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  • 2005-2009
  • 1990-1994  (3.428)
  • 1970-1974  (1.690)
  • 1930-1934
  • 1991  (3.428)
  • 1974  (1.690)
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Datenquelle
Materialart
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  • 2005-2009
  • 1990-1994  (3.428)
  • 1970-1974  (1.690)
  • 1930-1934
Jahr
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  • 1
    Digitale Medien
    Digitale Medien
    Diethylene glycol (DEG)-associated myocardial changes: A pilot investigation of chronic intoxication in guinea-pigs (1991)
    Springer
    International journal of legal medicine 104 (1991), S. 93-97 
    Details
    ISSN: 1437-1596
    Schlagwort(e): Diethylene glycol ; Intoxication ; Myocardium ; Myocytolysis ; Ultrastructure ; Mitochondria ; Guinea pig ; Diethylenglycol ; Intoxikation ; Myokard ; Myozytolyse ; Ultrastruktur ; Mitochondrien ; Meerschweinchen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Rechtswissenschaft
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Das Myokard von Meerschweinchen, welche mit subletalen Mengen von Diethylenglycol über eine Zeitdauer von 2–11 Tagen gefüttert worden waren, wurde mikroskopisch und elektronenmikroskopisch untersucht. Eine Koagulationsmyozytolyse und Verlust von Myofibrillen war fleckförmig verstreut über das Myokard. Diese Veränderungen waren in den Kontrollen nicht zu beobachten. Die begleitenden ultrastrukturellen Veränderungen bestanden in Schwellung, Pleomorphie, Hyperplasie von Mitochondrien, begleitet von einer Erweiterung der interfibrillären Räume und Verlagerung, Verzerrung und Ruptur angrenzender Fibrillen.
    Notizen: Summary The myocardium of guinea pigs fed on sublethal doses of diethylene glycol (DEG) over a period of 2–11 days was examined for microscopical and ultrastructural changes. Coagulative myocytolysis and loss of myofibrils, not observed in the controls, was patchily distributed throughout the myocardium. The accompanying ultrastructural features included swelling, pleomorphism and hyperplasia of mitochondria with an associated distension of the interfibrillary spaces and a displacement, distortion and rupture of adjacent myofibrils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01626038
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  • 2
    Digitale Medien
    Digitale Medien
    Effect of dopamine agonist medication on prolactin producing pituitary adenomas (1991)
    Springer
    Virchows Archiv 418 (1991), S. 439-446 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Bromocriptine ; Pituitary neoplasm ; Prolactin ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Conventional light microscopy, immunocyto-chemistry, electron microscopy and in situ hybridization were used to evaluate the effect of dopamine agonists (bromocriptine-LAR and bromocriptine) on the morphology of surgically removed prolactin (PRL)-producing pituitary adenomas. Dopamine agonist therapy resulted in decrease of serum PRL, clinical improvement and tumour shrinkage. Using light and electron microscopy cellular atrophy, interstitial and perivascular fibrosis were noted; in several tumours connective tissue accumulation was pronounced. The cellular response was not uniform. In some adenomas populations of large cells and small cells were distinguished. The large cells contained immunoreactive PRL and expressed the PRL gene indicating resistance to dopamine agonists. It appears that these cells retained the potential to secrete PRL and proliferate despite exposure to dopamine agonists. In the small cells, PRL immunoreactivity and PRL gene expression decreased providing evidence that both PRL release and synthesis were blocked. Small cells can persist in tumours after discontinuation of dopamine agonist medication suggesting these small cells are irreversibly suppressed and are not capable of regaining their endocrine function and proliferative capability. The formation of irreversibly suppressed PRL cells may explain why some PRL-producing adenomas do not recur after withdrawal of dopamine agonists.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01605931
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  • 3
    Digitale Medien
    Digitale Medien
    Immunohistochemical characterization of HLA-DR-antigen positive dendritic cells in phaeochromocytomas and paragangliomas as a prognostic marker (1991)
    Springer
    Virchows Archiv 418 (1991), S. 33-39 
    Details
    ISSN: 1432-2307
    Schlagwort(e): HLA-DR ; Phaeochromocytomas ; Paragangliomas ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Twelve cases of phaeochromocytoma (PCC) and four cases of paraganglioma (PGG) were studied by immunohistochemistry and immunoelectron microscopy in order to demonstrate HLA-DR (Ia)-antigen-positive dendritic cells (IaDCs). Dense infiltration of IaDCs was detected in the majority of PCCs revealing high urinary or serum catecholamine levels, but in aggressively growing PCCs, a familial PCC and all PGGs, few IaDCs were demonstrated. Interestingly, these IaDCs were negative for S-100 protein. Although S-100-protein-positive sustentacular-like cells (SCs), morphologically similar to IaDCs, were also present, these were clearly distinguished from IaDCs by our double immunostaining method. Ultrastructurally, IaDCs had smooth or slightly indented nuclei and contained a moderate amount of endoplasmic reticulum, small mitochondria and vacuoles, extending elongated cytoplasmic processes. These results suggest that determination of the quantity of IaDCs is a highly effective method of assessing the character of PCCs, in particular, their prognosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600242
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  • 4
    Digitale Medien
    Digitale Medien
    Cell-mediated cytotoxicity in acute rat cardiac allograft rejection: An immunological and ultrastructural study (1991)
    Springer
    Virchows Archiv 418 (1991), S. 41-50 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Cell-mediated cardiocyte injury ; Acute cardiac allograft rejection ; Mononuclear cellular infiltration ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To clarify the immune mechanism of cytotoxicity in acute cardiac allograft rejection, we observed interactions between cardiocytes and mononuclear cells using immunohistochemistry and light and electron microscopy. All allografted WKA rat hearts transplanted to F344 recipients stopped beating by the 7th day after the transplantation. The population of helper/inducer T cells (Th) and IL2R+ cells was large for the first 3 days, whereas that of cytotoxic/suppressor T cells (Tc-s) and macrophages increased from the 4th day. TheTh/Tc-s ratios were more than 2.0 until the 3rd day, then decreased to less than 1.0. In circulating T lymphocytes; theTh/Tc-s ratios were under 1.0 on the 1st, 6th and 7th days. Electron microscopically IL2R+ cells, Tc-s and macrophages were often seen in close contact with the plasma membrane of the cardiocytes. The majority of IL2R+ cells are NK cells, Tc-s andTh. Of these, the population of Tc-s was small until the 3rd day. Thus, NK cells play a pivotal role in the early stage of the rejection, and Tc-s and macrophages then aggravate cell-mediated cardiocyte injury.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600243
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  • 5
    Digitale Medien
    Digitale Medien
    Ultrastructure of oesophageal melanocytosis (1991)
    Springer
    Virchows Archiv 418 (1991), S. 515-522 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Oesophagus ; Melanocyte ; Melanoma ; Ultrastructure ; Endoscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Four examples of an endoscopically detected oesophageal melanotic lesion were examined by light microscopy, light microscope histochemistry and transmission electron microscopy, and were compared with 13 control samples of normal oesophageal epithelium. By light microscopy, pigmented melanocytes lacking atypia and mitoses were observed amongst the keratinocytes in the basal layer of the oesophageal mucosa. Junctional activity was absent. The mechanism of pigmentation was studied and found to consist of: an increase in the number of melanocytes in the basal layer of the mucosa, an increase in the quantity of melanin in these melanocytes, transfer of melanin from melanocytes to keratinocytes and to macrophages and fibroblasts in the tunica propria. Since all the lesions demonstrated increased numbers of both melanocytes and melanosomes, the term oesophagealmelanocytosis rather thanmelanosis is suggested, to emphasise the essential character of the lesion as a cellular proliferation. The value of sampling these pigmented lesions during endoscopy is emphasised as a means of obtaining well-preserved material for the evaluation of a lesion which some authorities have viewed as a possible precursor for oesophageal malignant melanoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606502
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  • 6
    Digitale Medien
    Digitale Medien
    Ultrastructural abnormalities of mitochondria and deficiency of myocardial cytochromec oxidase in a patient with ventricular tachycardia (1991)
    Springer
    Virchows Archiv 419 (1991), S. 63-68 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Mitochondrial cardiomyopathy ; Ultrastructure ; Cytochromec oxidase deficiency ; Ventricular tachycardia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A 30-year-old woman presented with lifethreatening ventricular tachycardia without overt heart disease. Ultrastructural investigation of endomyocardial biopsy disclosed abnormally structured and often enlarged mitochondria. Morphometry revealed the ratio of volume density of mitochondria to myofibrils to be markedly increased to 0.667 as compared with five controls (mean: 0.46; range: 0.445–0.479). Investigation of mitochondrial respiratory chain enzymes revealed a 90% reduction in activity of cytochromec oxidase. Our data suggest that mitochondrial cardiomyopathy may induce malignant ventricular arrhythmias.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600154
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  • 7
    Digitale Medien
    Digitale Medien
    Varicocele in the rat: a new experimental model (1991)
    Springer
    Urological research 19 (1991), S. 319-322 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Varicocele ; Rat, Histology ; Ultrastructure ; Temperature ; Infertility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary With no consistent animal prototype for the study of varicocele, we set out to create a model in the rat by complete ligation of the main branch of left spermatic vein (MBSV) or by partial ligation of the left renal vein. Three months later, the histology, ultrastructure and temperature of the testis and epididymis were studied. Microscopically, spermatogenic arrest was the most frequent anomaly seen. The most frequently noted ultrastructural change of the testis was distension of smooth endoplasmic reticula in Sertoli cells. The microvilli of columnar epithelia in epididymis were sparse and showed local defects. Lesions and increased temperatures in the testis and epididymis induced by the ligation of the left MBSV were similar to those seen in partial ligation of the left renal veins, with no significant differences between left and right. Significant differences were found, however, on comparison with the controls.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00299069
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  • 8
    Digitale Medien
    Digitale Medien
    Morphology of the synovium during its differentiation and development in the mouse knee joint (1991)
    Springer
    Anatomy and embryology 183 (1991), S. 537-544 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Synovial membrane ; Development ; Ultrastructure ; Scanning electron microscopy ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The prenatal and postnatal development of the mouse knee joint was investigated by transmission and scanning electron microscopy. In the prenatal stage, following the appearance of a narrow intercellular cleft between two skeletal elements on the 16th fetal day, clefting extended into the lateral synovial mesenchyme. In some regions, the extension of the cleft was very rapid, but in a certain region (future fat pad region), it was somewhat slower. Macrophage-like cells appeared in the synovial mesenchyme on the 16th fetal day, and then increased in number, and were distributed as if they were clustering around the presumptive clefting zone in the future fat pad region on the 17th–18th fetal day. This suggests that macrophage-like cells may participate in joint development, as they phagocytize and remove some kinds of solid extracellular matrix, and facilitate the cleft extension. In the early postnatal stage, scanning electron microscopic observations showed that there were two different types of cell in the synovial lining. One of them exhibited a surface morphology corresponding to that of macrophages: a spherical cell body and numerous pseudopodia. The other type of cell exhibited various cell shapes with many cytoplasmic processes extending along the synovial surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00187902
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  • 9
    Digitale Medien
    Digitale Medien
    Endothelial heterogeneity in the chick wing bud: A morphometric study (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 47-53 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Wing bud ; Endothelial cell ; Development ; Ultrastructure ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The microvascular endothelium of the chick wing bud at stages 22, 27, and 32 was evaluated by ultrastructural morphometry. The rationale for this study is based on the hypothesis that endothelial cells exhibit variation in structure and function during cytodifferentiation. The microvessels had a luminal diameter range such that they were classified as capillaries. The thin continuous endothelium was devoid of a basal lamina. The endothelium had a very small number of plasmalemmal vesicles; vacuoles were however present for all stages and in some cases were abundant. The temporal findings were that endothelial cell thickness increases, plasmalemmal vesicle densities decrease, and the densities of cytoplasmic vacuoles increase. The spatial results were that endothelial cells in proximal regions of the limb have a greater thickness, contain fewer vesicles and have more vacuoles than those in distal regions. In general, these results indicate that endothelial ultrastructural heterogeneity occurs within a 31/2 day timespan of wing bud development. The discussion considers the results with regard to recent reports on endothelial cell heterogeneity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01744260
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  • 10
    Digitale Medien
    Digitale Medien
    Development of taste organs inRana temporaria (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 363-369 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Taste organs ; Amphibia ; Development ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In tadpoles ofRana temporaria two successive generations of taste organs: taste buds (TBs) and taste disks were studied. The TBs are located in the apices of oral premetamorphic papillae. Each TB consists of vertically elongated receptor cells (probably taste) and supporting cells. No basal (Merkel) cells were observed there. Morphologically, two types of receptor cells have been distinguished in a TB. Complete synaptic structures were observed in the TBs between the 30th and 41st of Gosner's (1960) developmental stages, though synaptic vesicles occur already at stage 26. The taste disks consist of taste cells, supporting cells and basal cells. Dense-core synaptic vesicles occur in the gustatory cells at stage 41, but complete synaptic structures were not observed earlier than at stage 45. Synaptic junctions observed at some of the gustatory cells seem to be reciprocal (bidirectional).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00957898
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  • 11
    Digitale Medien
    Digitale Medien
    The anatomy and fine structure of the echidnaTachyglossus aculeatus snout with respect to its different trigeminal sensory receptors including the electroreceptors (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 371-393 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Tachyglossus aculeatus (echidna) ; Echidna bill ; Sensory receptors ; Electroreceptor ; Mechanoreceptor ; Trigeminal nerve ; Monotreme ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The gross anatomy and nerve supply of the bill of echidna (Tachyglossus aculeatus) is described in relation to its function as an outstanding sensory organ. The sensory innervation of the skin of the echidna snout was investigated by means of frontal serial sections, after decalcification of the specimens. A comprehensive light and electron microscopic description of the location and fine structure of cutaneous sensory receptors of the trigeminal system was made by this means. The encapsulated and non-encapsulated Ruffini receptors, the types of other free receptors in the connective tissue and the Merkel cell receptor do not differ morphologically from those of higher mammals, whereas the pacinian-like corpuscle shows a unique organization of its outer core. This is composed of large perineural cells containing a unique reticulum of parallel-orientated endoplasmic membranes. Lamellated corpuscles, seen in isolation or in association with push rods, are numerous in the snout and in the tip of the tongue of echidna. Push rod receptor organs occur in the hairless skin of the bill with a very dense array at its rostral end and in the pseudopalatal ridges. Gland duct receptors are restricted to the skin adjacent to the nostrils and the mouth opening, including the pseudopalatal plates. Only about one quarter of the total number of 400 seromucous glands receive a sensory innervation of their intraepidermal duct segment. Within each innervated gland two types of receptor terminals are identified. The distributions of the different receptor types are mapped for different regions of the skin, the mucous membrane of the nasal and oral vestibule and the tip of the tongue. The fine structure of nerve terminals is discussed from a comparative anatomical point of view, and some speculations are made about possible transduction processes that underlie the known electrophysiological properties. The sensory organs such as the “push rod” and “gland duct receptor”, and most of their sensory terminals, are less differentiated in echidna snout than in the platypus (Ornithorhynchus anatinus) bill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00957899
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  • 12
    Digitale Medien
    Digitale Medien
    Immunocytochemical and ultrastructural studies of hyaline inclusions in sporadic motor neuron disease (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 295-301 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Hyaline inclusions ; Motor neuron disease ; Amyotrophic lateral sclerosis ; Immunocytochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We investigated hyaline inclusion bodies (HI) immunocytochemically and ultrastructurally in six cases of sporadic motor neuron disease (MND). All HI contained large amounts of ubiquitin and some HI were stained at the core or the center with anti-neurofilament antibody, with the surrounding halo unstained. No HI were stained with antibodies raised against cytoskeletal proteins such as high-molecular weight microtubule-associated proteins and phosphorylated tau. Ultrastructurally, HI were chiefly composed of filaments measuring about 20 nm in diameter thicker than neurofilaments, and contained fine granules and frequently one or more of four characteristic profiles, i.e., small electron-dense materials resembling Bunina bodies, bundles of tubular filaments measuring approximately 20 nm in diameter, large electron-dense cores, and focal accumulations of randomly arranged neurofilaments. Hyaline inclusions can be regarded as one of the characteristic markers for sporadic MND as well as familial amyotrophic lateral sclerosis. Hyaline inclusions have a markedly heterogeneous ultrastructure and, therefore, differences in immunoreactivity with antineurofilament antibodies are not unexpected.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00308815
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  • 13
    Digitale Medien
    Digitale Medien
    Meningiomas differentiating to arachnoid trabecular cells: a proposal for histological subtype “arachnoid trabecular cell meningioma” (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 327-330 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Meningioma ; Microcystic meningioma ; Vacuolated meningioma ; Arachnoid trabecular cell ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Three cases of meningiomas which had abundant small vacuoles in the tumor tissue are reported. By electron microscopy, the tumor cells exhibited long and thin processes, the tips of which were united by desmosomes. The tumor tissue was revealed to have wide extracellular spaces which corresponded to the vacuoles observed by light microscopy. In previous literature, various terms have been used when referring to this meningioma, such as microcystic meningioma or vacuolated meningioma. Since the ultrastructure of the tumor showed similarity to that of normal arachnoid trabecular cells, we propose to call the tumor “arachnoid trabecular cell meningioma” denoting its morphological nature clearly.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296542
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  • 14
    Digitale Medien
    Digitale Medien
    Galactosialidosis: neuropathological findings in a case of the late-infantile type (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 331-339 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Galactosialidosis ; Neuronal storage disease ; Neuropathology ; Ultrastructure ; Neuronal loss
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The neuropathological findings in a 13-year-old Japanese male showing decrease of sialidase and β-galactosidase activities are reported. The patient was the product of normal pregnancy to consanguineous parents. He started to sit at 8 months, stand at 20 months and walk at the age of 2; mental retardation, visual disturbance, cerebellar ataxia, myoclonus and epilepsy developed by the age of 10, and he died at 13. Neuropathological investigation revealed neuronal loss and storage. Severe loss of neurons was observed in the thalamus, globus pallidus, lateral geniculate body, gracile nucleus, Purkinje and retinal ganglion cells. Marked ballooning was seen in the Betz cells and neurons in the basal forebrain, the motor neurons in the cranial nerve nuclei and spinal cord, and in the trigeminal and spinal ganglia. The storage material varied in staining from region to region and from neuron to neuron. Electron microscopic investigation revealed a variety of intracytoplasmic and intranuclear inclusions: membranous cytoplasmic bodies, parallel, wavy-lamellar or tortuous tubular structures, lipofuscin-like irregular-shaped pleomorphic bodies, and cytoplasmic vacuoles with fine granules and lamellar materials. The severity of the neuronal loss did not seem to correlate with the amount of the storage materials, but with the presence of tortuous tubular inclusion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296543
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  • 15
    Digitale Medien
    Digitale Medien
    Intramedullary secretory gangliocytoma (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 402-407 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Gangliocytoma ; Ultrastructure ; Catecholamines ; Hypertension ; Spinal cord
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An 8-year-old boy developed severe systemic hypertension during resection of an intramedullary tumor. The histological, ultrastructural and immunocytochemical characteristics of the tumor are those of a gangliocytoma. Based on the demonstration of tyrosine hydroxylase in neuronal tumor cells, it is postulated that catecholamine secretion was responsible for the systemic hypertension.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296552
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  • 16
    Digitale Medien
    Digitale Medien
    Immunocytochemical and ultrastructural studies of Werdnig-Hoffmann disease (1991)
    Springer
    Acta neuropathologica 81 (1991), S. 408-417 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Werdnig-Hoffmann disease ; Immunocytochemistry ; Ultrastructure ; Cytoskeleton ; Ubiquitin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neuronal alterations in two cases of Werdnig-Hoffmann disease (WH) were investigated immunocytochemically and ultrastructurally. Ballooned neurons (BNs) were found in anterior horn, Clarke's column, dorsal root ganglion and thalamus. Anti-phosphorylated neurofilament antibodies preferentially stained the peripheral perikarya and proximal neuronal processes of BNs, whereas anti-ubiquitin antibodies preferentially stained the central perikarya of BNs. Ultrastructurally, BNs showed degenerative changes ranging from a diffuse increase of neurofilaments to a centrally accentuated accumulation of mitochondria and vesicular or membranous profiles. Our studies suggest that ubiquitinated degradation products accumulate in the center of the BN's perikaryon and displace aberrantly phosphorylated neurofilaments to the periphery. BNs in WH probably reflect an intrinsic alteration in the metabolism of neurofilaments that is associated with regressive changes in the neuron and eventually neuronal death.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00293462
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  • 17
    Digitale Medien
    Digitale Medien
    The effect of denervation on the morphology of regenerating rat soleus muscles (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 21-32 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Muscle ; Regeneration ; Denervation ; Ultrastructure ; Snake toxin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This study examines the level to which muscle regeneration proceeds in the absence of innervation. Regeneration was monitored in rat soleus muscles following localised injection of a snake toxin, notexin. Muscles which had been concomittantly denervated were compared with those that were normally innervated. Until 3–4 days following toxin administration regeneration is identical in both groups. The muscles contain new myotubes in place of the degenerated “parent” fibres. Thereafter, the non-denervated muscles grow rapidly and by 28 days their myofibres attain the size of those from the contralateral controls. Growth of denervated regenerating muscles, however, is retarded and is superseded by a gradual atrophy. In such muscles we further identify ultrastructural abnormalities from 7 days post-injection. These a re loss of individual myosin filaments and the presence of immature and abnormal configurations of the transverse system and triads. We, thus, conclude that innervation is an obligatory requirement for the restoration of normal myofibrillar and sarcotubular morphology, as well as growth, but is not necessary for the neo-formation of myofibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310919
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  • 18
    Digitale Medien
    Digitale Medien
    Bone marrow transplant in a case of mucopolysaccharidosis I Scheie phenotype: skin ultrastructure before and after transplantation (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 33-38 
    Details
    ISSN: 1432-0533
    Schlagwort(e): MPS I-S ; Skin biopsy ; Ultrastructure ; Bone marrow transplant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An 11-year-old girl with mucopolysaccharidosis I Scheie phenotype (MPS I-S) received a bone marrow transplant (BMT) from her heterozygous HLA-identical LMC-non-reactive mother. Multidisciplinary studies were carried out and results evaluated 21 months after transplantation. Herein we report the ultrastructural findings pre-and post-BMT in skin. Multidisciplinary studies are commonly used to evaluate the benefits of metabolic correction following BMT in some MPS and other inherited metabolic disorders, and changes in morphology have been described in liver and few other tissues. In this case, we elected skin, since connective tissue is universally involved in MPS and is safely and easily obtainable. Comparison of skin biopsy specimens taken before and after BMT showed a considerable change in dermal fibroblast morphology, with marked reduction in cell size and the number and size of abnormal lysosomes, thus indicating the clearance of storage. Our results demonstrate that dermal cells respond to enzyme replacement therapy in MPS I-S, with the clearance of glycosaminoglycan lysosomal accumulation in connective tissue fibroblasts, which had near-normal morphology 21 months after BMT. Therefore, the practice of skin biopsy after BMT in MPS and other metabolic disorders in which dermal cells are involved should be encouraged.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310920
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  • 19
    Digitale Medien
    Digitale Medien
    Idiopathic prolactin cell hyperplasia of the pituitary mimicking prolactin cell adenoma: a morphological study including immunocytochemistry, electron microscopy, and in situ hybridization (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 147-151 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Hyperplasia ; Pituitary ; Pathology ; Prolactin ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Prolactin cell adenoma is the most frequently found lesion in surgically removed pituitaries of patients with hyperprolactinemia. However, in several instances, instead of prolactin cell adenoma, other lesions are encountered by morphological investigation. We report here the morphological findings in a patient with hyperprolactinemia who underwent transsphenoidal pituitary surgery for suspected prolactin cell adenoma. A morphological diagnosis of tumor could not be confirmed and massive diffuse prolactin cell hyperplasia was identified. The aim of this publication is to describe the lesion by histology, immunocytochemistry, electron microscopy, and in situ hybridization and to call attention to primary prolactin cell hyperplasia which can mimic prolactin cell adenoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00293958
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  • 20
    Digitale Medien
    Digitale Medien
    Fulminant blastomycosis with blastomycotic infection of a cerebral glioma (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 420-424 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Blastomycosis ; North American Blastomy-cosis ; Brain tumor ; Opportunistic infection ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Except for isolated case reports, blastomycosis has not been identified as a significant problem in immunosuppressed patients. We describe an unusual case with blastomycotic infection of a cerebral glioma in a 56-year-old man who underwent radiotherapy for his tumor and died of fulminant blastomycotic pneumonia. This is believed to be the first reported case of Blastomyces dermatitidis infection of a cerebral glioma. The light microscopic and ultrastructural features of B. dermatitidis, the giant forms of which were encountered in our patient, are described, and the role of immuno-suppression due to steroid therapy in the pathogenesis of this fulminant infection are reviewed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296555
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  • 21
    Digitale Medien
    Digitale Medien
    Scrapie inoculation of mice: light and electron microscopy of the superior colliculi (1991)
    Springer
    Acta neuropathologica 81 (1991), S. 562-571 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Scrapie ; Ultrastructure ; Vacuolation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural examination of the superior colliculi of mice intraocularly inoculated with the ME7 strain of scrapie showed vacuolation early in the course of infection. Brains were examined between 85–260 days after monocular inoculation with scrapie. The mean incubation period for the development of clinical disease was 302 days. Vacuolation was seen initially in the contralateral superior colliculus and subsequently in the ipsilateral colliculus. In coded trails light microscopical vacuolation was seen from 218 days but ultrastructural examination showed that sparse vacuoles were inconsistently present in either or both of the ipsilateral and contralateral colliculi from 85 days; frequent vacuoles were seen from 190 days. Scrapie-induced vacuoles were differentiated from vacuoles present in control tissue by the presence of loculation or by a limiting double membrane which showed protrusion or proliferation of the innermost lamella. Vacuolation was seen in neuronal perikarya, myelinated fibres, dendrites and axonal presynaptic terminals. Vacuoles of myelinated fibres were observed within myelin and possibly also in the inner tongue of oligodendroglial cytoplasm. Whorled membrane configurations were also seen. Tubulovesicular particles, 40 nm in diameter, were recognised in two scrapie-infected mice. It is suggested that some scrapie vacuoles arise as a result of incorporation of abnormal membrane into organelles, possibly mitochondria, in neuronal perikarya and neurites and probably also within oligodendroglial cytoplasm and myelin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310139
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  • 22
    Digitale Medien
    Digitale Medien
    Histopathogenesis of inflammatory linear verrucose epidermal naevus: histochemistry, immunohistochemistry and ultrastructure (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 491-499 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Inflammatory linear epidermal naevus ; Keratinization ; DACM ; Involucrin ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Skin lesions of three patients with inflammatory linear verrucose epidermal naevus (ILVEN) were examined. Histologically, orthokeratosis and parakeratosis were alternately seen in the acanthotic epidermis. By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, the horny cells in the parakeratotic epidermis showed a cytoplasmic SH pattern and a weak membranous SS pattern. The orthokeratotic epidermis revealed an increased involucrin expression, whereas the parakeratotic epidermis showed almost no involucrin expression. Ultrastructurally, in the parakeratotic epidermis, the living keratinocytes had prominent Golgi apparatuses and vesicles in the cytoplasm. In the intercellular spaces in the upper spinous layer through to the lower horny layer, an electron dense, homogeneous substance was deposited. The cytoplasm of the horny cells was filled with keratin filaments and contained remnants of nucleus and cytoplasmic membrane structures, and some lipid droplets. The marginal band formation was incomplete. Most of these ultrastructural abnormalities were not found in the orthokeratotic epidermis. There are both similarities and differences in histopathogenesis of the parakeratotic epidermis between ILVEN and psoriasis. A unique finding was the lack of involucrin expression in the ILVEN parakeratotic epidermis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00371921
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  • 23
    Digitale Medien
    Digitale Medien
    The rhino mouse model: the effects of topically applied all-trans retinoic acid and CD271 on the fine structure of the epidermis and utricle wall of pseudocomedones (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 100-107 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Rhino mouse skin ; All-trans retinoic acid ; CD271 ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The histological and ultrastructural effects following 3 weeks' topical treatment with two agents (all-trans retinoic acid and a new synthetic retinoid-like substance, CD271) were evaluated on the epidermis and the epithelial wall of the pseudocomedones in rhino mouse skin. The comedolytic effects of these drugs were similar, and consisted of a reduction of the utricular diameter, with normalization of follicular units. Morphological examinations revealed a hyperplastic response with an increase in the number of cell layers of both epidermis and follicular epithelium, and modifications in keratinocyte differentiation. Ultrastructural changes in the epidermis and epithelial wall were observed mainly in the granular and horny layers, with increased desquamation, and a decrease in the cohesiveness of corneocytes. During the first week of treatment, some cutaneous toxic effects were noticed, but they normalized within two weeks. On the other hand, a fine granular material persisted in the intercellular spaces. It is confirmed that the skin of the rhino mouse is a good model for the evaluation of the comedolytic effects of drugs. Moreover, it reveals the specific effects of retinoids on epidermal differentiation. We have demonstrated that topically applied CD271 induces modifications similar to those obtained with all-trans retinoic acid. It is thus concluded that CD271 is a potentially effective anti-acne agent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00371617
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  • 24
    Digitale Medien
    Digitale Medien
    Ultrastructural study of the skin in Sjögren — Larsson syndrome (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 141-148 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Sjögren ; Larsson syndrome ; Ichthyosis ; Ultrastructure ; Lamellar body ; Keratinization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ichthyosiform skin and the uninvolved skin of a 5-year-old Japanese female with Sjögren — Larsson syndrome were examined by light and electron microscopy to elucidate the keratinization disorder. Light microscopically, the epidermis of the ichthyosiform skin showed acanthosis, papillomatosis and hyperkeratosis. The horny cells had a basket-weave appearance. The granular cell layer was slightly thickened. Slight round cell infiltration and vascular dilatation were seen in the upper dermis. The uninvolved skin was histologically normal. Electron microscopically, in both ichthyosiform and uninolved skin, abnormal lamellar or membranous inclusions were present in the cytoplasm of horny cells of the epidermis. These inclusions appeared to be derived from some of the lamellar bodies and/or abnormal membranous structures found in the cytoplasm of spinous and granular cells. Mitochondria in the epidermal basal cells were more numerous in the ichthyosiform skin than in the uninvolved skin. These findings indicate that, whether the skin is involved or not, the epidermis of the patient with this disorder may always have a structural abnormality, which may be genetically determined. Local environmental factors may play a role in inducing the acanthosis and papillomatosis of the epidermis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372053
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  • 25
    Digitale Medien
    Digitale Medien
    Are accessory nuclei involved in the establishment of developmental gradients in hymenopteran oocytes? (1991)
    Springer
    Development genes and evolution 199 (1991), S. 423-426 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Oogenesis ; Accessory nuclei ; Developmental gradients ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In the oocytes ofTenthredo olivacea, accessory nuclei (AN) are formed by budding from the nuclear envelope of the oocyte nucleus. Newly formed AN contain electron-dense material of nuclear origin and are surrounded by a double envelope devoid of pores. Such structures are subsequently transported to the peripheral ooplasm (periplasm), where they grow to reach a final diameter of 5 µm. In the envelopes of advanced AN nuclear pores arise. Through these pores “nuage” material is extruded into the surrounding periplasm. These findings are discussed with respect to a possible involvement of AN in the establishment of developmental gradients in hymenopteran oocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01705853
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  • 26
    Digitale Medien
    Digitale Medien
    The origin of the nascent blastocoele in preimplantation mouse embryos ultrastructural cytochemistry and effect of chloroquine (1991)
    Springer
    Development genes and evolution 200 (1991), S. 77-85 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Lysosomes ; Ultrastructure ; Chloroquine ; Blastocyst ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mouse morulae are known to undergo cavitation as soon as some external cells have entered the sixth cell cycle (Garbutt et al. 1987). Since the early cytological features of cavitation are still unclear, we undertook a careful ultrastructural analysis of late morulae-nascent blastocysts. In addition, since maturation of lysosomes might be involved in the first step of cavity formation, we focused our attention on these organelles by means of the cytochemical localization of trimetaphosphatase activity and by the study of the effects of chloroquine on precavitation embryos. Our results suggest that cavitation starts in a few external cells (presumably competent cells entering the sixth cell cycle), by the chloroquine-sensitive formation of degradative autophagic vacuoles engulfing lipid droplets and vacuoles containing osmiophilic material. These complex structures enlarge (as a result of lipid metabolism?) and so transform into intrablastomeric cavities which, by means of a membrane fusion process, very rapidly become extracellular cavities that coalesce. The abembryonic pole of the blastocyst is determined in this way. Moreover, we suggest that the juxtacoelic cytoplasmic processes covering the inner cell mass (ICM) cells, which are known to restrict the expression of their totipotency during early cavitation (Fleming et al. 1984), are the latest remnants of the walls of the growing intrablastomeric cavities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00637187
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  • 27
    Digitale Medien
    Digitale Medien
    Contributions of sodium and chloride to ultrastructural damage after dendrotomy (1991)
    Springer
    Experimental brain research 86 (1991), S. 60-72 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Trauma ; Neuron ; Sodium ; Chloride ; Ultrastructure ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To determine the contributions of sodium and chloride to ultrastructural changes after mechanical injury, we amputated primary dendrites of cultured mouse spinal neurons in low calcium medium in which sodium chloride had been replaced with either choline chloride or sodium isethionate or sodium propionate. Uninjured cultured neurons were also exposed to the sodium ionophore, monensin. A third set of neurons was injured in medium in which all sodium and calcium chloride had been replaced with sucrose. Neurons injured in low-calcium, low-sodium medium exhibited few ultrastructural changes, except very near the lesion, where there was some dilation of mitochondria and cisternae of the smooth endoplasmic reticulum (SER). Mitochondria in other regions of the neurons developed an electron opaque matrix, and those nearer to the lesion converted to the condensed configuration, characterized by expanded intracristal spaces as well as a dense matrix. If sodium but not chloride was present in the medium, there was some dilation of the Golgi cisternae after injury, as well as some increased electron opacity of the mitochondria. Monensin treated neurons also exhibited dilation of the Golgi cisternae. Neurons injured in sucrose-substituted medium showed none of the changes associated with injury in normal culture medium. These results indicate that sodium influx through the lesion is involved in the dilation of the SER, which is seen even in low-calcium medium, and that a permeant anion, such as chloride, is also involved. This dilation of the SER may result from uptake of calcium released from mitochondria in response to elevated cytosolic sodium. Dilation of the Golgi cisternae appears to be a response only to elevated intracellular sodium. Condensation of the mitochondria after injury is thought to be due to increased demands for ATP synthesis and may involve a “futile cycling” of calcium across the mitochondrial membrane, involving sodium-mediated calcium release in response to elevated intracellular calcium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00231040
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  • 28
    Digitale Medien
    Digitale Medien
    Secretory tapetum of Brassica oleracea L.: polarity and ultrastructural features (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 28-35 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Tapetal cells ; Brassica oleracea L ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of the secretory, binucleate tapetum of Brassica oleracea in the micro spore mother cell (MMC) stage through to the mature pollen stage is reported. The tapetal cells differentiate as highly specialized cells whose development is involved in lipid accumulation in their final stage. They start breaking down just before anther dehiscence. Nuclei with dispersed chromatin, large nucleoli and many ribosomes in the cytoplasm characterize the tapetal cells. The wall-bearing tapetum phase ends at the tetrade stage. The dissolution of tapetal walls begins from the inner tangential wall oriented towards the loculus and proceeds gradually along the radial walls to the outer tangential one. The plasmodesmata transversing the radial walls between tapetal cells persist until the mature microspore, long after loss of the inner tangential wall. After wall dissolution, the tapetal protoplasts retain their integrity and position within the anther locule. The tapetal cell membrane is in direct contact with the exine of the microspores/pollen grains and forms tubular evaginations that increase its surface area and appear to be involved in the translocation of solutes from the tapetal cells to the microspores/ pollen grains. The tapetal cells exhibit a polarity expressed by spatial differentiation in the radial direction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194568
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  • 29
    Digitale Medien
    Digitale Medien
    Brassica napus pollen development during generative cell and sperm cell formation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 176-181 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Pollen ; Brassica napus ; Mitoses ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Brassica napus pollen development during the formation of the generative cell and sperm cells is analysed with light and electron microscopy. The generative cell is formed as a small lenticular cell attached to the intine, as a result of the unequal first mitosis. After detaching itself from the intine, the generative cell becomes spherical, and its wall morphology changes. Simultaneously, the vegetative nucleus enlarges, becomes euchromatic and forms a large nucleolus. In addition, the cytoplasm of the vegetative cell develops a complex ultrastructure that is characterized by an extensive RER organized in stacks, numerous dictyosomes and Golgi vesicles and a large quantity of lipid bodies. Microbodies, which are present at the mature stage, are not yet formed. The generative cell undergoes an equal division which results in two spindle-shaped sperm cells. This cell division occurs through the concerted action of cell constriction and cell plate formation. The two sperm cells remain enveloped within one continuous vegetative plasma membrane. One sperm cell becomes anchored onto the vegetative nucleus by a long extension enclosed within a deep invagination of the vegetative nucleus. Plastid inheritance appears to be strictly maternal since the sperm cells do not contain plastids; plastids are excluded from the generative cell even in the first mitosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190001
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  • 30
    Digitale Medien
    Digitale Medien
    Ultrastructure of the micropyle and its relationship to pollen tube growth and synergid degeneration in sunflower (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 166-175 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Helianthus annuus ; Ultrastructure ; Micropyle ; Pollen tube ; Synergid degeneration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Ultrastructural studies made on the micropyle of sunflower before and after pollination resulted in the following observations. (1) The micropyle is closed instead of a hole or canal. The inner epidermis of the integument on both sides of the micropyle is in close contact at the apex of the ovule. The boundary between the two sides consists of two layers of epidermal cuticle. (2) The micropyle contains a transmitting tissue. The micropyle is composed of an intercellular matrix produced by the epidermal cells of the integument. (3) The micropyle is asymmetrical, and is much wider on the side proximal to the funicle. On the funicle side the cells adjacent to the micropyle are similar to those of the transmitting tissue: they have large amounts of intercellular matrix and contain abundant dictyosomes, rough ER, and starch grains, and provide an appropriate environment for growth of the pollen tubes. The cells distal to the funicle are rich in rough ER and lipid bodies; they lack large intercellular spaces. (4) The micropyle is variable in the axial direction, i.e., it is much larger and more asymmetric at the level distal to the embryo sac than at a level close to the embryo sac. After pollination, one to four pollen tubes are seen in a micropyle. During their passage through the micropyle, most pollen tubes are restricted to the side proximal to the funicle. There is a greater tendency (81%) for the degenerate synergid to be located toward the funicle, i.e., at the same side as the pollen tube pathway. The data indicate a close relationship between micropyle organization, orientation of pollen tube growth, and synergid degeneration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190000
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  • 31
    Digitale Medien
    Digitale Medien
    Sperm cells of the pollen tubes of Brassica: Ultrastructure and isolation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 226-234 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Male germ unit ; Sperm cells ; Isolation ; Pollen tubes ; Brassica napus ; Pollen-tube inner plasma membrane ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Sperm cells of pollen tubes grown both in vivo and in vitro form a male germ unit. Extensions from both sperm cells of each pollen tube are closely associated with the tube nucleus. A high yield (2.7 × 104. 20 mg−1 pollen grains germinated) of intact sperm cells was obtained following release by osmotic shock from pollen tubes grown in vitro. Structural integrity of isolated sperm was maintained by isolation at low temperature in an osmotically balanced medium. At 4° C many isolated sperm pairs were still enclosed within the pollentube inner plasma membrane. Sperm cells not enclosed within this membrane no longer remained connected as a pair. During isolation vesicles formed on the sperm cell surface from disruption of the fibrillar components bridging the periplasmic space. Both in the pollen tube and after isolation the sperm nucleus is in close association with at least one region of the sperm plasma membrane. Sperm isolated at room temperature showed the presence of nucleopores, and nuclei were euchromatic, instead of heterochromatic as in intact sperm in the pollen tube.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190009
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  • 32
    Digitale Medien
    Digitale Medien
    Microsporogenesis and tapetal development in fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 215-225 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Cytoplasmic male sterility ; Beta vulgaris ; Microsporogenesis ; Tapetum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development of sporogenous and tapetal cells in the anthers of male-fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) plants was studied using light and transmission electron microscopy. In general, male-sterile anthers showed a much greater variability in developmental pattern than male-fertile anthers. The earliest deviation from normal anther development was observed to occur in sterile anthers at meiotic early prophase: there was a degeneration or irregular proliferation of the tapetal cells. Other early aberrant events were the occurrence of numerous small vesicles in the microspore mother cells (MMC) and a disorganized chromatin condensation. Deviations that occurred in sterile anthers at later developmental stages included: (1) less distinct inner structures in the mitochondria of both MMC and tapetal cells from middle prophase onwards. (2) dilated ER and nuclear membranes at MMC prophase, in some cases associated with the formation of protein bodies. (3) breakdown of cell walls in MMCs and tapetal cells at late meiotic prophase. (4) no massive increase in tapetal ER at the tetrad stage. (5) a general dissolution of membranes, first in the MMC, then in the tapetum. (6) abortion of microspores and the occurrence of a plasmodial tapetum in anthers reaching the microspore stage. (7) no distinct degeneration of tapetal cells after microspore formation. Thus, it seems that the factors that lead to abortive microsporogenesis are structurally expressed at widely different times during anther development. Aberrant patterns are not restricted to the tetrad stage but occur at early prophase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00190008
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  • 33
    Digitale Medien
    Digitale Medien
    Fluoride effects on leaf cell ultrastructure of olive trees growing in the vicinity of the Aluminium Factory of Greece (1991)
    Springer
    Trees 5 (1991), S. 83-89 
    Details
    ISSN: 1432-2285
    Schlagwort(e): Air pollutants ; Chloroplasts ; Fluoride ; Olive tree leaves ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Leaves of olive trees growing in the vicinity of the Aluminium Factory of Greece were ultrastructurally investigated in order to determine any malformations caused by environmental air pollutants, especially hydrogen fluoride, in comparison with control samples and normal seasonal senescence. Estimation of some elements accumulated by these leaves showed that they contained high amounts of F and Al attributable to the operation of the nearby factory. The most seriously effected cell components were found to be the mesophyll chloroplasts that show a dilation of the intrathylakoid space, increase of the number of plastoglobuli, discoloration of plastoglobuli, accumulation of large starch grains and an overall disorganized appearance of the organelle. The nuclear crystalloid inclusions have unusual shapes, while the vacuoles contain a fibrillar/granular material that increases their electron density. It is concluded that the ultrastructural malformations are caused by a combination of environmental stresses and air pollutants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227489
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  • 34
    Digitale Medien
    Digitale Medien
    Different epithelia in the distal human male urethra (1991)
    Springer
    Cell & tissue research 264 (1991), S. 23-32 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Male urethra ; Urethral epithelium ; Immunocytochemistry ; Ultrastructure ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distal segment of the human male urethra, in particular the fossa navicularis, was studied with light- and electron microscopy as well as by means of histochemical and immunocytochemical methods. The fossa navicularis of the urethra contains a circumscribed zone of extremely thick, non-keratinized stratified squamous epithelium composed of cells containing a large amount of glycogen. These cells lack acid phosphatase activity and lysozyme-like immunoreactivity, both of which can be demonstrated to varying extents in the other zones of the distal male urethra. These glycogen-rich cells are considered to be the substrate for an endogenous flora of lactobacteria, whereas the acid-phosphatase activity and the lysozyme-like immunoreactivity indicate the presence of macrophages and the secretion of bactericidal agents at the epithelial surface. These observations suggest that the different zones with heterogeneous properties in the distal male urethra probably represent a defense system against the invasion of pathogenic microorganisms. Moreover, the glycogen-rich zone, which resembles the glycogen-rich epithelium of the vagina, is estrogen-dependent. This is demonstrated in cases of sex reversal in which after long-lasting estrogen treatment the glycogen-rich zone becomes extremely extended by displacement of the neighbouring epithelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305719
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  • 35
    Digitale Medien
    Digitale Medien
    Ultrastructure of melatonin-responsive cells in the ovine pars tuberalis (1991)
    Springer
    Cell & tissue research 263 (1991), S. 529-534 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Melatonin ; Pituitary gland, pars tuberalis ; Secretory cells ; Cyclic AMP ; Ultrastructure ; Cell culture ; Sheep
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Functional receptors for melatonin have been localized and characterized on the pars tuberalis (PT) of a number of mammalian species, but the cell-type responsive to melatonin is unknown. The ultrastructure of the ovine pars tuberalis has been examined and these findings correlated with the functional response of the gland to melatonin. This study revealed that two secretory cell types predominate in the ovine PT, which differ in the abundance of dense-core granules. The most abundant of the cells are either agranular or very sparsely granulated and represent 90% of the total population, with the remaining 10% being composed of cells with abundant dense-core vesicles. Few follicular cells were observed. This ratio of secretory cell-types persisted in primary culture, with the two types non-separable by Percoll gradient centrifugation. Using forskolin, as a non-specific stimulant of adenylate cyclase, melatonin was shown to inhibit the formation of cyclic AMP by 80–90% in cells both before and after Percoll centrifugation. The results demonstrate that the agranular secretory cells of the ovine pars tuberalis are the melatonin responsive cell-type of this gland.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327285
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  • 36
    Digitale Medien
    Digitale Medien
    Ultrastructure and distribution of somatostatin-like immunoreactive neurons and nerve fibres in the coeliac ganglion of cats (1991)
    Springer
    Cell & tissue research 263 (1991), S. 567-572 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Somatostatin ; Coeliac ganglion ; Autonomic innervation ; Ultrastructure ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Somatostatin-like immunoreactivity was localized in nerve cell bodies and nerve terminals in the cat coeliac ganglion. Two types of somatostatin-immunoreactive cell bodies were revealed, the first being large (diameter 35 μm), numerous and weakly labelled, where—as the second was considerably smaller (diameter 10.4 μm), sparsely distributed and heavily stained. The immunoreactive nerve terminals were in synaptic contact with many immunonegative large neurons and dendrites. However, in a few cases, somatostatin-immunoreactive nerve terminals could also be observed on the surface of lightly stained neurons. Transection of vagal or mesenteric nerve failed to affect the distribution or density of somatostatin-like immunoreactive nerve terminals. These results demonstrate the existence of a synaptic input to the principal neurons of the coeliac ganglion of the cat by somatostatin-containing nerve terminals and suggest that this peptide may act as a neuromodulator or neurotransmitter. It is proposed that somatostatin-positive neurons provide intrinsic projections to other somatostatin-positive and to somatostatin-negative neurons throughout the coeliac ganglion, thereby creating a complex interneuronal system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327290
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  • 37
    Digitale Medien
    Digitale Medien
    Islets of preadipocytes highly committed to differentiation in cultures of adherent rat adipocytes (1991)
    Springer
    Cell & tissue research 264 (1991), S. 243-251 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Preadipocytes ; Adipocyte precursor cells ; Adipose tissue ; Differentiation-cell cultures ; Ultrastructure ; Rat (Fischer 344)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cultures of adherent mature adipocytes, obtained from collagenase-digests of adipose tissue of the rat, invaribly contain rapidly proliferating, fibroblastlike cells despite the washing and centrifugation procedures empolyed during isolation of the fat cells. Such spindle-like cells originate from low-density structures, which we term “islets”, that are present, together with the mature adipocytes, in the floating layer of the digest of adipose tissue. Islets are found in preparations from adult (3–4 months old) as well as aging (17–24 months old) rats. By light-and electron microscopy, the islets appear as clusters of closely associated cells containing a variable amount of lipid-like material. Cells of endothelial or pericytic origin are also present in the islets. Within a few hours of culture, the islets give rise to those spindle-like cells that have been seen to proliferate in the cultures. By 36–48 hours, such cells begin to accumulate lipid droplets and, by 150 hours, assume the morphology of small mature adipocytes (diameter 20–35 μm) with a large central lipid droplet. The pattern of differentiation of these cells recalls that of preadipocytes derived from the stromal-vascular fraction of adipose tissue digests. Nonetheless, the extent and rapidity of their adipose conversion, as well as the culture conditions necessary for differentiation, are different and suggest that these cells are a substantially uniform subpopulation of adipocyte-precursor cells highly committed to differentiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00313961
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  • 38
    Digitale Medien
    Digitale Medien
    Postnatal changes in the ultrastructure of the rat olfactory epithelium: the supranuclear region of the supporting cells (1991)
    Springer
    Cell & tissue research 265 (1991), S. 193-196 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Postnatal development ; Olfactory epithelium ; Supporting cells ; Receptor cell dendrites ; Ultrastructure ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present electron-microscopical study reports ultrastructural changes occurring in the supranuclear region of the supporting cells of the rat olfactory epithelium during the first 16 days of postnatal life. These changes are concerned with the enclosure of receptor cell dendrites and an increase in the amount of smooth endoplasmic reticulum, which has a specific distribution in the supporting cell. An increase in microvillous projections at the free cell surface is also observed. Moreover, this report demonstrates that the cytoarchitecture of the apical portion of the olfactory epithelium at the 16th day of postnatal life is similar, with respect to the relationship between supporting cells and receptor cell dendrites, to that of adult animals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318154
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  • 39
    Digitale Medien
    Digitale Medien
    Diversity of ultrastructure in different phenotypes of cultured microvessel endothelial cells isolated from bovine corpus luteum (1991)
    Springer
    Cell & tissue research 266 (1991), S. 37-49 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Microvessel endothelial cells ; Cell culture ; Corpus luteum ; Ultrastructure ; Cow
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Five different types of cultured microvessel endothelial cells defined by use of light microscopy and scanning electron microscopy in a preceding study were investigated by transmission electron microscopy. Type-1 cells displayed a deep invagination of the cell membrane or a single cilium. Granules of low electron density were abundant. A perinuclear ring of intermediate filaments occurred. Cultures of type-2 cells were subdivided into phenotype A, reminiscent of cell-type 1, and into phenotype B, assumed to be vascular smooth muscle cells. Many highly electron-dense granules appeared in late postconfluent cultures of both phenotypes. Cell-type 3 was conspicuous because of a large intracytoplasmic vacuole. Lysosomes with curvilinear bodies were found in cell-types 3 and 4. Both cell types developed a peripheral regular network of microfilaments. Cell-type 5 showed vesiculation of the rough endoplasmic reticulum, lipid droplets and a peripheral felt-like belt of microfilaments. Tubular forms seen in late postconfluent cultures of cell-types 1 to 3 displayed a core of extracellular matrix. Pseudotubular forms of cell-type 4 contained apoptotic bodies. Thus, as seen at the ultrastructural level, different features are maintained by cultured microvessel endothelial cells, suggesting that they have different inherent properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00678709
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  • 40
    Digitale Medien
    Digitale Medien
    Effect of cytokines on thymic hematopoietic precursors (1991)
    Springer
    Cell & tissue research 264 (1991), S. 369-375 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Thymus ; CD4- ; CD8- ; thymocyte ; Thymic hematopoietic precursors ; Cytokines ; Ultrastructure ; Mouse (DBA/2, H-2d)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We have previously shown that the interaction of thymocytes with thymic accessory cells (macrophages and/or interdigitating cells) is one of the factors required for thymocyte activation. Precursors of both thymic accessory cell and thymocytes are included in the CD4- CD8- Mac-1- Ia- subpopulation, and their respective maturation and/or activation may be modulated by granulocyte-macrophage colony-stimulating factor, interleukin 1 and interleukin 2. When CD4- CD8- thymic cells are activated with granulocyte-macrophage colony-stimulating factor plus interleukin 2, both macrophages and interdigitating-like cells are present, as shown by electron microscopy. When activated with interleukin 1 plus interleukin 2, the interdigitating-like cells is the only accessory cell present. In both culture conditions, large clusters are formed between interdigitating cells and lymphoid cells. These results have led us to propose two-step signals for thymocyte proliferation: first, the maturation of macrophages under granulocyte-macrophage colony-stimulating factor control and the production of interleukin 1, and secondly, the maturation of interdigitating cells under interleukin 1 control, their clustering with thymocytes which are then activated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00313976
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  • 41
    Digitale Medien
    Digitale Medien
    The fine structure of lamellate cells in the brain of amphioxus (Branchiostoma lanceolatum, Cephalochordata) (1991)
    Springer
    Cell & tissue research 263 (1991), S. 597-600 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Lamellate cell ; Ultrastructure ; Ciliary photoreceptors ; Nervous system, prochordates ; Branchiostoma lanceolatum (Acrania)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The lamellate cells of amphioxus have round nuclei, and cytoplasm with many mitochondria and a large amount of glycogen. Each of these cells projects a highly modified, branched cilium into the central canal, where it characteristically forms lamellar structures. Primary branches and secondary lamellae often contain accessory microtubules that are not derived from the axonema. The functional and evolutionary significance of this cell type is discussed in relation to the ciliary photoreceptors found in other chordates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327295
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  • 42
    Digitale Medien
    Digitale Medien
    Cell types in the fetal pars tuberalis of the human adenohypophysis at mid-gestation (1991)
    Springer
    Cell & tissue research 264 (1991), S. 161-165 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adenohypophysis ; Pars tuberalis ; Ultrastructure ; Immunohistochemistry ; Fetal ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pars tuberalis of the adenohypophysis was investigated in three human fetuses at mid-gestation by electron microscopy or immunohistochemistry. In addition to gonadotrophs and thyrotrophs, identified by immunohistochemistry and ultrastructural morphology, electron microscopy revealed the existence of an additional differentiated cell type closely resembling “pars tuberalis-specific” cells known from other species. The role of this cell type in the human endocrine regulation remains to be elucidated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305734
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  • 43
    Digitale Medien
    Digitale Medien
    Effect of 1,10-phenanthroline on ultrastructure of pea leaves (1991)
    Springer
    Protoplasma 161 (1991), S. 23-30 
    Details
    ISSN: 1615-6102
    Schlagwort(e): 1,10-Phenanthroline ; Photodynamic herbicides ; Pisum sativum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have examined ultrastructural changes of mesophyll cells in pea leaves induced by the photodynamic herbicide 1,10-phenanthroline (Phe). Dark incubation of pea plants did not cause any damage in plants or changes in the ultrastructure of mesophyll cells. Two hours of illumination after pretreatment with Phe caused photooxidative damage in plant but was not sufficient to markedly change the ultrastructure, although dilation of endoplasmic reticulum (ER) cisternae occurred. Illumination for 12 h caused inhibition of grana formation in pretreated plants. These ultrastructural changes and the inhibition of chlorophyll (Chl) accumulation may be due to the inhibition of transport of certain proteins to the plastids, diminished accumulation of chlorophyll proteins (e.g., LHCP) and a decrease in activity of the chlorophyll synthetase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01328894
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  • 44
    Digitale Medien
    Digitale Medien
    Intercellular permeability inAbutilon nectary trichomes (1991)
    Springer
    Protoplasma 161 (1991), S. 150-159 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Abutilon ; Lucifer Yellow ; Microinjection ; Nectary ; Transport ; Trichome ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Intercellular transport was examined in nectary hairs ofAbutilon slriatum var.thompsonii using dye-uptake and microinjection followed by fluorescence and electron microscopy. Dye-uptake experiments demonstrated that both Lucifer Yellow CH (LYCH) and diaminobenzidine (DAB) move centrifugally along an apoplastic pathway from the sepellary tissue towards the tip cell. Further, fluorescence of LYCH could also be detected inside the cells of the nectary trichome. When LYCH or LYCH/DAB were microinjected into the tip cell, the dye spread in a centripetal direction towards the stalk cell. Electron microscopical investigations of microinjected nectary hairs revealed numerous electron-opaque globules in the cytoplasm of the nectary hair cells. In addition, multivesicular bodies, nuclei with opaque regions and changes in the rough endoplasmic reticulum (RER) were seen in nectary hair cells even at very low concentrations of injected dye. Ultrastructural investigations provided evidence for cytological changes in microinjected nectary hairs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01322727
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  • 45
    Digitale Medien
    Digitale Medien
    Ultrastructure of the vegetative organisation and initial stages of silica plate deposition in the soil testate amoebaCorythion dubium (1991)
    Springer
    Protoplasma 163 (1991), S. 136-144 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Corythion dubium ; Silica deposition ; Testate amoeba ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The siliceous body plates ofCorythion dubium are bound by a band of organic cement which is thickest at the lateral margins. The anterior vacuolar cytoplasm is separated by a pigment zone, which forms a dark band in the mid-body region, from the compact posterior region containing a typical vesicular nucleus surrounded by a region of dense endoplasmic reticulum. A pellicular basket of microtubules surrounds the posterior cytoplasm. The large Golgi complex lies between the nucleus and the fundus. Numerous coated and uncoated vesicles from the Golgi cisternae are seen in the peripheral cytoplasm alongside developing plates. These small siliceous plates are enclosed in silicon deposition vesicles lying in surface ruffles of the plasmalemma, often in association with a pair of microtubules. Observations are made on the formation of these vesicles and the early stages of silica deposition. A comparison is drawn between silica deposition inC. dubium and choanoflagellates where there is a similar association between silicon deposition vesicles and microtubules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01323337
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  • 46
    Digitale Medien
    Digitale Medien
    Effects of heat shock and thermoadaptation on the ultrastructure of cowpea (Vigna unguiculata) cells (1991)
    Springer
    Protoplasma 163 (1991), S. 125-135 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cowpea ; Heat shock ; Thermoadaptation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Suspension culture cells of cowpea (Vigna unguiculata) were examined using transmission electron microscopy to characterize morphological changes associated with hyperthermal stress. Cultures maintained at 26°C (unadapted cells) and 38°C (thermoadapted cells) were examined before and after exposure to elevated temperatures of 34°C and 45°C, respectively. Observations indicate that while there were significant ultrastructural differences between unadapted and thermoadapted cells, the following structural modifications in response to heat stress were observed in cells of both cultures: (a) almost a complete loss of polyribosomes, rough ER, and dictyosomes, (b) migration of intracellular waste material (presumably proteinaceous in composition) into the cell vacuole, (c) swelling of the nucleolus with assumed accumulation of preribosomal RNP granules, and (d) retraction of the tonoplast from the cytoplasm into the vacuoles of some cells. Heat shock granules (two size classes) were observed in the cytoplasm of stressed thermoadapted cells along with hollow-cored granules within the leucoplasts. Apart from a few minor differences, the morphological modifications that were made in apparent response to hyperthermal stress were remarkably similar in both cultures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01323336
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  • 47
    Digitale Medien
    Digitale Medien
    Ontogeny and ultrastructure of spontaneous nodules in alfalfa (Medicago sativa) (1991)
    Springer
    Protoplasma 162 (1991), S. 1-11 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Rhizobium meliloti ; Development ; Symbiosis ; Nitrogen fixation ; Ultrastructure ; Spontaneous nodule
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development of spontaneous nodules, formed in the absence ofRhizobium and combined nitrogen, on alfalfa (Medicago sativa L. cv. Vernal) was investigated at the light and electron microscopic level and compared to that ofRhizobium-induced normal nodules. Spontaneous nodules were initiated from cortical cell divisions in the inner cortex next to the endodermis, i.e., the site of normal nodule development. These nodules, on uninoculated roots, were white multilobed structures, histologically composed of nodule meristems, cortex, endodermis, central zone and vascular strands. Nodules were devoid of intercellular or intracellular bacteria confirming microbiological tests. Early development of spontaneous nodules was initiated by series of anticlinal followed by periclinal divisions of dedifferentiated cells in the inner cortex of the root. These cells formed the nodular meristem from which the nodule developed. The cells in the nodule meristems divided unequally and differentiated into two distinct cell types, one larger type being filled with numerous membrane-bound starch grains, and the other smaller type with very few starch grains. There were no infection threads or bacteria in the spontaneous nodules at any stage of development. This size differentiation is suggestive of the different cell sizes seen inRhizobium-induced nodules, where the larger cell type harbours the invading bacteria and the smaller type is essential in supportive metabolic roles. The ontogenic studies further support the claim that these structures are nodules rather than aberrant lateral roots, and that plant possess all the genetic information needed to develop a nodule with distinct cell types. Our results suggest that bacteria and therefore theirnod genes are not necessarily involved in the ontogeny and morphogenesis of spontaneous and normal nodules in alfalfa.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403895
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  • 48
    Digitale Medien
    Digitale Medien
    The occurrence and ultrastructure of a mechanoreceptor in the human cricopharyngeus muscle (1991)
    Springer
    European archives of oto-rhino-laryngology and head & neck 248 (1991), S. 144-146 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Cricopharyngeus muscle ; Golgi tendon organ ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An encapsulated nerve structure resembling the Golgi tendon organ was found in a human cricopharyngeus muscle near the cricoid cartilage where muscle fibers terminate. The capsule consisted of lamellated flattened cells with a basal lamina. Capsular cells separated the lumen into small compartments which contained myelinated and/or nonmyelinated nerve fibers. Nonmyelinated nerve fibers were also found in the interlamellar spaces of the capsular cells. Some nonmyelinated nerve fibers were dilated and contained abundant mitochondria, being partly surrounded by a Schwann cell sheath and embedded in collagen bundles. These features indicate that the nerve structure is a mechanoreceptor similar to the Golgi tendon organ. Its location and structure indicate that it is placed to detect the tension of the cricopharyngeus muscle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00178924
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  • 49
    Digitale Medien
    Digitale Medien
    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991) 
    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.1130050101
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  • 50
    Digitale Medien
    Digitale Medien
    Biomedical applications of chiral liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 128-132 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Many drugs are recemic and therefore much effort has to be devoted towards the stereoselective synthesis of the most effective or less harmful component of a racemic mixture. High performance liquid chromatography will play an important role in the clinical analysis of racemic drugs in anticipation of regulations that are currently being discussed and are expected to be enforced by the end of this decade. In this review a number of methods for chiral resolution are outlined. These include the formation of diastereoisomers and the use of chiral stationary phases or chiral mobile phase additives.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050307
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  • 51
    Digitale Medien
    Digitale Medien
    Product news (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 141-141 
    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.1130050310
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  • 52
    Digitale Medien
    Digitale Medien
    Medium- and long-chain 3-hydroxymonocarboxylic acids: Analysis by gas chromatography combined with mass spectrometry (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 161-164 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Medium- and long-chain 3-hydroxymonocarboxylic acids represent intermediates in the β-oxidation of fatty acids: they accumulate in the plasma of patients with an inherited deficiency of long-chain 3-hydroxyacylcoenzyme A dehydrogenase. 3-Hydroxy acids with chain lengths varying from 6 to 16 were synthesized by a Reformatzky reaction. Capillary gas chromatography of the pertrimethylsilyl derivatives was performed on a CP-Sil 19 CB column, coupled to a quadrupole mass spectrometer in the electron impact mode. Calculation of the retention indices showed that the separation of the 3-hydroxy acids from the homologous straight-chain fatty acids may be troublesome, stressing the need for mass spectrometric identification.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050405
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  • 53
    Digitale Medien
    Digitale Medien
    Analysis of vitamin D and its metabolites using thermospray liquid chromatography/mass spectrometry (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 153-160 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A new method is described for the analysis of vitamin D and its metabolites utilizing thermospray (TSP) mass spectrometry as an on-line detector for high performance liquid chromatogrpahy. Ionization conditions were optimized for use with isocratic reversed phase chromatography. TSP mass spectrometry was employed in series with a UV absorbance detector to facilitate comparisons between the two methods of detection. Positive ion TSP mass spectra were recorded for vitamin D2, vitamin D3, 25-hydroxyvitamin D3 (25(OH)D3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3). The spectra contained protonated molecular ions, ammonium adduct ions and fragment ions due to the loss of one or more molecules of water. A comparison of quantitative precision was made by determining UV absorbance and TSP standard curves for vitamin D3 using two different methods: (1) External standard method with post-column (post UV detector) addition of ammonium acetate. (2) As (1) but using the method of internal standards with a closely eluting internal standard (vitamin D2). In each case the quantitative precision (correlation coefficient) for UV absorbance detection was superior owing to intrinsic instability of the TSP ion beam. A stable isotopically labelled internal standard was employed in the development of an assay for 1,25(OH)2D3. The assay was used to quantify in vitro enzymic conversion of 25(OH)D3 to 1,25(OH)2D3 in guinea pig and sheep renal mitochondrial incubations. TSP LC/MS was also applied to analysis of an extract of human blood plasma in which D3 and each of its principal metabolites were identified in a single analysis.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050404
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  • 54
    Digitale Medien
    Digitale Medien
    Chromatographic techniques in inborn errors of metabolism (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 113-121 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Chromatography has played a pivotal role in the advances made during the last 30 years in our knowledge of inborn errors of metabolism. This review discusses the application of some of these techniques to the analysis of organic acids and acylcarnitines. The separation of organic acids needed a comprehensive approach that would permit all of the many organic acids present in urine or other complex mixtures to be extracted, analysed and identified in a single run. This required analytical methods of great resolving power, wide linear range and universal detectors such as gas chromatography (GC), or GC coupled with mass spectrometry. Sample preparation was another problem that has been tackled by a variety of approaches. Organic solvents have been employed widely for the extraction of organic acids from physiological fluids. Unfortunately, recoveries of the different organic acids by this method are sometimes less than quantitative and variable depending on the compound. Other methods, such as the use of DEAE-Sephadex columns, have the advantage of resulting in close to 100% recoveries, but are more tedious. Liquid partition chromatography on short silicic acid columns has also been recommended as a useful clean-up step prior to GC, permitting both the identification and quantitation of organic acids in urine, plasma or amniotic fluid. Although many derivatization procedures have been used to prepare organic acids for gas chromatography, the most common is trimethylsilylation. Oxo acids are usually reacted with one of several commonly used reagents to form oximes. GC analysis of organic acids was initially done using packed columns with methylsilicone-based, non-polar stationary phases. In recent years most laboratories have switched to the commercially available, bonded-phase capillary columns. Some authors have recommended the use of two columns of slightly differing polarities to improve the reliability of identification without mass spectrometry. Carnitine and acylcarnitines are substances whose measurement may yield useful diagnostic information about inborn errors and about the basic biochemical mechanisms of disease. While free carnitine is usually measured by a radioenzymatic assay, the separation of acylcarnitines requires paper chromatography or high performance liquid chromatography. The identification of various acylcarnitines following separation has been accomplished by mass spectrometric methods. Another technique relies on gas chromatographic identification of the acyl groups liberated following alkaline hydrolysis. Recently, liquid chromatography/mass spectrometry has also been utilized to separate and identify the various acylcarnitines present in urine and other biological samples.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050305
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  • 55
    Digitale Medien
    Digitale Medien
    High performance liquid chromatography of glucose using a post-column reactor of immobilized enzyme followed by electrochemical detection (glucose-LCEC) (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 180-183 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A sensitive and selective, reasonably fast method for the determination of glucose content has been developed. A glucose oxidase immobilized column was coupled to a small-size anion exchange column/borate buffer chromatograph. The hydrogen peroxide produced in the enzyme reaction was detected directly by an amperometric detector using a platinum working electrode. The detection limit was 0.03 ppm (1.5 × 10-7 M, 3 pmol/injection). The linear dynamic range was three orders of magnitude at least. The system was stable and reproducible both in short-and long-term operation. The proposed method is suitable for analysis of complicated matrices of biological samples because of its good selectivity and sensitivity.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050409
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  • 56
    Digitale Medien
    Digitale Medien
    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991) 
    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.1130050501
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  • 57
    Digitale Medien
    Digitale Medien
    Plasma B-6 vitamer and plasma and urinary 4-pyridoxic acid concentrations in young women as determined using high performance liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 198-201 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Plasma B-6 vitamer and plasma and urinary 4-pyridoxic acid concentrations of 21 young white women, 21-27 years, having radiomonitored pyridoxal 5′-phosphate and coenzyme stimulation of erythrocyte alanine amino-transferase activities indicative of adequate vitamin B-6 status were determined in an effort to establish normal ranges for plasma B-6 vitamers. B-6 vitamers and 4-pyridoxic acid were quantitated using reversed phase high performance liquid chromatography with fluorometric and ultraviolet detection. Pyridoxal phosphate values obtained by radioenzymatic and chromatographic, fluorometric and ultraviolet, assays were highly correlated as were pyridoxine phosphate values determined using both detectors. The B-6 vitamer and 4-pyridoxic acid values of these subjects should be of use in the establishment of normal ranges of these congeners in women.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050504
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  • 58
    Digitale Medien
    Digitale Medien
    Comparative performance of ion exchange and ion-paired reversed phase high performance liquid chromatography for the determination of nucleotides in biological samples (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 207-211 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: We have compared anion exchange chromatography on APS-Hypersil (4.6 × 100 mm) eluted with a phosphate gradient with reversed phase chromatography on ODS-Hypersil (4.6 × 100 mm) in the presence of either tetrabutylammonium (TBA) or triethylammonium (TEA) ions with a methanol gradient. The systems have been compared both for ease of operation and for their resolving power with standard mixtures and acid extracts of both normal red cells (RBC) and ischaemic tissues. The two chromatographic modes exhibited similar separating efficiencies for standard mixtures of nucleotides but retention times were most stable using reversed phase liquid chromatography (RPLC) with TEA. Anion exchange columns slowly lost ion exchange capacity but selectivity was unchanged. RPLC in the presence of TBA gave reproducibile capacity factors only when operated isocratically due to irreversible changes to the silica surface. For RBCs the RPLC with TEA and anion exchange sysems resolved 17 and 15 peaks, respectively, and for the ischaemic samples 22 and 14 peaks, respectively. However, nucleosides and bases were also resolved by the ODS column causing chromatographic crowding and uncertain peak identification.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050506
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  • 59
    Digitale Medien
    Digitale Medien
    Liver high performance liquid chromatographic porphyrin profiles in experimental porphyria induced by peroxidizing herbicides (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 229-230 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The effect of peroxidizing herbicides on the liver porphyrin content of experimental animals was examined. Mice treated with the herbicide oxadiazon accumulated uroporphyrin and protoporphyrin in the liver. Fomesafen-treated mice accumulated uroporphyrin and heptacarboxylic porphyrin.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050511
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  • 60
    Digitale Medien
    Digitale Medien
    The measurement of nucleoside deaminases by high performance liquid chromatography and their use in clinical chemistry (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 235-239 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The measurement of the nucleoside deaminases - cytidine deaminase, guanosine deaminase and adenosine deaminase - by reversed phase high performance liquid chromatography is reviewed. The clinical value of assaying the enzyme activity is discussed for each of these enzymes. Both cytidine deaminase and adenosine deaminase measurements have proven clinical value, although the use of the assay of cytidine deaminase in the diagnosis of pre-eclampsia is probably not helpful.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050602
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  • 61
    Digitale Medien
    Digitale Medien
    Determination of the enantiomeric purity of scopolamine isolated from plant extract using achiral/chiral coupled column chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 3-7 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The optical purity of scopolamine derived from Datura sanguinea was determined using coupled column chromatography. A C18 column was used to separate scopolamine from the additional alkaloids and other biological material present in the vegetal extract. The C18 column was coupled through a six-port switching valve to two β-cyclodextrin columns in series which were used to resolve the scopolamine enantiomers. A single acetylated β-cyclodextrin column gives equivalent results to the native cyclodextrin columns because of slightly higher enantioselectivity for scopolamine. A multistep extraction procedure is used to isolate scopolamine from the vegetal material. 4-6% of the scopolamine in the final extract was found to be the d enantiomer. Sample extracts as well as commercial scopolamine hydrobromide were treated under various conditions commonly encountered during typical commercial extraction procedures and analyzed in order to determine if the d enantiomer was present in the original material or if it was produced during the extraction process and, if so, determine which step and conditions contribute to acemization. Both the salt and the extract were found to be susceptible to racemization under basic conditions (≥pH 9) although the extract appeared to be more susceptible than the salt. Tropic acid formed from the hydrolysis of scopolamine seemed to be completely racemized even though the remaining scopolamine was only partially racemized. Within experimental error, no d enantiomer was found in the original fresh plant material.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050103
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  • 62
    Digitale Medien
    Digitale Medien
    Enantiomeric analysis of phenylpropanolamine in plasma via resolution of dinitrophenylurea derivatives on a high performance liquid chromatographic chiral stationary phase (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 43-46 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Racemic phenylpropanolamine was resolved on a high performance liquid chromatographic (HPLC) chiral stationary phase (CSP) as the 3,5-dinitrophenyl ureide derivative. The CSP was prepared by a simple in situ procedure in which (R)-(1-naphthyl)ethyl isocyanate was bound to aminopropyl silanized silica through a urea linkage. The enantiomeric ureides were prepared by a room-temperature, 60-second procedure, accomplishing simultaneous extraction and derivatization and utilizing achiral 3,5-dinitrophenyl isocyanate as reagent. Baseline resolution was readily achieved under normal phase conditions, with a separation factor (α) of 1.16 and a resolution factor (Rs) of 2.2. Elution was complete within 10 min. A limit of detection, by UV at 235 nm, of 250 pg per isomer was established. Feasibility of the procedure for plasma determinations was demonstrated by assay of samples from a canine subject.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050110
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  • 63
    Digitale Medien
    Digitale Medien
    Evaluation of peroxyoxalate chemiluminescence postcolumn detection of fluphenazine in urine and blood plasma using high performance liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 47-52 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Peroxyoxalate chemiluminescence may be used for sensitive postcolumn detection of phenothiazine analytes separated by high performance liquid chromatography with appropriate optimization of measurement conditions such as solvent, pH and oxalate ester. Detectability of fluorescent analytes by chemical excitation varies greatly, but analytes with low oxidation potentials are generally more readily detected at low levels, as demonstrated for phenothiazines, an important class of fluorescent drugs. Some improvement in detection limits is observed for fluphenazine when chemiluminescence detection is compared to conventional fluorescence detection. Because of the specificity of chemical excitation, fewer interferences from fluorescent impurities in a urine matrix are observed.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050111
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  • 64
    Digitale Medien
    Digitale Medien
    Simultaneous determination of gemfibrozil and its metabolites in plasma and urine by a fully automated high performance liquid chromatographic system (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 68-73 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid®), a lipid-lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050205
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  • 65
    Digitale Medien
    Digitale Medien
    Separation of β- and γ-tocopherols in serum by high performance liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 83-85 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A simple and sensitive high performance liquid chromatographic method for the analysis of tocopherols (α, β, γ and δ) in serum with UV detection is described. In normal phase mode excellent separation of positional isomers (β and γ) was achieved by adjusting the proportion of isopropanol in the mobile phase. Detection limits for both β and γ were 0.62 mg/L and 0.42 and 1.2 mg/L for α and δ isomers, respectively. Measurement of all the tocopoherol structural isomers (α, β, γ and δ) in a sample required only 400 μL of serum and each run was completed in less than 22 min.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050208
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  • 66
    Digitale Medien
    Digitale Medien
    Chromatographic analysis of drugs in biological systems (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 1-1 
    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.1130050102
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  • 67
    Digitale Medien
    Digitale Medien
    High performance liquid chromatographic determination of theophylline metabolites in human liver microsomes (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 38-42 
    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 (HPLC) technique for the determination of three metabolites of theophylline, 3-methylxanthine (3-MX), 1-methylxanthine (1-MX) and 1,3-dimethyluric acid (1,3-DMU) in human liver microsomes is described. The analytes were extracted from human liver microsomes with methylene chloride/isopropanol and stepwise gradient elution was employed for the resolution of peaks. The limits of quantitation were 15 ng/mL for 3-MX, 20 ng/mL for 1-MX and 20 ng/mL for 1,3-DMU. The calibration range was linear for the three metabolites and the calibration ranges were 15-250 ng/mL for 3-MX, 20-250 ng/mL for 1-MX and 250-4000 ng/mL for 1,3-DMU. The absolute recovery ranged from 63-84% for 3-MX, 65-79% for 1-MX and 77-89% for 1,3-DMU over the calibration curve range. Accuracy for all three metabolites was within ± 10% and adequate seletivity was demonstrated by the lack of interfering peaks in blank chromatograms. The within-run and interday precision were within 10% RSD for all three metabolites tested at two concentrations. The advantage of this method over previous methods is that the use of quaternary ammonium ion pair reagents in the mobile phase has been obviated. Also, unlike a previous radiometric HPLC method, the need for radiolabelled theophylline has also been eliminated. The method was used to characterize theophylline metasbolism in human liver microsomes for immunoinhibition studies and to investigate the interaction of theophylline with selected quinolone antibiotitics.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050109
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  • 68
    Digitale Medien
    Digitale Medien
    Identification of peroxyacetic acid uroporphyrin I in the urine of patients with congenital erythropoietic porphyria by liquid chromatography and mass spectrometry (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 53-56 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A new porphyrin, peroxyacetic acid uroporphyrin I, has been isolated from the urine of patients with congenital erythropoietic porphyria by reversed phase high performance liquid chromatography. The porphyrin was characterized by high resolution mass spectrometry and by typical chemical reactions of a peroxyacid.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050202
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  • 69
    Digitale Medien
    Digitale Medien
    Direct enantiomeric high performance liquid chromatographic separation of aminoglutethimide and its major metabolite on a series of Chiralcel OD and Chiralcel OJ columns and its application to biological fluids (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 74-77 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A direct, isocratic, sensitive and precise liquid chromatographic method is presented for the enantiomeric separation of aminoglutethimide (AG) and its acetylated metabolite (AcAG) using cellulose tris-3,5-dimethyl phenyl carbamate (Chiralcel OD) and cellulose tris(4-methylphenyl benzoate) ester (Chiralcel OJ) columns in series. The enantiomeric elution order is determined by separate chromatography of the racemate AG and racemate AcAG and of their separate enantiomers under similar conditions. This method has been used to determine and identify the enantiomers of AG and AcAG in the urine sample collected from a metastatic breast cancer patient after administration of AG for 24 h. Large amounts of (+)-R-AG are excreted unchanged in the urine together with smaller quantities of (+)-R-AcAG, while most of the (-)-S-AG is metabolically converted into (-)-S-AcAG.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050206
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  • 70
    Digitale Medien
    Digitale Medien
    Microdetermination of hyaluronic acid in human urine by high performance liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 189-192 
    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 (HPLC) system is described for determination of the unsaturated disaccharide (ΔDi-HA) derived from hyaluronic acid (HA) in human urine by digestion with hyaluronidase SD. The effects of eluents on the separation of ΔDi-HA and ΔDi-OS, which is derived from the reaction of chondroitin with the enzyme, have been studied. The established chromatographic conditions were as follows-column: a stainless steel tube (4 mm i.d. × 250 mm) packed with TSKgel NH2-60; eluent: a mixture of acetonitrile and 0.1 M Tris-HCI buffer containing 0.1 M boric acid and 10 mM sodium sulphate, pH 7.0 (64:36, v/v). The strong fluorescence of unsaturated disaccharide after the reaction with 2-cyanoacetamide in alkaline medium was used for post-column detection. The calibration curve for ΔDi-HA was linear in the range 5 pmol-5 nmol with a practical detection limit of 2 pmol. The assay coefficients of variation (n = 5) at 200 pmol for ΔDi-HA and ΔDi-OS were 1.7 and 1.5%, respectively. This HPLC system has been applied to the determination of HA in human urine.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050502
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  • 71
    Digitale Medien
    Digitale Medien
    Determination and purification of metallothioneins by high performance liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 193-197 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A rapid, reproducible and sensitive high performance liquid chromatography (HPLC) method for the determination and purification of metallothionein-I (MT-I) and metallothionein-II (MT-II) in mouse and rabbit livers has been developed. Methallothioneins (MTs) were separated by an HPLC anion exchange column, eluted through a linear gradient of Tris buffer and the peak containing MTs was determined by atomic absorption spectrophotometry. Furthermore, the content of MT-I or MT-II was calculated by protein peak area in a short time (about 20 min). The sample to be tested was homogenized, centrifuged and saturated by cadmium. MT-I and MT-II were eluted at 15.9 and 19.3 min, respectively. The following mouse liver cytosols were tested: controls, Cd-injected samples and 60Co-irradiated samples. A detection limit of 5 μg/g liver was established for this method. We have analysed more than 100 biological samples and obtained satisfactory results.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050503
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  • 72
    Digitale Medien
    Digitale Medien
    Determination of short-chain fatty acids in equine caecal liquor by ion exchange high performance liquid chromatography after solid phase extraction (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 202-206 
    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 chromatography (HPLC) method was developed for the determination of seven short-chain fatty acids in equine caecal liquor. Samples were cleaned up on a Sep-pak (C18) cartridge, and the analyte was eluted from the extraction cartridge and filtered through a 0.45 μm cellulose nitrate filter. The analyte was chromatographed by ion exchange HPLC. Detection was by UV at 210 nm. Recovery from phosphate buffer (0.05 M, pH 7.0) and equine caecal liquor was 76.95% (lactic), 76.76% (acetic), 84.40% (propionic), 89.35% (isobutyric), 88.73% (butyric), 80.33% (isovaleric) and 72.61% (valeric). The limit of detection of the short-chain fatty acids in phosphate buffer was 0.00006 M (lactic), 0.0001 M (acetic), 0.0002 M (propionic), 0.0001 M (isobutyric), 0.0002 M (butyric), 0.0002 M (isovaleric) and 0.0003 M (valeric). The specificity and sensitivity of this method was sufficiently high to allow the characterization of the pattern of these short-chain fatty acids in equine caecal liquor following intravenous administration of oxytetracycline at the recommended dose rate in a pony.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050505
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  • 73
    Digitale Medien
    Digitale Medien
    Product news (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 273-273 
    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.1130050610
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  • 74
    Digitale Medien
    Digitale Medien
    Study of the solid phase extraction of pentoxifylline and its major metabolite as a basis of their rapid low concentration gas chromatographic determination in serum (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 256-261 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A gas - liquid chromatographic method for the determination of pentoxifylline and its secondary alcohol metabolite in serum has been developed. The method is based on the combination of solid phase extraction, capillary column separation and nitrogen - phosphorus detection of the analytes. Optimization of the solid phase extraction conditions permitted a low concentration determination, with limits of determination of 2 n/mL and 10 n/mL for pentoxifylline and its metabolite, respectively. The simplicity and rapidity of the extraction step was preserved.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050606
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  • 75
    Digitale Medien
    Digitale Medien
    Disopyramide analysis using REMEDi: Comparison with EMIT and conventional high performance liquid chromatographic methods (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 269-272 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: REMEDi (Rapid EMErgency Drug identification; Bio-Rad) is an automated high performance liquid chromatographic (HPLC) system designed to detect, identify and measure a range of basic and neutral drugs in 0.5-1.0 mL of urine or plasm/serum. We have evaluated REMEDi in the analysis of the antiarrhythmic drug disopyramide in patient samples. The specimens were also analysed by a conventional HPLC method, based on solvent extraction and UV detection (254 nm), and by EMIT. There were good correlations between the results obtained with each method (r = 0.91 or greater). REMEDi gave a lower mean result than EMIT [means±SD (m/L): REMEDi 2.64±1.10, EMIT 3.14±1.51; t = 4.0, p〈0.01; n = 25], but there were no other significant differences in mean results. The principal disopyramide metabolite, mono-N-desalkyldisopyramide, did not interfere in any method. Clearly REMEDi can be used for therapeutic drug monitoring of disopyramide provided enough sample is available.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050609
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  • 76
    Digitale Medien
    Digitale Medien
    High performance liquid chromatography as a tool in the definition of abnormalities in monoamine and tryptophan metabolites in cerebrospinal fluid from patients with neurological disorders (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 108-112 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: In this study we report the levels of 3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid, homovallinic acid, tryptophan, 5-hydroxyindole-3-acetic acid and serotonin in lumbar cerebrospinal fluid (CSF) from patients with multiple sclerosis, cerebrovascular disease and muscular tension headache the latter, as healthy controls. The separation of these substances was performed on a reversed phase column by ion pair high performance liquid chromatography and detection was made by a glassy carbon electrode set at +900 mV vs Ag+/AgCI. The whole separation was achieved within 25 min. Concentrations of all substances (10-1000 pmole/L) were linearly proportional to areas obtained. The system is sensitive, stable and reproducible. The significance of CSF levels of these metabolites from patient groups compared with healthy controls are discussed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050304
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  • 77
    Digitale Medien
    Digitale Medien
    Field flow fractionation in biomedical analysis (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 133-138 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Samples of biomedical interest which have been analysed by field-flow fractionation techniques are surveyed. The list begins with whole cells and microorganisms, going through viruses, nucleic acids, cell fragments and organelles, down to proteins and their aggregates. The principles of separation in the normal and steric mode of retention are illustrated, and instrumentation and techniques are described. The review concentrates mainly on the two systems of choice for biomedical applications: sedimentation and flow field-flow fractionation.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050308
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  • 78
    Digitale Medien
    Digitale Medien
    Mobile phase versus stationary phase approaches to the direct injection of biological fluids in liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 14-18 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The liquid chromatographic analysis of drugs in urine through direct injection without any sample pretreatment was extended to micellar chromatography with nonionic surfactants, the Pinkerton™ ISRP column and the shelded hydrophobic phase (Hisep™) column. The feasibility of using each was demonstrated through the determination of the diuretic, hydrochlorothiazide, in urine. Good separation, recovery, precision and linearity, and adequate limits of detection were obtained for this analysis with all three techniques. The advantages and limitations of the mobile phase approach of micellar chromatography and the two stationary phase approaches are discussed for the direct injection of urine as well as other biological fluids.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050105
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  • 79
    Digitale Medien
    Digitale Medien
    High performance liquid chromatographic determination of Picumast and two active metabolites in plasma using on-line sample preparation (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 32-37 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A method for determining Picumast, an antiallergic drug, in plasma by HPLC and column switching has been developed. The system consisted of two precolumns, an analytical column, three pumps, an autosampler and a fluorescence detector. The precolumns (17 × 4.6 mm i.d.) were packed with LiChroprep RPR (a moderately polar reversed phase) and the analytical column with Nucleosil ODS (RP 18, 5 μm). The columns were connected according to the alternating precolumn technique. The mobile phase consisted of 30% CH3CN/70% 0.05M KH2PO4, pH 2.5, with a flow gradient. Detection wavelengths were 333 nm for excitation and 383 nm for emission. The retention times of Picumast, M1 and M2 were 12, 3.6 and 4.0 min, respectively. Total run time was 15 min. The limit of detection was 3 ng/mL for M1 and 1 ng/mL for M2 and Picumast using an injection volume of 150 μL. The recoveries vary between 89% and 97% with standard deviations between 2.4 and 3.3%.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050108
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  • 80
    Digitale Medien
    Digitale Medien
    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991) 
    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.1130050201
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  • 81
    Digitale Medien
    Digitale Medien
    Characterization of human progesterone receptor by high performance hydrophobic interaction chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 62-67 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: High performance hydrophobic interaction chromatography has been used to separate progestin receptors (PRs) from human uterus and from the T47D human breast cancer cell line. Reproducible separations of high resolution were achieved using a TSK Phenyl-5PW column and a reverse salt gradient of 400 mM to 0 mM sodium sulfate in phosphate buffer, pH 7.4. Peaks of radioactivity exhibiting hydrophobic behaviour were isolated, as well as a smaller proportion of specific bound receptors located in the void volume fraction. No differences in retention times were observed between uterine and breast cell line samples. When the technique was used in conjunction with rapid vertical tube sucrose density gradient centrifugation, the 8S sedimenting PR from fresh, low-salt cytosol always eluted with a retention time of 24 min. The natural 4S receptor chromatographed as a single peak at 29 min while the 4S receptor species from high-salt cytosol appeared as two distinct peaks of radioactivity with retention times of 29 and 33 min. While specific binding was shown to occur in the void volume of the column, the origin of these receptors were indeterminate. These results would suggest that under these conditions the 8S receptor occurs as a single hydrophobic class of protein, whereas the data provides evidence that transformed 4S receptor may be proportioned into two unequal entities as a function of exposure to salt.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050204
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  • 82
    Digitale Medien
    Digitale Medien
    Separation of proteins by consecutive sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and reversed phase high performance liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 86-89 
    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 preparative separation of proteins was developed by using consecutively sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) and reversed phase high performance liquid chromatography (HPLC). The proteins were separated by SDS-PAGE and afterwards extracted from the gel. The extracted proteins were separated from SDS and other small molecular weight contaminants on a Fractogel TSK HW-40 (F) column in acidic aqueous acetonitrile. The proteins eluted from the Fractogel column were fractionated by HPLC. The identity and purity of the recovered proteins was confirmed by SDS-PAGE analysis.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050209
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  • 83
    Digitale Medien
    Digitale Medien
    Modern techniques in biomedical chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 99-99 
    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.1130050302
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  • 84
    Digitale Medien
    Digitale Medien
    Application of ion pair high performance liquid chromatography to the analysis of porphyrins in clinical samples (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 122-127 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Reversed phase ion pair chromatography is a highly selective separation technique for the determination of free porphyrin carboxylic acids from human materials. Isocratic and gradient elution methods can be used to analyse porphyrin isomers and to establish porphyrin profiles for the biochemical diagnosis of porphyrias. Ion pair high performance liquid chromatography led to the discovery of the atypical isomers II and IV of uroporphyrin and coproporphyrin in human urine. Advantages and limitations of the ion pair technique are discussed.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050306
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  • 85
    Digitale Medien
    Digitale Medien
    pH-dependent colum fractionation for characterization of endogenous digoxin-like immunoractive factors in pregnant urine (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 175-179 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Samples of pregnant urine were treated with three diatomaceous earth columns to fractionate organic solvent-soluble components. The first column was pre-injected with the urine sample. The second and the third columns were pre-injected with sodium bicarbonate and sodium hydroxide solutions, respectively; these played an important role in capturing acidic components in the urine extract from the first column. Neutral components could be eluted out from the columns with the organic solvent, while the basic components were retained in the first column. Once strongly and weakly acidic components were captured on the alkaline columns, they were separately treated with an acidic mobile phase and recovered. The digoxin-like activities of each fraction were examined for cross-reactivity to antidigoxin antibody and inhibitory effects on dog kidney Na+, K+-ATPase. Both types of reactivity were found in all three fractions and decreased in the following order: strongly acidic, neutral and weakly acidic. The neutral fraction of pregnant urine showed significantly greater cross-reactivity than that of the non-pregnant urine. Following hydrolysis of the pregnant urine with β-D-glucuronidase, the cross-reactivity of the neutral fraction increased significantly. High performance liquid chromatographic analysis showed that several components in the neutral fraction had apparently increased after the hydrolysis, showing the possible presence of unknown digoxin-like components in the pregnant urine.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050408
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  • 86
    Digitale Medien
    Digitale Medien
    Inorganic supports coated with N-substituted polyacrylamides: Application to biospecific chromatography of proteins (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 90-93 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Wide porous glass (WPG) chemically coated with a poly-N-(2-hydroxyethyl)acrylamide layer is proposed as a carrier of biospecific ligands in affinity chromatography. The method of WPG chemical modification includes synthesis of the γ-aminopropyl derivative followed by chemical adsorption of poly(p-nitrophenyl acrylate). Ester groups of the polyacrylate-coated WPG can be used for coupling the ligands bearing primary amino groups. Condensation of esters with ethanolamine yields a poly-N-(2-hydroxyethyl)acrylamide-coated support with non-specific adsorption properties resembling those of Sepharose 4B. Human IgG immobilized on the polyacrylate support was used for isolation of the first complement component from human serum and for its separation into subcomponents C1r, C1s and C1q by a one-step method. An unbound part of serum may be used as the R1 reagent for determining haemolytic C1 activity. The stepwise elution of C1r, C1s and C1q from the column reflects the course of C1 breakdown after its activation on immune complex formation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050210
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  • 87
    Digitale Medien
    Digitale Medien
    Chromatographic methods for the analysis of basic neurotransmitters and their acidic metabolites (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 101-107 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Chromatographic techniques for the determination of trace amounts of neurotransmitters were reviewed. The two techniques found to be most useful were GC-MS and the reversed-phase mode of HPLC with an electrochemical or fluorescent detector. For structure determination or unequivocal peak identification, GC-MS is the method of choice. In addition the limits of detection of GC-MS were better than those obtained by HPLC. However for routine analyses, HPLC is now being used in studies of mental illness and other diseases. Good resolution, reproducibility and sensitivity can be obtained without the derivatisation steps required for GC-MS, and catecholamines, serotonin, and their acidic metabolites can be concomitantly determined in one analysis.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050303
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  • 88
    Digitale Medien
    Digitale Medien
    Calendar of events (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 139-140 
    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.1130050309
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  • 89
    Digitale Medien
    Digitale Medien
    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991) 
    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.1130050401
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  • 90
    Digitale Medien
    Digitale Medien
    Solid phase extraction of oxcarbazepine and its metabolites from plasma for analysis by high performance liquid chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 212-215 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A rapid, sensitive and simple-to-operate high performance liquid chromatographic method for the simultaneous determination of oxcarbazepine, 10-hydroxycarbazepine and 10,11-dihydro-10,11-trans-dihydroxy-carbamazepine in plasma is described. The drug and its metabolites were extracted from plasma using commercially available reversed phase octadecylsilane bonded-silica columns (Bond Elut C18, 1 mL capacity). Chromatographic separation of oxcarbazepine and its metabolites was achieved using a mobile phase consisting of acetonitrile/methanol/water (13:25:62 by volume) at a flow rate of 1.2 mL/min in conjunction with a Waters Associates Nova-Pak C18 column. The analytical column, in Radial-Pak cartridge form, was used in combination with a LiChrospher 5 μm C18 guard column. By measuring the UV absorbance at 214 nm, plasma levels in the region of 50-100 ng/mL for the drug and its metabolites can be detected with only 100 μL of plasma. The method has been applied to pharmacokinetic studies of oxcarbazepine and its metabolites in children with epilepsy; preliminary pharmacokinetic findings in two patients at steady-state are presented.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050507
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  • 91
    Digitale Medien
    Digitale Medien
    C. W. Geherke and K. C. T. Kuo (eds.). Chromatography and modification of nucleosides. Part C: Modified nucleosides in cancer and normal metabolism - methods and applications. Elsevier Science Publishers, Amsterdam, 1990, ISBN 0-444-88598-6, $179.50 (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 231-231 
    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.1130050512
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  • 92
    Digitale Medien
    Digitale Medien
    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991) 
    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.1130050601
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  • 93
    Digitale Medien
    Digitale Medien
    A high performance liquid chromatographic post-column fluorescent ion pair extraction system: Application to physostigmine and its metabolite eseroline in human serum (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 8-13 
    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 post-column fluorescent ion pair extraction system was developed for the analysis of quaternary ammonium and amine drugs in serum. A new fluorescent ion pair reagent, sodium α-(3,4-dimethoxyphenyl) cinnamonitrile-2′-sulfonate (DPS), was synthesized and characterized. The post-column extraction system consisted of a three-dimensional knitted teflon mixing coil and a membrane phase separator which was modified from an original literature design. Physostigmine and its metabolite eseroline were used as model cations. A solid phase extraction procedure using octadecylsilane columns was developed to extract the compounds and neostigmine bromide (internal standard) from human serum. The compounds were chromatographed on a diol column using a 80:20 aqueous phosphate buffer pH 4 absolute methanol mobile phase at a flow rate of 1 mL/min. Methylene chloride was used as the on-line extraction solvent for the DPS ion pairs formed. Fluorescence of the extracted ion pairs was measured using an excitation of 243 nm and an emission cut-off filter at 418 nm. Linearity was in the 2-100 ng/mL and 5-100 ng/mL ranges for physostigmine and eseroline, respectively. Detection limits based on a signal-to-noise ratio of 2, were 2 and 5 ng/mL, respectively. Precision of the method was found to be in the 1.5-3% range and percentage error in the 1.5-7% range for both compounds.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050104
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  • 94
    Digitale Medien
    Digitale Medien
    Product news (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 232-232 
    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.1130050513
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  • 95
    Digitale Medien
    Digitale Medien
    Application of photodiode array detection and fast atom bombardment mass spectrometry for the identification of the arginine residue in neuropeptides (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 240-247 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Chemical derivatization by phenylgyoxal (PGX) was applied to the identification of arginine in the neuropeptides dynorphin A (1-6) and substance P. The obtained products were separated on a short reversed phase C18 column and analysed on-line with the photodiode array UV technique. The selective attachment of a chromogenic molecule into the arginine residue resulted in significant change in the absorbance spectra around 250 nm, depending on the number of PGX molecules attracted. Further analysis employed fast atom bombardment mass spectrometry (FAB MS) and C-terminal sequencing for detailed verification of the derivatives formed during modification with PGX. The results clearly demonstrated that the photodiode array technique, when combined with chemical modification of certain amino acids, provides new possibilities for the analysis of peptide structures.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050603
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  • 96
    Digitale Medien
    Digitale Medien
    Determination of 2-chloro-2′-deoxyadenosine in human plasma (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 262-264 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The first high performance liquid chromatographic method for determination of the plasma concentration of 2-chloro-2′-deoxyadenosine (CdA) in patients, which is significantly more sensitive than the previously used RIA method, is presented. CdA is a purine analogue with useful clinical activity against lymphoproliferative disorders and it has recently been found to be the single most active agent in the treatment of hairy cell leukaemia. Guaneran (6-nitroimidazol-6-thioguanine) was added to 1 mL plasma as the internal standard and CdA was extracted using ethyl acetate. A Perkin-Elmer C18, 3 μ, 8 cm column was used for the separation of CdA and the internal standard from endogenous compounds in the sample with a mixture of sodium phosphate buffer 10 mM, methanol and acetonitrile (85:10:5, pH = 3.0) as the mobile phase. The sensitivity of the method (1 nM) allows the determination of CdA in plasma 24 h after the administration of 0.14 m/kg as a 2 h infusion.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050607
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  • 97
    Digitale Medien
    Digitale Medien
    Identification and quantification of lipids from rabbit Harderian glands by gas chromatography/mass spectrometry (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 143-147 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Lipids from hydrolysed extracts of Harderian glands from the rabbit were examined as trimethylsilyl, acetonide, nicotinate and picolinyl esters and shown to consist mainly of acylated glycerol ethers and acylated hydroxyglycerol ethers. Constitutents amounting to 98.8% of the recovered secretion were identified. Fatty acids were mainly normal, saturated compounds with chain legths from 12 to 24 carbon atoms; n-16:0 and n-18:0 accounted for about 40% of the identified acids. Small concentrations of iso-17:0 and unsaturated acids with 18-carbon chains were also identified. Fatty alcohols were again mainly normal-unsaturated compounds; the chains varied from C18 to C25 with 20:0-OH and 22:0-OH being the most abundant. Three types of 1-alkyl glycerols were found. The major constituents had normal, saturated chains with from 14 to 23 carbon atoms with the even carbon chains predominating. These were accompanied by hydroxylated derivatives of the 16- and 18-carbon glycerol ethers with hydroxy groups in the 10, 11 and 12 positions. Branched-chain glycerol ethers were of low concentration and contained predominently iso chains. Many of these compounds have not been reported before in this secretion. Low concentrations of the previously reported hydroxy acids with n-C14, -C15 and -C16 chains were also found. Nicotinate derivatives were applied to the structural determination of glycerol ethers for the first time and shown to reveal the position of methyl branch points in an analogous manner to that previously shown for mono- and di-hydric alcohols. Acids were identified as picolinyl esters.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050402
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  • 98
    Digitale Medien
    Digitale Medien
    A high performance liquid chromatographic assay for AMP-deaminase activity in the erythrocytes of healthy subjects and patients with inherited purine disorders (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 171-174 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A novel method for measuring AMP-deaminase activity in human erythrocytes is presented, based on the determination of the reaction product, IMP, using high performance liquid chromatography. IMP formation was found to be proportional both to the incubation time and the amount of haemolysate over a wide range. The minimal detectable AMP-deaminase activity was more than 1000 times lower than the mean activity found in healthy controls (1083 nmol/h/mg Hb). No marked difference of activity was found in the patients with the following inherited purine disorders: familial juvenile gouty nephropathy and deficiencies of adenosine deaminase, hypoxanthine-guanine phosphoribosyltransferase or adenine phosphoribosyltransferase. The activity in the erythrocytes of patients with chronic renal failure was also similar to controls. The existence of subjects with low erythrocyte AMP-deaminase activity in the population has been confirmed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050407
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  • 99
    Digitale Medien
    Digitale Medien
    Calendar of events (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 187-187 
    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.1130050411
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  • 100
    Digitale Medien
    Digitale Medien
    Rapid high voltage isoelectric focusing of proteins in rod gels (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 221-225 
    Details
    ISSN: 0269-3879
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A rapid procedure of isoelectric focusing (IEF) of proteins in polyacrylamide rod gels (i.d., 1.1 mm; lenght, 7.5 cm) is described. The time required for IEF can be reduced to 0.5 h by using high voltages up to 3000 V in the presence or absence of urea in the gels. When used as the first dimension of a two-dimensional technique for IEF sodium dodecyl sulphate electrophoresis, high voltage IEF gives smaller protein spots on the second dimension gel, associated with an increase in resolution. The method has been tested by a two-dimensional separation of an eye sample of the goodeid fish Xenotoca eiseni.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bmc.1130050509
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