Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Cell & Developmental Biology  (21)
  • Analytical Chemistry and Spectroscopy  (7)
  • 11
    Electronic Resource
    Electronic Resource
    Octafluorotoluene as a derivatizing agent for steroids in human plasma (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1988), S. 211-213 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of octafluorotoluene (OFT) as a versatile gas chromatographic/mass spectrometric derivatizing agent for steroids containing alcoholic, phenolic or α,β-unsaturated keto functions, is described. Two distinct derivatizing schemes can be utilized, involving (method 1) a phase-transfer reaction, employing a two-phase system of CH2Cl2 and N NaOH with n-Bu4NHSO4 as catalyst (suitable for alcoholic and phenolic steroids) and (method 2) a reaction conducted in anhydrous dimethylformamide at 155°C with CsF as base (appropriate for α,β-unsaturated keto steroids). Perfluorotolyl (PFT) ethers and/or enol ethers have thus been generated. The electron impact spectra display abundant high-mass molecular ions where derivatization has occurred at a phenolic or enolic function. An extraction, derivatization and gas chromatographic/mass spectrometric scheme has been devised involving method 2 for the analysis of steroids in human plasma. A preliminary quantitative investigation of the levels of testosterone in plasma has been carried out employing these methods. The anomalously high level found is explained in terms of the presence in plasma of lipid-soluble derivatives of testosterone (probably fatty acid esters) which generate the testosterone bis-OFT derivative under the reaction conditions employed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200160138
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Quantitative analysis of disaturated lecithins in human plasma by ammonia chemical ionization mass spectrometry (1981)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 8 (1981), S. 503-505 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three physiologically important disaturated lecithins have been analyzed quantitatively as the acetate derivatives using a solids inlet probe and ammonia chemical ionization. Concentration independent response factors have been determined over a tenfold range that brackets human plasma levels. The results obtained serve as an independent corroboration of gas chromatographic analyses.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200081008
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Morphological characteristics of boar efferent ductules and epididymal duct (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 411-431 
    Details
    ISSN: 1059-910X
    Keywords: Corrosion casts ; LM ; SEM ; TEM ; Microvasculature ; Ultrastructure ; Absorption ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The aim of the present study was to provide a comprehensive morphological analysis of the porcine epididymis in view of the specific functions being performed in different regions of this organ. Blood supply and microvasculature of efferent ductules and epididymal duct were investigated by means of corrosion casts which were analysed macroscopically and by scanning electron microscopy. This revealed blood supply to the testis and epididymis to be closely related. The capillary pattern was typical for the efferent ductules, the caput, corpus, and distal cauda epididymidis, respectively. Corrosion casts were also used to visualize the course of the efferent ductules themselves. Tissue samples from different regions of the efferent ductules and epididymal duct were examined by light microscopy and both scanning and transmission electron microscopy, with special attention being payed to transitional areas. Morphological criteria allowed the distinction of three segments within the efferent ductules and of the initial segment, proximal caput, distal caput, corpus, proximal cauda, and distal cauda regions of the epididymal duct. Components of the endocytic apparatus of efferent ductule principal cells were identified by ferritin uptake. Ultrastructural evidence of absorption in the epididymal duct was particularly prominent in proximal and distal caput. Extensive cisternae of rough endoplasmic reticulum and a well-developed Golgi apparatus were indicative of active protein synthesis and secretion especially in the distal caput and corpus regions. However, assignment of various organelles in principal cells of the epididymal duct to either absorptive or secretory pathways still remains tentative. © 1994 Wiley-Liss, Inc.
    Additional Material: 53 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290603
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Improved preservation of rat epididymal sperm for high-resolution low-voltage scanning electron microscopy (HR-LVSEM) (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 34 (1993), S. 175-182 
    Details
    ISSN: 1040-452X
    Keywords: Fixation ; Artifact ; Ruthenium red ; Percoll ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Various fixation protocols were used in an attempt to improve preservation of rat epididymal sperm for high-resolution low-voltage scanning electron microscopy (HR-LVSEM). Wash solutions and fixatives of different composition and osmolarity were tested. Paraformaldehyde and glutaraldehyde concentrations were varied between 0.5% and 3%. Ruthenium red was tested as an additive in both primary fixation and postfixation, or in postfixation alone. HR-LVSEM revealed various degrees of ruffing, folding, blebbing, and peeling off of the plasma membrane, as well as holes of different sizes. The plasma membrane overlying the acrosome and the connecting piece proved to be particularly sensitive to varying fixation conditions. Consistent topographical differences were revealed among the different domains over the sperm head. Most of the differences were considered to be artifacts. Their consistency, however, suggests that structural and biochemical differences exist either within the membrane or in the structures subjacent to the membrane. Primary fixation turned out to be less critical than postfixation. Preservation of a smooth plasma membrane without holes could only be achieved when primary fixation in low aldehyde concentrations, with or without ruthenium red, was followed by postfixation with OsO4 and 1,000 ppm ruthenium red. Examination of thin sections of the same material confirmed that even a considerable number of small holes are difficult to detect in transmission electron microscopy. These results show that with the recent increase in resolution of LVSEM there is need for further effort to improve sample processing. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080340209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Analysis of mercapturic acid conjugates of xenobiotic compounds using negative ionization and tandem mass spectrometryPresented in part at the 36th Annual Conference on Mass Spectrometry and Allied Topics, San Francisco, 1988. (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 68-76 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra of mercapturic acid conjugates of two xenobiotic products of lipid peroxidation (trans-4-hydroxy-2-hexenal and trans-4-hydroxy-2-nonenal) as well as conjugates of 1,3-dichloropropene, styrene oxide, 1,2-naphthalene oxide and α-chlorotoluene were obtained using fast atom bombardment or negative chemical ionization. Fragmentation pathways were investigated using linked scan and mass-analyzed ion kinetic energy spectrometric techniques. Characteristics of the spectra obtained using different ionization and sample introduction techniques are compared. Deprotonated molecular ions of mercapturic acids gave simple daughter ion spectra, with the dominant mode of decomposition involving cleavage of C—S bonds giving a characteristic neutral loss of 129 Da Screening for mercapturates in urine samples was performed using neutral loss scanning and yielded limits of detection in the low nanogram per milliliter range. Quantitative analysis of the S-benzyl mercapturic acid at 1 p.p.b. in urine has been demonstrated using combined gas chromatography/electron capture mass spectrometry with d3-S-benzyl mercapturic acid as internal standard.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Confirmation of oxytetracycline, tetracycline and chlortetracycline residues in milk by particle beam liquid chromatography/mass spectrometryThis work was presented in part at the 38th ASMS Conference on Mass Spectrometry and Allied Topics, Tucson, Arizona, June 1990. (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1991), S. 789-795 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method using particle beam liquid chromatography/mass spectrometry was developed for the confirmation of oxytetracycline, tetracycline and chlortetracycline residues in bovine milk. This method is one of the first to apply particle beam technology to the confirmation of animal drug residues in food products for regulatory purposes. The milk is centrifuged, using molecular weight cut-off filters to remove components of 25 000 daltons and above from the milk. The filtrate is passed through a C-18 sample preparation cartridge which retains the tetracyclines. After the columns are washed with water, the tetracyclines are eluted with 0.1 M oxalic acid in methanol and concentrated. The compounds are separated on a Novapak C-18 column with a methanol-oxalic acid-acetonitrile mobile phase. Negative chemical ionization with selective ion monitoring is used to identify the tetracyclines. The procedure was used to confirm the presence of each tetracycline at 100 ng ml-1 in fortified and incurred milk samples.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200201208
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    The fine structure and development of the peritubular contractile cell component in the seminiferous tubules of the mouseSupported in part by grant AM-05433 from the National Institutes of Health. (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 121 (1967), S. 523-557 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Testes of sexually mature, as well as newborn and young mice of varying ages were studied by electron microscopy. The seminiferous tubules in the mature mouse possess a single cell layer of extremely flattened cells which form a sheath-like structure around the epithelium of the tubule. These peritubular cells are characterized by cytoplasmic filaments and other features which are typical of smooth muscle cells. A basement lamina is associated with the interstitial or peripheral surface of the cell. Peripherally, there is an additional cellular layer consisting of connective tissue fibrocytes.In newborn animals, the cells surrounding the tubule epithelium consist of a homogeneous population of fibroblasts, 3-4 layers in thickness. With growth and development of the testes the number of cell layers is reduced and the cells become more attenuated. At 13 days, those cells which are closest to the epithelium show localized aggregates of fine filaments, as well as what appears to be the elaboration of a basement lamina. By 17 days, the cytoplasmic filaments are more numerous and the basement lamina is well defined: by 19 days, the cells closely resemble the peritubular muscle cells of the adult.The probable functional role of these cells is discussed with respect to both sperm transport and the production and maintenance of the surrounding connective tissue stroma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001210307
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Myoid elements in the mammalian nephron and their relationship to other specializations in the basal part of kidney tubule cellsSupported in part by USPHS grants DE-2274-05, CA-11252, and 5398 (General Research grant). (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 129 (1970), S. 399-415 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The basal region of proximal convoluted tubule cells from mouse kidney was studied with the electron microscope. Particular attention was given to grazing sections, i.e., sections whose plane was approximately parallel to that of the basement lamina. The findings indicate that many of the “basal compartments” of the proximal convoluted cells are elongate parallel structures which contain aggregations of filaments resembling those of smooth muscle. These elongate structures, referred to as myoid bands, react positively with dyes which are selective for muscle tissue. Close membrane appositions are also seen in grazing sections, apparently related to the myoid bands, at least by virtue of location.In addition, the basal region of the proximal convoluted tubule cells possesses branching microvillous processes. Because of their arrangement, the basal extracellular space associated with the microvillous processes appears as a maze-like network of channels. The microvillous processes and the associated extracellular space are at a level just slightly higher than the level of the myoid bands. This space appears to be distinct from the basal labyrinth inasmuch as the latter extends well into the mitochondrial region of the cell, whereas the basal extracellular space does not. In places, the microvillous processes extend to the basement lamina between the myoid bands.It is postulated that the microvillous processes and the related extracellular space are associated with fluid transport and that the myoid bands may constitute a regulatory device related to the control of fluid movement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001290403
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Sertoli-Sertoli junctions and Sertoli-spermatid junctions after efferent ductule ligation and lanthanum treatment (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 148 (1977), S. 49-55 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Seminiferous tubules, partially dilated by ligation of the efferent ductules, were examined after treatment with lanthanum. Lanthanum penetrated the intercellular spaces of the seminiferous epithelium, but only to the level of the Sertoli-Sertoli junctions. Further penetration from the interstitial surface of the tubule was restricted by membrane fusions (tight junctions) at the junctional complex. Lanthanum also penetrated the epithelium from the luminal surface permeating the adluminal intercellular spaces, including the site of the Sertoli-spermatid junction. The lanthanum occupying the Sertoli-spermatid junctional site appeared as a slightly narrower electron-opaque zone than that found in the non-specialized intercellular areas. The findings clearly reveal that only the Sertoli-Sertoli junctional site forms a restrictive barrier. In contrast to the specializations of plasma membrane which form the tight junction, the associated filaments and cisterna of endoplasmic reticulum may be components more directly related to maintaining and regulating cell adhesion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001480105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Ultrastructural study of tension and pressure zones in a rabbit flexor tendon (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 157 (1980), S. 87-106 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The flexor digitorum profundus tendon of the rabbit hind limb is subject to tensional forces throughout most of its length but, within a localised area which is in contact with the calcaneum and talus, it is subjected to additional compressive forces. This pressure-bearing area, in marked contrast to the tensional areas, has a fibrocartilage-like organization and a high concentration of glycosaminoglycans (GAG).Ultrastructural features of the cells, collagen and matrix in the tension and pressure zones are also markedly different, with a full spectrum of transitional characteristics in the junctional region between the two zones. These findings support the concept that the cells in the various regions are sensitive and responsive to changes in physical load.In the tensional zone, elongated cells have extensive cytoplasmic flanges, which may contact flanges of neighbouring cells, and a scalloped cell surface that intimately conforms to the adjacent positively charged and tightly packed collagen fibrils of long periodicity (63 nm) and varying diameters. In the pressure zone, round and clustered fibrocartilage-like cells, characterized by dense arrays of 11-nm-diameter microfilaments and numerous lipid droplets, are surrounded by loosely packed collagen fibrils of short periodicity (53 nm) and predominantly small diameters, and an extensive matrix rich in GAG.It is suggested that these regional morphological variations in the extracellular components result from, and are indirectly the cause of, changes in the cellular synthetic activities which are known to occur in response to changes in the physical environment.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001570109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...