeneration was observed in four cases from the files of Montefiore Medical Center. Ultrastructurally, the ballooned neurons contained granule-coated fibrils of 25 to 40 nm in width and 10-nm neurofilaments. The immunohistochemical studies revealed that most ballooned neurons expressed αB-crystallin, with deposits of reaction products observed in the cytoplasm. A similar intracellular staining pattern was also seen with the antibody to phosphorylated neurofilament proteins (pNFP). Although the proportion of stained ballooned neurons was less, a positive reaction was also observed with antibodies against ubiquitin, stress-response protein 27 (srp 27) and synptophysin, but not with an antibody to srp 72. Our findings suggest that expression of pNFP and synaptophysin by ballooned neurons may reflect axonal impairment and that the presence of αB-crystallin, srp 27 and ubiquitin may be related to the degenerative processes that neurons undergo in CJD.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227673
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  • 20
    Digitale Medien
    Digitale Medien
    Colloid cysts of the third ventricle: ultrastructural features are compatible with endodermal derivation (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 605-612 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Colloid cyst ; Endoderm ; Respiratory epithelium ; Third ventricle ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The histogenesis of colloid cyst of the third ventricle remains unsettled. Ultrastructural and immunohistochemical analyses have suggested the following possible origins: (a) neuroepithelium, including paraphysis, ependyma, choroid plexus and tela chorioidea; and (b) endoderm, including respiratory and enteric epithelium. This report describes the ultrastructural features of the lining epithelium in four cases of colloid cyst. Six distinct cell types were recognized: (1) ciliated cells with occasional abnormal cilia; (2) non-ciliated cells with microvilli coated with granulofibrillary material; (3) goblet cells showing discharge of secretory granules; (4) basal cells with prominent tonofilaments and desmosomes; (5) basal-located cells with elongated electron-lucent cytoplasm and scattered membrane-bound dense-core granules (150–350 nm); and (6) small undifferentiated cells with scanty organelles. Junctional complexes were present in the former four cell types but absent in the latter two. The types of epithelial cells and their topographic distribution within the epithelium are both very similar to those of normal respiratory epithelium and to the lining epithelium of intraspinal bronchogenic cyst. The observations made in the present study are compatible with the hypothesis that colloid cysts of the third ventricle originate from the endoderm, most likely the respiratory epithelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00299409
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  • 21
    Digitale Medien
    Digitale Medien
    Silver staining of the postacrosomal sheath during human spermiogenesis (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 271-274 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Man ; Spermiogenesis ; Postacrosomal ; sheath ; Silver staining ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Applying the silver staining technique, it could be shown that in the early phase of spermiogenesis a layer of argyrophilic material accumulated at the base of the acrosomal vesicle and at the outer side of the nuclear envelope opposite that region, and, later, at the inner side of the plasma membrane near the base of the acrosomal vesicle. During further development of the postacrosomal region of the spermatozoon head, the argyrophilic material associated with the plasmalemma grew caudally to form the postacrosomal dense lamina, while the argyrophilic material associated with the nuclear envelope, staying the same size, shifted to the caudal end of the postacrosomal dense lamina to form the postnuclear band.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00211825
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  • 22
    Digitale Medien
    Digitale Medien
    Ultrastructural features of spongiform encephalopathy transmitted to mice from three species of bovidae (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 559-569 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Neuronal autophagy ; Bovine spongiform encephalopathy ; Lysosomes ; Ultrastructure ; Vactiolation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural neuropathology of mice experimentally inoculated with brain tissue of nyala (Tragelaphus angasi; subfamily Bovinae), or kudu (Tragelaphus strepsiceros; subfamily Bovinae) affected with spongiform encephalopathy was compared with that of mice inoculated with brain tissue from cows (Bos taurus: subfamily Bovinae) with bovine spongiform encephalopathy (BSE). As fresh brain tissue was not available for nyala or kudu, formalin-fixed tissues were used for transmission from these species. The effect of formalin fixation was compared with that of fresh brain in mice inoculated with fixed and unfixed brain tissue from cows with BSE. The nature and distribution of the pathological changes were similar irrespective of the source of inoculum or whether the inoculum was from fresh or previously fixed tissue. Vacuolation caused by loss of organelles and swelling was present in dendrites and axon terminals. Vacuoles were also seen as double-membrane-bound and single-membrane-bound structures within myelinated fibres, axon terminals and dendrites. Vacuoles are considered to have more than one morphogenesis but the structure of vacuoles in this study was nevertheless similar to previous descriptions of spongiform change in naturally occurring and experimental scrapie, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome and kuru. Other features of the ultrastural pathology of the transmissible spongiform encephalopathies including dystrophic neurites and scrapie-associated particles or tubulovesicular bodies were also found in this study. Neuronal autophagy was a conspicuous finding. It is suggested that excess prion protein (PrP) accumulation, or accumulation of the scrapie-associated protease-resistant isoform of PrP, may lead to localised sequestration and phagocytosis of neuronal cytoplasm and ultimately to neuronal loss.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00304476
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  • 23
    Digitale Medien
    Digitale Medien
    Placental iron transfer regulation in the haemophagous region of the badger placenta: ultrastructural localization of ferritin in trophoblast and endothelial cells (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 175-179 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Badger-placenta ; Ultrastructure ; Ferritin ; Iron transfer regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The haemophagous region of the badger (Meles meles L.) placenta is involved in iron transfer, and maternal erythrocytes are the only source of iron for the fetus. This ultrastructural study provides morphological evidence of placental ferritin iron storage intervening if haem-iron uptake exceeds fetal needs. Such placental ferritin is assumed to play an active role in iron transfer regulation. In this paper we demonstrate that this regulatory process of iron transfer by storage in placental ferritin occurs on at least two levels: the cytotrophoblast and the fetal endothelium. The latter could then act as a final monitor in the transfer of iron into the fetal circulation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185919
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  • 24
    Digitale Medien
    Digitale Medien
    “Reducing body”-like inclusions in skeletal muscle in childhood-onset acid maltase deficiency (1992)
    Springer
    Acta neuropathologica 85 (1992), S. 111-115 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Muscle ; Ultrastructure ; Lysosome ; Metabolic disorder ; Glycogenosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Unusual inclusions with some of the features of “reducing bodies” were encountered in the skeletal muscle biopsy of a 2.5-year-old boy with childhoodonset acid maltase deficiency. The biopsy revealed a vacuolar myopathy with lysosomal storage of glycogen and eosinophilic refractile inclusions in myofibers, which appeared dark blue with the menadione-nitroblue tetrazolium reaction. The significance of the association of inclusions with reducing properties in the setting of acid maltase deficiency is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00304641
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  • 25
    Digitale Medien
    Digitale Medien
    Caudate nucleus pathology in Parkinson's disease: ultrastructural and biochemical findings in biopsy material (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 352-360 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Parkinson's disease ; Ultrastructure ; Catecholomines ; Trans-synaptic degeneration ; Axonal dystrophy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural and biochemical properties of caudate nucleus (CN) biopsies in two patients with advanced Parkinson's disease (PD) were compared with three CN specimens removed during surgery for intracranial tumors. An additional two specimens from neurologically intact patients (59 and 86 years old) were removed during autopsy (performed 3 and 4 h post mortem, respectively) for electron microscopic studies. Dopamine levels in PD were reduced to less than 15% of control values. Both PD patients showed frequent dystrophic neurites and transsynaptic degeneration of neurons and neuritic processes. These changes were not found in CN from the four control individuals. Only a few dystrophic neurites were noticed in one 67-year-old control patient. The development of neuroaxonal dystrophy in CN is consistent with a dying-back process, probably accompanying abnormalities of axonal transport in PD. Transsynaptic degeneration of neurons in CN very likely represents a morphological marker of disease severity. The occurrence of this change may account for the poor clinical response of patients with advanced PD to intracerebral implantation of dopaminergic tissues.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00713525
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  • 26
    Digitale Medien
    Digitale Medien
    Novel eosinophilic inclusion in astrocytes (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 659-663 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Eosinophilic inclusion ; Neuroglia ; Astrocyte ; Aicardi's syndrome ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Intracytoplasmic and brightly eosinophilic inclusions within neuroglias are reported in a patient with Aicardi's syndrome. Most inclusion-bearing neuroglias were protoplasmic astrocytes in the cerebral cortex. Compared with similar eosinophilic and intracytoplasmic inclusions in other studies using both light and electron microscopy, the inclusions in this report are regarded as being novel and not previously described. Ultrastructually, the inclusions were composed of electron-dense granules and amorphous substances, and were not surrounded by a limiting membrane. They were numerous in the cerebral cortex, especially in part of the microgyrus, but absent in the deep cerebral white matter, subcortical nuclei, brain stem and the cerebellum. Therefore, they may be closely associated with brain malformation and congenital astrocytic dysfunction. They also suggested a functional difference in protoplasmic astrocytes themselves, according to the differentiation of related gray matter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00299417
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  • 27
    Digitale Medien
    Digitale Medien
    Morphological observations on the Harderian gland of the North American opossum (Didelphis virginiana) (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 145-152 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Harderian gland ; Tubuloalveolar endpieces ; Serous endpieces ; Ultrastructure ; Opossum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Harderian gland of the North American opossum (Didelphis virginiana) is large and well developed, despite the absence of a nictitating membrane in the adult of this species. The elongate glands are surrounded by a delicate connective tissue capsule from which thin septae extend, subdividing the gland into numerous lobules. The secretory units of the opossum Harderian gland are drained by a well defined but not extensive intralobular and interlobular duct system. Most of the secretory end pieces consist of tubuloalveolar units with widely dilated lumina filled with secretory product. Numerous intact lipid vesicles suspended within an amorphous material constitute the luminal contents. Cells lining the tubuloalveolar secretory endpieces are usually columnar in shape, and characterized by numerous lipid-containing secretory vesicles and aggregations of polytubular complexes 40–60 nm in diameter. In addition, these cells contain numerous large irregularly shaped mitochondria, whose matrix is of considerable electron density. Intralobular and interlobular ducts are lined by electron-lucent epithelial cells that lack both the lipid-containing vesicles and the large mitochondria, although typical smaller mitochondria are found scattered within the cytoplasm. Both secretory endpieces and ductal elements are invested by an abundance of myoepithelial cells. A second, smaller serous type of secretory unit may occur near the centre of some Harderian gland lobules. In these units secretory tubules and acini are compactly arranged surrounding a narrow lumen. Serous cells are pyramidal in shape and the cytoplasm is characterized by numerous electron-dense secretory granules and scattered profiles of rough endoplasmic reticulum. Basolateral cell membranes show extensive infoldings and intercellular canaliculi are present. The overall size of cells forming the serous secretory units is much less than that comprising the tubuloalveolar secretory endpieces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00174952
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  • 28
    Digitale Medien
    Digitale Medien
    Immunocytochemical and ultrastructural studies of upper motor neurons in amyotrophic lateral sclerosis (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 518-524 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Amyotrophic lateral sclerosis ; Upper motor neurons ; Ultrastructure ; Neurofilament ; Ubiquitin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The pathological alterations in upper motor neurons were investigated in 27 cases of adult-onset sporadic amyotrophic lateral sclerosis (ALS). No signficant cytoskeletal alterations were found in the Betz cells of any of the cases except one, although cytoskeletal pathology was consistently present in lower motor neurons. The one case had severe circumscribed atrophy of the precentral gyrus and, microscopically, had argentophilic intracytoplasmic inclusions in Betz cells and other pyramidal neurons in the primary motor area as eell as in the lower motor neurons. Immunocytochemically these inclusions contained the epitope of phosphorylated neurofilament and ubiquitin and ultrastructurally consisted of granule-associated filaments with neurofilaments. This is the first demonstration of alterations of cytoskeleton and ubiquitination in the giant cells of Betz, an established subset of upper motor neurons in ALS. Thus, although uncommon, cytoskeletal changes can be found in upper motor neurons in some ALS cases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310029
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  • 29
    Digitale Medien
    Digitale Medien
    Primary leptomeningeal glioma: ultrastructural and laminin immunohistochemical studies (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 538-542 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Primary leptomeningeal glioma ; Ultrastructure ; Basal lamina ; Laminin ; Heterotopic glial tissue
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We studied a case of primary leptomeningeal glioma (PLG) on the left parietal lobe of a 74-year-old woman and compared the tissue with heterotopic glial tissue from another case. The PLG tumor consisted of spindle-shaped cells with marked nuclear atypism, which tended to be arranged in a fascicular pattern, and the majority of its cells were positive for glial fibrillary acidic protein. Ultrastructural examination demonstrated that most of the tumor cells contained intermediate filaments and often junctional complexes were present on their plasma membranes. Frequently, basal lamina-like structures surrounding the tumor, cell surfaces were observed. Laminin immunohistochemistry clearly demonstrated a fine network of linear positive staining around the cytoplasm and processes of the tumor cells. The ultrastructure of the heterotopic glial tissue consisted of many astrocytes partially surrounded by basal lamina. These findings strongly suggest that PLG is a distinct tumor, which arises from the heterotopic astrocytes within the subarachnoid space.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310033
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  • 30
    Digitale Medien
    Digitale Medien
    Morphological findings on peripheral nerve biopsies in 15 patients with human immunodeficiency virus infection (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 618-623 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Peripheral nerve biopsy ; HIV infection ; Ultrastructure ; in situ hybridization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A peripheral nerve biopsy was performed in 15 patients with human immunodeficiency virus (HIV) infection and polyneuropathy. Two cases [1 asymptomatic, 1 AIDS-related complex (ARC)] presented with chronic inflammatory demyelinating polyneuropathy; there was 1 case (asymptomatic) of mononeuropathy multiplex and 12 cases (1 asymptomatic, 1 ARC, 10 AIDS) with distal symmetrical polyneuropathy. Epi- or endoneurial microvasculitis was observed in 6 cases. Electron microscopy showed that nerve fiber lesions were mainly axonal. Severe segmental demyelination was also present in both cases of chronic inflammatory demyelinating polyneuropathy, with characteristic features of active demyelination in one. Numerous plasmacytoid cells were found in the endoneurium in 4 patients. Tubuloreticular inclusions were present in endothelial cells in the 10 cases with AIDS but absent in the other patients. Direct immunopathological examination with anti-immunoglobulin sera was negative in all cases. HIV was evidenced by in situ hybridization in 2 AIDS patients; no Epstein-Barr virus or cytomegalovirus was detected.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00299411
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  • 31
    Digitale Medien
    Digitale Medien
    Ultrastructure of the microglia that phagocytose amyloid and the microglia that produce β-amyloid fibrils (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 225-233 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer's disease ; Tissue culture ; Microglia ; Amyloid ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The function of microglia associated with β-amyloid deposits still remains a controversial issue. On the basis of recent ultrastructural data, microglia were postulated to be cells that form amyloid fibrils, not phagocytes that remove amyloid deposits. In this electron microscopic study, we examined the ability of microglia to ingest and digest exogenous amyloid fibrils in vitro. We demonstrate that amyloid fibrils are ingested by cultured microglial cells and collected and stored in phagosomes. The ingested, nondegraded amyloid remains within phagosomes for up to 20 days, suggesting a very limited effectiveness of microglia in degrading β-amyloid fibrils. On the other hand, we showed that in microglial cells of classical plaques in brain cortex of patients with Alzheimer's disease, amyloid fibrils appear first in altered endoplasmic reticulum and deep infoldings of cell membranes. These differences in intracellular distribution of amyloid fibrils in microglial cells support our observations that microglial cells associated with amyloid plaques are engaged in production of amyloid, but not in phagocytosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227813
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  • 32
    Digitale Medien
    Digitale Medien
    Tubulovesicular structures in Creutzfeldt-Jakob disease (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 238-243 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Creutzfeldt ; Jakob disease ; Tubulovesicular structures ; Prion diseases ; Ultrastructure ; Transmissible spongiform encephalopathies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary By electron microscopy tubulovesicular structures (TVS) have been consistently observed in brain tissue of transmissible spongiform encephalopathies such as natural and experimental scrapie, bovine spongiform encephalopathy and experimentally induced, but not naturally occurring, Creutzfeldt-Jakob disease (CJD). For the first time we report here the presence of TVS in human brains with CJD as detected by transmission electron microscopy. TVS were observed in all three CJD specimens (two biopsies, one autopsy), but they were rare and were found only in one or two location(s) per grid. TVS were seen in distended pre- and postsynaptic terminals and measured approximately 35 nm in diameter; they were smaller and of higher electron density than synaptic vesicles. Their occurrence in all types of transmissible spongiform encephalopathies irrespective of the affected host and the strain of the infectious agent suggests their biological significance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227815
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  • 33
    Digitale Medien
    Digitale Medien
    Morphometrical variations of prolactin cells in response to prolonged and systemic administration of Met-enkephalin in female rats (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 99-105 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Prolactin cell ; Met-enkephalin ; Immunocytochemistry ; Ultrastructure ; Morphometr ; Rat(Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A stimulatory effect on prolactin secretion had been describe after acute and systemic administration of met-enkephalin, but the effects of this opioid after chronic administration has not been reported, and the response of mammotroph cells is not clear. As a complement to previous studies, a morphometric analysis (light and electron microscopy) was carried out on prolactin cells from female rats treated chronically with met-enkephalin. Clear features of cellular hyperactivity appeared after chronic and systemic administration of the opioid, and these persisted for two weeks. The changes consisted in increases of cellular, cytoplasmic and nuclear areas, volume and surface densities of the Golgi complex and rough endoplasmic reticulum, as well as the numbers of exocytotic figures. These morphological alterations were paralleled by an increase in serum prolactin levels as detected by RIA. It is concluded that the increase in the synthesis and secretory activity of prolactin cells following chronic and systemic administration of met-enkephalin is very similar to those observed after acute and intraventricular administration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00710406
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  • 34
    Digitale Medien
    Digitale Medien
    Electron microscopic investigations on the growing tip of nerve fibres in the developing distal forelimb of the mouse (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 201-206 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Development ; Mouse ; Peripheral nerves ; Schwann cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The distal course of the sensory nerve fibres on the palmar side of the hand of 12-day-old mouse embryos was followed by serial ultrathin cross-sections of conventionally fixed tissue. Small nerves fibres are to be found in the space between the layer of the cutaneous blood vessels and the epidermis. A special arrangement of the tissue which is traversed by the nerve fibres is not visible. In most cases the nerve fibres are in intimate contact with fibroblasts. More distally the nerve fibres consist only of one axon encircled by a Schwann cell. The sheath of the Schwann cell decreases gradually, and finally disappears completely. The distal tips of the naked axons are a few μm ahead. In some cases they are considerably enlarged and contain only a fine fuzzy material without special cell organelles. Other axons may end in a more finger-like fashion, and contain also in the naked parts many cell organelles. Also the naked axons contact fibroblasts over long ranges. Collagen was not found aligned to the distal nerve fibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185922
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  • 35
    Digitale Medien
    Digitale Medien
    Light and electron microscopic morphology of the temporomandibular joint in growing and mature crab-eating monkeys (Macaca fascicularis): the condylar calcified cartilage (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 189-199 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Mandibular condyle ; Calcified cartilage ; Ultrastructure ; Maturation ; Macaca fascicularis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In an attempt to show maturational alterations in the calcified cartilage, mandibular condyles of four growing and four adult male monkeys (Macaca fascicularis) were studied using light microscopy as well as transmission and scanning electron microscopy. All specimens were initially fixed by perfusion in the presence of ruthenium red. For examination of the hard tissue surfaces in the scanning electron microscope, uncalcified tissues were removed with sodium hypochlorite. In growing animals, almost the entire hard tissue surface in the joint region of the condyle was formed by calcified cartilage, while in adult animals, calcified cartilage was confined to load-bearing regions. In growing animals, the appearance of the calcified cartilage surface suggested a continuously advancing mineralizing front similar to that seen in the epiphyseal plate. Chondrocytes mostly exhibited a terminal stage of hypertrophy, and seemed to die and get lost through vascular invasion and subsequent endochondral ossification. In adult animals, most of the calcified cartilage surface appeared comparatively stable, and resembled the tidemark of articular cartilage. Chondrocytes were usually small and appeared viable. However, on the adult condyles, there were always circumscribed islands where chondrocytes and the pattern of mineralization resembled those seen in growing animals. In these regions, prominent chondroclastic activity indicated extensive articular remodelling. These observations suggest that at the end of somatic growth, condylar calcified cartilage undergoes considerable maturation from a type reminiscent of hyaline growth cartilage to a type resembling articular cartilage. Concomitantly, chondrocytes appear to change their developmental program, in that they stop enlarging and lose their commitment to death. However, they may be able to retain, or switch back to, a more immature stage, in case there is need for extensive articular remodelling.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185921
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  • 36
    Digitale Medien
    Digitale Medien
    Clinical, light and electron microscopic features of recessive ichthyosis congenita type III (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 259-265 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Genodermatoses ; Ultrastructure ; Membrane structures ; Abnormal keratinosomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The recessively inherited congenital ichthyoses have ultrastructural features which indicate abnormal epidermal lipid metabolism. The ultrastructural markers of the three recessive congenital ichthyosis groups are lipid droplets in horny layers (type I), cholesterol clefts (type II) and membrane structures (type III). We describe six patients from five families belonging to the last group. The variable clinical phenotype alone does not allow the delineation of this disease, but together with the ultrastructural characteristics the subtype is unequivocal. In addition to the membrane structures, half of the cases showed abnormal keratinosomes and vesicular complexes. Membrane-bound vacuoles and needle-like slits were exceptionally found. The onset of the ichthyosis was variable, in contrast to other patients described under the heading recessive congenital ichthyosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372578
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  • 37
    Digitale Medien
    Digitale Medien
    Relationship between tissue reactions and morphological changes of the fungi in chromoblastomycosis: morphometry and electron microscopy (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 95-99 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Chromoblastomycosis ; Host-fungus relationship ; Morphometry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To investigate the histological distribution and the morphology of the fungi and the tissue reactions in chromoblastomycosis, especially in the process of trans-epidermal elimination, cutaneous lesions of two patients with this disease were studied morphometrically and ultrastructurally. In the dermis, most of the fungal elements appeared as sclerotic cells and their cell wall showed an irregular, worm-eaten leaf-like appearance; they seemed to be continuously attacked by polymorphonuclear neutrophils. The epidermis eliminated 10–20% of all the organisms in the skin lesions, and the hypha-forming activity tended to be higher in the epidermis than in the dermis. Ultrastructurally, basal keratinocytes facing the dermal abscess containing fungal elements frequently appeared as dark cells, suggesting an increased proliferation activity. Spinous keratinocytes facing intraepidermal microabscesses containing fungal elements showed an abnormal accumulation of tonofilaments and further early keratinization in the spinous cell layer. All of the morphological changes of the dermis and epidermis are regarded as defence reactions against the fungi existing in the skin lesions. There is a close relationship between tissue reactions and morphological changes of fungi in chromoblastomycosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00373377
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  • 38
    Digitale Medien
    Digitale Medien
    Increase in types IV and VI collagen in cherry haemangiomas (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 275-282 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Cherry haemangioma ; Type IV collagen ; Type VI collagen ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The capillaries in cherry haemangiomas show perivascular hyalinized sheaths. In order to clarify the nature of this sheath material, the extracellular matrix of cherry haemangiomas from 20 normal volunteers (age range 30–64 years) was investigated using immunohistochemical and electronmicroscopical methods. Antibodies against collagen types III, IV and VI and laminin were used. Hyaluronic acid was visualized using the hyaluronic acid binding region of the cartilage proteoglycan as ligand. Electronmicroscopically, the sheaths contained multilaminated basement membrane-like material, collagen fibres 20–25 nm thick with a periodicity of 67 nm and broad-banded aggregates with a periodicity of 100 nm (zebra bodies or fibrous long-spacing fibres). Immunohistochemically, type IV collagen was stained throughout the whole sheath material. Staining for laminin was more confined to the endothelial side of the sheath. Intense staining for type III collagen and hyaluronic acid was found in the connective tissue of the subpapillary layer and between the cherry haemangioma capillaries. Much weaker staining for type III collagen and no staining for hyaluronic acid were found invariably in an area 4–10 Μm thick directly around the capillaries. Both sheath material and intercapillary connective tissue of the haemangiomas showed pronounced staining for collagen type VI. Immunogold staining revealed that type VI collagen was localized to microfibrils 5–6 nm thick and to the broad-banded aggregates with 100 nm periodicity. These findings further underline the assumption that the broad-banded aggregates consist of type VI collagen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372581
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  • 39
    Digitale Medien
    Digitale Medien
    Early events during the establishment of the Gunnera/Nostoc symbiosis (1992)
    Springer
    Planta 188 (1992), S. 403-413 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Cyanobacterium ; Gunnera ; Infection process ; Nostoc ; Symbiosis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The symbiosis between Gunnera and Nostoc was reconstituted using G. chilensis Lam. and G. manicata Linden, respectively, and three different Nostoc strains. Six stages characterised by specific modifications in both the cyanobiont and the host were recognised during the infection process. Mucilage-secreting stem glands developed on the Gunnera stems independent of the presence of cyanobacteria (Stage I). Soon after addition of the Nostoc isolates to the plant apices, an abundant differentiation of motile hormogonia commenced. The cyanobacteria accumulated in the mucilage on the surface of the gland (Stage II), and the hormogonia then proceeded into the stem tissue through intercellular channels (Stage III). At the channel bases, Nostoc was detected between the cell walls of small, densely cytoplasmic Gunnera cells and also in elaborate folds of these (Stage IV). The Gunnera cell walls subsequently dissolved adjacent to the cyanobacteria and Nostoc entered the host cells (Stage V). Once the intracellular association was formed, a high proportion of the vegetative Nostoc cells differentiated into heterocysts (Stage VI). Nostoc changed from being rich in inclusions (particularly cyanophycin) while on the gland surface into a comparatively “non-storing” form during penetration and the early intracellular stages. Bacteria were numerous on the gland surface, fewer in the channels, and were never detected within the Gunnera cells, indicating the existence of specific recognition mechanisms discriminating between conceivable microsymbionts. Mechanisms behind mutual adaptations and interactions between the two symbionts are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00192808
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  • 40
    Digitale Medien
    Digitale Medien
    High-pressure freezing of soybean nodules leads to an improved preservation of ultrastructure (1992)
    Springer
    Planta 188 (1992), S. 155-163 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Bradyrhizobium ; Electron microscopy ; Glycine (root nodules) ; High-pressure freezing ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract High-pressure freezing of chemically untreated nodules of soybean (Glycine max (L.) Merr.), in sharp contrast to chemical fixation and prefixation, appears to preserve the ultrastructure close to the native state. This is supported by the observation that the peribacteroid membrane of high-pressure-frozen samples is tightly wrapped around the bacteroids, a finding that is fully consistent with the current views on the physiology of oxygen and metabolite transport between plant cytosol and bacteroids. In soybean root nodules, the plant tissue and the enclosed bacteria are so dissimilar that conventional aldehyde-fixation procedures are unable to preserve the overall native ultrastructure. This was demonstrated by high-pressure freezing of nodules that had been pre-fixed in glutaraldehyde at various buffer molalities: no buffer strength tested preserved all ultrastructural aspects that could be seen after high-pressure freezing of chemically untreated nodules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00216809
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  • 41
    Digitale Medien
    Digitale Medien
    The microtubule cytoskeleton and the rounding of isolated generative cells ofNicotiana tabacum (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 64-71 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Generative cell ; Isolation ; Microtubules ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Upon squashing of the pollen grain, the isolated generative cell ofNicotiana tabacum looses its spindle shape to become spherical; this phenomenon is independent of the sucrose concentration used. The time necessary for this change can vary from 1 min (0% sucrose) to 20 min (30% sucrose). The microtubular cytoskeleton was studied by means of immunofluorescence and electron microscopy. Just after isolation, 5 to 15 clearly visible bundles in microtubules organized in a basket-like structure are present. After 15 min in medium with 15% sucrose, the microtubular cytoskeleton disappears, and a diffusely spread tubulin can be observed. Neither the addition of 10–20 μM taxol to the medium, nor the omission of Ca2+ to the medium has any effect on the changes in cell shape and loss of microtubular bundles after isolation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00714559
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  • 42
    Digitale Medien
    Digitale Medien
    Ultrastructure and microtubule organization of isolated generative cells ofAllemanda neriifolia at interphase and prophase (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 27-33 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Isolated generative cells ; Ultrastructure ; Microtubule ; Immunofluorescence microscopy ; Allemanda neriifolia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of isolated generative cells ofAllemanda neriifolia at interphase and prophase was studied. The microtubule organization of the isolated cells was also investigated by immunofluorescence microscopy with a monoclonal anti-α-tubulin. After the generative cells had been isolated from the growing pollen tubes by osmotic shock, most of the cells were at prophase and only a few were at interphase. The interphase cell is spindle shaped and contains an ellipsoidal nucleus. In addition to the usual organelles, the cytoplasm of the interphase cell contains numerous vesicles (each measuring 40–50 nm in diameter) and two sets of longitudinally oriented microtubule bundles — one in the cortical region and the other near the nucleus. Most of the prophase cells are spherical in shape. Based on the ultrastructure and the pattern of microtubule cytoskeleton organization three types of prophase cells can be recognized. (1) Early prophase cell, which contains the usual organelles, numerous vesicles, and a spherical nucleus with condensed chromosomes. Longitudinally oriented microtubule bundles can no longer be seen present in the early prophase cell. A new type of structure resembling a microtubule aggregate appears in the cytoplasm. (2) Mid prophase cell, which has a spherical nucleus containing chromosomes that appear more condensed than those seen in the early prophase cell. In addition to containing the usual organelles, the cytoplasm of this cell contains numerous apparently randomly oriented microtubules. Few vesicles are seen and microtubule aggregates are no longer present. (3) Late prophase cell, typified by the lack of a nuclear envelope. Consequently, the chromosomes become randomly scattered in the cytoplasm. Microtubules are still present and some become closely associated with the chromosomes. The changes in the ultrastructure and in the pattern of microtubule organization in the interphase and prophase cells are discussed in relation to the method of isolation of the generative cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00714555
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  • 43
    Digitale Medien
    Digitale Medien
    The formation of the generative cell in Polystachia pubescens (Orchidaceae) (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 131-137 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Pollen grain ; Generative cell ; Formation and detachment ; Ultrastructure ; Polystachia pubescens ; Orchidaceae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The formation and nature of the generative cell wall and the detachment mode of the generative cell from the intine in Polystachia pubescens were observed by LM and TEM. Vesicles evenly positioned within the phragmoplast fuse to form a cell plate that divides the microspore into the generative and vegetative cell. This cell plate consists of callose. Before the generative cell leaves the intine, however, the callose is completely resorbed and is not replaced by any other substance. The generative cell becomes detached from the intine by moving towards the centre of the pollen grain. A constriction formed thereby gives the generative cell a bulb-like appearance and leads ultimately to the generative cell being pinched off. Plasma-filled vesicles originating from the generative cell remain between the intine and the plasma membrane of the vegetative cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194872
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  • 44
    Digitale Medien
    Digitale Medien
    Ultrastructural and immunohistochemical study of degenerate neurite-bearing ghost tangles (1992)
    Springer
    Journal of neurology 239 (1992), S. 191-194 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Ghost tangles ; Degenerate neurites ; Astrocytes ; Senile plaques ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Some ghost tangles in the brains of Alzheimer patients were accompanied by many small argyrophilic structures which were electron microscopically confirmed to be degenerate neurites. In these ghost tangles, roughly dispersed 15 nm straight and occasional twisted tubules were penetrated by proliferated astrocytic processes. Immunohistochemically, these ghost tangles lost immunoreactivities to anti-NFT, -tau and -ubiquitin antibodies, but were thioflavine-S fluorescent, though antigenicity to β-protein was not proved. This similarity in composition of degenerate neurite-bearing ghost tangles to senile plaques might be induced by the amyloid nature of tubules, which probably provokes the reaction of neuropils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00839138
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  • 45
    Digitale Medien
    Digitale Medien
    Electron microscopic examination of sporulation-deficient mutants of the fission yeast Schizosaccharomyces pombe (1992)
    Springer
    Archives of microbiology 158 (1992), S. 249-255 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Sporulation ; Meiosis ; Ultrastructure ; Spindle pole body ; Spo mutants ; Schizosaccharomyces pombe ; Fission yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A homothallic haploid strain of the fission yeast Schizosaccharomyces pombe initiates sexual reproduction (mating, meiosis and sporulation) in nitrogen-free sporulation medium. Cellular fine structures of eleven sporulation-deficient mutants (spo2, spo3, spo4, spo5, spo6, spo13, spo14, spo15, spo18, spo19 and spo20) of S. pombe in sporulation medium were examined by serial section-electron microscopy. The striking features of these spo mutants were: 1) the disappearance of the spindle pole bodies (SPBs) after the second meiotic division, and 2) the accumulation of unorganized structures. Based on histochemical staining, these structures were presumably unorganized spore wall precursors. In some mutants (spo3, spo5, spo6, spo19 and spo20), diploid zygotes contained four spore-like bodies which had walls similar to complete spore walls but failed to enclose any nuclei. After completion of the second meiotic division the nuclei were abnormally distributed in zygotic diploid cells. In the spo5, spo13, spo14, spo15 and spo19 mutants, the nuclei remained attached to each other. In spo5 and spo19, the inner membrane of the nuclear envelope was separated, but its outer membrane was shared by two sister nuclei. These observations suggest that the spo+ gene products play important roles in spatial and temporal organization of cellular structures during ascospore development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00245240
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  • 46
    Digitale Medien
    Digitale Medien
    Frequency and structure of spinae on Chlorobium spp. (1992)
    Springer
    Archives of microbiology 157 (1992), S. 319-322 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Chlorobiaceae ; Spinae ; Chlorobium ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several Chlorobium species have been observed to possess spinae. Spinae are non-prosthecate, helically wound, rigid structures that extend from the outer bacterial cell surface into the external environment. Spinae length was variable within and between Chlorobium species. Spinae width was fairly consistent within species but varied between species (39.4 ± 2.6 nm to 82.6 ± 8.0 nm). The number of spinae per cell varied. The spinae did not penetrate the bacterial cell envelope and were randomly located on the cell surface. Spinae were not geographically restricted. The observation of spinae on pure cultures of Chlorobium spp. maintained for 25–30 years suggests that spinae may be of significant use to the cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248675
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  • 47
    Digitale Medien
    Digitale Medien
    Ultrastructural investigations of Arbutus unedo-Laccaria amethystea mycorrhiza synthesized in vitro (1992)
    Springer
    Trees 7 (1992), S. 40-47 
    Details
    ISSN: 1432-2285
    Schlagwort(e): Arbutus unedo ; Laccaria amethystea ; Mycorrhiza ; Synthesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Anatomy and ultrastructure of the arbutoid mycorrhiza of Arbutus unedo-Laccaria amethystea from axenic culture are described. In comparison to non-inoculated roots, the rhizodermal cells of mycorrhizas are of greater volume, their nuclei are enlarged and show an irregular shape, plasmalemma and cytoplasm with mitochondria, plastids, endoplasmic reticulum and dictyosomes are increased. Several ontogenetical states are documented. The arbutoid mycorrhiza as a connecting link between ectomycorrhiza and ericoid mycorrhiza is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00225230
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  • 48
    Digitale Medien
    Digitale Medien
    Immunocytochemical and electron-microscopic study of the elasmobranch nucleus sacci vasculosi (1992)
    Springer
    Cell & tissue research 270 (1992), S. 395-404 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Nucleus sacci vasculosi ; Ultrastructure ; Immunocytochemistry ; Hypothalamus ; Tuberculum posterius ; Scyliorhinus caniculus, Raja undulata (Elasmobranchii)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The elasmobranch nucleus sacci vasculosi was studied by means of electron microscopy (in the dogfish) and immunocytochemistry (in the dogfish and the skate) by using antibodies against tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P. Ultrastructural study of the dogfish nucleus sacci vasculosi shows the presence of medium-sized cells that possess numerous mitochondria but that have no dense-core vesicles in the cytoplasm or in cell processes. Fibres of the conspicuous tractus sacci vasculosi have a beaded appearance and form conventional synapses with dendrites and cell perikarya of the nucleus sacci vasculosi. The perikarya of this hypothalamic nucleus were not immunoreactive to any of the antibodies tested, and fibres immunopositive to tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P were scarce within this nucleus, in both the dogfish and the skate. Dorsal to the nucleus sacci vasculosi, there are numerous positive neuronal processes in addition to many small neurons that show immunoreactivity to alpha-melanocyte-stimulating hormone, somatostatin and tyrosine hydroxylase. Two types of neuron occur in this dorsal region, displaying dense-core vesicles of either 100–160 nm or 60–100 nm diameter in their cytoplasm; they were identified as peptide-containing and monoamine-containing neurons, respectively. The neuropil of this region has a significantly different ultrastructure from that of the nucleus sacci vasculosi, with many processes containing dense-core vesicles. This group of neurons, located dorsal to the nucleus sacci vasculosi and showing (a) immunoreactivity to neuropeptides or to monoamine-synthesizing enzyme, and (b) cytoplasm with dense-core vesicles, was considered not to be a part of the nucleus sacci vasculosi but rather part of the nucleus tuberculi posterioris. These results support the non-peptidergic and non-aminergic character of the nucleus sacci vasculosi.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00328023
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  • 49
    Digitale Medien
    Digitale Medien
    Culture and characterization of dental follicle cells from rat molars (1992)
    Springer
    Cell & tissue research 267 (1992), S. 483-492 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Dental follicle ; Cell culture ; Fibroblasts ; Immunocytochemistry ; Ultrastructure ; Collagen ; Gel-electrophoresis ; Western blotting ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Because the dental follicle is necessary for the eruption of teeth of limited eruption, it was the objective of this study to determine if the cells of the follicle could be cultured in vitro. To achieve this, dental follicles and associated enamel organs were dissected from the first and second mandibular molars of 6–7-day-old rats (secretory stage of amelogenesis), and then cultured in a medium that promotes fibroblast growth — the predominant cell type of the dental follicle. The cultured cells grew to confluency and were kept through 3 passages before experimentation. The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained an abundant rough endoplasmic reticulum, but did not form desmosomes. Immunofluorescent staining for anti-vimentin showed that all the cells stained and electron-microscopic immunogold labeling indicated that the antibody was associated with intermediate filaments. As revealed by SDS-polyacrylamide gel electrophoresis and Western blotting, the cultured cells synthesized and secreted the extracellular matrix molecules fibronectin and procollagens. Subsequent immunofluorescence staining of permeabilized and non-permeabilized cells confirmed the presence of fibronectin and type I collagen both intra- and extracellularly. Thus, based on all the above characteristics, the cultured cells appeared to be fibroblasts derived from the dental follicle, although a few of the fibroblasts may be derived from undifferentiated mesenchymal cells interposed between the alveolar bone and follicle. Experiments now can be conducted to determine how these cultured cells respond directly to growth factors that alter the rates of tooth eruption.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319370
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  • 50
    Digitale Medien
    Digitale Medien
    Structural organization of two fast, rhythmically active crustacean muscles (1992)
    Springer
    Cell & tissue research 267 (1992), S. 571-582 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Crustacean muscle ; Ultrastructure ; Dye coupling ; Flagellum ; Scaphognathite ; Fascicles ; Mitochondria ; Carcinus maenas (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The organization of the flagellum abductor muscle and of a scaphognathite levator muscle of the green crab, Carcinus maenas, has been compared quantitatively using light and electron microscopy. These muscles are rhythmically active at relatively high frequencies and for long durations. Fibers of both muscles are interconnected to form fascicles of 50 or more fibers within which there is cytoplasmic continuity. A single muscle is made up of 8–12 fascicles. Individual fibers consist of a peripheral rind of densely packed mitochondria, a thick region of glycogen granules, and myofibrils arranged into scattered central islands. Less than half the volume-density of these muscles is contractile material, the balance being largely mitochondria and glycogen. The fibers within a muscle are structurally similar. They have short sarcomeres (about 2 μm), thin to thick filament ratios of about 3:1, and junctions between the sarcoplasmic reticulum and the transverse tubules at the M line. Sarcoplasmic reticulum occupies about 10% of the myofibrillar volume-density. A well developed sarcoplasmic reticulum appears to underlie the capacities of these two muscles for high frequency contraction; extensive mitochondria and glycogen stores should confer fatigue resistance under both aerobic and anaerobic conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319380
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  • 51
    Digitale Medien
    Digitale Medien
    Bethanechol and a G-protein activator, NaF/AlCl3, induce secretory response in Paneth cells of mouse intestine (1992)
    Springer
    Cell & tissue research 269 (1992), S. 213-220 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Paneth cells ; Ultrastructure ; Morphometry ; Bethanechol ; Fluoride ion ; G-protein ; Mouse (Balb/c)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Paneth cells located at the bottom of intestinal crypts may play a role in controlling the bacterial milieu of the intestine. Using morphometry to clarify the secretory mechanism of the Paneth cells, we studied the ultrastructural changes in mouse Paneth cells produced following intra-arterial perfusion with Hanks' balanced salt solution containing a cholinergic muscarinic secretagogue (bethanechol), a neuroblocking agent (tetrodotoxin), or a G-protein activator (NAF/AlCl3). Bethanechol (2×10-4 mol/l) induced Paneth-cell secretion. Many Paneth cells massively exocytosed their secretory material into the crypt lumen; the enhanced secretion caused degranulation and vacuole formation. However, tetrodotoxin (2×10-6 mol/l) did not prevent the bethanechol-enhanced secretion by the Paneth cells. NaF (1×10-2 mol/l) and AlCl3 (1×10-5 mol/l) induced massive exocytosis of the Paneth cells; the exocytotic figures were similar to those observed in mice stimulated by bethanechol. G-protein activation was followed by a sequence of intracellular events, resulting in exocytosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319611
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  • 52
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in primordial germ cells during early gonadal development of the common carp (Cyprinus carpio L., teleostei) (1992)
    Springer
    Cell & tissue research 267 (1992), S. 337-346 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Primordial germ cell ; Ultrastructure ; Gonadal differentiation ; Cyprinus carpio (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A description is given of primordial germ cell (PGC) differentiation and gonadal development in carp from hatching until the age of 6 weeks. This period was chosen as the PGCs are mitotically silent before they start to proliferate rapidly after week 6. The PGCs increased in size between week 2 and week 4 after fertilization. Ultrastructurally, the perinuclear dense bodies present in PGCs from hatching onwards increased in size and formed the ‘cement’ between mitochondria. Moreover, from week 2 onwards, an elaborate Golgiapparatus was present in PGCs, indicating synthetic activity that may be related to PGC enlargement. During the observation period, gonadal tissue was gradually formed around the PGCs. From the age of 4 and 5 weeks onwards, two somatic cell types could be distinguished; the central type had a light appearance and was closely associated with the PGCs, the other type being darker and forming the peripheral layer of the developing gonads. Thus, during the period of mitotic quiescence, the PGCs and the gonads actively differentiate in preparation for the fast PGC proliferation that occurs after 6 weeks.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302972
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  • 53
    Digitale Medien
    Digitale Medien
    Ultrastructural study of the retinal pigment epithelium during metamorphosis in the sea lamprey (Petromyzon marinus L.) (1992)
    Springer
    Cell & tissue research 267 (1992), S. 375-384 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Retinal pigment epithelium ; Ultrastructure ; Organelle differentiation ; Metamorphosis ; Lamprey, Petromyzon marinus (Cyclostomata)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The sequence of morphological changes in the retinal pigment epithelium during the metamorphic period of the sea lamprey Petromyzon marinus L. has been investigated using electron microscopy. At early metamorphic stages (stages I and II), photoreceptors are present in a small zone of the retina. During these stages, the lateral surface of the epithelial cells shows zonulae occludentes and adhaerentes. The degree of cell differentiation varies throughout the retinal pigment epithelium. Cells covering the differentiated photoreceptors in the central retina have phagosomes, whereas pigment granules appear only in the retinal pigment epithelium dorsal to the optic nerve head. Most epithelial cells have myeloid bodies; their morphology is more complex around the optic nerve head. At stage III, when photoreceptors develop over the whole retina, the distribution of cytoplasmic organelles is almost homogeneous in the retinal pigment epithelium. Subsequently, the basal plasma membrane of the epithelial cells becomes progressively folded and their apical processes enlarged. In addition, extensive gap junctions develop between retinal pigment cells. In late metamorphic stages, noticeable growth of myeloid bodies occurs and consequently the retinal pigment epithelium resembles that of the adult. This study also describes, for the first time, the presence of wandering phagocytes in the retinal pigment epithelium of lampreys; their role in melanosome degradation is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302976
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  • 54
    Digitale Medien
    Digitale Medien
    In-vitro effects of angiotensin II on steroid production by hamster ovarian follicles and on ultrastructure of the theca interna (1992)
    Springer
    Cell & tissue research 268 (1992), S. 191-196 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Angiotensin II ; Ovarian follicles ; Theca interna ; Ultrastructure ; Steroidogenesis ; Atresia ; Golden hamster (Rodentia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Angiotensin II (AII) is present in the mammalian ovary and has been correlated with atresia in follicles. Since the theca interna may be one site at which atresia is intiated, we wished to determine whether AII exerts an effect on theca interna from explanted ovarian follicles of hamsters. Hamsters were sacrified on the morning of proestrus, and ovaries were removed. Preovulatory follicles were excised from the ovaries, and cultured with one of the following components: medium alone (control); medium plus AII (1x10-6 M); the AII-receptor antagonist [Sar1, Ile8] AII (1x10-4 M); or AII plus antagonist. After 72 h, the follicles were processed for transmission electron microscopy (to determine quantities of theca interna organelles involved in the steroid synthetic pathway) or for protein determination (to normalize steroid production rates). The incubation medium was drawn off and analyzed by radioimmunoassay for progesterone, androstenedione, or estradiol-17β. There was a significant positive correlation (r=0.92, P〈0.01) between follicular androstenedione secretion and area comprising theca interna smooth endoplasmic reticulum. In the theca interna, AII induced a two-fold and 1.6-fold increase in lipid droplet number and area comprising smooth endoplasmic reticulum, respectively (P〈0.05). Excess antagonist negated the increase in cell or-ganelles and also reduced androstenedione secretion compared with AII alone (P〈0.05). Most importantly, AII significantly augmented the ratio of androstenedione: estradiol-17β secretion by 44% over that of control. The ultrastructural changes observed in this study and the increase in the andostenedione: estradiol-17β production ratio are consistent with atresia-like changes in ovarian follicles. We believe, therefore, that AII is involved, possibly at its membrane receptor, in an aspect of the overall process of follicular atresia, operating in part at the level of the theca interna.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00338068
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  • 55
    Digitale Medien
    Digitale Medien
    Ultrastructure of the basement membrane and its precursor in developing rat submandibular gland as shown by alcian blue staining (1992)
    Springer
    Cell & tissue research 268 (1992), S. 233-238 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Alcian blue ; Basement membrane ; Lamina densa ; Meshwork ; Submandibular gland ; Ultrastructure ; Rat (Wistar-Imamichi)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the epithelial basement membrane and membrane precursor was studied in rat submandibular rudiment and a model system of the reconstructed basement membrane, by transmission electron microscopy following alcian blue staining. Directly beneath the epithelial plasma membrane, a meshwork layer was found to consist of anastomosing thin fibers arranged as a three-dimensional meshwork (100–400 nm in thickness). Straight strands (5–10 nm in diameter) could sometimes be seen to pass through the meshwork. Adjacent to this layer, a coarse network composed of threads (20–40 nm in diameter) connected the meshwork layer with collagen fibers of the underlying connective tissue. The earliest precursors recognized in the reconstruction-model system were part of the fine-meshwork structure, and showed this structure to be a fundamental component of the basement membrane.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318791
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  • 56
    Digitale Medien
    Digitale Medien
    Immunogold labelling of the cytoplasmic estradiol receptor in resting porcine endometrium (1992)
    Springer
    Cell & tissue research 270 (1992), S. 1-6 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Estradiol receptor ; Endometrium ; Ovariectomy ; Immunohistochemistry ; Ultrastructure ; Pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Serial sections of resting porcine endometrium were analyzed with the monoclonal antibody 13H2 using goat antimouse IgG/5 nm gold as secondary reagent or with either polyclonal antibodies from goat #402 or the rat monoclonal antibody H222, both in combination with protein G/12 nm gold. A modestly higher labelling of nuclei than of cytoplasm was seen only with the monoclonal antibody H222. Polyclonal #402 and monoclonal 13H2 showed fewer attachments over nuclear than over cytoplasmic areas. The highest densities of attachment and of predominantly cytoplasmic labelling were obtained with the monoclonal antibody 13H2. The results confirm the earlier assumption of a restricted accessiblity of estradiol receptor in the cytoplasm of resting cells for immunoreagents.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00381873
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  • 57
    Digitale Medien
    Digitale Medien
    Electron microscopical studies ofThorea ramosissima (Thoreaceae, Rhodophyta): Taxonomic implications ofThorea pit plug ultrastructure (1992)
    Springer
    Plant systematics and evolution 181 (1992), S. 233-244 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Algae ; Rhodophyta ; Thorea ramosissima ; T. riekei ; Ultrastructure ; pit plugs as a taxonomic character
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The thallus ofThorea ramosissima was studied electron microscopically. The cells of the medulla, the cortex and the assimilatory hairs differ not only in size and number of plastids and their equipment with thylakoids but also in cell wall structure, the number of mitochondria and the activity of the Golgi apparatus, with dictyosomes transforming complete cisternae into Golgi vesicles with mucilaginous contents in the outer region of the cortex. The pit connections have plugs with a distinct plate—like (not dome-like) outer cap layer. BecauseT. riekei was reported to have dome-like outer cap layers and because this character was the main reason to place theThoreaceae into theBatrachospermales (Pueschel & Cole 1982),T. riekei was reinvestigated, too. A distinct outer cap could not be detected. The reliability of pit plug structure as a taxonomic character and the taxonomic position ofThorea is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937447
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  • 58
    Digitale Medien
    Digitale Medien
    Biochemical and immunological characterization of intermicrotubular cement in the feeding apparatus of phagotrophic eugienoids:Entosiphon, Peranema, andPloeotia (1992)
    Springer
    Protoplasma 168 (1992), S. 113-124 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cytoskeleton ; Phagotrophic ; Eugienoids ; Immunochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A monoclonal antibody (IIID12) obtained from mice immunized against the entireEntosiphon cytoskeleton highlights the feeding apparatus ofEntosiphon, Peranema, andPloeotia by IF. IGS at the ultrastructural level shows that it labels the cementing material surrounding the microtubular bundles in the three species studied. InEntosiphon additional structures, such as the supplementary plaque, the scaffold structure and the lenticular structure or canal thickening, are also detected by the antibody. Immunoblotting analysis after SDS-PAGE reveals a positive reaction with this antibody to the 58 and 66kDa protein bands inEntosiphon, 82 and 84kDa inPeranema, and 56 and 60kDa inPloeotia. These results demonstrate biochemical homologies in the proteins of the cement material in the three heteronematal eugienoids studied. The possible role of these proteins in microtubule assembly and stabilization is discussed, as well as the role of the cementing material in the mode of the feeding apparatus motion during the ingestion of food.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01666257
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  • 59
    Digitale Medien
    Digitale Medien
    Ultrastructural characterization of somatic embryos regenerated from NaCl selected and nonselected calli ofDactylis glomerata (1992)
    Springer
    Protoplasma 170 (1992), S. 177-185 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Dactylis glomerata L. ; Orchardgrass ; Sodium chloride tolerance ; Somatic embryo ; Tissue culture ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Calli were induced from leaf expiants of aDactylis glomerata L. (orchardgrass) genotype which has a high capacity for somatic embryogenesis. After 7 months culture on SH medium containing NaCl, a line was selected which was tolerant to 200 mM NaCl. When both selected and nonselected calli were maintained for 56 days on media containing 0 to 300 mM NaCl, the selected line showed significantly higher regeneration capacity than nonselected calli when placed on media containing more than 50 mM NaCl. Ultrastructural features of control somatic embryos not exposed to the salt were compared to those from nonselected and selected embryos cultured on 200 mM NaCl medium. In the presence of NaCl there were changes in the appearance of cell walls and mitochondria, accumulation of lipids and a higher degree of vacuolation in cells of nonselected embryos compared to control and selected embryos.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01378792
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  • 60
    Digitale Medien
    Digitale Medien
    Immunocytochemical localization of callose in root cortical cells parasitized by the ring nematodeCriconemella xenoplax (1992)
    Springer
    Protoplasma 171 (1992), S. 1-6 
    Details
    ISSN: 1615-6102
    Schlagwort(e): (1→3)-β-Glucose ; Callose ; Cell wall ; Host-parasite interface ; Immunocytochemical ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Polyclonal antibodies specific to (1→3)-β-glucose were used to localize callose around stylets ofCriconemella xenoplax in parasitized cortical cells in root explants of carnation, crimson clover, and tomato. The nematode's stylet was inserted 5–6 μm through the wall of the parasitized cell without piercing the plasma membrane, which became invaginated around the stylet tip. A layer of electron-transparent callose was localized by immunogold labelling between the invaginated plasma membrane and the inserted stylet, except at the stylet orifice. The callose was continuous with the inner surface of the wall of the parasitized cell around the site where the stylet penetrated. When the parasitized cell was located in the second layer of the cortex, the nematode's stylet first passed through a subepidermal cortical cell. The integrity of the plasma membrane of the transected cell was maintained and callose was deposited around the portion of the nematode's stylet that traversed the cell. We suggest that callose deposition around nematode stylets in parasitized cells is a common wound response elicited when plant-parasitic nematodes feed from cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01379274
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  • 61
    Digitale Medien
    Digitale Medien
    Rose leaf structure in relation to different stages of micropropagation (1992)
    Springer
    Protoplasma 166 (1992), S. 165-176 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cuticle ; Humidity ; Leaf structure ; Micropropagation ; Rosa ; Stomata ; Ultrastructure ; Wax
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The Mme Isaac Pereire rose was investigated in an attempt to establish how micropropagated roses might best be weaned into normal growth conditions. Leaves of in vitro grown plants, weaned plants and the stock plant were studied, using light microscopy and different scanning and transmission electron microscopical techniques. Features that varied in the different growing conditions were leaf size and thickness, amount of wax, thickness of cuticle and external epidermal cell wall, number and aperture of the stomata, size of the epidermal cells, number of layers of the palisade cells, and size of the chloroplasts in the mesophyll. The rose in the present study had wax on the in vitro cultured plants; this wax was of similar ultrastructural appearance to that of the stock plant, even though in smaller quantities. Weaned plants had an intermediate amount of wax. The cuticle was thin, ranging from 0.04 μm on plants growing in vitro to 0.3-0.6 μm on weaned plants and stock plants. Stomata were always wide-open on leaves taken from cultures with a relative humidity of 100%. After four weeks in a humidity lowered to 85% stomata had closed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01322779
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  • 62
    Digitale Medien
    Digitale Medien
    Ultrastructure of cuticular exudations in parasitic juvenileHeterodera schachtii, as related to cuticle structure (1992)
    Springer
    Protoplasma 166 (1992), S. 67-77 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cuticle ; Cuticular exudations ; Exudations ; Heterodera schachtii ; Ultrastructure ; Host-parasite interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development ofHeterodera schachtii inside roots of a cruciferous host plant grown under monoxenic conditions in an agar medium was observed with video-enhanced contrast light microscopy. One to 6 days after inoculation, roots were excised and processed for electron microscopic observations. Exudates were present on the cuticle surfaces of J 2 and early J 3 juveniles located at feeding sites. Fibrillar exudations were correlated with similar fibrillar patterns in the epicuticle, exocuticle, intermediate zone, and the striated endocuticle. Secretion vesicles assembled at many Golgi sites in the hypodermis, appeared to coalesce and form large electron translucent vesicles in the cytoplasm. We propose that secretion vesicles migrate toward the cuticle, contact the plasmalemma and transfer their contents by exocytosis or a similar mechanism to a secretion accumulation site. These contents are associated with cuticle structure and emerge as surface exudations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01320145
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  • 63
    Digitale Medien
    Digitale Medien
    Morphogenesis of the feeding apparatus ofEntosiphon sulcatum (1992)
    Springer
    Protoplasma 168 (1992), S. 125-135 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Morphogenesis ; Phagotrophic ; Euglenoids ; Immunocytochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The disruption and development of the siphon during division ofEntosiphon have been followed by immunofluoresence with both an anti-cement MAb (IIID12) and an anti-tubulin MAb. (IVA10), by nuclear DNA labelling and by electron microscopy of serial section. The disruption of the parental siphon begins at the reservoir level where two new transversely orientated daughter siphons arise. In the degenerating bundles the cement disappears, first liberating the microtubules which then depolymerize. The first structure which surrounds the anterior part of the two young siphons is a loop of 5 microtubules linked to the reservoir membrane. From around this loop a row of perpendicular microtubules sink in the cytosplasm; they will form the primary row of microtubules in the definitive bundles. Inside the loop, reinforced microtubules are seen beneath the membrane, they will generate the future vanes, and also penetrate into the cytosplasm. Amorphous material surrounds the young siphons and may correspond to cement material. The growth of the siphons proceeds as they adopt a central longitudinal position in the cell. The cement material progressively condenses on structures such as the primary row of microtubules. The bundles, the supplementary plaque, and the scaffold. After flagellar partition each of the canals becomes distinct and cytokinesis occurs from the anterior end. These observations indicate that the microtubular loop could be the source of microtubule-organizing centre (MTOC) proteins initiating the assembly of the primary row of microtubules. Bundle microtubules start to assemble at the anterior end and extend backwards. The microtubules of the loop could be linked to roots associated with the basal bodies which double in number before division. The cement later condenses, linking and stabilizing the structures. Microfibrils play an important role in basal body and siphon separation and positioning.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01666258
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  • 64
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in the cell wall, nucleus and cytoplasm of pollen mother cells during meiotic prophase I inLycopersicon esculentum (Mill.) (1992)
    Springer
    Protoplasma 169 (1992), S. 139-147 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cell wall ; Lycopersicon esculentum ; Microsporogenesis ; Pollen development ; Prophase I ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Throughout the premeiotic to late prophase I stages of meiosis in the anthers of tomato (Lycopersicon esculentum) extensive changes occurred in the ultrastructure of pollen mother cells (PMCs). During early prophase, the wall of each PMC developed a layered appearance and was broadened both by the widening of the middle lamella as well as by intensive deposition of microfibrils in the wall. By late prophase, however, the microfibrils adjacent to the plasmalemma dissipated. At the same time, callose was deposited between the wall and the plasmalemma. The nucleus of the PMCs also underwent changes. During early prophase, the nucleolus consisted of a linear series of three segments, with a separation of the granular and fibrillar portions. By late prophase, the nucleoli were less distinct as the nucleus was highly vacuolate. Mitochondria were initially simple with lightly stained matrix and few cristae but, during the course of prophase, they acquired a more densely-stained matrix with dilated cristae. Plastids remained relatively undifferentiated and, at late prophase, many were convoluted in appearance and constricted at intervals indicating their division. Cytoplasmic connections between adjacent PMCs were broad enough to permit the passage of organelles and were retained through to metaphase I. These cytological and wall changes appear to be a prerequisite for the subsequent development of microspores.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01323613
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  • 65
    Digitale Medien
    Digitale Medien
    Ultrastructure of freeze-substituted pollen tubes ofLilium longiflorum (1992)
    Springer
    Protoplasma 167 (1992), S. 215-230 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Lilium ; Freeze substitution ; Pollen tubes ; Rapid freeze fixation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In view of the importance of the lily pollen tube as an experimental model and the improvements in ultrastructural detail that can now be attained by the use of rapid freeze fixation and freeze substitution (RF-FS), we have reexamined the ultrastructure of these cells in material prepared by RF-FS. Several previously unreported details have been revealed: (1) the cytoplasm is organized into axial “slow” and “fast” lanes, each with a distinct structure; (2) long, straight microtubule (MT) and microfilament (MF) bundles occur in the cytoplasm of the fast lanes and are coaligned with every organelle present; (3) the cortical cytoplasm contains complexes of coaligned MTs, MFs, and endoplasmic reticulum (ER); (4) the cortical ER is arranged in a tight hexagonal pattern and individual elements are closely appressed to the plasma membrane with no space between; (5) mitochondria and ER extend into the extreme apex along the flanks of the pollen tube, and vesicles and ER are packed into an inverted cone-shaped area at the center of the apex; (6) MF bundles in the tip region are fewer, finer, and in random orientation in comparison to those of the fast lanes; (7) the generative cell (GC) cell wall complex contains patches of plasmodesmata; (8) The GC cytoplasm contains groups of spiny vesicles that are closely associated with and seem to be fusing with or pinching off from mitochondria, and (9) the vegetative nucleus (VN) contains internal MT-like structures as well as numerous cytoplasmic MTs associated with its membrane and also located between the VN and GC.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403385
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  • 66
    Digitale Medien
    Digitale Medien
    Changes in the lysosome structure during the formation of zoospores inTrebouxia potteri (1992)
    Springer
    Protoplasma 171 (1992), S. 19-27 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Lysosome ; Morphogenesis ; Trebouxia potteri ; Ultrastructure ; Zoospore formation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Changes in the lysosome structures were examined by electron microscopy during the formation of zoospores inTrebouxia potteri. Lysosomes in vegetative cells were homogeneously filled with electron-dense material. At the beginning of zoospore formation, lysosomes invaginated or evaginated to take up mitochondria, ER, or cytoplasmic ground plasma. The ingested organelles became disorganized within the lysosomes. During this disruption of these organelles, the lysosomal contents became heterogeneous, suggesting a decrease in the amount of enzymes within the lysosomes. Golgi bodies and ER seemed to be involved with the disruption of the organelles, probably supplying some substances necessary for the functioning of the lysosomes. Amount of electron-dense materials decreased and, finally, only one to three small spherical aggregates remained in the lysosomes. Then the lysosomes appeared to shrink via loss of watery substances or cutting off of electron-transparent regions. After these changes in lysosome structure, nuclei started to divide successively for formation of the zoospores. The possibility is proposed that the drastic cytoplasmic changes operated by lysosomes trigger the following morphogenetic events in the formation of zoospores.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01379276
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  • 67
    Digitale Medien
    Digitale Medien
    Aortic features in tangier disease and pathogenetic considerations — Part I. Fatty dots and streaks (1992)
    Springer
    European journal of epidemiology 8 (1992), S. 36-47 
    Details
    ISSN: 1573-7284
    Schlagwort(e): Tangier disease ; Aortic morphology ; Ultrastructure ; Atherosclerosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Morphological studies of aortic fatty dots and streaks, and the adjacent normally appearing intima, in a 5 3/4-year-old boy who died of pneumonia, showed several hitherto unreported features. In lesions, lipid vacuoles and/or other cytoplasmic “inclusions” (ultrastructurally considered to present complex forms of lipids) were present on occasion in the endothelium but consistently involved the (intimal) smooth muscle cells (SMC). Similar changes were present in the adjacentintima, but were here less prominent and “tapered off” distally. A moderate number of macrophages also contained cytoplasmic lipids but such cells entirely free of lipid inclusions were observed, too. Most surprisingly, dilated and manycisternae of rough-surfaced endoplasmicreticulum (ER) in the SMC of lesions were associated spatially with cytoplasmic droplets and other forms of lipids. The results of these studies question the generally accepted central role of macrophages as being primarily involved in the pathogenesis of tissue changes in Tangier disease. It is possible that in view of the absence or paucity of high-density lipoproteins (HDL) and alterations of (their) apo A-I and apo A-II (as well as of other lipids), the arterial SMC may be in some way involved in the metabolism of the above substances in this disorder. Support of this tentative (and highly speculative) assumption must await further work utilizing tissues and cells other than those containing macrophages and other derivatives of reticuloendothelial system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00145348
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  • 68
    Digitale Medien
    Digitale Medien
    Cytometric and electron microscopic studies of the direct interaction of divalent nickel with intact and chemically modified HuT-78 lymphoblasts (1992)
    Springer
    Cell biology and toxicology 8 (1992), S. 27-41 
    Details
    ISSN: 1573-6822
    Schlagwort(e): Lymphoblasts ; Nickel ; Cytometry ; Ultrastructure ; Membrane
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Cytometric and ultrastructural studies on 24 hr cultures of intact, 1.0 mM H5I06, and 0.1 mM SeO2-oxidized HuT-78 lymphoblasts were performed after their direct, 30 min interaction with 1.0 mM NiCl2. Except for moderately depressed cell viability, divalent nickel did not alter the progression of intact and oxidized target cells through the phases of the cell cycle. Although the plasma membrane remained structurally intact, marked distortion of mitochondria structure and increased osmiophilia were an invariable attribute of all nickel-pulsed cells. Moreover, numerous electron-opaque, intracellular depositions were detected in SeO2-oxidized, nickel-pulsed cells. It is concluded that the initial state of plasma membrane, and the interaction of nickel with other trace elements, have jointly determined the response of HuT-78 cells to brief and direct, divalent nickel pulses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00119293
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  • 69
    Digitale Medien
    Digitale Medien
    Determination of Nifedipine in plasma by a rapid capillary gas chromatographic method (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 20-23 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A rapid, specific and reliable gas chromatographic assay procedure for Nifedipine in plasma has been developed. With a single-step solvent extraction, and electron capture detection, the method is sensitive to 0.5 ng/mL of plasma and the standard curve is linear from 0.5 to 500 ng/mL. Samples are protected from light to prevent formation of photodecomposition products. The method has been used to monitor drug concentrations in patients receiving therapeutic doses.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060107
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  • 70
    Digitale Medien
    Digitale Medien
    Favourable biospecific reactivity of blood group B antigenic trisaccharide chemically attached to poly-N-(2-hydroxyethyl)acrylamide-coated porous glass (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 39-42 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Blood group B antigenic trisaccharide-β-aminopropyl glycoside (B-TSAP) covalently attached to poly-N-(2-hydroxyethyl)acrylamide-coated porous glass interacts with anti-B monoclonal antibodies faster than the ligand coupled to CNBr-activated Sepharose 4B and Affi-Gel 10. Rates of hydrophobic adsorption of antibodies on the butyl derivatives of the same supports were measured to evaluate the diffusion input to overall kinetics. The lowest average affinity adsorption time [t1(aff) = 250 s] observed for polymer-coated glass probably arises because of the flexibility of the extended segments of chemisorbed N-substituted polyacrylamide acting as effective spacer arms.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060111
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  • 71
    Digitale Medien
    Digitale Medien
    Combined application of analytical high performance thin layer chromatography and electroblotting for the detection of anti-ganglioside antibodies in human sera (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 67-71 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Antibodies against gangliosides isolated from small tumour and nervous tissue specimens can be reliably detected in serum samples by the ganglioside electrotransfer technique without the need for previous purification steps. After separation by high performance thin layer chromatography gangliosides are transferred from silica gel plates to hydrophobic polyvinylidene difluoride membranes. These membranes are highly suitable for immuno-staining. The use of a 15-slit device allows simulataneous testing of up to 15 serum samples. Samples of serum from 39 patients with clear-cell carcinoma of the kidney, mammary carcinoma, ovarian carcinoma and neurological disorder together with samples from healthy controls were tested for anti-ganglioside antibodies from various tissues.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060205
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  • 72
    Digitale Medien
    Digitale Medien
    High performance liquid chromatographic determination of 1,5-anhydroglucitol in human plasma for diagnosis of diabetes mellitus (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 63-66 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: This paper describes a high performance liquid chromatographic (HPLC) method for determining 1,5-anhydroglucitol in plasma, in which anion exchange chromatography and pulsed amperometric detection are used. Plasma samples deproteinized with trichloroacetic acid are passed through a three-layer column packed with (1) strongly basic anion (BO3-3 form, the upper layer), (2) strongly basic anion (OH- form, the middle layer) and (3) strongly acidic cation (H+ form, the lower layer) exchange resins. 1,5-Anhydroglucitol is efficiently recovered in the flow-through fraction and interfering substances are completely removed by the column treatment. The analytical response of the method is linear with concentration to 40 mg/L, and it is possible to detect as little as 0.1 mg 1,5-anhydroglucitol per litre of plasma. Analytical recovery is between 96 and 103%, and there is good agreement between the results measured by our method and by a gas/liquid chromatographic method (r = 0.998). The method has been successfully used for the determination of very low 1,5-anhydroglucitol concentrations (〈 1 mg/L) in the plasma of diabetic patients.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060204
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  • 73
    Digitale Medien
    Digitale Medien
    Peroxyoxalate chemiluminescence detection of condensates of malondialdehyde with thiobarbituric acids using a flow system (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 55-58 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The peroxyoxalate chemiluminescence(CL) detection method for the evaluation of the CL intensity of malondialdehyde(MDA) condensates with seven 2-thiobarbituric acid derivatives is described. The method consists of a flow injection technique together with a CL detection system using bis(2,4,6-trichlorophenyl) oxalate(TCPO) and hydrogen peroxide as chemiluminogenic reagents. Linear correlations between CL intensity and concentration are obtained for pmol levels of condensates. Among the condensates, 1,3-diethyl-2-thiobarbituric acid(DETBA)-MDA shows the largest CL intensity. High performance liquid chromatography (HPLC)/CL detection of DETBA-MDA and 1,3-diphenyl-2-thiobarbituric acid(DPTBA)-MDA using a mixture of TCPO and hydrogen peroxide in acetonitrile as a postcolumn reagent solution is also described. The detection limits for DETBA-MDA and DPTBA-MDA are 20 and 200 fmol, respectively, per 20 μL injection at a signal-to-noise ratio of 2. This HPLC/CL detection system was applied to the defermination of MDA in rat brains by using DETBA as a fluorescent derivatizing reagent.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060202
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  • 74
    Digitale Medien
    Digitale Medien
    Phosphotungstate as a useful eluent for hepatitis-B virus surface antigen purification by heparin-sepharose affinity chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 72-76 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: On the basis of the heparin-like effect of phosphotungstate (PTA), we have shown that it is useful for the purification of hepatitis-B virus surface antigen (HBsAg) using heparin-Sepharose affinity chromatography. HBsAg was eluted with 0.2-0.6 M NaCl. HBsAg was also eluted with PTA at approximately 1 mM, and the HBsAg fraction thus obtained contained fewer impurities than the corresponding fraction eluted with NaCl. Moreover, PTA yielded HBsAg and hepatitis-B virus e-antigen simultaneously. PTA may specifically reduce the affinity of HBsAg for heparin as well as simply competing with heparin for an anion-binding site of HBsAg. Residual PTA in the eluate was easily decomposed by alkalization, which was useful for subsequent studies.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060206
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  • 75
    Digitale Medien
    Digitale Medien
    Simultaneous determination of paraquat and diquat in serum using capillary electrophoresis (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 91-94 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The use of capillary electrophoresis for simultaneous separation and detection of the two bipyridylium herbicides, paraquat and diquat, was investigated. Both herbicides were extracted from fortified sera with disposable ODS-silica cartridges. Separation was carried out using a capillary tube (50 μm i.d., 750 mm) of fused silica containing 10 mM glycine-HCl buffer (pH 3.0), 40 mM NaCl and 20% methanol as the carrier. Paraquat and diquat were completely separated in 10 min at an applied potential of 20 kV. On-column UV monitoring allowed detection of both herbicides simultaneously. The assay sensitivity was 0.05 μg/mL (signal-to-noise ratio, 2:1), which probably increases with increase in the sample volume of serum. Analytical recovery of both herbicides added to serum was about 97% at concentrations of 0.5-2.0 μg/mL.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060210
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  • 76
    Digitale Medien
    Digitale Medien
    Simple and highly sensitive determination of free fatty acids in human serum by high performance liquid chromatography with fluorescence detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 120-123 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A highly sensitive and simple reversed phase high performance liquid chromatographic (HPLC) method for the quantitative determination of free fatty acids in human serum is presented. The method is based on the direct derivatization of serum fatty acids with 6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone-3-propionylcarboxylic acid hydrazide. The derivatization reaction proceeds in aqueous solution in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at 37°C. The resulting derivatives are separated within 75 min on a reversed phase column (YMC Pack C8) with a gradient elution of aqueous acetonitrile and detected fluorimetrically. The detection limits are 2.5-5 fmol in a 10 μL injection volume. The sensitivity permits precise determination of free fatty acids in 5 μL serum. The method is simple and is without the conventional liquid-liquid extraction steps of serum fatty acids.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060304
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  • 77
    Digitale Medien
    Digitale Medien
    Measurement of N-acetylneuraminic acid in human serum and urine by high performance liquid chromatography with chemiluminescence detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 135-140 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A highly sensitive method for the determination of N-acetylneuraminic acid in human serum and urine is investigated. This method employs high performance liquid chromatography with chemiluminescence detection. N-Acetylneuraminic acid, released by hydrochloric acid hydrolysis of serum and urine, and N-glycolylneuraminic acid (internal standard) are converted into chemiluminescent derivatives with 4,5-diaminophthalhydrazide dihydrochloride, a chemiluminescence derivatization reagent for α-keto acids. The derivatives are separated within 35 min on a reversed phase column, TSKgel ODS-120T, with isocratic elution, followed by chemiluminescence detection; the chemiluminescence is produced by the reaction of the derivatives with hydrogen peroxide in the presence of potassium hexacyanoferrate(III) in alkaline solution. The detection limit for N-acetylneuraminic acid is 9 fmol (signal-to-noise ratio = 3). This sensitivity permits precise determination of N-acetylneuraminic acid in 10 nL of serum or 50 nL of urine. The method is applied to the determination of the N-acetylneuraminic acid in human sera from normal subjects and cancer patients and in normal urine.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060308
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  • 78
    Digitale Medien
    Digitale Medien
    Dissolution assay of theophylline, diprophylline and proxyphylline from a sustained release dosage form by high performance thin layer chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 141-142 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The content and dissolution rate of theophylline, diprophylline and proxyphylline from a sustained release formulation were determined by UV in situ densitometry. After separation the chromatographic zones corresponding to the spots of theophylline, diprophylline and proxyphylline on the high performance thin layer chromatographic plates were scanned in reflectance/absorbance mode at 275 nm. Quantification was performed with a second degree polynomial function over the range 40-200 ng for theophylline and 60-300 ng for diprophylline and proxyphylline. Percentages of dissolved theophylline, diprophylline and proxyphylline were monitored over 1, 3 and 6 h. The method was found to be simple, accurate, reliable, time-saving (up to 18 samples can be determined simultaneously) and low-cost.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060309
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  • 79
    Digitale Medien
    Digitale Medien
    An improved method for preparation of perbenzoylated ganglioside-derived sialic acids and nanogram detection of N-acetyl- and N-glycolylneuraminic acid by high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 155-159 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: An improved method for the preparation of perbenzoylated ganglioside-derived sialic acids is described. After mild acid hydrolysis, isolation of sialic acids can be achieved by Folch partition (Method A) or by anion exchange chromatography (Method B). Perbenzoylated sialic acids were freed from benzoylation reagents by a second Folch partition. Total recoveries of both methods were found to be ≥90%, calculated from metabolically labelled gangliosides. Derivatized N-acetylneuraminic and N-glycolylneuraminic acids were separated and quantified by isocratic high performance liquid chromatography using a RP18 column as the stationary phase and methanol: water (8:2) as the mobile phase. Both sialic acids were completely separated and eluted as single peaks within 15 min, monitored by UV detection. As little as 20 ng of neuraminic acid could be detected, the detector being linear up to 5 μg tested.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060312
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  • 80
    Digitale Medien
    Digitale Medien
    Use of immobilized metal ions as a negative adsorbent for purification of enzymes: Application to phosphoglycerate mutase from chicken muscle extract and horseradish peroxidase (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 172-176 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Two enzymes, phosphoglycerate mutase and peroxidase, were purified by using an immobilized metal ion adsorbent for the removal of unwanted proteins. The mutase was obtained pure from a single column, whereas the purification of peroxidase required the use of a thiophilic adsorbent in a tandem. The capacity was 2.5 mg pure peroxidase per mL gel.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060404
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  • 81
    Digitale Medien
    Digitale Medien
    TLC separation of certain tetracycline and amino glycopeptide antibiotics (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 196-197 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The separation of tetracycline and amino glycopeptide antibiotics was achieved on silica gel thin layers. Tetracycline antibiotics were resolved on a Co+2 (1.0%) impregnated silica gel layer using ethanol:acetic acid: water (10:6:6, v/v/v) as the mobile phase. Amino glycopeptide antibiotics were separated on an untreated silica gel layer using the mobile phase n-butanol: formic acid: water (6:5:7, v/v/v). The spots of these antibiotics were located by exposing the chromatoplate to iodine vapours.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060409
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  • 82
    Digitale Medien
    Digitale Medien
    Isolation of human haemopexin in apo-form by chromatography on S-sepharose fast flow and blue sepharose CL-6B (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 212-214 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060412
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  • 83
    Digitale Medien
    Digitale Medien
    A simple method for the quantification of famotidine in human plasma and urine by paired-ion high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 222-223 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A new method for the quantification of famotidine consists of a simple extraction procedure and paired-ion high performance liquid chromatography with ultraviolet detection. The method has good accuracy and precision and should be suitable for the routine measurement of plasma and urine samples for clinical studies.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060503
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  • 84
    Digitale Medien
    Digitale Medien
    Determination of naphazoline in rat plasma using column liquid chromatography with ultraviolet detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 241-243 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A sensitive (1 ng/mL) and rapid method for the determination of naphazoline in rat plasma is described. Following extraction, the compound is analysed by reversed phase high performance liquid chromatography and ultraviolet detection at 214 nm.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060508
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  • 85
    Digitale Medien
    Digitale Medien
    A new method for the purification of cytochrome-P450 from human liver microsomes (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 248-250 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A procedure for the solubilization and purification of cytochrome-P450 (cyt-P450) from human liver microsomes is described. Successive treatment of microsomes with protease XXVII and 3-(3-cholamidopropyl)dimethylammoniopropanesulphonic acid gave a solubilized cyt-P450 in more than 80% yield and with a three-fold increae in specific activity. With this treatment it was possible to eliminate 80% of cytochrome-b5 and 75% of NADPH cyt-P450 reductase. The solubilized cyt-P450 was filtered on a Sephacryl-200 column and then subjected to high performance liquid chromatography with a Mono-P column (chromatofocussing). The recovery of separated cyt-P450 was about 50% with a specific activity of 11.5 nmol cyt-P450/mg protein. Also with this technique it was possible to determinate the isoelectric points of cyt-P450. These results allowed us to confirm the usefulness of our method, for the study the cyt-P450 from surgical biopsies.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060510
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  • 86
    Digitale Medien
    Digitale Medien
    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992) 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060201
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  • 87
    Digitale Medien
    Digitale Medien
    The retention behaviour of conjugated bile acids in reversed phase high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 255-257 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The retention behaviour of conjugated bile acids has been studied in a reversed phase high performance liquid chromatographic (RP-HPLC) system by using the mixture of methanol and aqueous phosphate buffer as the mobile phase. The retentions of the conjugates in RP-HPLC have been found to be mainly controlled by the glycine and taurine groups. The selectivity between five different glycine and taurine conjugated bile acids is a constant in RP-HPLC. This selectivity has been used for peak identification in the practical separation of conjugated bile acids.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060512
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  • 88
    Digitale Medien
    Digitale Medien
    Editorial (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 263-263 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060603
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  • 89
    Digitale Medien
    Digitale Medien
    A Selective HPLC/RIA for dexamethasone and its prodrug dexamethasone-21-sulphobenzoate sodium in biological fluids (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 283-286 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A combined high performance liquid chromatography/radioimmunoassay procedure is described for the simultaneous determination of dexamethasone (DEX) and its prodrug dexamethasone-21-sulphobenzoate sodium (DSS) in plasma. After precipitation of the plasma proteins by acetonitrile, the protein-free supernatant was injected onto a C18 reversed phase liquid chromatographic system and DSS- and DEX-containing fractions were collected. Hydrolysis of DSS by 0.01 N NaOH, followed by fractions extraction of both hydrolysed DSS and DEX fractions with ethyl acetate allowed the use of a dexamethasone-specific radioimmunoassay for the selective determination of both compounds. The method is accurate and reproducible (intraday variability for DSS and DEX〈6%, interday variability for DEX 14%), allowing quantification of DEX and DSS as low as 0.3 ng/mL and 0.7 ng/mL, respectively.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060607
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  • 90
    Digitale Medien
    Digitale Medien
    High performance ion exclusion chromatographic characterization of the vaginal organic acids in women with bacterial vaginosis (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 231-235 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Vaginal organic acids have previously been detected by gas-liquid chromatography, but we have applied an ion exclusion high performance liquid chromatographic procedure to the analysis of vaginal discharge samples. This procedure has the advantage of not requiring derivitization of non-volatile acids and provides the convenience of a technique which does not require the use of flammable gasses, while allowing the identification of at least 18 different acids from the same chromatographic analysis. Vaginal discharge from women with symptoms of bacterial vaginosis was collected on weighed swabs and analysed for the presence of organic acids. The results were compared to the organic acid content of samples obtained from the same cohort of women after treatment with metronidazole. In addition, samples were obtained from asymptomatic women and these samples were analysed in the same manner. The number of organic acids present in samples from women with bacterial vaginosis was greater than the number found after treatment or among asymptomatic women. Succinic acid appeared to be inversely related to lactate concentration and succinate:lactate ratios were greater among women with bacterial vaginosis before treatment than after treatment. Liquid chromatography has proven useful as a means of evaluating the metabolic end-products of vaginal microorganisms in situ.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060506
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  • 91
    Digitale Medien
    Digitale Medien
    Quantitative determination of CGS 18102A, a new anxiolytic, in human plasma using capillary gas chromatography/mass spectrometry (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 244-247 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: CGS 18102A is a novel hexahydrobenzopyranopyridine that has a mixed pharmacological profile of 5-HT-1A agonist and 5-HT-2 antagonist properties. Based upon these mechanisms, the compound is predicted to have anxiolytic efficacy with possible efficacy in depression. Preclinical studies in the rat have shown the drug to be well absorbed and extensively metabolized. Because of the anticipated low plasma levels in humans a gas chromatography/mass spectrometry (GC/MS) analytical method has been developed and validated to determine plasma concentrations of CGS 18102A in early clinical studies. The method utilizes CGS 18416A as the internal standard. Samples (1 mL) were extracted with pentane:ethyl acetate (75:25, v:v). Extracts were then concentrated and analysed directly by GC/MS. Separation was accomplished on a methylsilicone capillary column (30 m × 0.32 mm i.d.). GC/MS was carried out under positive ion ammonia CI conditions, with selected ion monitoring of the [M + H]+ ions (m/z = 262 and 248) for CGS 18102A and CGS 18416A, respectively. The method was successively applied to the analysis of clinical samples from an ascending multidose safety and tolerability study conducted in six normal healthy male volunteers.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060509
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  • 92
    Digitale Medien
    Digitale Medien
    Determination of low molecular weight aliphatic primary amines in urine as their benzenesulphonyl derivatives by gas chromatography with flame photometric detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 251-254 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A selective and sensitive method for the determination of low molecular weight aliphatic primary amines in urine is described. These amines were converted into their benzenesulphonyl derivatives by a modified Hinsberg procedure, and measured by gas chromatography with flame photometric detection (FPD-GC) using a DB-1 capillary column. The derivatives were very stable and provided excellent FPD responses. By FPD-GC, linear calibration curves were obtained in the range 10-200 ng of methylamine, ethylamine, n-propylamine, isobutylamine and n-butylamine using tert-butylamine as an internal standard, and the detection limits of these amines were ca. 6-25 pg as the injection amount. Benzenesulphonamide derived from ammonia was converted into its N-dimethylaminomethylene derivative which has a longer retention time, and separated from benzenesulphonyl derivatives of low molecular weight primary amines on the chromatogram. The recoveries of aliphatic primary amines added to urine samples were 91-107% and the relative standard deviations were 0.2-4.5%. Analytical results of aliphatic primary amine contents in urine samples of normal subjects are presented.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060511
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  • 93
    Digitale Medien
    Digitale Medien
    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992) 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060601
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  • 94
    Digitale Medien
    Digitale Medien
    Mixed-bed polymeric o-nitrobenzophenone reagents for the on-line derivatization of amines in high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 269-277 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Several polymer-bound o-nitrobenzophenone reagents containing different detector-sensitive tags have been combined in the same reactor for the on-line derivatization of amine samples. The formation of multiple derivatives allows numerous opportunities for quantitation from the same injection, and also allows improved identification from the retention times of the multiple derivatives. Changing the reaction conditions changes the ratio of the products formed, so that changes in the ratio of peak heights and areas can also be used for analyte identification. In this work, propylamine was derivatized in acetonitrile on-line, precolumn. Changing the reaction conditions, of reaction time, temperature, solvent, presence of catalyst and the components of the reactor, changed the ratio of the derivatives formed. These changes in product formation with changing reaction conditions were applied to the identification and quantitation of amphetamine and methamphetamine in urine. The drugs were identified by the retention times of their derivatives, the ratio of te peak areas of the derivatives and the change in the ratios after changing reaction conditions. Each derivative was also used for quantitation of levels of spiked concentrations of amphetamine and methamphetamine, with relative errors less than 8%.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060605
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  • 95
    Digitale Medien
    Digitale Medien
    A high performance liquid chromatographic method for the determination of albuterol enantiomers in human serum using solid phase extraction and chemical derivatization (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 291-294 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A high performance liquid chromatographic method was developed for the simultaneous assay of R(-)- and S(+)-albuterol in human serum. The assay involves solid phase extraction as a sample clean-up step and derivatization of racemic albuterol to its diastereomeric thioureas with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl isothiocyanate. Chromatographic separation was accomplished under isocratic conditions using an octadecylsilane column and a mobile phase consisting of 29:71 acetonitrile:distilled water containing 0.1% triethylamine, pH 4.0 (adjusted with concentrated phosphoric acid) at a flow rate of 0.8 mL/min. The diastereomers were detected using a fluorescence detector set at 223 nm excitation and no emission filter. Racemic bamethane was used as internal standard. Drug to internal standard peak-height ratios were linear over a 2-20 ng/mL range for each enantiomer. The limit of detection of each analyte was 1.0 ng/mL (S/N = 3).
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060609
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  • 96
    Digitale Medien
    Digitale Medien
    Robotic solid phase extraction and high performance liquid chromatographic analysis of ranitidine in serum or plasma (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 311-316 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A fully automated assay for the analysis of ranitidine in serum and plasma, with and without an internal standard, was validated. It utilizes robotic solid phase extraction with on-line high performance liquid chromatographic (HPLC) analysis. The ruggedness of the assay was demonstrated over a three-year period. A Zymark Py Technology II® robotic system was used for serial processing from initial aspiration of samples from original collection containers, to final direct injection onto the on-line HPLC system. Automated serial processing with on-line analysis provided uniform sample history and increased productivity by freeing the chemist to analyse data and perform other tasks. The solid phase extraction efficiency was 94% throughout the assay range of 10-250 ng/mL. The coefficients of variation for within- and between-day quality control samples ranged from 1 to 6% and 1 to 5%, respectively. Mean accuracy for between-day standards and quality control results ranged from 97 to 102% of the respective theoretical concentrations.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060613
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  • 97
    Digitale Medien
    Digitale Medien
    Determination of 10α-methoxy-9,10-dihydrolysergol, a nicergoline metabolite, in human urine by high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 9-11 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A specific method for the determination of 10α-methoxy-9,10-dihydrolysergol, a nicergoline metabolite (metabolite 2), in urine is described. Metabolite 2 was well separated from the urine components on a reversed phase column, Hypersil ODS 5 μm, using an acetonitrile: pH 3.5 phosphate buffer (40:60, v/v) as the mobile phase at a flow rate of 1 mL/min. UV detection was set up at 220 nm. After addition of a known amount of lysergamide as the internal standard, the compounds were extracted from alkalysed urine on a pre-packed glass column (Extrelut 1) with dichloromethane. With 0.5 mL urine, concentrations down to 0.56 μmol/L could be determined.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060104
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  • 98
    Digitale Medien
    Digitale Medien
    Preparation of glycine-conjugated bile acids and their gas/liquid chromatographic analysis on an aluminum-clad flexible fused silica capillary column (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 4-8 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: This paper describes a method for the direct gas/liquid chromatographic (GC) analysis of 46 glycine-conjugated bile acids, which differ from one another in the number, position and configuration of the hydroxyl groups at positions C-2, C-3, C-4, C-6, C-7 and/or C-12. Free bile acids were converted quantitatively on a micro scale to ethyl ester-trimethylsilyl (Et-TMS) and methyl ester-dimethylethylsilyl (Me-DMES) ether derivatives of the corresponding glycine conjugates. The Et-TMS and Me-DMES ethers of the glycine conjugates were chromatographed on an aluminum-clad flexible fused-silica capillary column coated with a thin film (0.1 μm) of chemically bonded and cross-linked methylpolysiloxane. Relative retention time (RRT) and methylene unit (MU) values were determined for the 46 compounds and their GC behaviour was discussed. The derivatization procedure and the retention data would be useful for the direct GC identification of unknown glycine-conjugated bile acid mixtures extracted from biological samples.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060103
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  • 99
    Digitale Medien
    Digitale Medien
    Quantitative determination of valproic acid and 14 metabolities in serum and urine by gas chromatography/mass spectrometry (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 24-29 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A method for the determination of the antiepileptic drug valproic acid and 14 of its metabolites in serum and urine by gas chromatography/mass spectrometry with selected ion monitoring of the trimethylsilylated derivatives has been developed. Sample preparation, including hydrolysis of VPA-conjugates and removal of urea in urine is carried out at pH 5.0 and is rapid and simple. The samples are extracted with ethyl acetate and the concentrated extracts are trimethylsilylated. Analysis with adequate separation of metabolites is achieved with a DB 1701 fused silica (Megabore) capillary column. The method exhibits high recovery and reproducibility and is sufficiently sensitive and selective for analysis of small sample volumes. Application of the method for screening patient serum and urine samples for unusual metabolite patterns, with possible predictive value for early detection of liver injury, is presented.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060108
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  • 100
    Digitale Medien
    Digitale Medien
    Calendar of events (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 108-108 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130060214
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