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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Regulatory Peptides 54 (1994), S. 527-542 
    ISSN: 0167-0115
    Keywords: Enterochromaffin system ; Immunohistochemistry ; Neuropeptide ; Rectum ; Skin
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0568
    Keywords: Key words Congenital heart defects ; Cushions ; Extracellular matrix ; Immunohistochemistry ; Morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Using various microscopical techniques we studied the development of the atrioventricular valves in human hearts between 5 and 19 weeks of development. Within the atrioventricular cushions two different layers could be recognized that remained present in all ages studied. The atrial layer, being present at the side of the atrioventricular orifice, was positive for laminin while the ventricular layer, that was connected to the myocardium, was positive for fibronectin and collagen III. Fate-mapping of these two layers, morphometrics, and scanning electron microscopy, supplemented with in vivo labeling of cushion tissue in chicken hearts have lead to new insights in the process of valve development. The cushions became freely movable prevalvular leaflets by delamination of ventricular myocardium underneath the cushion tissue. This myocardium gradually retracted towards annulus and papillary muscles and finally disappeared, resulting in fibrous, non-myocardial valves. The atrial layer of the cushions remained present as a jelly-like surface on the valve leaflets while the ventricular layer of the cushions became the compact fibrous tissue of the leaflets and the chords. Chordal development was first visible at 10 weeks of development when gaps were formed in the ventricular layer of the cushions on top of the papillary muscles. These gaps enlarged into the interchordal spaces while the cushion tissue in between the gaps lengthened to form the chords. We conclude that the leaflets as well as the chords of the atrioventricular valves are derived from atrioventricular cushion tissue. Myocardium is only important for loosening of the leaflets while keeping connection with the developing papillary muscles. Errors in delamination or retraction of myocardium or remodeling of cushion tissue into chords form the basis for various congenital valve anomalies.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2307
    Keywords: Brain proteins ; Immunohistochemistry ; Melanoma ; Neuron-specific enolase ; S-100 ; Skin ; Tumour markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The brain proteins S-100 and neuron-specific enolase have been reported by separate groups to be present in human malignant melanomas. There is no systematic study comparing the occurrence of these proteins in the same tumour specimens. We have examined 33 primary malignant melanomas, including 5 which were amelanotic, and 25 metastatic melanomas using immunohistochemical methods with specific, non-cross-reacting antibodies to S-100 and NSE. We found S-100 immunoreactivity to be present in all cases but one, whereas NSE immnoreaction was very weak and patchy, and present in only 6 cases. S-100 immunoreactivity was not demonstrated in 40 control tumours, either primary or metastatic in skin, including basal- and squamous-cell carcinomas, spindle-cell sarcomas, lymphomas and Merkel cell tumours. All intradermal (n=4) and compound (n=1) naevi were positive for S-100, 2 blue naevi showing much less reaction. NSE immunoreactivity was detected in Merkel cell tumours (n=8), undifferentiated (n=2) and small cell (n=1) carcinomas, and all melanocytic naevi. It is suggested therefore that antibody to S-100 is the reagent of choice for demonstration of melanocytic tumours, and may be especially valuable in the diagnosis of amelanotic melanoma or metastatic tumours of doubtful origin where melanoma is suspected.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0878
    Keywords: Key words: Collagen ; Type XV ; Basement membrane zones ; Basement membrane ; Immunohistochemistry ; Antibody ; Recombinant protein ; Human tissues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The collagen family of proteins consists of 19 types encoded by 33 genes. One of the more recently discovered collagens is the α1 chain of type XV. Type XV collagen is comprised of a 577-amino-acid, highly interrupted, triple-helical region that is flanked by amino and carboxy noncollagenous domains of 555 and 256 residues, respectively. To address questions of where this collagen is localized and what its function may entail, we produced a bacteria-expressed recombinant protein representing the first half of the type XV collagen carboxy-terminal domain in order to generate highly specific polyclonal antisera. Immunoscreening of an expression library with the affinity-purified antibody revealed three clones coding for part of the type XV triple-helical region and the entire noncollagenous carboxy-terminus. Western blot analysis of human tissue homogenates identified a 116-kDa collagenase-sensitive protein and a 27-kDa collagenase-resistant fragment, whose electrophoretic mobilities were unchanged in the presence and absence of reductant. Northern blot hybridization to human tissue RNAs indicated that type XV has a prevalent and widespread distribution. To determine the precise localization of type XV collagen, immunohistochemical analyses at the light- and electron-microscopic levels were performed. Type XV exhibited a surprisingly restricted and uniform presence in many human tissues as evidenced by a strong association with vascular, neuronal, mesenchymal, and some epithelial basement membrane zones. These data suggest that type XV collagen may function in some manner to adhere basement membrane to the underlying connective tissue stroma.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0878
    Keywords: Immunohistochemistry ; Melanotropins ; Insects ; Pro-opiomelanocortin ; Nervous system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By use of well characterized antisera in the peroxidase-antiperoxidase method, we were able to demonstrateαMSH andβMSH immunoreactive cells and nerve fibres within the nervous system of adults and larvae ofLocusta migratoria and 3-, 5- and 8-day-old adultSarcophaga bullata. In neither of these insect species, any immunoreaction was obtained with aγ 3MSH-antiserum. Double immuno-histochemical stainings revealed thatαMSH-like andβMSH-like substances are located in different cells. These cells show no immunoreactivity to a number of antisera against other POMC-derivatives (anti-βlipotropin, anti-βendorphin, anti-ACTH1–24); thus they appear to containαMSH- orβMSH-like material in a specific way. The function of the immunologically detected peptides remains to be demonstrated. The distribution of the immunoreactive material suggests that, like in amphibians and other lower vertebrates, the synthesis or release of melanotropins might be under the influence of external stimuli. The present observations support the recently developed concept that even some of the smallest neuropeptides, the melanotropins, have been highly conserved during a long period of evolution.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0878
    Keywords: Glucagon-like peptide 1 ; Endocrine tumors ; Immunohistochemistry ; Ultrastructure ; Multiple endocrine neoplasia type 1 ; Co-localization ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The preproglucagon gene encodes, in addition to glucagon, two smaller peptides with structural similarity: glucagon-like peptides 1 and 2. Glucagon-like peptide 1 (GLP-1) 7–36 amide is the most powerful incretin candidate. In the present study, GLP-1 immunoreactivity was investigated in tissue specimens of various types of gastroenteropancreatic tumors, and the serum-levels of GLP-1 were assayed. Immunohistochemical staining of 88 tumors revealed GLP-1 immunoreactivity in 17 neoplasias (19.3 %), viz., in 7 out of 33 non-functioning tumors, 4 out of 20 gastrinomas, 4 out of 13 insulinomas, 1 out of 3 vasoactive-intestinal-polypeptide (VIP)omas and 1 adrenocorticotropic-hormone (ACTH)-producing tumor. In these tumors, GLP-1-immunoreactive cells were distributed either diffusely, arranged in clusters, or as single cells. All GLP-1-positive tumors were immunoreactive for glucagon or glicentin, 10 tumors were immunoreactive for pancreatic polypeptide, and 8 tumors for insulin. Ultrastructural analysis of 8 GLP-1-positive tumors, with the immunogold technique, demonstrated GLP-1 immunoreactivity mainly in cells resembling the A-cells of the pancreas or the L-cells of the gut. Of the 17 GLP-1-immunoreactive tumors, 15 were primarily located in the pancreas. Additionally, 2 non-functioning tumors of the rectum were GLP-1 immunoreactive. Five tumors were GLP-1 immunoreactive from 9 patients with multiple endocrine neoplasia I syndrome. Patients with GLP-1-immunoreactive tumors were characterized by a significantly lower rate of distant metastases (P〈0.01) and a higher rate of curative resections (P〈0.05). In 2 out of 22 patients, elevated serum-levels of GLP-1 were found: one patient with a vasoactive-intestinal-polypeptide (VIP)oma and 1 patient with a non-functioning tumor. This indicates that GLP-1 might be secreted at least by a few gastroenteropancreatic endocrine tumors.
    Type of Medium: Electronic Resource
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