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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 163 (1969), S. 248-258 
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Es wird über histopathologische Untersuchungen des chronologischen Verlaufs an der durchSelyes „Ventrikel-Ligatur“ hervorgerufenen Herzspitzennekrose bei Ratten berichtet. In dem der Nekrose verfallenen Myokard setzt alsbald Organisation ein; dann wandelt sich allmählich das Granulationsgewebe in eine zellarme und faserreiche Narbe um. In den subendokardialen Schichten des Narbengewebes entstehen erst Knorpel-, später Knochenherde. Der Prozeß der Knorpelbildung wird nicht von Verkalkung eingeleitet; vielmehr werden zuerst die Fibroblasten zu Knorpelzellen, um die sich dann sekundär Kalziumsalze ablagern; danach spielt sich eine typische endochondrale Ossifikation ab. Schließlich erscheint Knochenmarkgewebe zwischen den Knochenbalken. Triamcinolon hemmt geringgradig die Bindegewebsproliferation, Thyroxin steigert die Knorpel- und Knochenbildung, während Östradiol diese Vorgänge nicht beeinflußt.
    Notes: Summary A chronologic study was made of the histopathologic changes which occur in the cardiac apex of the rat following the application of Selye's „ventricular ligature“. Organisation in the necrotic cardiac muscle begins soon after ligature. Later, the granulationtissue is gradually replaced by scar tissue which is poor in cells but rich in fibers. In the subendocardial fibrous tissue, cartilage and bone develop. It is emphasized that cartilage formation is not initiated by calcification. Instead, the fibroblasts are converted to cartilage cells and, later, calcium salts are deposited in the matrix. This is followed by endochondral bone formation. Finally, bone marrow appears in the intertrabecular spaces. Triamcinolone mildly hindered connective-tissue proliferation, thyroxine increased cartilage and bone formation, while estradiol did not influence these processes.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 100 (2000), S. 106-110 
    ISSN: 1432-0533
    Keywords: Key words Posterior pituitary ; Ganglion cell ; Immunohistochemistry ; Ectopia ; Transdifferentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Histologic examination revealed large ganglion cells within the posterior pituitary of an 80-year-old woman who died of myocardial infarction. Apparently fully mature, the cells were an incidental finding scattered within hyperplastic foci of pars intermedia (PI)-derived cells (basophil invasion) on histologic examination of the pituitary obtained at autopsy. Immunocytochemistry showed staining reactivity for neuron-specific enolase, synaptophysin, alpha subunit of the glycoprotein hormones and beta-endorphin. The presence of these ganglion cells with features similar to those of magnocellular hypothalamic neurons could be considered the result of abnormal migration during the early phase of embryonic life, or differentiation/maturation of neuroblasts, presumed to occur in the embryonic neurohypophysis. Alternatively, transdifferentiation from proliferating PI cells may explain the emergence of neurons; a hypothesis supported by the proximity and shared alpha subunit, and beta-endorphin immunoreactivities of the two cell types.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0533
    Keywords: Acromegaly ; Growth hormone cell adenoma ; Hypothalamic neuronal hamartoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A hypothalamic neuronal hamartoma associated with a sparsely granulated growth hormone cell adenoma of the pituitary and acromegaly is reported. It is suggested that the patient had a primary neuronal tumor, whose neurosecretory activity promoted the development of the growth hormone secreting pituitary adenoma causing acromegaly.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2307
    Keywords: Pituitary adenoma ; Ultrastructure ; Immunocytochemistry ; Acromegaly ; Hyperprolactinemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nine cases of a hitherto undescribed morphologic entity, termed mammosomatotroph cell adenoma of the human pituitary, are reported. These tumors, occurring mostly in men, are invariably associated with acromegaly (or gigantism) and high-normal or slightly elevated blood prolactin levels, and it cannot be distinguished clinically from well-differentiated growth hormone cell or mixed growth hormone cell-prolactin cell adenomas. They show a slow growth rate and usually exhibit a diffuse pattern and intense cytoplasmic acidophilia by histology. The immunoperoxidase technique detects both growth hormone and prolactin within the same cells. Electron microscopy reveals monomorphous tumors with a fine structure markedly similar to that of well-differentiated, densely granulated growth hormone cell adenomas. An added feature and diagnostic marker of mammosomatotroph cell adenoma is the presence of extracellular deposits of secretory material. One tumor shows a marked abnormality of hormone packaging and storage, resulting in the cytoplasmic accumulation of pleomorphic bodies containing semicrystalline secretory material.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 387 (1980), S. 165-174 
    ISSN: 1432-2307
    Keywords: Adenoma ; Electron microscopy ; Immunocytology ; Pituitary ; Pituitary tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Among 343 surgically-removed pituitary adenomas, 56 tumors were unassociated clinically or biochemically with increased hormone secretion and contained no adenohypophysial hormones by the immunoperoxidase technique, except for 10 cases in which a few scattered cells showed positive immunostaining for β-TSH or β-FSH, β-EH, prolactin and/or α-subunit. These tumors were chromophobic adenomas with no PAS, lead hematoxylin or carmoisine positivity and electron microscopy failed to reveal their morphogenesis. The term null cell adenoma of the pituitary is proposed to designate this tumor type. This term recognizes the most obvious features of these tumors: the absence of markers which would permit the disclosure of their cellular origin. Null cells are also found in the nontumorous adeno-hypophysis, suggesting that null cell adenomas derive from preexisting nonneoplastic null cells. The question of whether pituitary null cells are hormonally inactive committed precursors, uncommitted stem cells or dedifferentiated cells remains to be elucidated.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2307
    Keywords: Acromegaly ; hyperprolactinemia ; McCune-Albright syndrome ; pathology ; Pituitary ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An 11-year-old girl, with the McCune-Albright syndrome, exhibited fibrous dysplasia of several bones, skin pigmentation, precocious puberty, growth hormone hypersecretion, acromegaly and hyperprolactinemia. Histologic, immunocytologic and ultrastructural investigation of the surgically-removed pituitary showed massive mammosomatotroph hyperplasia. Since no adenoma was found, the abundance of these bihormonal cells, capable of producing both growth hormone and prolactin, was implicated in the causation of growth hormone and prolactin excess. Somatoliberin overproduction and/or somatostatin and dopamine deficiency could not account for the hypophysial abnormality, since changes in secretory rates of these hypothalamic hormones would lead to proliferation of mature somatotrophs and lactotrophs, rather than mammosomatotrophs. In our patient, a congenital hypothalamic malfunction might have been accompanied by hypersecretion of an unidentified releasing factor, resulting in pathologic differentiation of the pituitary and mammosomatotroph hyperplasia. Alternatively, mammosomatotroph hyperplasia may have been due to an inherent genetic or embryonic defect affecting primarily the pituitary. According to this interpretation, the pituitary lesion represented yet another developmental error in the setting of the McCune-Albright syndrome.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 395 (1982), S. 59-68 
    ISSN: 1432-2307
    Keywords: Adenohypophysis ; Electron microscopy ; Growth hormone ; Immunocytology ; Pituitary adenoma ; Thyroid-stimulating hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A pituitary adenoma removed by surgery from a 22-year-old man was studied by histology, immunocytology, transmission electron microscopy and immunoelectron microscopy. Clinically, the patient had acromegaly and euthyroidism with elevated blood GH concentrations. Blood TSH and T4 levels were within the normal range. Histologically, the adenoma was chromophobic and exhibited no PAS, lead hematoxylin, aldehyde thionin or Grimelius silver positivity. By the immunoperoxidase technique GH, β-TSH and α-subunit but no PRL, ACTH, α-endorphin, β-FSH or β-LH were demonstrated in the adenoma cells. Electron microscopy revealed adenoma cells which were similar to TSH cells and showed no resemblance to GH cells of nontumorous pituitaries or GH-secreting tumors. Immunoelectron microscopy demonstrated GH and β-TSH in the secretory granules. It is concluded that pituitary adenomas composed of TSH-like cells may secrete GH, resulting in acromegaly. Production of GH by adenomatous TSH cells cannot be explained on the basis of the one cell- one hormone theory. The question is raised whether bihormonal or multihormonal clones, capable of synthesizing more than one hormone, exist in the human pituitary. These cells are apparently dormant under normal conditions, but in the course of neoplastic transformation may undergo functional dedifferentiation and acquire the ability to produce two or more different hormones.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2307
    Keywords: Corticotrophs ; In situ hybridization ; Pituitary adenomas ; Pro-opiomelanocortin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pro-opiomelanocortin (POMC) mRNA was detected on paraffin sections by in situ hybridization (ISH) in corticotrophs of 12 nontumorous pituitaries, 11 functioning corticotroph, and 11 silent pituitary adenomas. ISH combined with immunocytochemistry for adrenocorticotrophic hormone (ACTH), a POMC-derived peptide, was also performed. ACTH immunoreactive cells of the anterior lobes and those invading the posterior lobe showed a high or moderate level of POMC mRNA that was not correlated with the intensity of ACTH immunoreactivity. Variable levels of POMC gene expression were present in Crooke's cells, corticotrophs suppressed by glucocorticoid excess. Most functioning corticotroph adenomas and silent subtype 1 adenomas had an intense hybridization signal and ACTH immunoreactivity. In silent subtype 2 and 3 adenomas, POMC mRNA had a diffuse low level or was absent; in these adenomas ACTH immunoreactivity was diffuse, restricted to some cells, or negative. The results indicate that POMC gene is expressed in both normal and suppressed nontumorous corticotrophs. Intense signals for POMC mRNA are found in most functioning corticotroph adenomas. The difference between POMC gene expression in silent 1 and silent 2 and 3 adenomas suggests that different mechanisms are responsible for the lack of endocrine activity.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2307
    Keywords: Electron microscopy ; Morphometry ; Null cell adenoma ; Oncocytoma ; Pituitary adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study, light microscopic and ultrastructural morphometric features of oncocytomas and null cell adenomas were compared and the morphometric data were correlated with in vitro endocrine activity. All tumours were unassociated with clinical or biochemical evidence of hormone excess and were diagnosed as oncocytomas or null cell adenomas, using histology, immunohistochemistry and electron microscopy. In oncocytomas, when compared with null cell adenomas, light microscopic morphometry revealed that total cell areas were significantly larger and nuclear cytoplasmic ratios were smaller due to an increase in cytoplasmic areas. Ultrastructural morphometry disclosed an abundance of mitochondria in oncocytomas. Absolute volumes of cytoplasmic organelles per cell were not reduced in oncocytomas compared with those of null cell adenomas. These results indicate that accumulating mitochondria do not replace other cytoplasmic organelles, and furthermore that the functional potential of oncocytomas is not lost. In vitro study demonstrated the production of pituitary hormones, primarily gonadotropins in oncocytomas and null cell adenomas. It can be concluded that oncocytomas, which represent the final stage of oncocytic transformation, have a close relationship with null cell adenomas based on morphometric comparison as well as in vitro studies.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 229 (1980), S. 57-65 
    ISSN: 1432-0711
    Keywords: Electron microscopy ; Gonadotroph hormones ; Pathology ; Pituitary adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 57-year-old woman, with long-standing hypogonadism secondary to irradiation of the ovaries, was found to have a pituitary tumor which was removed and investigated by histology, immunocytology and electron microscopy. Histologically, the tumor corresponded to a chromophobe, slightly PAS positive adenoma and the immunoperoxidase stain revealed the presence of both FSH and LH in the cytoplasm of the adenoma cells. The structural features of the adenoma cells resembled those of FSH cells in the nontumorous adenohypophysis. We thus believe that pituitary adenomas consisting of gonadotrophin-producing cells occur and that these may produce both FSH and LH. The relation between the gonadotrophin-producing adenoma and the preceding hypogonadism is uncertain.
    Type of Medium: Electronic Resource
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