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  • ZIB Catalog
  • Articles: DFG German National Licenses  (2,490)
  • 1990-1994  (2,490)
  • 1970-1974
  • 1992  (2,490)
  • Cell & Developmental Biology  (1,697)
  • Engineering General  (725)
  • Ultrastructure
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  • ZIB Catalog
  • Articles: DFG German National Licenses  (2,490)
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  • 1990-1994  (2,490)
  • 1970-1974
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 65 (1992), S. 50-52 
    ISSN: 1432-0584
    Keywords: TNF ; K 562 ; Leukemia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report here that tumor necrosis factor alpha (TNF) induces peculiar cytoplasmic vesicles in the human erythromyeloid leukemia cell line K 562, sensitized to the cytotoxic action of TNF by a treatment with the inhibitor of transcription actinomycin D. These vesicles are well delineated ultrastructurally. The formation of these vesicles is characteristic for the combination of actinomycin D with TNF and precedes the changes of apoptosis and cellular disintegration. These vesicles correspond to an intermediate step in the cytotoxicity caused by TNF and may indicate that reactive metabolites are involved in the mechanism of action of TNF.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0827
    Keywords: Periodontal ligament fibroblast ; Mineralized nodule ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purposes of this study were to determine whether periodontal ligament (PDL) cells are capable of producing mineralized nodules in vitro and to analyze ultrastructural features of the nodules. Rat PDL cells were obtained from coagulum in the socket at 2 days after tooth extraction and cultured at confluence in standard medium containing Dulbecco's Modified Eagle's Medium supplemented with 10% FBS and antibiotics. To test mineralized nodule formation, cells were further cultured for an additional 3 weeks in the standard medium containing (1) ascorbic acid (50 μg/ml) and sodium β-glycerophosphate (10 mM), (2) ascorbic acid, sodium β-glycerophosphate, and dexamethasone (5 μM), or (3) ascorbic acid alone. Cells were then fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4, and prepared for light and electron microscopy. Threedimensional nodules containing mineralized matrices were formed only when the cells were cultured in the presence of ascorbic acid and dexamethasone. They were composed of multilayered fibroblasts (up to 13 layers), and highly organized collagen fibrils with 64 nm cross-banding patterns between the cell layers. The fibroblasts in the nodules exhibited an elongated shape with a high degree of cytoplasmic polarity throughout the nodule, and have the morphological features of PDL fibroblasts as seen in vivo. Mineral deposition with needle-like crystals was initiated on collagen fibrils located in intercellular spaces of the upper cell layers and became increasingly heavier towards the bottom half of the nodules. X-ray microanalysis and electron diffraction analysis confirmed that mineral deposition contained calcium and phosphate in the form of immature hydroxyapatite. These nodules contained neither osteoblasts nor osteocytes, and have their own morphological organization and characteristics which differ from those formed by bone cells in culture. Therefore, these data suggest that PDL cells are capable of forming mineralized tissue in vitro with the morphological characteristics different from bone mineralized nodules.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Comparative clinical pathology 2 (1992), S. 166-169 
    ISSN: 1433-2981
    Keywords: Erythrocytes ; Flow cytometry ; Frog hibernation ; Image analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Morphometrical (image analysis of cell and nuclear shape factor), morphological (electron microscopy) and cytochemical (acridine orange fluoro-chromasia and propidium iodide-DNA flow cytometry) features of circulating red blood cells were investigated during two periods of the annual cycle of Rana esculenta: the active phase (July) and the underground hibernating phase (January). The results showed that the hibernating phase is marked by more homogeneity of the red cells, both at nuclear (strongly condensed chromatin) and cytoplasmic level (loss of intact organelles and acridine orange fluorochromasia). The almost complete disappearance of the ‘immature’ erythrocytes from the circulation, during the hibernating phase, should be related to a decrease of haemopoietic activity and to an increase of life span accompanied by uncommon storage in different organs both at vascular and intracellular level.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 421 (1992), S. 351-354 
    ISSN: 1432-2307
    Keywords: Krabbe's disease ; Eccrine gland storage ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lysosomal storage inclusions were observed in skin eccrine gland secretory and myoepithelial cells in three cases of Krabbe's disease. In addition to storage there were numerous degenerative changes, occasionally resulting in cell necrosis. These findings suggest a generalized nature of the storage process in this lysosomal enzymopathy and point to high galactocerebroside turnover in eccrine gland epithelium. This knowledge may be of value in the biopsy diagnosis of Krabbe's disease.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 421 (1992), S. 379-385 
    ISSN: 1432-2307
    Keywords: Multicystic mesothelial proliferation ; Immunohistochemistry ; Ultrastructure ; DNA analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated the clinicopathological findings in five cases of multicystic mesothelial proliferation (MMP). All masses consisted of multiloculated cysts attached to pelvic organs and sometimes growing into the upper abdominal cavity. The cystic spaces were lined by flattened or cuboidal cells. The stroma showed fibrosis, oedema and chronic inflammation. Immunohistochemistry revealed strong positive staining for cytokeratin and epithelial membrane antigen, and focal positivity for vimentin and carcinoembryonic antigen. The endothelial markers were negative. Electron microscopy showed abundant surface microvilli and well-developed basal lamina. DNA analysis identified euploid cell populations in all cases. All but one case had a previous history of abdominal surgery. Despite the worrying appearance the clinical outcome was favourable in all cases; there was one recurrence. Clinical and pathological data support the hypothesis that MMP represent a reactive mesothelial proliferation and not a neoplastic process.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2307
    Keywords: Eosinophilic granuloma of bone ; Eosinophil granule proteins ; Immunostaining ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eosinophils from two patients with eosinophilic granuloma of bone (EGB) were studied by combined immunohistochemical and immuno-ultrastructural methods with antibodies directed against three eosinophil granule proteins: major basic protein, eosinophil cationic protein, and eosinophil peroxidase. Immunohistostaining showed the presence and distribution of large numbers of eosinophils in the granuloma. Immuno-ultrastructural methods showed alterations of eosinophil fine structure associated with some steps in the release of granule proteins. No granule extrusion was seen, but rather cationic proteins diffused within cytoplasmic tubulo-vesicular structures. Furthermore, the three granule proteins were found within phagolysosomes of surrounding macrophages, suggesting an interaction between eosinophils and phagocytic cells at the destructive stage of EGB.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2307
    Keywords: Small cell carcinoma ; Ovary ; Immunohistochemistry ; Ultrastructure ; Literature review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This is an immunohistochemical and ultrastructural study of two small cell carcinomas of the ovary with a review of the literature. These cases showed a dimorphic population of small and large cells sharply demarcated from each other. Cytokeratin 18 and vimentin were mainly expressed in the large tumour cells, some of which also stained for alpha-smooth muscle actin. Periodic-acid-Schiff-positive, alpha-1-antitrypsin-positive hyaline globules were present in one case. Ultrastructural findings included filamentous nucleolonema as well as evidence of smooth muscle differentiation. Some of these observations have not been previously reported. Certain of the above features seem to support a germ cell origin of small cell carcinoma, but they cannot be considered specific for germ cell neoplasms. Thus, small cell carcinoma of the ovary cannot be classified into one of the known categories of ovarian tumours at the present time.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2307
    Keywords: Crystalloid ; Prostatic cancer ; Epithelial membrane antigen ; Phosphotungstic acid hematoxylin stain ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intraluminal crystalloids (ICr) observed in 19 cases of incidental or invasive human prostatic carcinoma (PCa) and in a case of benign prostatic hyperplasia were examined extensively by immunohistochemistry and electron microscopy. They were brilliantly eosinophilic with haematoxylin and eosin, manifesting needlelike, triangular, rectangular, hexagonal and irregular lump-like in shape. They were strongly positive, dark blue, with phosphotungstic acid -haematoxylin (PTAH) stain in all cases examined. Among the human antibodies tested, epithelial membrane antigen (EMA) gave specifically positive immunostainability with ICr in all cases. Annual ring-like lamellar or concentric structures were detected by electron microscopy. Positive staining of ICr with PTAH and anti-EMA antibody is very useful as a diagnostic marker for PCa in human prostatic tissues.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2307
    Keywords: Islets of Langerhans ; Monocytic phagocytes ; Streptozocin ; Type 1 diabetes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to observe the ultrastructural events, during the onset of diabetes mellitus in the low-dose streptozocin (LDS)-treated mouse model with emphasis on the infiltrating elements. Forty male C57 BL/6J mice were given 40 mg/streptozocin on 5 consecutive days and killed 5, 6, 7, 8, 9, 10, 15, and 18 days after the first injection. Results demonstrated that islet infiltration occurring in LDS-treated mice is characterized by a very early pre-infiltration state in which mononuclear phagocytes in islet capillary vessels were considerably increased in number. A new histopathological time sequence for the early insulitis is described, in which attraction of blood mononuclear phagocytes into the islet capillary lumen is the first step. During the successive stage, occurring on days 6–8 we observed that mononuclear phagocytes migrate through capillary and venule walls into the islet parenchyma, where they differentiate into tissue macrophages. It was only later (step 3) that these macrophages acquired novel properties, typical of their “activated state” and started to phagocytose islet beta-cell debris. These data suggest that during the pre-infiltration and early insulitis the mononuclear phagocyte system plays a key role in the onset of LDS diabetes.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-2307
    Keywords: Malignant rhabdoid tumour ; Uterus ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Malignant rhabdoid tumours (MRTs) are highly aggressive neoplasms which most frequently occur in the kidney of young children. Several cases of primary MRT occurring in extra-renal sites have been reported, particularly in the soft tissues. We report a case of primary MRT of the uterus, a very rare site for this neoplasm, with morphological, immunohistochemical and ultrastructural features corresponding to restrictive morphological criteria for MRT. The possible differential diagnoses were considered.
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  • 11
    ISSN: 1432-2307
    Keywords: Diabetes mellitus ; Renovascular hypertension ; Myocardium ; Stereology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of combined renovascular hypertension and diabetes mellitus on the rat heart were investigated in order to detect possible synergistic effects of the two conditions. Hypertensive diabetic and hypertensive non-diabetic animals were compared to diabetic and non-diabetic controls. Hypertension was established for 12 weeks by a surgical stenosis of the left renal artery; diabetes mellitus was maintained for 8 weeks by a single intraperitoneal injection of 60 mg/kg streptozotocin. Light microscopic stereology did not reveal significant divergences between diabetic hypertensives and non-diabetic hypertensives. Hypertension induced a focal perivascular and interstitial fibrosis with increased volume densities of non-vascular interstitium and fibrosis (P〈0.001). Capillary density (QA) was decreased in transverse sections (P〈0.01) and increased in longitudinal sections (P〈0.01). This indicates a three-dimensional remodelling of the capillary bed with an increased number of obliquely running capillaries. At least the length density (LV) of capillaries (mm/mm3) tends to be normalized in long-term renovascular hypertension. At the ultrastructural level, a synergism of hypertension and diabetes mellitus was observed: the volume ratio of mitochondria to myofibrils was significantly decreased in hypertensive diabetics, but not in non-diabetic hypertensives or in diabetics. This may enhance the risk of cardiac deterioration. We conclude that the primary target of the synergistic damage in hypertensive diabetic heart muscle disease is the myocardial cell and not the cardiac interstitium.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-2307
    Keywords: Leiomyoma ; Myometrium ; Cytoskeleton ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The filamentous components of the cytoskeleton in smooth muscle cells of leiomyomata and normal myometrium were studied by immunohistochemistry and electron microscopy. Fourteen patients hysterectomised for non-malignant disease provided leiomyomata of conventional histological type and histologically normal myometrium: four samples of fetal myometrium were studied by immunohistochemistry alone. All samples of leiomyoma and myometrium were strongly positive for α-smooth muscle actin and desmin, the latter often as paranuclear columns or granules. Vimentin was also stained in most samples but less intensely, while cytokeratin stained in about half the samples with an intensity comparable to that of vimentin. By electron microscopy, myofilaments with focal densities were abundant in both normal myometrium and leiomyomata. Intermediate filaments corresponding to the desmin and vimentin demonstrated by immunohistochemistry were also recognised in a variety of architectural arrangements. At one extreme, comparatively small numbers of filaments were loosely distributed around membranous organelles; at the other, filaments formed conspicuous aggregates, largely excluding other organelles and corresponding to the paranuclear granules seen by immunohistochemistry. A comparison of these findings with those of the literature and comments on the possible significance and origin of these aggregates are provided.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 420 (1992), S. 219-226 
    ISSN: 1432-2307
    Keywords: Breast ; Granular cell tumour ; Mammography ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eight cases of benign granular cell tumour of the breast are reported. Seven patients were women and one was male. The age at the time of the excision ranged from 17 to 73 (average 40.1) years. All tumours were positive for S-100 protein and negative for keratin, myoglobin and gross cystic disease fluid protein. In two cases ultrastructural studies revealed findings identical to those in the previously reported cases of granular cell tumours. None of these cases were diagnosed preoperatively. In six cases the clinical and mammographic findings, and in one case the frozen section, led to an erroneous diagnosis of malignancy. The clinico-pathological features of the cases are delineated in order to draw attention to a benign condition which closely simulates malignancy.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1432-2307
    Keywords: Fetus ; Small intestine ; Ultrastructure ; Malnutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fetal swallowing is established early in development and if fetal ingestion is prevented, the gastrointestinal (GI) tract fails to grow normally. In this article we describe the ultrastructural features of GI tissues developing in the absence of swallowing, in the fetal sheep. We have noted a number of defects in enterocyte morphology. These include abnormal or absence of microvilli, inappropriate cell extrusion, glycogen accumulation and altered lysosomal morphology. Many of these changes resemble those seen in malnourished infants. It is possible that fetal ingestion provides a significant source of nutrients, ensuring adequate GI tract growth in utero, in addition to specific growth factors which may be present in ingested fluid.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1432-2307
    Keywords: Eccrine porocarcinoma ; Ultrastructure ; Giant cell ; Elastic fibre ; Globular filamentous body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five cases of eccrine porocarcinoma were studied by light and electron microscopy. Histopathologically, these could be classified into two types; the common and the giant cell type. The common type was characterized by almost uniform medium-sized cuboidal tumour cells and a formation of well-developed intracytoplasmic lumina. A broad diversity of histopathological and ultrastructural features was seen in these tumours. The tumours of the giant cell type consisted of mononu-clear polygonal cells and bizarre giant cells. This type was considered to be an undifferentiated form of porocarcinoma.
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  • 16
    ISSN: 1432-0533
    Keywords: Spinal cord neurofibrillary tangles ; Parkinsonism-dementia complex on Guam ; Guamanian amyotrophic lateral sclerosis ; Ultrastructure ; Immunoelectron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The immunohistochemical and ultrastructural characteristics of spinal cord neurofibrillary tangles (NFTs) were examined in Guamanian amyotrophic lateral sclerosis and in parkinisonism-dementia complex on Guam. The spinal cord NFTs reacted with antibodies to tau protein (tau-2), ubiqitin and paired helical filaments (PHFs). Ultrastructurally, the components of the NFTs were seen as randomly arranged fibrils which were often associated with osmiophilic granules; small bundle-like arrangements were also occasionally observed. Individual NFT fibrils appeared as straight fibrils with a diameter of approximately 15 nm and constricted fibrils with a periodicity of approximately 80 nm. Ultrastructural microscopic examination of specimens stained by the modified Bielschowsky method and with the antibodies revealed silver particles and the products of the tau, ubiquitin and PHF immunoreactions on the NFT fibrils. This is the first demonstration of the fine structure of the spinal cord NFTs.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 83 (1992), S. 408-414 
    ISSN: 1432-0533
    Keywords: Eosinophilic granular body ; Astrocytoma ; Ultrastructure ; Immunocytochemistry ; αB-crystallin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eosinophilic granular bodies (EGBs) are studied immunocytochemically and ultrastructurally in a case of low-grade and a case of high-grade astrocytoma. EGBs are recognized as brightly eosinophilic round bodies of variable size in hematoxylin and eosin-stained sections. Immunocytochemically some EGBs are positive for antibodies raised against αB-crystallin, ubiquitin and glial fibrillary acidic protein with the staining patterns for each being different from one another. Ultrastructurally EGBs consist of membrane-bound round body of various diameter ranging from 50 nm to 20 μm. Small EGBs contain electron-dense homogeneous material with occasional myelin figures, while large EGBs contain small EGB-like structures within electron-dense homogeneous material or loose granular profiles. Our studies demonstrate (1) ultrastructural variety of EGB; (2) and αB-crystallin epitope in EGB; and (3) the presence of EGB in high-grade as well as low-grade astrocytoma.
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  • 18
    ISSN: 1432-0533
    Keywords: Alzheimer disease ; Amyloid angiopathy ; Pericytes ; Microglia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural studies of serial sections of the vessels with amyloid deposits in the brain cortex of patients with Alzheimer's disease showed that cells in the position of pericytes — perivascular cells - and perivascular microglial cells are producers of amyloid fibrils in the vascular wall. Three types of changes from normal are distinguishable in the vessel wall: (1) semicircular or circular thickening of vascular wall containing a large amount of amorphous material and various number of amyloid fibrils, (2) tuberous amyloid deposits containing both amorphous material and amyloid fibrils, some of the fibrils being arranged in strata and others arranged radially, and (3) amyloid star composed of a predominantly radial arrangement of bundles of amyloid fibrils and a less prominent amorphous component. A mixture of amorphous material and amyloid fibrils is present in cell membrane envaginations of perivascular cells, and occasionally perivascular microglial cells. Bundles of amyloid fibrils are found in altered cisternae of the endoplasmic reticulum and in the channels confluent with the infoldings of the plasma membrane of perivascular microglial cells. The amyloid deposition in the wall of the vessel causes degeneration of endothelial cells and the reduction of, and in some vessels obliteration of, the vessel lumen. In areas affected by amyloid angiopathy, extensive degeneration both of the neuropil and of neurons was observed. These changes were accompanied by astrogliosis. This study demonstrates similarities in amyloid formation in amyloid angiopathy and in β-amyloid plaques in the neuropil and suggests that cells of the mononuclear phagocyte system of the brain (perivascular cells and perivascular microglia) are engaged in amyloid fibril formation.
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  • 19
    ISSN: 1432-0533
    Keywords: Creutzfeldt-Jakob disease ; Ballooned neurons ; Ultrastructure ; αB-Crystallin ; Stress-response proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This report concerns ultrastructural and immunohistochemical studies on ballooned neurons of ten patients with Creutzfeldt-Jakob disease (CJD). While abundant ballooned neurons and severe white matter degeneration was seen in six Japanese cases, only occasional ballooned neurons and no white matter degeneration was observed in four cases from the files of Montefiore Medical Center. Ultrastructurally, the ballooned neurons contained granule-coated fibrils of 25 to 40 nm in width and 10-nm neurofilaments. The immunohistochemical studies revealed that most ballooned neurons expressed αB-crystallin, with deposits of reaction products observed in the cytoplasm. A similar intracellular staining pattern was also seen with the antibody to phosphorylated neurofilament proteins (pNFP). Although the proportion of stained ballooned neurons was less, a positive reaction was also observed with antibodies against ubiquitin, stress-response protein 27 (srp 27) and synptophysin, but not with an antibody to srp 72. Our findings suggest that expression of pNFP and synaptophysin by ballooned neurons may reflect axonal impairment and that the presence of αB-crystallin, srp 27 and ubiquitin may be related to the degenerative processes that neurons undergo in CJD.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 83 (1992), S. 605-612 
    ISSN: 1432-0533
    Keywords: Colloid cyst ; Endoderm ; Respiratory epithelium ; Third ventricle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histogenesis of colloid cyst of the third ventricle remains unsettled. Ultrastructural and immunohistochemical analyses have suggested the following possible origins: (a) neuroepithelium, including paraphysis, ependyma, choroid plexus and tela chorioidea; and (b) endoderm, including respiratory and enteric epithelium. This report describes the ultrastructural features of the lining epithelium in four cases of colloid cyst. Six distinct cell types were recognized: (1) ciliated cells with occasional abnormal cilia; (2) non-ciliated cells with microvilli coated with granulofibrillary material; (3) goblet cells showing discharge of secretory granules; (4) basal cells with prominent tonofilaments and desmosomes; (5) basal-located cells with elongated electron-lucent cytoplasm and scattered membrane-bound dense-core granules (150–350 nm); and (6) small undifferentiated cells with scanty organelles. Junctional complexes were present in the former four cell types but absent in the latter two. The types of epithelial cells and their topographic distribution within the epithelium are both very similar to those of normal respiratory epithelium and to the lining epithelium of intraspinal bronchogenic cyst. The observations made in the present study are compatible with the hypothesis that colloid cysts of the third ventricle originate from the endoderm, most likely the respiratory epithelium.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 185 (1992), S. 271-274 
    ISSN: 1432-0568
    Keywords: Man ; Spermiogenesis ; Postacrosomal ; sheath ; Silver staining ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Applying the silver staining technique, it could be shown that in the early phase of spermiogenesis a layer of argyrophilic material accumulated at the base of the acrosomal vesicle and at the outer side of the nuclear envelope opposite that region, and, later, at the inner side of the plasma membrane near the base of the acrosomal vesicle. During further development of the postacrosomal region of the spermatozoon head, the argyrophilic material associated with the plasmalemma grew caudally to form the postacrosomal dense lamina, while the argyrophilic material associated with the nuclear envelope, staying the same size, shifted to the caudal end of the postacrosomal dense lamina to form the postnuclear band.
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  • 22
    ISSN: 1432-0533
    Keywords: Neuronal autophagy ; Bovine spongiform encephalopathy ; Lysosomes ; Ultrastructure ; Vactiolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural neuropathology of mice experimentally inoculated with brain tissue of nyala (Tragelaphus angasi; subfamily Bovinae), or kudu (Tragelaphus strepsiceros; subfamily Bovinae) affected with spongiform encephalopathy was compared with that of mice inoculated with brain tissue from cows (Bos taurus: subfamily Bovinae) with bovine spongiform encephalopathy (BSE). As fresh brain tissue was not available for nyala or kudu, formalin-fixed tissues were used for transmission from these species. The effect of formalin fixation was compared with that of fresh brain in mice inoculated with fixed and unfixed brain tissue from cows with BSE. The nature and distribution of the pathological changes were similar irrespective of the source of inoculum or whether the inoculum was from fresh or previously fixed tissue. Vacuolation caused by loss of organelles and swelling was present in dendrites and axon terminals. Vacuoles were also seen as double-membrane-bound and single-membrane-bound structures within myelinated fibres, axon terminals and dendrites. Vacuoles are considered to have more than one morphogenesis but the structure of vacuoles in this study was nevertheless similar to previous descriptions of spongiform change in naturally occurring and experimental scrapie, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome and kuru. Other features of the ultrastural pathology of the transmissible spongiform encephalopathies including dystrophic neurites and scrapie-associated particles or tubulovesicular bodies were also found in this study. Neuronal autophagy was a conspicuous finding. It is suggested that excess prion protein (PrP) accumulation, or accumulation of the scrapie-associated protease-resistant isoform of PrP, may lead to localised sequestration and phagocytosis of neuronal cytoplasm and ultimately to neuronal loss.
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  • 23
    ISSN: 1432-0568
    Keywords: Badger-placenta ; Ultrastructure ; Ferritin ; Iron transfer regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The haemophagous region of the badger (Meles meles L.) placenta is involved in iron transfer, and maternal erythrocytes are the only source of iron for the fetus. This ultrastructural study provides morphological evidence of placental ferritin iron storage intervening if haem-iron uptake exceeds fetal needs. Such placental ferritin is assumed to play an active role in iron transfer regulation. In this paper we demonstrate that this regulatory process of iron transfer by storage in placental ferritin occurs on at least two levels: the cytotrophoblast and the fetal endothelium. The latter could then act as a final monitor in the transfer of iron into the fetal circulation.
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  • 24
    ISSN: 1432-0533
    Keywords: Muscle ; Ultrastructure ; Lysosome ; Metabolic disorder ; Glycogenosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Unusual inclusions with some of the features of “reducing bodies” were encountered in the skeletal muscle biopsy of a 2.5-year-old boy with childhoodonset acid maltase deficiency. The biopsy revealed a vacuolar myopathy with lysosomal storage of glycogen and eosinophilic refractile inclusions in myofibers, which appeared dark blue with the menadione-nitroblue tetrazolium reaction. The significance of the association of inclusions with reducing properties in the setting of acid maltase deficiency is discussed.
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  • 25
    ISSN: 1432-0533
    Keywords: Parkinson's disease ; Ultrastructure ; Catecholomines ; Trans-synaptic degeneration ; Axonal dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural and biochemical properties of caudate nucleus (CN) biopsies in two patients with advanced Parkinson's disease (PD) were compared with three CN specimens removed during surgery for intracranial tumors. An additional two specimens from neurologically intact patients (59 and 86 years old) were removed during autopsy (performed 3 and 4 h post mortem, respectively) for electron microscopic studies. Dopamine levels in PD were reduced to less than 15% of control values. Both PD patients showed frequent dystrophic neurites and transsynaptic degeneration of neurons and neuritic processes. These changes were not found in CN from the four control individuals. Only a few dystrophic neurites were noticed in one 67-year-old control patient. The development of neuroaxonal dystrophy in CN is consistent with a dying-back process, probably accompanying abnormalities of axonal transport in PD. Transsynaptic degeneration of neurons in CN very likely represents a morphological marker of disease severity. The occurrence of this change may account for the poor clinical response of patients with advanced PD to intracerebral implantation of dopaminergic tissues.
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  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 83 (1992), S. 659-663 
    ISSN: 1432-0533
    Keywords: Eosinophilic inclusion ; Neuroglia ; Astrocyte ; Aicardi's syndrome ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracytoplasmic and brightly eosinophilic inclusions within neuroglias are reported in a patient with Aicardi's syndrome. Most inclusion-bearing neuroglias were protoplasmic astrocytes in the cerebral cortex. Compared with similar eosinophilic and intracytoplasmic inclusions in other studies using both light and electron microscopy, the inclusions in this report are regarded as being novel and not previously described. Ultrastructually, the inclusions were composed of electron-dense granules and amorphous substances, and were not surrounded by a limiting membrane. They were numerous in the cerebral cortex, especially in part of the microgyrus, but absent in the deep cerebral white matter, subcortical nuclei, brain stem and the cerebellum. Therefore, they may be closely associated with brain malformation and congenital astrocytic dysfunction. They also suggested a functional difference in protoplasmic astrocytes themselves, according to the differentiation of related gray matter.
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  • 27
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    Anatomy and embryology 186 (1992), S. 145-152 
    ISSN: 1432-0568
    Keywords: Harderian gland ; Tubuloalveolar endpieces ; Serous endpieces ; Ultrastructure ; Opossum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The Harderian gland of the North American opossum (Didelphis virginiana) is large and well developed, despite the absence of a nictitating membrane in the adult of this species. The elongate glands are surrounded by a delicate connective tissue capsule from which thin septae extend, subdividing the gland into numerous lobules. The secretory units of the opossum Harderian gland are drained by a well defined but not extensive intralobular and interlobular duct system. Most of the secretory end pieces consist of tubuloalveolar units with widely dilated lumina filled with secretory product. Numerous intact lipid vesicles suspended within an amorphous material constitute the luminal contents. Cells lining the tubuloalveolar secretory endpieces are usually columnar in shape, and characterized by numerous lipid-containing secretory vesicles and aggregations of polytubular complexes 40–60 nm in diameter. In addition, these cells contain numerous large irregularly shaped mitochondria, whose matrix is of considerable electron density. Intralobular and interlobular ducts are lined by electron-lucent epithelial cells that lack both the lipid-containing vesicles and the large mitochondria, although typical smaller mitochondria are found scattered within the cytoplasm. Both secretory endpieces and ductal elements are invested by an abundance of myoepithelial cells. A second, smaller serous type of secretory unit may occur near the centre of some Harderian gland lobules. In these units secretory tubules and acini are compactly arranged surrounding a narrow lumen. Serous cells are pyramidal in shape and the cytoplasm is characterized by numerous electron-dense secretory granules and scattered profiles of rough endoplasmic reticulum. Basolateral cell membranes show extensive infoldings and intercellular canaliculi are present. The overall size of cells forming the serous secretory units is much less than that comprising the tubuloalveolar secretory endpieces.
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  • 28
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    Acta neuropathologica 83 (1992), S. 518-524 
    ISSN: 1432-0533
    Keywords: Amyotrophic lateral sclerosis ; Upper motor neurons ; Ultrastructure ; Neurofilament ; Ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pathological alterations in upper motor neurons were investigated in 27 cases of adult-onset sporadic amyotrophic lateral sclerosis (ALS). No signficant cytoskeletal alterations were found in the Betz cells of any of the cases except one, although cytoskeletal pathology was consistently present in lower motor neurons. The one case had severe circumscribed atrophy of the precentral gyrus and, microscopically, had argentophilic intracytoplasmic inclusions in Betz cells and other pyramidal neurons in the primary motor area as eell as in the lower motor neurons. Immunocytochemically these inclusions contained the epitope of phosphorylated neurofilament and ubiquitin and ultrastructurally consisted of granule-associated filaments with neurofilaments. This is the first demonstration of alterations of cytoskeleton and ubiquitination in the giant cells of Betz, an established subset of upper motor neurons in ALS. Thus, although uncommon, cytoskeletal changes can be found in upper motor neurons in some ALS cases.
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  • 29
    ISSN: 1432-0533
    Keywords: Primary leptomeningeal glioma ; Ultrastructure ; Basal lamina ; Laminin ; Heterotopic glial tissue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied a case of primary leptomeningeal glioma (PLG) on the left parietal lobe of a 74-year-old woman and compared the tissue with heterotopic glial tissue from another case. The PLG tumor consisted of spindle-shaped cells with marked nuclear atypism, which tended to be arranged in a fascicular pattern, and the majority of its cells were positive for glial fibrillary acidic protein. Ultrastructural examination demonstrated that most of the tumor cells contained intermediate filaments and often junctional complexes were present on their plasma membranes. Frequently, basal lamina-like structures surrounding the tumor, cell surfaces were observed. Laminin immunohistochemistry clearly demonstrated a fine network of linear positive staining around the cytoplasm and processes of the tumor cells. The ultrastructure of the heterotopic glial tissue consisted of many astrocytes partially surrounded by basal lamina. These findings strongly suggest that PLG is a distinct tumor, which arises from the heterotopic astrocytes within the subarachnoid space.
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  • 30
    ISSN: 1432-0533
    Keywords: Peripheral nerve biopsy ; HIV infection ; Ultrastructure ; in situ hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A peripheral nerve biopsy was performed in 15 patients with human immunodeficiency virus (HIV) infection and polyneuropathy. Two cases [1 asymptomatic, 1 AIDS-related complex (ARC)] presented with chronic inflammatory demyelinating polyneuropathy; there was 1 case (asymptomatic) of mononeuropathy multiplex and 12 cases (1 asymptomatic, 1 ARC, 10 AIDS) with distal symmetrical polyneuropathy. Epi- or endoneurial microvasculitis was observed in 6 cases. Electron microscopy showed that nerve fiber lesions were mainly axonal. Severe segmental demyelination was also present in both cases of chronic inflammatory demyelinating polyneuropathy, with characteristic features of active demyelination in one. Numerous plasmacytoid cells were found in the endoneurium in 4 patients. Tubuloreticular inclusions were present in endothelial cells in the 10 cases with AIDS but absent in the other patients. Direct immunopathological examination with anti-immunoglobulin sera was negative in all cases. HIV was evidenced by in situ hybridization in 2 AIDS patients; no Epstein-Barr virus or cytomegalovirus was detected.
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  • 31
    ISSN: 1432-0533
    Keywords: Alzheimer's disease ; Tissue culture ; Microglia ; Amyloid ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The function of microglia associated with β-amyloid deposits still remains a controversial issue. On the basis of recent ultrastructural data, microglia were postulated to be cells that form amyloid fibrils, not phagocytes that remove amyloid deposits. In this electron microscopic study, we examined the ability of microglia to ingest and digest exogenous amyloid fibrils in vitro. We demonstrate that amyloid fibrils are ingested by cultured microglial cells and collected and stored in phagosomes. The ingested, nondegraded amyloid remains within phagosomes for up to 20 days, suggesting a very limited effectiveness of microglia in degrading β-amyloid fibrils. On the other hand, we showed that in microglial cells of classical plaques in brain cortex of patients with Alzheimer's disease, amyloid fibrils appear first in altered endoplasmic reticulum and deep infoldings of cell membranes. These differences in intracellular distribution of amyloid fibrils in microglial cells support our observations that microglial cells associated with amyloid plaques are engaged in production of amyloid, but not in phagocytosis.
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  • 32
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    Acta neuropathologica 84 (1992), S. 238-243 
    ISSN: 1432-0533
    Keywords: Creutzfeldt ; Jakob disease ; Tubulovesicular structures ; Prion diseases ; Ultrastructure ; Transmissible spongiform encephalopathies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By electron microscopy tubulovesicular structures (TVS) have been consistently observed in brain tissue of transmissible spongiform encephalopathies such as natural and experimental scrapie, bovine spongiform encephalopathy and experimentally induced, but not naturally occurring, Creutzfeldt-Jakob disease (CJD). For the first time we report here the presence of TVS in human brains with CJD as detected by transmission electron microscopy. TVS were observed in all three CJD specimens (two biopsies, one autopsy), but they were rare and were found only in one or two location(s) per grid. TVS were seen in distended pre- and postsynaptic terminals and measured approximately 35 nm in diameter; they were smaller and of higher electron density than synaptic vesicles. Their occurrence in all types of transmissible spongiform encephalopathies irrespective of the affected host and the strain of the infectious agent suggests their biological significance.
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  • 33
    ISSN: 1432-0568
    Keywords: Prolactin cell ; Met-enkephalin ; Immunocytochemistry ; Ultrastructure ; Morphometr ; Rat(Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A stimulatory effect on prolactin secretion had been describe after acute and systemic administration of met-enkephalin, but the effects of this opioid after chronic administration has not been reported, and the response of mammotroph cells is not clear. As a complement to previous studies, a morphometric analysis (light and electron microscopy) was carried out on prolactin cells from female rats treated chronically with met-enkephalin. Clear features of cellular hyperactivity appeared after chronic and systemic administration of the opioid, and these persisted for two weeks. The changes consisted in increases of cellular, cytoplasmic and nuclear areas, volume and surface densities of the Golgi complex and rough endoplasmic reticulum, as well as the numbers of exocytotic figures. These morphological alterations were paralleled by an increase in serum prolactin levels as detected by RIA. It is concluded that the increase in the synthesis and secretory activity of prolactin cells following chronic and systemic administration of met-enkephalin is very similar to those observed after acute and intraventricular administration.
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  • 34
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    Anatomy and embryology 185 (1992), S. 201-206 
    ISSN: 1432-0568
    Keywords: Development ; Mouse ; Peripheral nerves ; Schwann cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distal course of the sensory nerve fibres on the palmar side of the hand of 12-day-old mouse embryos was followed by serial ultrathin cross-sections of conventionally fixed tissue. Small nerves fibres are to be found in the space between the layer of the cutaneous blood vessels and the epidermis. A special arrangement of the tissue which is traversed by the nerve fibres is not visible. In most cases the nerve fibres are in intimate contact with fibroblasts. More distally the nerve fibres consist only of one axon encircled by a Schwann cell. The sheath of the Schwann cell decreases gradually, and finally disappears completely. The distal tips of the naked axons are a few μm ahead. In some cases they are considerably enlarged and contain only a fine fuzzy material without special cell organelles. Other axons may end in a more finger-like fashion, and contain also in the naked parts many cell organelles. Also the naked axons contact fibroblasts over long ranges. Collagen was not found aligned to the distal nerve fibres.
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  • 35
    ISSN: 1432-0568
    Keywords: Mandibular condyle ; Calcified cartilage ; Ultrastructure ; Maturation ; Macaca fascicularis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In an attempt to show maturational alterations in the calcified cartilage, mandibular condyles of four growing and four adult male monkeys (Macaca fascicularis) were studied using light microscopy as well as transmission and scanning electron microscopy. All specimens were initially fixed by perfusion in the presence of ruthenium red. For examination of the hard tissue surfaces in the scanning electron microscope, uncalcified tissues were removed with sodium hypochlorite. In growing animals, almost the entire hard tissue surface in the joint region of the condyle was formed by calcified cartilage, while in adult animals, calcified cartilage was confined to load-bearing regions. In growing animals, the appearance of the calcified cartilage surface suggested a continuously advancing mineralizing front similar to that seen in the epiphyseal plate. Chondrocytes mostly exhibited a terminal stage of hypertrophy, and seemed to die and get lost through vascular invasion and subsequent endochondral ossification. In adult animals, most of the calcified cartilage surface appeared comparatively stable, and resembled the tidemark of articular cartilage. Chondrocytes were usually small and appeared viable. However, on the adult condyles, there were always circumscribed islands where chondrocytes and the pattern of mineralization resembled those seen in growing animals. In these regions, prominent chondroclastic activity indicated extensive articular remodelling. These observations suggest that at the end of somatic growth, condylar calcified cartilage undergoes considerable maturation from a type reminiscent of hyaline growth cartilage to a type resembling articular cartilage. Concomitantly, chondrocytes appear to change their developmental program, in that they stop enlarging and lose their commitment to death. However, they may be able to retain, or switch back to, a more immature stage, in case there is need for extensive articular remodelling.
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  • 36
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    Archives of dermatological research 284 (1992), S. 259-265 
    ISSN: 1432-069X
    Keywords: Genodermatoses ; Ultrastructure ; Membrane structures ; Abnormal keratinosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The recessively inherited congenital ichthyoses have ultrastructural features which indicate abnormal epidermal lipid metabolism. The ultrastructural markers of the three recessive congenital ichthyosis groups are lipid droplets in horny layers (type I), cholesterol clefts (type II) and membrane structures (type III). We describe six patients from five families belonging to the last group. The variable clinical phenotype alone does not allow the delineation of this disease, but together with the ultrastructural characteristics the subtype is unequivocal. In addition to the membrane structures, half of the cases showed abnormal keratinosomes and vesicular complexes. Membrane-bound vacuoles and needle-like slits were exceptionally found. The onset of the ichthyosis was variable, in contrast to other patients described under the heading recessive congenital ichthyosis.
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  • 37
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    Archives of dermatological research 284 (1992), S. 95-99 
    ISSN: 1432-069X
    Keywords: Chromoblastomycosis ; Host-fungus relationship ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the histological distribution and the morphology of the fungi and the tissue reactions in chromoblastomycosis, especially in the process of trans-epidermal elimination, cutaneous lesions of two patients with this disease were studied morphometrically and ultrastructurally. In the dermis, most of the fungal elements appeared as sclerotic cells and their cell wall showed an irregular, worm-eaten leaf-like appearance; they seemed to be continuously attacked by polymorphonuclear neutrophils. The epidermis eliminated 10–20% of all the organisms in the skin lesions, and the hypha-forming activity tended to be higher in the epidermis than in the dermis. Ultrastructurally, basal keratinocytes facing the dermal abscess containing fungal elements frequently appeared as dark cells, suggesting an increased proliferation activity. Spinous keratinocytes facing intraepidermal microabscesses containing fungal elements showed an abnormal accumulation of tonofilaments and further early keratinization in the spinous cell layer. All of the morphological changes of the dermis and epidermis are regarded as defence reactions against the fungi existing in the skin lesions. There is a close relationship between tissue reactions and morphological changes of fungi in chromoblastomycosis.
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  • 38
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    Archives of dermatological research 284 (1992), S. 275-282 
    ISSN: 1432-069X
    Keywords: Cherry haemangioma ; Type IV collagen ; Type VI collagen ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The capillaries in cherry haemangiomas show perivascular hyalinized sheaths. In order to clarify the nature of this sheath material, the extracellular matrix of cherry haemangiomas from 20 normal volunteers (age range 30–64 years) was investigated using immunohistochemical and electronmicroscopical methods. Antibodies against collagen types III, IV and VI and laminin were used. Hyaluronic acid was visualized using the hyaluronic acid binding region of the cartilage proteoglycan as ligand. Electronmicroscopically, the sheaths contained multilaminated basement membrane-like material, collagen fibres 20–25 nm thick with a periodicity of 67 nm and broad-banded aggregates with a periodicity of 100 nm (zebra bodies or fibrous long-spacing fibres). Immunohistochemically, type IV collagen was stained throughout the whole sheath material. Staining for laminin was more confined to the endothelial side of the sheath. Intense staining for type III collagen and hyaluronic acid was found in the connective tissue of the subpapillary layer and between the cherry haemangioma capillaries. Much weaker staining for type III collagen and no staining for hyaluronic acid were found invariably in an area 4–10 Μm thick directly around the capillaries. Both sheath material and intercapillary connective tissue of the haemangiomas showed pronounced staining for collagen type VI. Immunogold staining revealed that type VI collagen was localized to microfibrils 5–6 nm thick and to the broad-banded aggregates with 100 nm periodicity. These findings further underline the assumption that the broad-banded aggregates consist of type VI collagen.
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  • 39
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    Planta 188 (1992), S. 403-413 
    ISSN: 1432-2048
    Keywords: Cyanobacterium ; Gunnera ; Infection process ; Nostoc ; Symbiosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The symbiosis between Gunnera and Nostoc was reconstituted using G. chilensis Lam. and G. manicata Linden, respectively, and three different Nostoc strains. Six stages characterised by specific modifications in both the cyanobiont and the host were recognised during the infection process. Mucilage-secreting stem glands developed on the Gunnera stems independent of the presence of cyanobacteria (Stage I). Soon after addition of the Nostoc isolates to the plant apices, an abundant differentiation of motile hormogonia commenced. The cyanobacteria accumulated in the mucilage on the surface of the gland (Stage II), and the hormogonia then proceeded into the stem tissue through intercellular channels (Stage III). At the channel bases, Nostoc was detected between the cell walls of small, densely cytoplasmic Gunnera cells and also in elaborate folds of these (Stage IV). The Gunnera cell walls subsequently dissolved adjacent to the cyanobacteria and Nostoc entered the host cells (Stage V). Once the intracellular association was formed, a high proportion of the vegetative Nostoc cells differentiated into heterocysts (Stage VI). Nostoc changed from being rich in inclusions (particularly cyanophycin) while on the gland surface into a comparatively “non-storing” form during penetration and the early intracellular stages. Bacteria were numerous on the gland surface, fewer in the channels, and were never detected within the Gunnera cells, indicating the existence of specific recognition mechanisms discriminating between conceivable microsymbionts. Mechanisms behind mutual adaptations and interactions between the two symbionts are discussed.
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  • 40
    ISSN: 1432-2048
    Keywords: Bradyrhizobium ; Electron microscopy ; Glycine (root nodules) ; High-pressure freezing ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract High-pressure freezing of chemically untreated nodules of soybean (Glycine max (L.) Merr.), in sharp contrast to chemical fixation and prefixation, appears to preserve the ultrastructure close to the native state. This is supported by the observation that the peribacteroid membrane of high-pressure-frozen samples is tightly wrapped around the bacteroids, a finding that is fully consistent with the current views on the physiology of oxygen and metabolite transport between plant cytosol and bacteroids. In soybean root nodules, the plant tissue and the enclosed bacteria are so dissimilar that conventional aldehyde-fixation procedures are unable to preserve the overall native ultrastructure. This was demonstrated by high-pressure freezing of nodules that had been pre-fixed in glutaraldehyde at various buffer molalities: no buffer strength tested preserved all ultrastructural aspects that could be seen after high-pressure freezing of chemically untreated nodules.
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  • 41
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    Sexual plant reproduction 5 (1992), S. 64-71 
    ISSN: 1432-2145
    Keywords: Generative cell ; Isolation ; Microtubules ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Upon squashing of the pollen grain, the isolated generative cell ofNicotiana tabacum looses its spindle shape to become spherical; this phenomenon is independent of the sucrose concentration used. The time necessary for this change can vary from 1 min (0% sucrose) to 20 min (30% sucrose). The microtubular cytoskeleton was studied by means of immunofluorescence and electron microscopy. Just after isolation, 5 to 15 clearly visible bundles in microtubules organized in a basket-like structure are present. After 15 min in medium with 15% sucrose, the microtubular cytoskeleton disappears, and a diffusely spread tubulin can be observed. Neither the addition of 10–20 μM taxol to the medium, nor the omission of Ca2+ to the medium has any effect on the changes in cell shape and loss of microtubular bundles after isolation.
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  • 42
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    Sexual plant reproduction 5 (1992), S. 27-33 
    ISSN: 1432-2145
    Keywords: Isolated generative cells ; Ultrastructure ; Microtubule ; Immunofluorescence microscopy ; Allemanda neriifolia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of isolated generative cells ofAllemanda neriifolia at interphase and prophase was studied. The microtubule organization of the isolated cells was also investigated by immunofluorescence microscopy with a monoclonal anti-α-tubulin. After the generative cells had been isolated from the growing pollen tubes by osmotic shock, most of the cells were at prophase and only a few were at interphase. The interphase cell is spindle shaped and contains an ellipsoidal nucleus. In addition to the usual organelles, the cytoplasm of the interphase cell contains numerous vesicles (each measuring 40–50 nm in diameter) and two sets of longitudinally oriented microtubule bundles — one in the cortical region and the other near the nucleus. Most of the prophase cells are spherical in shape. Based on the ultrastructure and the pattern of microtubule cytoskeleton organization three types of prophase cells can be recognized. (1) Early prophase cell, which contains the usual organelles, numerous vesicles, and a spherical nucleus with condensed chromosomes. Longitudinally oriented microtubule bundles can no longer be seen present in the early prophase cell. A new type of structure resembling a microtubule aggregate appears in the cytoplasm. (2) Mid prophase cell, which has a spherical nucleus containing chromosomes that appear more condensed than those seen in the early prophase cell. In addition to containing the usual organelles, the cytoplasm of this cell contains numerous apparently randomly oriented microtubules. Few vesicles are seen and microtubule aggregates are no longer present. (3) Late prophase cell, typified by the lack of a nuclear envelope. Consequently, the chromosomes become randomly scattered in the cytoplasm. Microtubules are still present and some become closely associated with the chromosomes. The changes in the ultrastructure and in the pattern of microtubule organization in the interphase and prophase cells are discussed in relation to the method of isolation of the generative cells.
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    Sexual plant reproduction 5 (1992), S. 131-137 
    ISSN: 1432-2145
    Keywords: Pollen grain ; Generative cell ; Formation and detachment ; Ultrastructure ; Polystachia pubescens ; Orchidaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The formation and nature of the generative cell wall and the detachment mode of the generative cell from the intine in Polystachia pubescens were observed by LM and TEM. Vesicles evenly positioned within the phragmoplast fuse to form a cell plate that divides the microspore into the generative and vegetative cell. This cell plate consists of callose. Before the generative cell leaves the intine, however, the callose is completely resorbed and is not replaced by any other substance. The generative cell becomes detached from the intine by moving towards the centre of the pollen grain. A constriction formed thereby gives the generative cell a bulb-like appearance and leads ultimately to the generative cell being pinched off. Plasma-filled vesicles originating from the generative cell remain between the intine and the plasma membrane of the vegetative cell.
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  • 44
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    Journal of neurology 239 (1992), S. 191-194 
    ISSN: 1432-1459
    Keywords: Ghost tangles ; Degenerate neurites ; Astrocytes ; Senile plaques ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Some ghost tangles in the brains of Alzheimer patients were accompanied by many small argyrophilic structures which were electron microscopically confirmed to be degenerate neurites. In these ghost tangles, roughly dispersed 15 nm straight and occasional twisted tubules were penetrated by proliferated astrocytic processes. Immunohistochemically, these ghost tangles lost immunoreactivities to anti-NFT, -tau and -ubiquitin antibodies, but were thioflavine-S fluorescent, though antigenicity to β-protein was not proved. This similarity in composition of degenerate neurite-bearing ghost tangles to senile plaques might be induced by the amyloid nature of tubules, which probably provokes the reaction of neuropils.
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  • 45
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    Archives of microbiology 158 (1992), S. 249-255 
    ISSN: 1432-072X
    Keywords: Sporulation ; Meiosis ; Ultrastructure ; Spindle pole body ; Spo mutants ; Schizosaccharomyces pombe ; Fission yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A homothallic haploid strain of the fission yeast Schizosaccharomyces pombe initiates sexual reproduction (mating, meiosis and sporulation) in nitrogen-free sporulation medium. Cellular fine structures of eleven sporulation-deficient mutants (spo2, spo3, spo4, spo5, spo6, spo13, spo14, spo15, spo18, spo19 and spo20) of S. pombe in sporulation medium were examined by serial section-electron microscopy. The striking features of these spo mutants were: 1) the disappearance of the spindle pole bodies (SPBs) after the second meiotic division, and 2) the accumulation of unorganized structures. Based on histochemical staining, these structures were presumably unorganized spore wall precursors. In some mutants (spo3, spo5, spo6, spo19 and spo20), diploid zygotes contained four spore-like bodies which had walls similar to complete spore walls but failed to enclose any nuclei. After completion of the second meiotic division the nuclei were abnormally distributed in zygotic diploid cells. In the spo5, spo13, spo14, spo15 and spo19 mutants, the nuclei remained attached to each other. In spo5 and spo19, the inner membrane of the nuclear envelope was separated, but its outer membrane was shared by two sister nuclei. These observations suggest that the spo+ gene products play important roles in spatial and temporal organization of cellular structures during ascospore development.
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  • 46
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    Archives of microbiology 157 (1992), S. 319-322 
    ISSN: 1432-072X
    Keywords: Chlorobiaceae ; Spinae ; Chlorobium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several Chlorobium species have been observed to possess spinae. Spinae are non-prosthecate, helically wound, rigid structures that extend from the outer bacterial cell surface into the external environment. Spinae length was variable within and between Chlorobium species. Spinae width was fairly consistent within species but varied between species (39.4 ± 2.6 nm to 82.6 ± 8.0 nm). The number of spinae per cell varied. The spinae did not penetrate the bacterial cell envelope and were randomly located on the cell surface. Spinae were not geographically restricted. The observation of spinae on pure cultures of Chlorobium spp. maintained for 25–30 years suggests that spinae may be of significant use to the cell.
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  • 47
    ISSN: 1432-2285
    Keywords: Arbutus unedo ; Laccaria amethystea ; Mycorrhiza ; Synthesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Anatomy and ultrastructure of the arbutoid mycorrhiza of Arbutus unedo-Laccaria amethystea from axenic culture are described. In comparison to non-inoculated roots, the rhizodermal cells of mycorrhizas are of greater volume, their nuclei are enlarged and show an irregular shape, plasmalemma and cytoplasm with mitochondria, plastids, endoplasmic reticulum and dictyosomes are increased. Several ontogenetical states are documented. The arbutoid mycorrhiza as a connecting link between ectomycorrhiza and ericoid mycorrhiza is discussed.
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  • 48
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    Cell & tissue research 270 (1992), S. 395-404 
    ISSN: 1432-0878
    Keywords: Nucleus sacci vasculosi ; Ultrastructure ; Immunocytochemistry ; Hypothalamus ; Tuberculum posterius ; Scyliorhinus caniculus, Raja undulata (Elasmobranchii)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The elasmobranch nucleus sacci vasculosi was studied by means of electron microscopy (in the dogfish) and immunocytochemistry (in the dogfish and the skate) by using antibodies against tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P. Ultrastructural study of the dogfish nucleus sacci vasculosi shows the presence of medium-sized cells that possess numerous mitochondria but that have no dense-core vesicles in the cytoplasm or in cell processes. Fibres of the conspicuous tractus sacci vasculosi have a beaded appearance and form conventional synapses with dendrites and cell perikarya of the nucleus sacci vasculosi. The perikarya of this hypothalamic nucleus were not immunoreactive to any of the antibodies tested, and fibres immunopositive to tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P were scarce within this nucleus, in both the dogfish and the skate. Dorsal to the nucleus sacci vasculosi, there are numerous positive neuronal processes in addition to many small neurons that show immunoreactivity to alpha-melanocyte-stimulating hormone, somatostatin and tyrosine hydroxylase. Two types of neuron occur in this dorsal region, displaying dense-core vesicles of either 100–160 nm or 60–100 nm diameter in their cytoplasm; they were identified as peptide-containing and monoamine-containing neurons, respectively. The neuropil of this region has a significantly different ultrastructure from that of the nucleus sacci vasculosi, with many processes containing dense-core vesicles. This group of neurons, located dorsal to the nucleus sacci vasculosi and showing (a) immunoreactivity to neuropeptides or to monoamine-synthesizing enzyme, and (b) cytoplasm with dense-core vesicles, was considered not to be a part of the nucleus sacci vasculosi but rather part of the nucleus tuberculi posterioris. These results support the non-peptidergic and non-aminergic character of the nucleus sacci vasculosi.
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  • 49
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    Cell & tissue research 267 (1992), S. 483-492 
    ISSN: 1432-0878
    Keywords: Dental follicle ; Cell culture ; Fibroblasts ; Immunocytochemistry ; Ultrastructure ; Collagen ; Gel-electrophoresis ; Western blotting ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Because the dental follicle is necessary for the eruption of teeth of limited eruption, it was the objective of this study to determine if the cells of the follicle could be cultured in vitro. To achieve this, dental follicles and associated enamel organs were dissected from the first and second mandibular molars of 6–7-day-old rats (secretory stage of amelogenesis), and then cultured in a medium that promotes fibroblast growth — the predominant cell type of the dental follicle. The cultured cells grew to confluency and were kept through 3 passages before experimentation. The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained an abundant rough endoplasmic reticulum, but did not form desmosomes. Immunofluorescent staining for anti-vimentin showed that all the cells stained and electron-microscopic immunogold labeling indicated that the antibody was associated with intermediate filaments. As revealed by SDS-polyacrylamide gel electrophoresis and Western blotting, the cultured cells synthesized and secreted the extracellular matrix molecules fibronectin and procollagens. Subsequent immunofluorescence staining of permeabilized and non-permeabilized cells confirmed the presence of fibronectin and type I collagen both intra- and extracellularly. Thus, based on all the above characteristics, the cultured cells appeared to be fibroblasts derived from the dental follicle, although a few of the fibroblasts may be derived from undifferentiated mesenchymal cells interposed between the alveolar bone and follicle. Experiments now can be conducted to determine how these cultured cells respond directly to growth factors that alter the rates of tooth eruption.
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  • 50
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    Cell & tissue research 267 (1992), S. 571-582 
    ISSN: 1432-0878
    Keywords: Crustacean muscle ; Ultrastructure ; Dye coupling ; Flagellum ; Scaphognathite ; Fascicles ; Mitochondria ; Carcinus maenas (Crustacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The organization of the flagellum abductor muscle and of a scaphognathite levator muscle of the green crab, Carcinus maenas, has been compared quantitatively using light and electron microscopy. These muscles are rhythmically active at relatively high frequencies and for long durations. Fibers of both muscles are interconnected to form fascicles of 50 or more fibers within which there is cytoplasmic continuity. A single muscle is made up of 8–12 fascicles. Individual fibers consist of a peripheral rind of densely packed mitochondria, a thick region of glycogen granules, and myofibrils arranged into scattered central islands. Less than half the volume-density of these muscles is contractile material, the balance being largely mitochondria and glycogen. The fibers within a muscle are structurally similar. They have short sarcomeres (about 2 μm), thin to thick filament ratios of about 3:1, and junctions between the sarcoplasmic reticulum and the transverse tubules at the M line. Sarcoplasmic reticulum occupies about 10% of the myofibrillar volume-density. A well developed sarcoplasmic reticulum appears to underlie the capacities of these two muscles for high frequency contraction; extensive mitochondria and glycogen stores should confer fatigue resistance under both aerobic and anaerobic conditions.
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  • 51
    ISSN: 1432-0878
    Keywords: Paneth cells ; Ultrastructure ; Morphometry ; Bethanechol ; Fluoride ion ; G-protein ; Mouse (Balb/c)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Paneth cells located at the bottom of intestinal crypts may play a role in controlling the bacterial milieu of the intestine. Using morphometry to clarify the secretory mechanism of the Paneth cells, we studied the ultrastructural changes in mouse Paneth cells produced following intra-arterial perfusion with Hanks' balanced salt solution containing a cholinergic muscarinic secretagogue (bethanechol), a neuroblocking agent (tetrodotoxin), or a G-protein activator (NAF/AlCl3). Bethanechol (2×10-4 mol/l) induced Paneth-cell secretion. Many Paneth cells massively exocytosed their secretory material into the crypt lumen; the enhanced secretion caused degranulation and vacuole formation. However, tetrodotoxin (2×10-6 mol/l) did not prevent the bethanechol-enhanced secretion by the Paneth cells. NaF (1×10-2 mol/l) and AlCl3 (1×10-5 mol/l) induced massive exocytosis of the Paneth cells; the exocytotic figures were similar to those observed in mice stimulated by bethanechol. G-protein activation was followed by a sequence of intracellular events, resulting in exocytosis.
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  • 52
    ISSN: 1432-0878
    Keywords: Primordial germ cell ; Ultrastructure ; Gonadal differentiation ; Cyprinus carpio (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A description is given of primordial germ cell (PGC) differentiation and gonadal development in carp from hatching until the age of 6 weeks. This period was chosen as the PGCs are mitotically silent before they start to proliferate rapidly after week 6. The PGCs increased in size between week 2 and week 4 after fertilization. Ultrastructurally, the perinuclear dense bodies present in PGCs from hatching onwards increased in size and formed the ‘cement’ between mitochondria. Moreover, from week 2 onwards, an elaborate Golgiapparatus was present in PGCs, indicating synthetic activity that may be related to PGC enlargement. During the observation period, gonadal tissue was gradually formed around the PGCs. From the age of 4 and 5 weeks onwards, two somatic cell types could be distinguished; the central type had a light appearance and was closely associated with the PGCs, the other type being darker and forming the peripheral layer of the developing gonads. Thus, during the period of mitotic quiescence, the PGCs and the gonads actively differentiate in preparation for the fast PGC proliferation that occurs after 6 weeks.
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  • 53
    ISSN: 1432-0878
    Keywords: Retinal pigment epithelium ; Ultrastructure ; Organelle differentiation ; Metamorphosis ; Lamprey, Petromyzon marinus (Cyclostomata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sequence of morphological changes in the retinal pigment epithelium during the metamorphic period of the sea lamprey Petromyzon marinus L. has been investigated using electron microscopy. At early metamorphic stages (stages I and II), photoreceptors are present in a small zone of the retina. During these stages, the lateral surface of the epithelial cells shows zonulae occludentes and adhaerentes. The degree of cell differentiation varies throughout the retinal pigment epithelium. Cells covering the differentiated photoreceptors in the central retina have phagosomes, whereas pigment granules appear only in the retinal pigment epithelium dorsal to the optic nerve head. Most epithelial cells have myeloid bodies; their morphology is more complex around the optic nerve head. At stage III, when photoreceptors develop over the whole retina, the distribution of cytoplasmic organelles is almost homogeneous in the retinal pigment epithelium. Subsequently, the basal plasma membrane of the epithelial cells becomes progressively folded and their apical processes enlarged. In addition, extensive gap junctions develop between retinal pigment cells. In late metamorphic stages, noticeable growth of myeloid bodies occurs and consequently the retinal pigment epithelium resembles that of the adult. This study also describes, for the first time, the presence of wandering phagocytes in the retinal pigment epithelium of lampreys; their role in melanosome degradation is discussed.
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  • 54
    ISSN: 1432-0878
    Keywords: Angiotensin II ; Ovarian follicles ; Theca interna ; Ultrastructure ; Steroidogenesis ; Atresia ; Golden hamster (Rodentia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Angiotensin II (AII) is present in the mammalian ovary and has been correlated with atresia in follicles. Since the theca interna may be one site at which atresia is intiated, we wished to determine whether AII exerts an effect on theca interna from explanted ovarian follicles of hamsters. Hamsters were sacrified on the morning of proestrus, and ovaries were removed. Preovulatory follicles were excised from the ovaries, and cultured with one of the following components: medium alone (control); medium plus AII (1x10-6 M); the AII-receptor antagonist [Sar1, Ile8] AII (1x10-4 M); or AII plus antagonist. After 72 h, the follicles were processed for transmission electron microscopy (to determine quantities of theca interna organelles involved in the steroid synthetic pathway) or for protein determination (to normalize steroid production rates). The incubation medium was drawn off and analyzed by radioimmunoassay for progesterone, androstenedione, or estradiol-17β. There was a significant positive correlation (r=0.92, P〈0.01) between follicular androstenedione secretion and area comprising theca interna smooth endoplasmic reticulum. In the theca interna, AII induced a two-fold and 1.6-fold increase in lipid droplet number and area comprising smooth endoplasmic reticulum, respectively (P〈0.05). Excess antagonist negated the increase in cell or-ganelles and also reduced androstenedione secretion compared with AII alone (P〈0.05). Most importantly, AII significantly augmented the ratio of androstenedione: estradiol-17β secretion by 44% over that of control. The ultrastructural changes observed in this study and the increase in the andostenedione: estradiol-17β production ratio are consistent with atresia-like changes in ovarian follicles. We believe, therefore, that AII is involved, possibly at its membrane receptor, in an aspect of the overall process of follicular atresia, operating in part at the level of the theca interna.
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  • 55
    ISSN: 1432-0878
    Keywords: Alcian blue ; Basement membrane ; Lamina densa ; Meshwork ; Submandibular gland ; Ultrastructure ; Rat (Wistar-Imamichi)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the epithelial basement membrane and membrane precursor was studied in rat submandibular rudiment and a model system of the reconstructed basement membrane, by transmission electron microscopy following alcian blue staining. Directly beneath the epithelial plasma membrane, a meshwork layer was found to consist of anastomosing thin fibers arranged as a three-dimensional meshwork (100–400 nm in thickness). Straight strands (5–10 nm in diameter) could sometimes be seen to pass through the meshwork. Adjacent to this layer, a coarse network composed of threads (20–40 nm in diameter) connected the meshwork layer with collagen fibers of the underlying connective tissue. The earliest precursors recognized in the reconstruction-model system were part of the fine-meshwork structure, and showed this structure to be a fundamental component of the basement membrane.
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  • 56
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    Cell & tissue research 270 (1992), S. 1-6 
    ISSN: 1432-0878
    Keywords: Estradiol receptor ; Endometrium ; Ovariectomy ; Immunohistochemistry ; Ultrastructure ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Serial sections of resting porcine endometrium were analyzed with the monoclonal antibody 13H2 using goat antimouse IgG/5 nm gold as secondary reagent or with either polyclonal antibodies from goat #402 or the rat monoclonal antibody H222, both in combination with protein G/12 nm gold. A modestly higher labelling of nuclei than of cytoplasm was seen only with the monoclonal antibody H222. Polyclonal #402 and monoclonal 13H2 showed fewer attachments over nuclear than over cytoplasmic areas. The highest densities of attachment and of predominantly cytoplasmic labelling were obtained with the monoclonal antibody 13H2. The results confirm the earlier assumption of a restricted accessiblity of estradiol receptor in the cytoplasm of resting cells for immunoreagents.
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  • 57
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    Plant systematics and evolution 181 (1992), S. 233-244 
    ISSN: 1615-6110
    Keywords: Algae ; Rhodophyta ; Thorea ramosissima ; T. riekei ; Ultrastructure ; pit plugs as a taxonomic character
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The thallus ofThorea ramosissima was studied electron microscopically. The cells of the medulla, the cortex and the assimilatory hairs differ not only in size and number of plastids and their equipment with thylakoids but also in cell wall structure, the number of mitochondria and the activity of the Golgi apparatus, with dictyosomes transforming complete cisternae into Golgi vesicles with mucilaginous contents in the outer region of the cortex. The pit connections have plugs with a distinct plate—like (not dome-like) outer cap layer. BecauseT. riekei was reported to have dome-like outer cap layers and because this character was the main reason to place theThoreaceae into theBatrachospermales (Pueschel & Cole 1982),T. riekei was reinvestigated, too. A distinct outer cap could not be detected. The reliability of pit plug structure as a taxonomic character and the taxonomic position ofThorea is discussed.
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  • 58
    ISSN: 1615-6102
    Keywords: Cytoskeleton ; Phagotrophic ; Eugienoids ; Immunochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A monoclonal antibody (IIID12) obtained from mice immunized against the entireEntosiphon cytoskeleton highlights the feeding apparatus ofEntosiphon, Peranema, andPloeotia by IF. IGS at the ultrastructural level shows that it labels the cementing material surrounding the microtubular bundles in the three species studied. InEntosiphon additional structures, such as the supplementary plaque, the scaffold structure and the lenticular structure or canal thickening, are also detected by the antibody. Immunoblotting analysis after SDS-PAGE reveals a positive reaction with this antibody to the 58 and 66kDa protein bands inEntosiphon, 82 and 84kDa inPeranema, and 56 and 60kDa inPloeotia. These results demonstrate biochemical homologies in the proteins of the cement material in the three heteronematal eugienoids studied. The possible role of these proteins in microtubule assembly and stabilization is discussed, as well as the role of the cementing material in the mode of the feeding apparatus motion during the ingestion of food.
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  • 59
    ISSN: 1615-6102
    Keywords: Dactylis glomerata L. ; Orchardgrass ; Sodium chloride tolerance ; Somatic embryo ; Tissue culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Calli were induced from leaf expiants of aDactylis glomerata L. (orchardgrass) genotype which has a high capacity for somatic embryogenesis. After 7 months culture on SH medium containing NaCl, a line was selected which was tolerant to 200 mM NaCl. When both selected and nonselected calli were maintained for 56 days on media containing 0 to 300 mM NaCl, the selected line showed significantly higher regeneration capacity than nonselected calli when placed on media containing more than 50 mM NaCl. Ultrastructural features of control somatic embryos not exposed to the salt were compared to those from nonselected and selected embryos cultured on 200 mM NaCl medium. In the presence of NaCl there were changes in the appearance of cell walls and mitochondria, accumulation of lipids and a higher degree of vacuolation in cells of nonselected embryos compared to control and selected embryos.
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  • 60
    ISSN: 1615-6102
    Keywords: (1→3)-β-Glucose ; Callose ; Cell wall ; Host-parasite interface ; Immunocytochemical ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Polyclonal antibodies specific to (1→3)-β-glucose were used to localize callose around stylets ofCriconemella xenoplax in parasitized cortical cells in root explants of carnation, crimson clover, and tomato. The nematode's stylet was inserted 5–6 μm through the wall of the parasitized cell without piercing the plasma membrane, which became invaginated around the stylet tip. A layer of electron-transparent callose was localized by immunogold labelling between the invaginated plasma membrane and the inserted stylet, except at the stylet orifice. The callose was continuous with the inner surface of the wall of the parasitized cell around the site where the stylet penetrated. When the parasitized cell was located in the second layer of the cortex, the nematode's stylet first passed through a subepidermal cortical cell. The integrity of the plasma membrane of the transected cell was maintained and callose was deposited around the portion of the nematode's stylet that traversed the cell. We suggest that callose deposition around nematode stylets in parasitized cells is a common wound response elicited when plant-parasitic nematodes feed from cells.
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  • 61
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    Protoplasma 166 (1992), S. 165-176 
    ISSN: 1615-6102
    Keywords: Cuticle ; Humidity ; Leaf structure ; Micropropagation ; Rosa ; Stomata ; Ultrastructure ; Wax
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Mme Isaac Pereire rose was investigated in an attempt to establish how micropropagated roses might best be weaned into normal growth conditions. Leaves of in vitro grown plants, weaned plants and the stock plant were studied, using light microscopy and different scanning and transmission electron microscopical techniques. Features that varied in the different growing conditions were leaf size and thickness, amount of wax, thickness of cuticle and external epidermal cell wall, number and aperture of the stomata, size of the epidermal cells, number of layers of the palisade cells, and size of the chloroplasts in the mesophyll. The rose in the present study had wax on the in vitro cultured plants; this wax was of similar ultrastructural appearance to that of the stock plant, even though in smaller quantities. Weaned plants had an intermediate amount of wax. The cuticle was thin, ranging from 0.04 μm on plants growing in vitro to 0.3-0.6 μm on weaned plants and stock plants. Stomata were always wide-open on leaves taken from cultures with a relative humidity of 100%. After four weeks in a humidity lowered to 85% stomata had closed.
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  • 62
    ISSN: 1615-6102
    Keywords: Cuticle ; Cuticular exudations ; Exudations ; Heterodera schachtii ; Ultrastructure ; Host-parasite interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development ofHeterodera schachtii inside roots of a cruciferous host plant grown under monoxenic conditions in an agar medium was observed with video-enhanced contrast light microscopy. One to 6 days after inoculation, roots were excised and processed for electron microscopic observations. Exudates were present on the cuticle surfaces of J 2 and early J 3 juveniles located at feeding sites. Fibrillar exudations were correlated with similar fibrillar patterns in the epicuticle, exocuticle, intermediate zone, and the striated endocuticle. Secretion vesicles assembled at many Golgi sites in the hypodermis, appeared to coalesce and form large electron translucent vesicles in the cytoplasm. We propose that secretion vesicles migrate toward the cuticle, contact the plasmalemma and transfer their contents by exocytosis or a similar mechanism to a secretion accumulation site. These contents are associated with cuticle structure and emerge as surface exudations.
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  • 63
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    Protoplasma 168 (1992), S. 125-135 
    ISSN: 1615-6102
    Keywords: Morphogenesis ; Phagotrophic ; Euglenoids ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The disruption and development of the siphon during division ofEntosiphon have been followed by immunofluoresence with both an anti-cement MAb (IIID12) and an anti-tubulin MAb. (IVA10), by nuclear DNA labelling and by electron microscopy of serial section. The disruption of the parental siphon begins at the reservoir level where two new transversely orientated daughter siphons arise. In the degenerating bundles the cement disappears, first liberating the microtubules which then depolymerize. The first structure which surrounds the anterior part of the two young siphons is a loop of 5 microtubules linked to the reservoir membrane. From around this loop a row of perpendicular microtubules sink in the cytosplasm; they will form the primary row of microtubules in the definitive bundles. Inside the loop, reinforced microtubules are seen beneath the membrane, they will generate the future vanes, and also penetrate into the cytosplasm. Amorphous material surrounds the young siphons and may correspond to cement material. The growth of the siphons proceeds as they adopt a central longitudinal position in the cell. The cement material progressively condenses on structures such as the primary row of microtubules. The bundles, the supplementary plaque, and the scaffold. After flagellar partition each of the canals becomes distinct and cytokinesis occurs from the anterior end. These observations indicate that the microtubular loop could be the source of microtubule-organizing centre (MTOC) proteins initiating the assembly of the primary row of microtubules. Bundle microtubules start to assemble at the anterior end and extend backwards. The microtubules of the loop could be linked to roots associated with the basal bodies which double in number before division. The cement later condenses, linking and stabilizing the structures. Microfibrils play an important role in basal body and siphon separation and positioning.
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  • 64
    ISSN: 1615-6102
    Keywords: Cell wall ; Lycopersicon esculentum ; Microsporogenesis ; Pollen development ; Prophase I ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Throughout the premeiotic to late prophase I stages of meiosis in the anthers of tomato (Lycopersicon esculentum) extensive changes occurred in the ultrastructure of pollen mother cells (PMCs). During early prophase, the wall of each PMC developed a layered appearance and was broadened both by the widening of the middle lamella as well as by intensive deposition of microfibrils in the wall. By late prophase, however, the microfibrils adjacent to the plasmalemma dissipated. At the same time, callose was deposited between the wall and the plasmalemma. The nucleus of the PMCs also underwent changes. During early prophase, the nucleolus consisted of a linear series of three segments, with a separation of the granular and fibrillar portions. By late prophase, the nucleoli were less distinct as the nucleus was highly vacuolate. Mitochondria were initially simple with lightly stained matrix and few cristae but, during the course of prophase, they acquired a more densely-stained matrix with dilated cristae. Plastids remained relatively undifferentiated and, at late prophase, many were convoluted in appearance and constricted at intervals indicating their division. Cytoplasmic connections between adjacent PMCs were broad enough to permit the passage of organelles and were retained through to metaphase I. These cytological and wall changes appear to be a prerequisite for the subsequent development of microspores.
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  • 65
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    Protoplasma 167 (1992), S. 215-230 
    ISSN: 1615-6102
    Keywords: Lilium ; Freeze substitution ; Pollen tubes ; Rapid freeze fixation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In view of the importance of the lily pollen tube as an experimental model and the improvements in ultrastructural detail that can now be attained by the use of rapid freeze fixation and freeze substitution (RF-FS), we have reexamined the ultrastructure of these cells in material prepared by RF-FS. Several previously unreported details have been revealed: (1) the cytoplasm is organized into axial “slow” and “fast” lanes, each with a distinct structure; (2) long, straight microtubule (MT) and microfilament (MF) bundles occur in the cytoplasm of the fast lanes and are coaligned with every organelle present; (3) the cortical cytoplasm contains complexes of coaligned MTs, MFs, and endoplasmic reticulum (ER); (4) the cortical ER is arranged in a tight hexagonal pattern and individual elements are closely appressed to the plasma membrane with no space between; (5) mitochondria and ER extend into the extreme apex along the flanks of the pollen tube, and vesicles and ER are packed into an inverted cone-shaped area at the center of the apex; (6) MF bundles in the tip region are fewer, finer, and in random orientation in comparison to those of the fast lanes; (7) the generative cell (GC) cell wall complex contains patches of plasmodesmata; (8) The GC cytoplasm contains groups of spiny vesicles that are closely associated with and seem to be fusing with or pinching off from mitochondria, and (9) the vegetative nucleus (VN) contains internal MT-like structures as well as numerous cytoplasmic MTs associated with its membrane and also located between the VN and GC.
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  • 66
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    Protoplasma 171 (1992), S. 19-27 
    ISSN: 1615-6102
    Keywords: Lysosome ; Morphogenesis ; Trebouxia potteri ; Ultrastructure ; Zoospore formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in the lysosome structures were examined by electron microscopy during the formation of zoospores inTrebouxia potteri. Lysosomes in vegetative cells were homogeneously filled with electron-dense material. At the beginning of zoospore formation, lysosomes invaginated or evaginated to take up mitochondria, ER, or cytoplasmic ground plasma. The ingested organelles became disorganized within the lysosomes. During this disruption of these organelles, the lysosomal contents became heterogeneous, suggesting a decrease in the amount of enzymes within the lysosomes. Golgi bodies and ER seemed to be involved with the disruption of the organelles, probably supplying some substances necessary for the functioning of the lysosomes. Amount of electron-dense materials decreased and, finally, only one to three small spherical aggregates remained in the lysosomes. Then the lysosomes appeared to shrink via loss of watery substances or cutting off of electron-transparent regions. After these changes in lysosome structure, nuclei started to divide successively for formation of the zoospores. The possibility is proposed that the drastic cytoplasmic changes operated by lysosomes trigger the following morphogenetic events in the formation of zoospores.
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  • 67
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    European journal of epidemiology 8 (1992), S. 36-47 
    ISSN: 1573-7284
    Keywords: Tangier disease ; Aortic morphology ; Ultrastructure ; Atherosclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Morphological studies of aortic fatty dots and streaks, and the adjacent normally appearing intima, in a 5 3/4-year-old boy who died of pneumonia, showed several hitherto unreported features. In lesions, lipid vacuoles and/or other cytoplasmic “inclusions” (ultrastructurally considered to present complex forms of lipids) were present on occasion in the endothelium but consistently involved the (intimal) smooth muscle cells (SMC). Similar changes were present in the adjacentintima, but were here less prominent and “tapered off” distally. A moderate number of macrophages also contained cytoplasmic lipids but such cells entirely free of lipid inclusions were observed, too. Most surprisingly, dilated and manycisternae of rough-surfaced endoplasmicreticulum (ER) in the SMC of lesions were associated spatially with cytoplasmic droplets and other forms of lipids. The results of these studies question the generally accepted central role of macrophages as being primarily involved in the pathogenesis of tissue changes in Tangier disease. It is possible that in view of the absence or paucity of high-density lipoproteins (HDL) and alterations of (their) apo A-I and apo A-II (as well as of other lipids), the arterial SMC may be in some way involved in the metabolism of the above substances in this disorder. Support of this tentative (and highly speculative) assumption must await further work utilizing tissues and cells other than those containing macrophages and other derivatives of reticuloendothelial system.
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  • 68
    ISSN: 1573-6822
    Keywords: Lymphoblasts ; Nickel ; Cytometry ; Ultrastructure ; Membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Cytometric and ultrastructural studies on 24 hr cultures of intact, 1.0 mM H5I06, and 0.1 mM SeO2-oxidized HuT-78 lymphoblasts were performed after their direct, 30 min interaction with 1.0 mM NiCl2. Except for moderately depressed cell viability, divalent nickel did not alter the progression of intact and oxidized target cells through the phases of the cell cycle. Although the plasma membrane remained structurally intact, marked distortion of mitochondria structure and increased osmiophilia were an invariable attribute of all nickel-pulsed cells. Moreover, numerous electron-opaque, intracellular depositions were detected in SeO2-oxidized, nickel-pulsed cells. It is concluded that the initial state of plasma membrane, and the interaction of nickel with other trace elements, have jointly determined the response of HuT-78 cells to brief and direct, divalent nickel pulses.
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  • 69
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 23-29 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Different types and degrees of “spontaneous” and artificially induced cyclopic malformation in fishes are defined. Symmetrical cyclopia ranges from approximation of the eyes, to partial merger of the eyes in the midline, to complete cyclopia with a single median eye. It is always associated with dorsal displacement of the rostral-nasal apparatus to the top of the head. Skeletal reorganization associated with symmetrical cyclopia is described for the first time, using hatchery material of Salmo gairdneri and S. trutta. Development of the nasal capsule is essentially normal, except for position; the trabeculae cranii remain in the normal position but show modified shape corresponding to the degree of cyclopia. The jaw apparatus is modified through anterior foreshortening, especially the upper jaws. The branchial apparatus is unaffected. The condition demonstrates that later morphogenesis of the nasal capsule and trabeculae cranii are independent of each other. Cyclopia appears to result from alteration of relative position and timing in developmental events in the head, especially the prosencephalon.
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  • 70
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    Journal of Morphology 211 (1992), S. 201-206 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The interrenal (adrenal) of Ichthyophis beddomei lies on the ventral side of the kidney, distributed in four zones. It is separated from the renal tissue by a thin layer of connective tissue and contains both adrenocortical and chromaffin cells. Adrenocortical tissue constitutes a major portion of the interrenal islets; the chromaffin tissue consists of a few cells located at the peripheries of the interrenal islets. Histochemical studies demonstrate the presence of Δ53β-hydroxysteroid dehydrogenase, 17 β-hydroxysteroid dehydrogenase, glucose-6-phosphate dehydrogenase, succinate dehydrogenase, and sudanophilic lipids in the adrenocortical tissue, suggesting its steroidogenic potential. Annual histometric and histochemical studies show two peaks of interrenal activity: (1) during the breeding phase of the reproductive cycle (January and February) and (2) during the season of heavy monsoon rains (June and July) in the postbreeding phase.
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  • 71
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    Journal of Morphology 211 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 72
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    Journal of Morphology 211 (1992), S. 259-268 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The avian wrist is extraordinarily adapted for flight. Its intricate osteology is constructed to perform four very different, but extremely important, flight-related functions. (1) Throughout the downstroke, the cuneiform transmits force from the carpometacarpus to the ulna and prevents the manus from hyperpronating. (2) While gliding or maneuvering, the scapholunar interlocks with the carpometacarpus and prevents the manus from supinating. By employing both carpal bones simultaneously birds can lock the manus into place during flight. (3) Throughout the downstroke-upstroke transition, the articular ridge on the distal extremity of the ulna, in conjuction with the cuneiform, guides the manus from the plane of the wing toward the body. (4) During take-off or landing, the upstroke of some heavy birds exhibits a pronounced flick of the manus. The backward component of this flick is produced by reversing the wrist mechanism that enables the manus to rotate toward the body during the early upstroke. The upward component of the flick is generated by mechanical interplay between the ventral ramus of the cuneiform, the ventral ridge of the carpometacarpus, and the ulnocarpo-metacarpal ligament.Without the highly specialized osteology of the wrist it is doubtful that birds would be able to carry out successfully the wing motions associated with flapping flight. Yet in Archaeopteryx, the wrist displays a very different morphology that lacks all the key features found in the modern avian wrist. Therefore, Archaeopteryx was probably incapable of executing the kinematics of modern avian powered flight.
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  • 73
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    Journal of Morphology 211 (1992), S. 207-212 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Analyses of the histology, histochemistry, and ultrastructre of the Harderian gland of Coluber viridiflavus prove the gland to be compound acinar and to produce a seromucous secretion. Acinar cells (type I) contain secretory granules that are composite, consisting ultrastructurally of three distinct parts that are sharply separated. They are similar to the “special secretory granules” described in the cells of the Harderian gland of the lizard Podarcis s. sicula. Some acini of the most anterior and posterior parts of the gland are mucous. Acinar cells (type II) of this type contain secretory granules that are Alcian blue/PAS positve. At the ultrastructural level, they appear homogeneous and of low density, characteristic of mucous secretions. These mucus-secreting anterior and posterior parts of the Harderian gland may by considered as regions of intial differentiation of the anterior and posterior lacrimal galnds.
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  • 74
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    Journal of Morphology 211 (1992), S. 243-258 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Subdigital adhesive pads play an important role in the locomotion of many species of gekkonid lizards. These pads consist of integrated components derived from the epidermis, dermis, vascular system, subcuticular tendons, and phalanges. These components become intimately associated with each other during the developmental differentiation of the digits and the sequence of this integration is outlined herein in Ptyodactylus guttatus. The pads initially appear as paired swellings at the distal tips of the digits. Subsequently, a fan-like array of naked scansors develops on the ventral surface of each digit, at about the same time that scales differentiate over the surface of the foot as a whole. At the time of appearance of the naked scansors, the vascular sinus system of the pad also differentiates, along with subcuticular connective tissue specializations. At this stage the digits, along with the rest of the body, are clad in an embryonic periderm. Only after hatching and as the periderm is shed, do the epidermal setae and spines appear. The developmental sequence described here is consistent with predictions previously advanced about the evolutionary origin and elaboration of subdigital pads in gekkonid lizards. The paucity of available staged embryonic material leaves many questions unresolved.
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  • 75
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    Journal of Morphology 211 (1992), S. 295-306 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histology, histochemistry, and biochemistry of the oviduct change seasonally in relationship to the annual ovarian cycle of Calotes versicolor. Histological changes show distinct changes in various components of the infundibulum, uterus and vagina of the oviduct. The active phase in the oviduct cycle of C. versicolor is relatively long, extending from April to October. Histochemical results of the oviduct during the breeding season show PAS-positive glycosaminoglycans in the mucosal epithelium as well as the presence of hydroxysteroid dehydrogenases, esterase, and intense acid phosphatase activity in the uterine glands. Biochemically alkaline and acid phosphatase show marked cyclic changes in the infundibulum and uterus respectively during the oviduct cycle. Greater activity was observed during the breeding season. β-Glucuronidase, on the other hand, shows an inverse relationship with the oviduct cycle being most active during the regressive phase and least at the time of reproductive phase.
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  • 76
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    Journal of Morphology 212 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 77
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    Journal of Morphology 212 (1992), S. 37-53 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The innervation of the musculature of the tongue and the hyobranchial apparatus of caecilians has long been assumed to be simple and to exhibit little interspecific variation. A study of 14 genera representing all six families of caecilians demonstrates that general patterns of innervations by the trigeminal, facial, glossopharyngeal, and vagus nerves are similar across taxa but that the composition of the “hypoglossal” nerve is highly variable. Probably in all caecilians, spinal nerves 1 and 2 contribute to the hypoglossal. In addition, in certain taxa, an “occipital,” the vagus, and/or spinal 3 appear to contribute fibers to the composition of the hypoglossal nerve. These patterns, the lengths of fusion of the contributing elements, and the branching patterns of the hypoglossal are assessed according to the currently accepted hypothesis of phylogenetic relationships of caecilians, and of amphibians. An hypothesis is proposed that limblessness and a simple tongue, with concomitant reduced complexity of innervation of muscles associated with limbs and the tongue, has released a constraint on pattern of innervation. As a consequence, a greater diversity and, in several taxa, greater complexity of neuroanatomical associations of nerve roots to form the hypoglossal are expressed.
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  • 78
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    Journal of Morphology 212 (1992), S. 65-70 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The electron density of the lipid droplets and mitochondrial matrix of the interrenal cells of Rana perezi differs during the year. This makes it possible to characterize the different stages of interrenal cell activity. A droplet/mitochondria index, based on their relative size, may provide an indicator of cellular activity.
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  • 79
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    Journal of Morphology 212 (1992), S. 71-85 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nereid polychaete, Platynereis dumerilii, possess two pairs of post-trochophoral eyes with one vitreous body each. The development of these eyes has first been observed in 2-day-old larvae. Whether the eye anlagen arise from stem cells or from undifferentiated ectodermal tissue was not determined. At first, the anlagen of the anterior and the posterior eyes adjoin each other. They separate in late 3-day-old larvae. The first separated eye complexes consist each of two supporting and two sensory cells. The supporting cells synthesize two different kinds of granules, the pigment granules of the pigment cup and the prospective tubules of the vitreous body. These tubules accumulate in the distal process of the supporting cell. The vitreous body is formed by compartments of the supporting cells filled with the osmiophilic vitreous body tubules. The short, bulbar photosensory processes bear microvilli that emerge into the ocular cavity. At the apex of each sensory cell process, a single cilium (or occasionally two) arises. The sensory cells contain a different kind of pigment granule within their necks at the level of the pigment cup. The rate of eye development and differentiation varies. New supporting cells are added to the rim of the eye cup. They contribute to the periphery of the vitreous body like onion skins, and sensory cells move between supporting cells. The older the individual compartments of the vitreous body are, the more densely packed is their content of vitreous body tubules. Elongation of the sensory and supporting cell processes of the older cells increases the volume of the eye. The eyespots of the trochophore are briefly described as of the two-celled rhabdomeric type with a single basal body with ciliary rootlet.
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  • 80
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    Journal of Morphology 212 (1992), S. 141-154 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Movements of the neck, jaws, and hyolingual apparatus during inertial feeding in Caiman crocodilus were studied by cineradiography. Analysis reveals two kinds of cycles: inertial bites (reposition, kill/crush, and transport) and swallowing cycles. They differ in their gape profile and in displacement of the neck, cranium, and hyolingual apparatus.Inertial bites are initiated by an elevation of the neck and cranium; the head is then retracted backward, the prey simultaneously being lifted by the hyolingual apparatus. Next the lower jaw is depressed, and the prey is rapidly pushed further upward by the hyolingual apparatus. Thereafter fast mouth-closure occurs with the neck and cranium being abruptly depressed, the lower jaw elevated, and the hyolingual apparatus rapidly retracted ventrally. Depression of the neck and cranium thrusts the head forward and impacts the backward moving prey more posteriorly in the oral cavity.Swallowing cycles initially involve movement of the hyoid in front of the prey followed by rapid posteroventrad retraction of the hyoid, forcing the prey into the esophagus during opening and closing of the mouth. After mouth-closure, the hyoid apparatus is again protracted.Jaws, neck, tongue, and hyoid apparatus play an active role during intertial feeding sequences. At the beginning of a feeding sequence, the hyolingual apparatus mainly moves dorsoventrally, whereas toward the end of a sequence anteroposterior displacements of the hyoid are prominent. © 1992 Wiley-Liss, Inc.
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  • 81
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    Notes: The morphology of the female reproductive tract and corpus luteum is examined in Sphenomorphus fragilis, a lizard from the lowland regions of New Guinea exhibiting incipient viviparity. Females oviposit eggs that hatch either immediately or within a few hours. Corpora lutea form from ovulated follicles and decrease in diameter as embryonic development progresses. The oviduct from vitellogenic females is sparsely populated with well developed uterine glands containing secretory granules. The eggs are covered with a relatively thin shell (10 μm thick) composed of an inner boundary layer and proteinacous fibers. The secreted shell is complete by early neurulation. Shell morphology does not change throughout the remainder of the in utero incubation period. A well vascularized uterus and chorioallantoic membrane provide simple placentation. These findings suggest that the reduction in shell thickness associated with the evolution of a placenta is due to a decrease in the number of shell glands in the uterus and is not a delay or inhibition of the shelling process per se. This hypothesis further suggests that the selective forces favoring shell gland loss act on the vitellogenic female during gland recruitment which occurs prior to ovulation and not on the pregnant female. © 1992 Wiley-Liss, Inc.
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  • 82
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    Journal of Morphology 212 (1992), S. 191-200 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Study of the esophageal microscopic morphology of adult Rana perezi by light and electron microscopy discloses some large folds throughout the esophagus that are in themselves ringed. Glandular ostia open in the furrows of the luminal surface. The esophageal wall is made up of a connective adventitia rich in melanocytes, a muscular tunica, a connective and glandular subepithelial layer, and a pseudostratified ciliated epithelium. This epithelium basically consists of ciliated, goblet, basal, microvillous-apex, and migratory cells. Two types of goblet cells are distinguished with regard to the granular ultrastructure. The microvillous-apex cell has not been found in other amphibians. It shows a very differentiated morphology with a high number of mitochondria. The basal cells give the epithelium a pseudostratified morphology, and they have a proliferative function. Glands are branched and drain through an excretory duct that has a monolayered mucosecreting epithelium. The glandular units are formed by two principal types of cells: mucosecretory and serous. © 1992 Wiley-Liss, Inc.
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  • 83
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    Journal of Morphology 212 (1992), S. 281-290 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spermathecae of Eurycea cirrigera are exocrine glands in the cloaca that secrete a substance that bathes sperm stored in the lumen after mating and prior to oviposition. Many sperm remain in the spermathecae after oviposition, and the spermathecal epithelium becomes spermiophagic. Pseudopodia enclose sperm into endocytic vacuoles. The vacuoles become associated with primary lysosomes in the cytoplasm. Following formation of secondary lysosomes and resulting condensation of the sperm fragments, residual bodies are exocytized into the surrounding connective tissue stroma. By the start of the next breeding cycle, most sperm remaining from the previous mating have been degraded, but some sperm remain in the lumen, and the viability of these sperm is unknown. © 1992 Wiley-Liss, Inc.
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  • 84
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    Notes: Basement membranes (BMs) of vertebrates and invertebrates have been shown to contain glycoproteins and proteoglycans, which include oligosaccharides and glycosaminoglycans. Lectin binding sites were characterized in the BM of gastrulating embryos of the starfish, Pisaster ochraceus. In early and mid-gastrulae, the fluorescein isothiocyanate (FITC)-lectin conjugates of concanavalin A (Con A) and wheat germ agglutinin (WGA) reveal the presence of mannose/glucose and glucosamine/sialic acid residues in the BM of all regions of the embryos. However, in the late gastrula embryo, an apparent reduction of these components is observed over the esophageal BM. Ultrastructural studies using the lectin-gold conjugates Con A, Limax flavus agglutinin (LFA), specific for sialic acid, and Dolichos biflorus agglutinin (DBA), specific for galactosamine, demonstrate that most mannose/glucose and galactosamine containing residues lie in the lamina densa, whereas most sialic acid residues are located over the lamina lucida. In addition, a statistical analysis of lectin binding in the late gastrula embryo reveals that the amount of labelling with both Con A and LFA is significantly reduced in the esophageal region, suggesting that mannose/glucose and sialic acid residuces are reduced in this region. These results confirm the observations of the FITC-lectin studies described above. They also confirm earlier studies that demonstrated a difference in BM morphology of the esophageal region (Crawford, '88). Mesenchyme cells, some of which arise from the forming coeloms (Crawford, '90), and which may represent a distinct population, colonize exclusively on this esophageal BM, where they later differentiate into muscle. Quantitative differences in BM glycoconjugates may act to direct the presumptive muscle cells to the region of the esophagus. © 1992 Wiley-Liss, Inc.
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  • 85
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    Journal of Morphology 213 (1992), S. 47-83 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A large sample of embryological material of the North American paddlefish Polyodon spathula (Acipenseriformes: Polyodontidae) confirms that early development in Polyodon is very similar to that reported for the sister group of Polyodontidae, the sturgeons (Acipenseridae). Polyodon illustrates many basic aspects of acipenseriform (and actinopterygian) head development that have not been adequately described. In this paper, we provide an overview of external features of cranial development using scanning electron microscopy. The observations are correlated with staging schemes previously proposed for paddlefishes and other acipenseriforms. Events that occur after the start of neurulation (stage 19) to the start of feeding (stage 46) are emphasized. New information on the structure and folding of the mandibular and hyoid segments permits an understanding of the early development of the pharyngeal region. In addition, we offer new descriptions of the hatching gland, the olfactory organ, the sensory barbel, and the initiation of paddle outgrowth. We also comment on the mode of origin of the hypophysis, and refute the notion that it is derived from the lips of the anterior neuropore as suggested in older literature. This information sets the stage for future comparative and experimental studies of the embryology of basal actinopterygians. © 1992 Wiley-Liss, Inc.
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  • 86
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    Journal of Morphology 213 (1992), S. 15-20 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The presence of seminal receptacula in the female reproductive tract of Opisthopatus cinctipes (Purcell, 1900) has been disputed (Choonoo, '47; Ruhberg, '85; Herzberg et al., '80). However, they do occur and are described here from observations by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). No spermatozoa are associated with the surface of the ovary; in contrast the ovary of Peripatopsis capensis is covered with spermatozoa and numerous small rounded cells. The seminal receptacula of O. cinctipes are formed from a loop in the proximal region of the uterus and contain remnants of spermatozoa in their lumens. The epithelial cells lining the seminal receptacula contain numerous vesicles and residual bodies. It is suggested that these cells absorb those spermatozoa not required for fertilization, and that the seminal receptacula in the Peripatopsidae act as short-term storage sites for spermatozoa. By contrast, the seminal receptacula of the Peripatidae are considered to act as long-term storage sites for spermatozoa. © 1992 Wiley-Liss, Inc.
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  • 87
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    Notes: Scanning and transmission electron microscopy of the antennae of Culicoides impunctatus and Culicoides nubeculosus show that males and females share five sensillum types. Sensilla chaetica resemble mechanoreceptors, each innervated by a single neurone whose dendrite terminates distally in a tubular body: the arrangement of sensilla on male antennae suggests that females are located by sound. The antennae have both sharp- and blunt-tipped sensilla trichodea, sharp-tipped sensilla on only the distal third and blunttipped sensilla on all subsegments. These sensilla are typical of olfactory receptors, having multiporous walls and being innervated by a number of neurones with bifurcating dendrites ascending the hair shafts. Sensilla basiconica occur on the distal five subsegments of the female antenna and the distal three subsegments of the male antenna. Sensilla coeloconica always occur on subsegment one and sometimes on a number of other subsegments, depending on sex and species. Both basiconic and coeloconic sensilla have double walls and unbranched dendrites and may be either olfactory or thermo- and/or hygroreceptors. All antennae except those of male C. impunctatus antennae have sensilla ampullacea, apparently deep-seated olfactory or thermoreceptors. Small peg sensilla fitting the description of contact chemoreceptors occur only at the tip of the male antenna. © 1992 Wiley-Liss, Inc.
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  • 88
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    Journal of Morphology 213 (1992), S. 159-169 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Monoclonal antibody (mAb) WE3 recognizes an antigen that is developmentally expressed in the wound epithelium during adult newt limb regeneration. Experiments were designed to determine whether retinoic acid (RA), dissolved in dimethyl sulfoxide (DMSO) and administered by intraperitoneal injection, would enhance the temporal appearance of the WE3 antigen. RA given on days 1 or 4 after amputation, when the WE3 antigen is not yet detectable, resulted in moderate reactivity to mAb 2 days after injection and strong reactivity throughout the wound epithelium 4 days after injection. DMSO alone had no enhancing effect. RA also caused limb skin epidermis to exhibit reactivity to mAb WE3, initially near the amputation level, but then also more proximally. By 4 and 6 days after RA injection, epidermis of the flank, eye lid, and unamputated hind limbs also became strongly reactive to mAb WE3. Outer layers of skin epidermis were shed, resulting in an epidermis only one or two cells thick. Epidermis of newts given DMSO alone remained non-reactive to mAb WE3. When RA was given on days 7 and 10 after amputation, when a low level of mAb WE3 reactivity is already present in the wound epithelium, a considerable enhancement of mAb WE3 reactivity occurred through the next few days. No such enhancement was seen with DMSO alone. RA also greatly increased mAb WE3 reactivity in the wound epithelium of denervated limbs, in which case the wound epithelial reactivity to mAb WE3 is normally low. Retinol palmitate also increased mAb WE3 reactivity. The results raise the possibility that the WE3 antigen is a component of most if not all retinoid target tissues in newts. © 1992 Wiley-Liss, Inc.
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  • 89
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    Journal of Morphology 213 (1992), S. 197-224 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mechanics of the skull of the pigeon are analyzed quantitatively, based on a three-dimensional kinematic computer model that considers the skull as a mechanism (Goodman, '60). The degrees of freedom at each cranial joint are defined and translated into geometric relations, using the method of Elshoud ('80). The model predicts the positions of cranial elements from three input variables: the positions of the upper and lower bills and the length of the M. protractor quadrati et pterygoidei. Simulations with the model suggest the presence of a locking mechanism for the lower bill, which prevents its depression. High speed films of feeding pigeons confirmed that locking can occur at different upper bill positions. The locking mechanism may permit feeding pigeons to use the elastic energy stored in the hinge of the upper bill during the grasp, producing simultaneous fast closing of the upper and lower bills. Simulation of jaw muscle activity suggests that these jaw muscles should not be divided into “openers” and “closers.” © 1992 Wiley-Liss, Inc.
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  • 90
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    Journal of Morphology 213 (1992), S. 287-294 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Neurons in whole mount preparations of the frontal ganglion (FG) of the cockroach, Periplaneta americana, were mapped with the aid of cobalt chloride staining and silver intensification techniques. Eighty-six neurons were counted in the FG after staining with reduced methylene blue. The cell size ranged between 20 to 35 μm in diameter. Of the somata located in the FG, 44 were found to contribute their fibers to the nervus recurrens, 26 to the right frontal commissure, 28 to the left frontal commissure, and 6 to the nervus connectivus. In addition, a few neurons presumably from the tritocerebral region also contribute their fibers in the formation of nervus connectivus. The present study has helped delineate the neuronal connections of the FG with the brain and neuroendocrine system (corpora cardiaca and corpora allata). This information will be useful in facilitating the positioning of microelectrodes in our future electrophysiological experiments. © 1992 Wiley-Liss, Inc.
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  • 91
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    Journal of Morphology 213 (1992), S. 335-340 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microcorrosion casts of the renal vascular system of tadpoles of the Clawed Frog, Xenopus laevis, were observed by scanning electron microscopy. Glomerular differentiation was studied qualitatively and quantitatively during developmental stages 56-66 (metamorphic climax). The general structure of the renal vascular system corresponds to the pattern commonly found in anurans; however, the arterial supply has conspicuous connecting vessels that supply groups of glomeruli. In the dorsal part of the kidney, qualitative differentiation of glomerular structures precedes quantitative growth. The ventral part of the kidney has larger, well-developed renal corpuscles of nearly adult appearance. Four developmental stages of glomerulogenesis are distinguished morphologically and their glomerular and vascular growth is analyzed. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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  • 92
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 93
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 1-41 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Postembryonic skeletal development of the pipid frog Xenopus laevis is described from cleared-and-stained whole-mount specimens and sectioned material representing Nieuwkoop and Faber developmental Stages 46-65, plus postmetamorphic individuals up to 6 months old. An assessment of variation of skeletogenesis within a single population of larvae and comparison with earlier studies revealed that the timing, but not the sequence, of skeletal development in X. laevis is more variable than previously reported and poorly correlated with the development of external morphology. Examination of chondrocranial development indicates that the rostral cartilages of X. laevis are homologous with the suprarostral cartilages of non-pipoid anurans, and suggests that the peculiar chondrocranium of this taxon is derived from a more generalized pattern typical of non-pipoid frogs. Derived features of skeletal development not previously reported for X. laevis include (1) bipartite formation of the palatoquadrate; (2) precocious formation of the adult mandible; (3) origin of the angulosplenial from two centers of ossification; (4) complete erosion of the orbital cartilage during the later stages of metamorphosis; (5) development of the sphenethmoid as a membrane, rather than an endochondral bone; and (6) a pattern of timing of ossification that more closely coincides with that of the pelobatid frog Spea than that recorded for neobatrachian species. © 1992 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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  • 94
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    Journal of Morphology 213 (1992), S. 349-364 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The central nervous system of Ixodes scapularis is fused into a single compact synganglion. The esophagus runs through the synganglion and divides it into supraesophageal and subesophageal parts. The supraesophageal portion contains a single protocerebrum with four pairs of glomeruli, paired optic lobes and cheliceral ganglia, and a single stomodeal bridge. The subesophageal portion contains a centrally located network of commissures and connectives, a pair of palpal ganglia, paired olfactory lobes of the first pedal ganglia, four pairs of pedal ganglia, and a single opisthosomal ganglion. A retrocerebral organ complex (ROC) in close vicinity of the digestive tract, as described in some other tick species, apparently is lacking. Perhaps the function of the ROC is performed by the paired, large, ganglion-like bodies that lie anterolaterad to the cheliceral ganglia.The rind, which is formed from the neuronal somata and glial cells, surrounds the central fibrous core or neuropile. Neurosecretory cells (NSC) are distinct among rind cells due to their large size and concentration of cytoplasmic neurosecretions. NSC are present throughout the synganglion, although the subesophageal portion contains larger groups of these cells. Histological serial sections, stained with Meola's (Trans Am Microsc Soc 89:66-71, '70) paraldehyde fuchsin (PAF) procedure revealed 24 PAF-stained, putative neurosecretory regions in the synganglion of virgin, unfed females. All of these regions appear to be connected and associated with the nearest ganglion and are correspondingly named. Eighteen PAF-positive regions occur in the synganglion. In addition, PAF-negative (green-stained) cells occupy 6 distinct regions in the synganglion of unfed, unmated females. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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  • 95
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 43-48 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Female Thamnophis sirtalis were administered intraperitoneal implants of either estradiol 17β (E2), testosterone (T), 5α-dihydrotestosterone (DHT), or empty silastic capsules for 3 weeks. Plasma levels of E2 and T, measured by specific radioimmunoassay, were significantly elevated in E2 and T-implanted females when compared to controls. T-implanted females did not have elevated circulating E2 levels, suggesting that E2 in the plasma normally is not derived from peripheral conversion of T to E2. Implantation of DHT did not significantly change circulating levels of E2, T, or DHT. All three sex steroid - treated groups of animals had increased oviductal mass compared to controls, while hepatic mass of only E2-treated animals was significantly greater. None of the steroid treatments influenced ovarian mass. Oviductal epithelial cell height and area were greater in the three steroid-treated groups. Testosterone increased myometrial area while DHT drastically altered oviductal morphology. Hepatic cell area and number increased significantly in E2-treated females. However, a small increase in both hepatic cell area and number was noted in T- and DHT-treated females as well. These results suggest that androgen in both an aromatizable and non-aromatizable form can affect the oviduct of females but that the liver primarily responds to estrogenic steroids. © 1992 Wiley-Liss, Inc.
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  • 96
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    Journal of Morphology 214 (1992), S. 333-340 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The labial palpus of the elephant louse Haematomyzus elephantis has six sensilla that represent three different types: trichoid, basiconic, and styloconic. Two rows of basiconic sensilla are situated on the dorsal and ventral surfaces of the rostrum, and each row consists of three sensilla. Male and female antennae have 15-17 trichoid sensilla situated on the scape, pedicel, and three antennal annuli. Both sexes have two sensilla basiconica on the dorsal surface of the pedicel near the junction of the scape and pedicel. Two coeloconic (tuft) sensilla are situated on the antennae of both sexes, one sensillum on each of the last two annuli. There are three plate organs, two on the last annulus and one on the penultimate annulus of the male and female antennae. Sexual dimorphism is exhibited in the male and female antennae, in that the male has about twice as many sensilla basiconica on the apex of the last annulus as does the female. The total number of sensilla basiconica on the apex of the male antennae is at least two times the number that is known to be present in any other species of lice. © 1992 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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  • 97
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 341-350 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Representative functional teeth from Cryptobranchus alleghaniensis (Cryptobranchidae), Amphiuma means (Amphiumidae), Dicamptodon ensatus (Dicamptodontidae), Necturus maculosus (Proteidae), and Dermophis sp. (Costa Rica) (Caeciliidae) were prepared for transmission electron microscope and electron microprobe analysis of the trace elements of the enamel layer. The enamel layer of these species is very thin and the arrangement of enamel crystals variable. In particular, the outer part of the enamel layer in which hydroxyapatite elements (Ca, P) and trace elements (e.g., F, Fe, Mg) are concentrated, is most heavily mineralized. The concentrations and alignment of crystals in the outer and inner parts of the enamel layer differ among these species.The presence of collagen fibers in the inner part of the enamel layer of Cryptobranchus and Dermophis indicates that it is enameloid rather than true enamel. The presence of trace elements may be related to the pattern of mineralization of enamel or enameloid, as suggested for tetra-odontiform fishes by Suga et al. (J. Dent. Res. 68:1115-1123, 1989). © 1992 Wiley-Liss, Inc.
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  • 98
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    Journal of Morphology 214 (1992), S. 357-374 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A statistical and functional relationship between neural canal anatomy and locomotor mode is demonstrated in living marine mammals of the Order Carnivora. This relationship is interpreted to be the result of differential innervation and territory of musculature involved in generating the six locomotor patterns analyzed. This osteological reflection of a behavioral trait allows prediction of locomotor pattern in extinct genera of closely related taxa. The robust data allow such predictions even when a considerable number of presacral vertebrae are missing in the fossil specimens. In some cases, these predictions conflict with interpretations based solely on limb osteology. © 1992 Wiley-Liss, Inc.
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  • 99
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 100
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 1-6 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oosorption has been considered an important strategy in many invertebrate species which occurs in response to behavioral, ecological, or physiological factors. In crustaceans, the early light microscopic studies of the ovary attributed a role in oosorption to follicle cells, hemocytes, or phagocytes. In this study, ovaries were collected from female golden crabs following spawning and processed for examination by electron microscopy.Following spawning, several unspawned oocytes which had become dissociated from their follicle cells were found in the ovaries. They appeared to be lodged within the lumen. Such oocytes were observed undergoing various stages of autolysis. At no time were hemocytes or recognizable phagocytes found in the lumen of the ovaries or in contact with the degenerating oocytes. Follicle cells which had surrounded the oocytes prior to the time of spawning exhibited disrupted membranes. Resorption of unspawned eggs appears to occur by autolysis of the individual oocytes.Several of the females who had recently spawned had numerous sperm in their ovaries. Such sperm may have been pressed into the lumen at the time of spawning or during the fixation process.
    Additional Material: 11 Ill.
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