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  • 1990-1994  (2,289)
  • 1970-1974
  • 1955-1959
  • 1890-1899
  • 1993  (2,289)
  • Life and Medical Sciences  (2,230)
  • Ultrastructure
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  • 1990-1994  (2,289)
  • 1970-1974
  • 1955-1959
  • 1890-1899
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Rhabdoid tumours of the central nervous system (1993)
    Springer
    Virchows Archiv 422 (1993), S. 81-85 
    Details
    ISSN: 1432-2307
    Keywords: Rhabdoid tumour ; Central nervous system ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of rhabdoid tumour of the central nervous system arising in a supratentorial location are reported. The patients were 18, 14, and 7 years old. All three tumours showed a common morphology. The neoplastic cells were usually globoid with round nuclei and prominent nucleoli and large acidophilic, cytoplasmic inclusions were present in many of them. These inclusions showed strong immunoreactivity for vimentin, weak immunoreactivity for epithelial membrane antigen and focal immunoreactivity for cytokeratins. Ultrastructurally they were made up of whorls of intermediate filaments, 8–10 nm in thickness. Rhabdoid tumours of the central nervous system, whatever the cell of origin, appear to be an independent entity with identifiable histology and aggressive behaviour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01605137
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  • 2
    Electronic Resource
    Electronic Resource
    Localized amyloidosis in squamous cell carcinoma of uterine cervix: Electron microscopic features of nodular and star-like amyloid deposits (1993)
    Springer
    Virchows Archiv 422 (1993), S. 225-231 
    Details
    ISSN: 1432-2307
    Keywords: Amyloid ; Amyloidosis ; Squamous cell carcinoma ; Keratin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An ultrastructural study of amyloid deposits in four cases of squamous cell carcinoma of uterine cervix was performed. The amyloid deposits reacted with anti-keratin antiserum on frozen sections. Amyloid deposits showed nodular (4 cases) and star-like forms (3 cases). Nodular amyloid deposits were composed of slightly whorled fibrils, measuring 7–10 nm in width. Some of them contained cellular debris and thicker, more electron-dense filaments than amyloid fibrils. In three cases, filamentous tumour cells and filamentous masses were observed together with amyloid. Star-like amyloid deposits were composed of bundles of straight amyloid fibrils. Some of the tumour cells in contact with star-like amyloid deposits had deep cytoplasmic invaginations, where closely packed amyloid fibrils were arrayed in parallel fasion. In addition, a few tumour cells had membrane-bound amyloid fibrils in the cytoplasm. It is suggested that nodular amyloid deposits are derived from the tumour cells through filamentous degeneration. Amyloid fibrils in star-like amyloid deposits are thought to be formed within the cytoplasm or in the vicinity of invaginated cytoplasmic membranes of the tumour cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01621806
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  • 3
    Electronic Resource
    Electronic Resource
    Widening of capillary neck and alteration of extracellular matrix ultrastructure in diabetic rat glomerulus as revealed by computer morphometry and improved tissue processing (1993)
    Springer
    Virchows Archiv 423 (1993), S. 121-129 
    Details
    ISSN: 1432-2307
    Keywords: Ultrastructure ; Morphometry ; Diabetic nephropathy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Morphological and morphometric studies of glomeruli were carried out in streptozotocin-induced diabetic rats using improved tissue processing and computerized morphometry. Increased mesangial matrix, occupying the enlarged diabetic mesangium, contained an abundance of dark granular material in addition to the microfibrils which were usually found in the control glomeruli. In the diabetic glomeruli, the lamina densa was thick and heterogeneous showing a dense layer both on its epithelial and endothelial aspects, and the lamina rara externa contained more fibrils than in control rats. Detailed estimation of the absolute values of the various compartments of the diabetic glomeruli by using perfusion-flxed materials and a computer-assisted digitizer revealed that the volume and surface area of the mesangium were increased more extensively than those of the capillary; the enlargement of the mesangial-capillary interface area was the most pronounced among the morphometric changes of the diabetic glomeruli; and that the moderate increase in capillary volume was associated with an increased radius. Our quantitative results showed that capillaries in the diabetic glomeruli had an extensively wider neck which may be the first sign of structural damage to the glomerular tuft.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606586
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  • 4
    Electronic Resource
    Electronic Resource
    Altered intestinal development after jejunal ligation in fetal sheep (1993)
    Springer
    Virchows Archiv 423 (1993), S. 45-50 
    Details
    ISSN: 1432-2307
    Keywords: Fetus ; Small intestine ; Ultrastructure ; Intestinal atresia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Experimental obstruction of the fetal small intestine resulted in massive hypertrophy of the segment proximal to the site of obstruction. Villus morphology was grossly abnormal. Enterocytes developed many irregular features, most notably cytoplasmic extensions (pseudopods, or blebs) from their apical surface. Distal to the site of obstruction, morphological anomalies which resembled those seen after experimental oesophageal ligation were found. These included delayed disappearance of the apical endocytic network, disrupted or absent microvilli, glycogen accumulation and inappropriate cell extrusion. Proximal to the obstruction, where stasis of swallowed fluid occurs, distension and abnormal intestinal development ensues. Distal to the obstruction where the intestine develops in the absence of swallowed fluid, development is also abnormal. The anomalies resemble those noted after oesophageal ligation in utero, and possibly are the results of reduced cellular nutrition. These results suggest that fetal ingestion provides the developing gastrointestinal tract with an important stimulus for normal growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606431
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  • 5
    Electronic Resource
    Electronic Resource
    Comparative study of histopathological alterations during intestinal infection of mice with pathogenic and non-pathogenic strains ofYersinia enterocolitica serotype O:8 (1993)
    Springer
    Virchows Archiv 423 (1993), S. 97-103 
    Details
    ISSN: 1432-2307
    Keywords: Yersinia enterocolitica ; Peyer's patches ; Ultrastructure ; M-cell ; Invasiveness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Yersinia enterocolitica is an invasive pathogen capable of causing a wide spectrum of gastrointestinal diseases in man. While there is a considerable body of data on the invasiveness ofY. enterocolitica in vitro, little is known about the events in vivo leading to the translocation of the bacteria from the intestinal lumen into the ileal tissue. There is no detailed ultrastructural information describing the course of infection of pathogenicY. enterocolitica in comparison with an avirulent strain. We compared a virulent plasmid-bearing strain and an isogenic avirulent plasmid-free derivative strain ofY. enterocolitica serotype O∶8 at the ultrastructural level, in the established model of murine yersiniosis. At 12 h postinoculation we found no indications of an active invasion of the intestinal epithelium, although microcolonies of the pathogenic strain were detectable closely under the follicle-associated epithelium of the Peyer's patches. The plasmid-bearing strain ofY. enterocolitica affected the gut-associated lymphoid tissue which was destroyed 36 h post-infection. Unlike the pathogenic strain ofY. enterocolitica, the nonpathogenic plasmid-free strain caused no detectable morphological alterations in the ileal tissue by this time. Morphological evidence is provided thatYersinia does not invade the ileal epithelium in an active manner, as has been observed in vitro, but appears to be transported across the epithelial barrier by M-cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606583
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  • 6
    Electronic Resource
    Electronic Resource
    Cytogenetic study of botryoid rhabdomyosarcoma of the uterine cervix (1993)
    Springer
    Virchows Archiv 422 (1993), S. 87-91 
    Details
    ISSN: 1432-2307
    Keywords: Botryoid rhabdomyosarcoma ; Uterine cervix ; Immunohistochemistry ; Ultrastructure ; Chromosomal analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report a case of sarcoma botryoides of the uterine cervix occurring in a 19-year-old woman. By light microscopy the tumor showed round and spindle cells with hyperchromatic nuclei and, focally, a cambium layer subjacent to the surface epithelium and surrounding endocervical glands. Strap-shaped cells with and without cross-striations and small foci of immature cartilage were also present. Immunohistochemical studies showed positive staining within the tumor cells for myoglobin, desmin, vimentin, muscle-specific actin and CD56. By electron microscopy, tumor cells showed cytoplasmic filaments in an alternating pattern of thick and thin filaments. Chromosomal analysis demonstrated deletion of the short arm of chromosome 1, and trisomies 13 and 18. To our knowledge, this is the first reported case of sarcoma botryoides of the endocervix with chromosomal analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01605138
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  • 7
    Electronic Resource
    Electronic Resource
    Cellular and matrix changes in drug abuser liver sinusoids: A semiquantitative and morphometric ultrastructural study (1993)
    Springer
    Virchows Archiv 422 (1993), S. 145-152 
    Details
    ISSN: 1432-2307
    Keywords: Heroin ; Sinusoids ; Fibrosis ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the present work was to analyse, at the ultrastructural level, the action of heroin of 150 centrilobular sinusoids from liver biopsies of five intravenous drug abusers, who presented clinical and biological manifestations of hepatic impairment. A comparative study of 90 sinusoids from liver biopsies of three control patients was performed. Electron microscopic observations showed a thickening of the sinusoidal wall related to endothelial cell hypertrophy and to fibrosis of the space of Disse. This was generally associated with basement-membrane-like material and hepatocyte microvilli flattening. In addicts, hepatic vascular pole changes were a constant finding, accompanied by interhepatocyte space disjunction and perisinusoidal collagenization. Morphometric assessment confirmed a significant increase of sinusoidal wall surface, endothelial cell body and processes and Ito cell process surface was significantly different between the patient groups. This cellular hypertrophy may represent hyperactivation of the sinusoidal cell functional capacity, triggering the fibrogenesis in the space of Disse. While this mechanical barrier might hinder the free exchange through the space of Disse, it may equally well protect the liver against heroin toxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01607166
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructural study ofCryptococcus neoformans by quick-freezing and deep-etching method (1993)
    Springer
    Mycopathologia 121 (1993), S. 133-141 
    Details
    ISSN: 1573-0832
    Keywords: Capsule ; Cryptococcus neoformans ; Deep-etching ; Quick-freezing ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The three-dimensional ultrastructure ofCryptococcus neoformans was studied by quick-freezing and deep-etching (QF-DE) method.C. neoformans, strain CDC551, was cultured on agar. The viable yeast cells (107 cells) were inoculated into each mouse from the tail vein. Three weeks after the inoculation, the brains of the mice were perfused with fixatives, quickly frozen, freeze-fractured, deeply etched and rotary shadowed with platinum and carbon. In addition, the viable cells ofC. neoformans on agar were picked up and quickly frozen, and replica membranes were prepared as described above. The ultrastructure ofC. neoformans was three-dimensionally demonstrated by the QF-DE method. The capsule was composed of fine meshworks of microfibrils (10–13 nm in diameter), which were directly attached to the cell walls. The capsule of the in vivo yeasts (yeast cells in the brain lesion) was thicker than that of the in vitro yeasts (yeast cells on agar culture). At the outer part of the cell wall, a particle-accumulating layer was observed. This layer in vivo was thicker than that in vitro. Occasionally, the yeast cells were ingested by phagocytes in the mouse brain. Although the cytoplasm of such yeast cells was destroyed, the capsular meshworks were well preserved. The ultrastructure of the capsule was the same both in cultured and phagocytized yeasts in the cystic lesions of the brains. This lack of morphological changes of the capsular meshworks suggests that they are resistant to the digestion by phagocytes. This stability of capsular structures may provide one of the important pathogenic factors in cystic lesions byC. neoformans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01104068
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  • 9
    Electronic Resource
    Electronic Resource
    Morphological assessment of ethyl choline mustard aziridinium-induced neurotoxicity in rat brain reaggregate cultures (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 154-162 
    Details
    ISSN: 1432-0533
    Keywords: Ethylcholine mustard aziridinium (ECMA, AF64A) ; Brain reaggregate cultures ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Foetal rat brain reaggregate cultures have been employed to investigate the morphological changes associated with the neurotoxic action of ethylcholine mustard aziridinium (ECMA). In a companion study we provided evidence for apparent selective cholinergic neurotoxicity. Exposure of 9-day-old cultures to 12.5 μM ECMA for 3 days produced dilatation of selected axon preterminals and terminals in the outer core tissue layer. Axoplasm in these dilated terminals was electron lucent and contained a flocculent, plasma-like material with remnants of the smooth endoplasmic reticulum. Their synaptic vesicle content was much reduced or, absent. Microglial cells were engaged in phagocytosis of these effete structures and a few necrotic neurons were enveloped by glial processes. Exposure to 50 μM ECMA produced widespread necrosis with some surviving neurons, surrounded by the still-persisting capsular layer. Treatment with 100 μM ECMA generated a greater extent of tissue necrosis, with only a few surviving neurons and glial cells being contained within the necrotic tissue mass. Reaggregates frequently disintegrated following capsule loss. Our results indicate that the initial morphological manifestation of ECMA-induced toxicity is dilatation of axon terminals, that are probably of cholinergic origin and are targeted due to their possession of the high-affinity choline transport system which is unique to these neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334882
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  • 10
    Electronic Resource
    Electronic Resource
    Nephrosialidosis: ultrastructural and lectin histochemical study (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 198-205 
    Details
    ISSN: 1432-0533
    Keywords: Nephrosialidosis ; Sialidosis ; α-neuraminidase deficiency ; Ultrastructure ; Lectin histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The neuropathological findings in a Japanese male with nephrosialidosis are reported. Clinically, coarse face, psychomotor retardation, macular cherryred spot and proteinuria were noted at 1 year and 7 months. He was diagnosed to have nephrosialidosis on the basis of a deficiency of α-neuraminidase activity in both lymphocytes and cultured skin fibroblasts, and of severe glomerular and tubular involvement on renal biopsy. He died of multiple organ failure at 8 years and 6 months. There were numerous vacuoles and storage materials in visceral organs, particularly in the glomerular and tubular epithelial cells of the kidney and Kupffer cells as well as hepatocytes in the liver. Neuropathological examination revealed severe neuronal storage in the selected part of the central nervous system; lower motor neurons of the brain stem and spinal anterior horn cells, as well as neurons in the basal nucleus of Meynert. In the peripheral nervous system, sympathetic ganglia were severely affected. There was little or no neuronal storage in the basal ganglia, cerebral cortex or cerebellum, and demyelination was not found. Electron microscopic examination showed fine wavy multilamellar structures in the spinal anterior horn cells or Zebra body-like structures in the neurons of the Meynert's basal nucleus. Lectin histochemistry was positive for wheat germ agglutinin, Ricinus communis agglutinin-1 and peanut agglutinin within distended neurons. We conclude that the neuropathological feature in nephrosialidosis is not specific except for the selectiveness of the anatomical sites of involvement. It shares some aspects found in other types of sialidosis or galactosialidosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334891
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  • 11
    Electronic Resource
    Electronic Resource
    A simple method of rapid freezing adequately preserves brain tissue for immunocytochemistry, light and electron microscopic examination (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 645-650 
    Details
    ISSN: 1432-0533
    Keywords: Brain ; Freezing ; Immunocytochemistry ; Microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A simple and reproducible method for cryo-preservation of brain tissue from patients with Alzheimer's disease is described. Fresh brain slices (1 cm thick) obtained less than 6 h postmortem are placed in sealed plastic bags, sandwiched between 0.3-cm-thick aluminium sheets, and frozen by placing the entire “sandwich” between layers of dry ice pellets. The frozen brain slices are stored at −85 °C. Specific anatomic areas can be retrieved at any time for light and electron microscopic, immunocytochemical, autoradiographic and neurochemical studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294305
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  • 12
    Electronic Resource
    Electronic Resource
    Stereological and morphometric analysis of dermal fibroblasts before and after bone marrow transplantation in a case of mucopolysaccharidosis I Scheie phenotype (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 21-28 
    Details
    ISSN: 1432-0533
    Keywords: Mucopolysaccharidosis I Scheie phenotype ; Bone marrow transplantation ; Fibroblasts ; Stereologic analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bone marrow transplantation (BMT) has been used therapeutically in several types of mucopoly-saccharidoses (MPS) and other inherited metabolic disorders. Fibroblasts are severely affected in MPS due to the intralysosomal accumulation of glycosaminoglycans. We report a stereological and morphometric study at light and electron microscopy levels of dermal fibroblasts before and 21 months after BMT in a young girl with MPS I Scheie phenotype (MPS I-S). Dermal fibroblasts showed remarkable morphological changes although their density, expressed as number of fibroblasts per unit volume of dermis (number density), was not modified in the post-BMT samples as compared to pre-BMT ones. Stereological and morphometric parameters referring to cell characteristics of post-BMT fibroblasts (nuclear and cell surface densities, and both nucleus/cell and cell/nucleus volume densities) showed significant differences when compared with pre-BMT fibroblasts, and non-significant differences regarding control cells. On the other hand, quantitative parameters of the lysosomal compartment from post-BMT fibroblasts showed intermediate values between pre-BMT and control fibroblasts. These results, at cellular level, are in agreement with previous biochemical and clinical results, and clearly showed a progressive course to a non-pathological state. All parameters estimated may be considered useful tools in evaluating the success of BMT. These parameters provide quantitative data which can be statistically compared, showing the changes due to the reduction of storage material after BMT. Cell/nucleus volume density is especially interesting since not only is it easy to estimate, even by automatic procedures, but it could also constitute a numerical expression of skin anatomopathological analyses performed post-BMT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454894
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  • 13
    Electronic Resource
    Electronic Resource
    Rosenthal fibers producing a granular cell appearance in a glioblastoma (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 100-104 
    Details
    ISSN: 1432-0533
    Keywords: Glioblastoma ; Granular cell tumor ; Intermediate filaments ; Rosenthal fibers ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this report we describe a glioblastoma multiforme with focal granular cell change. In most astroglial tumors with granular cells, the granular appearance is due to the presence of periodic acid-Schiff-positive, membrane-bound cellular debris. In the present case the granular appearance was due to the presence of many small Rosenthal fibers, which were immunoreactive for glial fibrillary acidic protein, vimentin, ubiquitin, and heat-shock protein 27, but not for α-B crystallin. The ultrastructural characteristics are described. These findings demonstrate that granulofilamentous inclusions with the appearance of Rosenthal fibers in glial tumors are a structurally heterogeneous feature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454907
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  • 14
    Electronic Resource
    Electronic Resource
    Intracranial extraskeletal myxoid chondrosarcoma with special reference to lamellar inclusions in the rough endoplasmic reticulum (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 525-528 
    Details
    ISSN: 1432-0533
    Keywords: Extraskeretal myxoid chondrosarcoma ; Ultrastructure ; Collagen type II ; Rough endoplasmic reticulum ; Lamellar inclusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An extraskeletal myxoid chondrosarcoma in the pineal region was studied by light and electron microscopy. The immunohistochemical positivity for S-100 protein, vimentin and collagen type II favored a chondrocytic origin of the tumor. In addition to the well-described ultrastructural features suggestive of a cartilagenous nature, this tumor had unusual lamellar inclusions in the rough endoplasmic reticulum. To the best of our knowledge, this is the first report of these special inclusion bodies in a myxoid chondrosarcoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228591
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  • 15
    Electronic Resource
    Electronic Resource
    Uncommon types of polyglucosan bodies in the human brain: distribution and relation to disease (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 484-490 
    Details
    ISSN: 1432-0533
    Keywords: Polyglucosan bodies ; Bielschowsky bodies ; Adult polyglucosan body disease ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The significance of the development of polyglucosan bodies (PBs) in the CNS is incompletely understood. We present the clinicopathological features of three autopsy cases with numerous PBs other than the common corpora amylacea or Lafora bodies. The first patient had pleomorphic PBs in the neuronal processes of pallidum and substantia nigra which, thus, are consistent with Bielschowsky bodies. Bielschowsky bodies involved also the hypothalamus and tegmentum of midbrain and medulla. The present case was the first not associated with any clinical symptoms. The second patient also had incidental Bielschowsky bodies in the external pallidum, substantia nigra, and pallidothalamic, pallidonigral and nigrostriatal tracts. Additionally, unique clusters of small PBs appeared in the cerebral cortex, putamen, pallidum, and caudate nucleus. Immunostaining suggested that these small clustered PBs were located in the cytoplasm and processes of astrocytes. Ultrastructurally, these clustered PBs were in agreement with previous descriptions of PBs. The third patient had adult polyglucosan body disease. Most PBs in the white matter were corpora amylacea situated in astrocytic processes or axons. In the gray matter, many pleomorphic PBs resembling Bielschowsky bodies occurred in neuronal processes. In the peripheral nervous system, a few PBs were seen in myelinated axons. The following conclusions may be drawn from this study: (1) each type of PBs develops in distinct cell types of the human brain in variable distribution; (2) Bielschowsky bodies may not manifest clinically; (3) PBs other than corpora amylacea or Lafora bodies may be distributed in localized or diffuse patterns; (4) in the localized pattern (patients 1 and 2), PBs occur as Bielschowsky bodies or clustered PBs, and tend to involve certain systems (pallidum, striatum, and substantia nigra); and (5) in the diffuse pattern (patient 3), PBs develop as corpora amylacea and Bielschowsky-like bodies of adult polyglucosan body disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228584
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  • 16
    Electronic Resource
    Electronic Resource
    Ontogenesis of the rabbit pituitary intermediate lobe (1993)
    Springer
    Anatomy and embryology 187 (1993), S. 87-97 
    Details
    ISSN: 1432-0568
    Keywords: Pituitary intermediate lobe ; Rabbit ; Ontogenesis ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The development of the intermediate lobe of the rabbit pituitary was investigated by light and electron microscopy and by using immunocytological techniques. The first immunoreactive melanotrophic cells were detected at the fetal day 17 in the dorsal zone of Rathke's pouch epithelium facing the neural lobe; this coincided ultrastructurally with the appearance in this area of a few cells exhibiting secretory vesicles and granular condensations in the Golgi saccules. The differentiation of the gland probably required an infundibular inductive effect. Secretory cells increased in number following a dorsoventral gradient during the next fetal and neonatal stages until postnatal day 20, the stage at which the intermediate lobe exhibited its definitive organization. The gland innervation occurred during the first days after birth. The advent of these oxytocin- and neurophysin-immunoreactive fibres coincided with an obvious stimulation of the synthetic activity of the melanotrophic cells. The possible neurotrophic effect of these cells on their innervating system remains to be established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00208199
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  • 17
    Electronic Resource
    Electronic Resource
    The ciliary ganglion of the cat: a light and electron microscopic study (1993)
    Springer
    Anatomy and embryology 187 (1993), S. 591-599 
    Details
    ISSN: 1432-0568
    Keywords: Ciliary ganglion ; Quantitative study ; Ultrastructure ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ciliary ganglia of eight healthy adult cats were studied by light and electron microscopy. The ganglion, measuring about 2 mm in length, was consistently found to be attached to the branch from the oculomotor nerve supplying the inferior oblique muscle. The number of neurons varied from 2773 to 3794 after applying Abercrombie's correction. The mean of average somal diameter of the neurons was 36.5 μm (SD = 5.0 μm) and the mean of somal cross-sectional area was 904.2 μm2 (SD = 262.8 μm2). The mean of average nuclear diameter was 13.9 urn (SD = 1.8 μm) and the mean of nuclear cross-sectional area was 142.2 μm2 (SD = 37.1 μm2). The mean of the aspect ratios of the soma and nucleus were 1.2 (SD = 0.1) and 1.1 (SD = 0.1) respectively. The frequency distributions of these parameters were all unimodal. Under the light microscope, the Nissl granules in the neurons were prominent and were distributed peripherally, perinuclearly or randomly in the cytoplasm. Under the electron microscope, the rough endoplasmic reticulum showed a similar pattern of distribution in the cytoplasm. In some neurons, glycogen-like granules were present; these were either distributed randomly throughout the cell, or aligned in single rows in relation to sub-surface cisterns and between the cisterns of smooth and rough endoplasmic reticulum. Most of the dendrites were short protrusions from the cell body; some contained glycogen-like granules. Occasionally, the dendritic protrusions were electron-dense. All the synapses encountered were axodendritic. In most axon terminals, the synaptic vesicles were spherical and measured 30–50 nm in diameter; in some, they were flattened, measuring 50 nm by 20 nm. Some axon terminals containing either spherical or flattened synaptic vesicles also contained large dense-cored vesicles that measured 80–100 nm, while their dense core measured 40–60 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214438
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  • 18
    Electronic Resource
    Electronic Resource
    Morphological analysis of in vitro human hair growth (1993)
    Springer
    Archives of dermatological research 285 (1993), S. 158-164 
    Details
    ISSN: 1432-069X
    Keywords: Hair follicle ; Culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The histological and ultrastructural aspect of normal human hair follicles maintained ex vivo for 12 days was evaluated. Anagen hair follicles, dissected free of contaminating connective tissue, were maintained for up to 12 days in a serum-free medium. Macroscopic observations revealed continued viability for 12 days, at which time some follicles involuted in a manner morphologically similar to catagen. Increased growth of maintained follicles was measured from the abrupt ending of the connective tissue sheath (CTS), as no increase in this component was observed from initiation of culture. In general follicles maintained up to 8 days exhibited little divergence from normal in vivo morphologies including the persistence of functional hair bulb melanocytes — a marker of anagen. After this time melanin granules were present in dermal papilla cells, as occurs during impending involution in vivo. Heterotypic cell contact occurred in the middle to upper follicle between outer root sheath (ORS) keratinocytes and disorganized CTS. Herniation of some ORS cells away from the follicle and the occurrence of loose desmosomal junctions between ORS keratinocytes reflected loss of normal follicular cell interactions in upper follicles maintained after 8 days. Continued follicle growth correlated with the presence of mitotic matrix keratinocytes even at 12 days. After 12 days in culture most follicles involuted displaying apoptotic-like keratinocytes and hair bulb melanocytes and the presence of highly keratinized hair ‘club’ structures. While most follicles exhibited this orderly sequence of events, a few follicles involuted after 24 h with synchronous degeneration of all cells. Two follicles exhibited upregulated cortical cell differentiation at the level of the dermal papilla (DP). Normal cell cytoplasmic constituents were replaced with ribosomes and keratin bundles. This study reveals for the first time the histology and ultrastructure of normal hair follicles in culture for up to 12 days in serum-free medium. Although involuted hair follicles may exhibit some features of catagen, it is possible that the mechanisms involved are entirely different.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01112919
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  • 19
    Electronic Resource
    Electronic Resource
    Mayflies (ephemeroptera), the most “primitive” winged insects, have telotrophic meroistic ovaries (1993)
    Springer
    Development genes and evolution 203 (1993), S. 18-27 
    Details
    ISSN: 1432-041X
    Keywords: Oogenesis ; Germ line cell cluster ; Oocyte determination ; Ultrastructure ; Mayflies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Germ line cell cluster formation in ovarioles of three different stages, each from a different mayfly species, was studied using ultra-thin serial sectioning. In the analysed ovariole of Cloeön sp., only one linear, zigzag germ line cell cluster was found, consisting of sibling cells connected by intercellular bridges which represent remnants of preceding synchronized mitotic cycles followed by incomplete cytokinesis. A polyfusome stretched through all sibling cells. At the tip of the ovariole, cytokinesis occurred without preceding division of nuclei; thus, intercellular bridges were lined up but the remaining cytoplasm between the bridges had no nuclei. The analysed Siphlonurus armatus vitellarium contained five oocytes at different stages of development. Each oocyte in the vitellarium was connected via a nutritive cord to the linear cluster of its sibling cells in the terminal trophic chamber. Each cluster had the same architecture as was found in Cloëon. The 3-dimensional arrangement and distribution of closed intercellular bridges strongly suggest that all five clusters are derived from a single primary clone. The position of oocytes within each cluster is random. However, each oocyte is embraced by follicular or prefollicular cells whilst all other sibling cells are enclosed by somatic inner sheath cells, clearly distinguishable from prefollicular cells. In the analysed ovariole of Ephemerella ignita, two small linear clusters were found in the tropharium beside two single cells, two isolated cytoplasmic bags with intercellular bridges but no nuclei, and some degenerating aggregates. One cluster was still connected to a growing oocyte via a nutritive cord. In all species the nurse cells remained small and no indications of polyploidization were found. We suggest that this ancient and previously unknown telotrophic meroistic ovary has evolved directly from panoistic ancestors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539886
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  • 20
    Electronic Resource
    Electronic Resource
    Ultrastructural expression of cytoplasmic male sterility in sugar beet (Beta vulgaris L.) (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 22-32 
    Details
    ISSN: 1432-2145
    Keywords: Cytoplasmic male sterility ; Ultrastructure ; Mitochondria morphometry ; Beta vulgaris L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of microspore mother cells (MMC) and tapetum in male-fertile and male-sterile anthers of Beta vulgaris L. was compared at the electron microscope level. These studies were complemented by morphometric analyses of mitochondria in both tissues through successive stages of microsporogenesis. The earliest irregularities in the ultrastructure of male-sterile anthers were noted within the tapetum at the tetrad stage. These disturbances were initially expressed by a slight reduction in mitochondrial size and the appearance of concentric configurations of endoplasmic reticulum. As development proceeded, a further decrease in mitochondrial size become more conspicuous and was accompanied by a reduction in ribosome population and a failure of the tapetum to produce Ubisch bodies. This failure to produce Ubisch bodies is reflected in the underdevelopment of sterile microspore exine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227579
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  • 21
    Electronic Resource
    Electronic Resource
    Megaspore development in Selaginella. I. “Wicks”, their presence, ultrastructure, and presumed function (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 98-107 
    Details
    ISSN: 1432-2145
    Keywords: Selaginella ; Megaspore ; Exospore ; Ultrastructure ; Tapetal cells ; Plasmodesmata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Structures have been found in the locular space between the tapetal cells and megaspores in Selaginella argentea and S. kraussiana that enter the megaspore wall and extend to the plasma membrane of the megaspore cytoplasm. We have called these structures “wicks”. Unless special fixation procedures are used wicks are either very poorly preserved or not apparent. Wicks appear to be routes for the transport of materials from the tapetum to developing megaspores. The entry of the wicks into the megaspore wall and their passage throughout the wall implies that the megaspore wall of Selaginella is a three-dimensional mesh-work of inter-connecting spaces. Wicks have several macromolecular-sized subunits, and the results of our histochemical reactions indicated the presence of glycoprotein and/or mucopolysaccharide. X-ray microanalysis of the S. convoluta exospore showed that silicon is present in rod-shaped structures between units of the exospore in mature megaspores. Because of the size and form of the structures between the exospore units we consider that they are remnants of wicks stabilized by silicon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227654
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  • 22
    Electronic Resource
    Electronic Resource
    Chemical agents that inhibit pollen development: effects of the phenyl-cinnoline carboxylates SC-1058 and SC-1271 on the ultrastructure of developing wheat anthers (Triticum aestivum L. var Yecora rojò) (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 108-212 
    Details
    ISSN: 1432-2145
    Keywords: Wheat pollen ; Chemical hybridizing agents ; Male sterility ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Phenylcinnoline carboxylate compounds SC-1058 and SC-1271 cause complete male sterility in wheat when applied at suitable dosages at the pre-meiotic stage of anther development. Anthers from treated and untreated plants were compared using light and electron microscopy from the pre-meiotic stage through the formation of nearly mature pollen. Overall anther development is gradually slowed in treated plants and pollen development is generally arrested in the late prevacuolate or early vacuolate microspore stage, although the first pollen mitosis does sometimes occur. The sporopollenin-containing exine walls are thinner, and show abnormally developed foot and tectum layers with sparse connecting baculi. Microspore cytoplasm degenerates and the cells eventually collapse. At the early, prevacuolate, free microspore stage treated tapetal cells hypertrophy, expanding into the locule. They contain abnormally large vacuoles that appear to form from the fusion of secretory vesicles, and some vacuoles contain electrondense deposits. The sporopollenin-containing orbicular wall and Ubisch bodies are retarded in their development and are structurally deformed. Acetolysis of whole anthers and of thick sections shows that the sporopollen-in-containing structures of treated materials are greatly reduced in thickness and are less rigid than in the control. We conclude that application of these compounds causes interference with the secretory function of tapetal cells which supplies sporopollenin cell-wall polymers to the exine of the microspores and to the tapetal orbicular wall and associated Ubisch bodies. Interference with the tapetal secretion of other nutrients required for microspore development is strongly suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227655
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  • 23
    Electronic Resource
    Electronic Resource
    The embellum: a newly defined structure in the grass ovule (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 191-198 
    Details
    ISSN: 1432-2145
    Keywords: Micropyle ; Transfer cells ; Ultrastructure ; Nucellus ; Poaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Several kinds of outgrowth from the grass ovule are known. Attention is focused here on one outgrowth that occurs within or around the micropyle and is of nucellar origin. Grass species in which it is currently known to occur are listed and examples of variants briefly described. Attention is concentrated upon Pennisetum, where the cell structure is described in detail with a series of electron photomicrographs. The tissue representing an aggregation of these transfer cells is newly named with the term ‘embellum’, and its significance for pollen tube growth is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228648
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  • 24
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in the appendix of the Sauromatum guttatum inflorescence during anthesis (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 153-170 
    Details
    ISSN: 1432-2145
    Keywords: Appendix ; Sauromatum guttatum ; Ultrastructure ; Mitochondrion ; Amyloplast ; Peroxisome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of the epidermal and sub-epidermal cells of the appendix of the Sauromatum guttatum inflorescence reveals developmental changes during anthesis. These changes precede, and probably make possible, heat and odor production. Two days before D-day (the day of heat production and inflorescence-opening) the mitochondria of the epidermis divide; apparent division of the amyloplasts was observed at the same time. The presence of lipid bodies and peroxisomes in the epidermis was clearly evident. On D-day, the epidermis becomes a continuous layer in which the cell walls separating two adjacent cells disappear. At the same time, in the sub-epidermal cells, the mitochondria and the amyloplasts undergo division. The mitochondria become electron-dense, and their DNA is clearly visible. On that day, lipids as well as starch are being depleted. The peroxisomes change in structure every day, from D-2 to D-day. It has also been demonstrated by histochemical techniques that during anthesis the activity of cytochrome c oxidase (3,3-diaminobenzidine as a substrate) decreases whereas the activity of NADH dehydrogenase [tetrazolium salts: nitro-blue tetrazolium chloride (NBT) or neotetrazolium chloride (NT) in the presence of NADH], increases. Oxygen consumption of isolated mitochondria from the D-day appendix was inhibited in the presence of the two tetrazolium salts to a different degree: oxidation of NADH in the presence of NBT was the most sensitive to inhibition, more so than the oxidation of malate and succinate. NT was less effective as an inhibitor in the presence of those three respiratory substrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228644
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  • 25
    Electronic Resource
    Electronic Resource
    Ultrastructure of the cortical epithelium of the rat thymus after in vivo exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (1993)
    Springer
    Archives of toxicology 67 (1993), S. 558-564 
    Details
    ISSN: 1432-0738
    Keywords: 2,3,7,8-Tetrachlorodibenzo-p-dioxin ; TCDD ; Thymus ; Epithelium ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is known for inducing cortical atrophy in the rat thymus. The present study was conducted to provide ultrastructural evidence for the cortical epithelium to be a target for TCDD in vivo. Juvenile male Wistar rats were orally intubated once with either 50 or 150 μg/kg TCDD and killed 4 or 10 days thereafter. Major changes were found in the cortical thymic epithelium. First, a relative shift occurred from “pale” to darker cortical epithelial cell types, as judged by their nuclear and cytoplasmic electron density. This effect was most prominent at 10 days after exposure to 150 μg/kg TCDD. The increased electron density of the cortical epithelium indicates an altered state of cellular differentiation. Secondly, at the 150 μg/kg dose level focal epithelial cell aggregates were seen both at day 4 and day 10 after administration. This aggregation may either be compound induced or represent a secondary event to the collapse of the thymic stroma. Thirdly, increased vacuolation of cortical epithelial cells was apparent. This effect is interpreted as a consequence rather than a cause of thymocyte depletion from the cortex. This study indicates that TCDD exposure affects the cortical epithelium of the rat thymus at a high dose level. Electron microscopy reveals that the differentiation of epithelial cells is altered. In addition, epithelial cell aggregates are formed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01969269
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  • 26
    Electronic Resource
    Electronic Resource
    Identification of Naemacyclus minor hyphae within needle tissues of Pinus sylvestris by immunoelectron microscopy (1993)
    Springer
    Archives of microbiology 160 (1993), S. 265-272 
    Details
    ISSN: 1432-072X
    Keywords: Pinus sylvestris ; Naemacyclus minor ; Immunocytochemical identification ; Ultrastructure ; Plant-fungus interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cultural investigations revealed that Naemacyclus minor, Lophodermium seditiosum and Cenangium ferruginosum were the most frequent colonizers of asymptomatic and symptomatic Pinus sylvestris needles. Since ultrastructural observations showed that morphological features were not suitable to differentiate hyphae of N. minor from hyphae of other isolates, the on-section immunogold labelling technique was applied in combination with an anti-N. minor specific immunoserum. The specificity of this serum was tested against culture hyphae of all isolates. Anti-N. minor specific immunoserum was then used to identify N. minor hyphae in thin sections of green P. sylvestris needles. The infection loci identified were restricted to small tissue areas located in the vicinity of stomata. In the hypodermis, hyphae and endocell-containing hyphae were located within the lumina of host cells but outside the protoplast. The growth of hyphae from cell to cell occurred through pits. The hyphae spreat into the mesophyll intercellularly and continued with the intracellular colonization of moribund and dead mesophyll cells in a later stage of infection. The observed host-parasite interactions at cellular and ultrastructural level are discussed in connection with the still controversial interpretation of the pathogenicity of N. minor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292075
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  • 27
    Electronic Resource
    Electronic Resource
    Ultrastructure of Bacillus pulvifaciens (1993)
    Springer
    Archives of microbiology 159 (1993), S. 114-118 
    Details
    ISSN: 1432-072X
    Keywords: Bacillus pulvifaciens ; Vegetative cells ; Spotes ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ultrastructure of vegetative cells and spores of Bacillus pulvifaciens was studied by CTEM and SEM methods. The vegetative cells are rods, 1.6–4.5 μm long and 0.4–0.6 μm wide, exhibiting typical ultrastructural features of Gram-positive bacteria. The spores are of ellipsoidal shape, 0.6×1.2 μm in size, with six longitudinal ribs reaching up to 130 nm in height. There are satelite ribs on both sides of the longitudinal ribs, reaching up to 20 nm in height. Between the longitudinal ribs, additional transversal ribs were observed in SEM. A special tubular layer, separating the outer and inner coat of the spores, was revealed in ultrathin sections. This layer seems to be a typical ultrastructural feature of Bacillus pulvifaciens spores.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250269
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  • 28
    Electronic Resource
    Electronic Resource
    Development of quasi-multicellular bodies of Treponema denticola (1993)
    Springer
    Archives of microbiology 160 (1993), S. 206-213 
    Details
    ISSN: 1432-072X
    Keywords: Treponema denticola ; Spirochetes ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The formation of quasi-multicellular bodies of Treponema denticola was analysed using different electron microscopical methods. These bacteria could develop four different conformations: (i) normal helical forms; (ii) twisted spirochetes, forming plaits; (iii) twisted spirochetes, forming club-like structures; (iv) spherical bodies in different size. Treponemes within spherical bodies, plaits, and clubs proved to be enclosed in a common outer sheath in which the normal arrangement of their axial flagella was lost. The development of the quasi-multicellular bodies starting from the monoforme spirochetes was elucidated and this morphogenetic process is illustrated by a schematic drawing. Factors which might be involved in the induction of the structures are discussed and their possible pathogenetic importance is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249126
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  • 29
    Electronic Resource
    Electronic Resource
    Avian epidermis contains ATPase- and Ia-positive Langerhans-like cells (1993)
    Springer
    Cell & tissue research 271 (1993), S. 103-106 
    Details
    ISSN: 1432-0878
    Keywords: Skin ; Langerhans cell ; ATPase-histochemistry ; Ultrastructure ; Ia antigen ; Four avian species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The occurrence of cells resembling mammalian Langerhans cells in the avian epidermis was studied by ATPase histochemistry, Ia immunoreactivity and electron microscopy. The existence of MHC class II antigen-(Ia) expressing, ATPase-positive dendritic cells, which are ultrastructurally similar to mammalian Langerhans cells except for the absence of Birbeck granules, was demonstrated. These cells may be a basic component of the immune system of birds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297547
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  • 30
    Electronic Resource
    Electronic Resource
    Development of the diffuse endocrine system in the chicken proventriculus (1993)
    Springer
    Cell & tissue research 271 (1993), S. 107-113 
    Details
    ISSN: 1432-0878
    Keywords: Proventriculus ; Endocrine ontogenesis ; Ultrastructure ; Regulatory peptides ; Immunocytochemistry ; Silver impregnations ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of endocrine cells in the chicken proventriculus has been investigated using light-and electron-microscopy in conjunction with silver and immunocytochemical techniques. The first morphologically detectable endocrine cells were found in 5-day-old embryos by electron microscopy. From the 9th to the 13th day, endocrine cells in contact with the lumen of the organ could be detected both by electron and light (silver impregnation) microscopy. The number of open-type endocrine cells progressively decreased and the number of closed-type increased after this stage. Until the 16th day, endocrine cells were located exclusively in the luminal epithelium, but afterwards they appeared in progressively greater numbers in the compound glands. After hatching, long cytoplasmic processes could be seen in the endocrine cells. Immunoreactivities to regulatory substances appeared in the following order: serotonin (day-14), avian pancreatic polypeptide, glucagon and somatostatin (day-16), bombesin and neurotensin (day-18), and finally, met-enkephalin (day-21).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297548
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  • 31
    Electronic Resource
    Electronic Resource
    Immunocytochemical effects of thyroxine stimulation on the adenohypophysis of dwarf (dw) mutant mice (1993)
    Springer
    Cell & tissue research 274 (1993), S. 579-585 
    Details
    ISSN: 1432-0878
    Keywords: Thyroxine ; Pituitary gland, pars distalis ; Immunocytochemistry ; Ultrastructure ; Mouse (Snell dwarf)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The effects of dietary thyroxine on the immunoreactivity of cells in the pars distalis of the adenohypophysis in dwarf (dw/dw) mice were determined by ultrastructural immunocytochemistry. In nontreated dwarfs only adrenocorticotropic hormone (ACTH) cells and luteinizing hormone (LH) cells showed positive reactions to their respective antibodies, whereas no cells showed immunoreactivity to antibodies to growth hormone (GH), thyroid-stimulating hormone (TSH), or prolactin (Prl). In dwarfs supplemented postnatally with dietary thyroxine for 9 wks, the treatment failed to produced immunoreactive GH, TSH or Prl cells. However, LH cells became more prominent and fully developed, with denser concentrations of immunoreactive particles overlying the secretory granules than occurred in nontreated dwarfs. In thyroxine-treated dwarfs, ACTH cells were similar in ultrastructural features and immunoreactivity to those in nontreated dwarfs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314556
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  • 32
    Electronic Resource
    Electronic Resource
    Biphasic effect of ACTH on growth of rat adrenocortical cells in primary culture (1993)
    Springer
    Cell & tissue research 271 (1993), S. 169-176 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Differentiation ; Tissue culture ; Proliferation ; Ultrastructure ; Steroids ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The proliferation rate of differentiating fetal rat adrenocortical cells was studied in primary culture. In this system, stimulation with ACTH induces differentiation of zona glomerulosa-like cortical cells into zona fasciculata-like cells. Incorporation of bromodeoxyuridine (BrdU) was studied immunocytochemically by use of anti-BrdU antibody, and the proliferation rate was counted from the monolayer colonies of adrenocortical cells. After 21 days of cultivation in the absence of ACTH, the proliferation rate of zona glomerulosa-like cells was 10%. The rate slowly declined to 1% at the age of 100 days during continuous cultivation in the absence of ACTH. Stimulation with ACTH induced a strong inhibition in the proliferation rate (down to 2% during the first 24 h). Treatment with ACTH during the following 48 h led to an extremely intense proliferation of adrenocortical cells at a proliferation rate of 25%. Continuous treatment with ACTH up to 100 days led to a persistent growth of adrenocortical cells, and a proliferation rate over 2-fold higher than in control cells cultivated in the absence of ACTH. Thus, ACTH is the principal growth-promoting factor also in vitro, as has been found in in vivo studies. This growth effect is mediated by a biphasic course; at the beginning of differentiation the effect is inhibitory and is followed by a persistent stimulation of the growth of adrenocortical cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297555
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  • 33
    Electronic Resource
    Electronic Resource
    Ultrastructure and morphometry of testicular Leydig cells and the interstitial components correlated with testosterone in aging rats (1993)
    Springer
    Cell & tissue research 271 (1993), S. 241-255 
    Details
    ISSN: 1432-0878
    Keywords: Leydig cell ; Testis ; Interstitium ; Aging ; Ultrastructure ; Morphometry ; Testosterone ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ultrastructure of testicular interstitium in young and aged adult rats was analysed using morphometric methods, and the plasma testosterone concentration was measured. With increasing age there was an augumentation in the volume of collagen fibrils in the intercellular matrix and in blood vessels. During the aging process (approximately two years) the average volume of the Leydig cell decreased from 1364 μm3 to 637 μm3, but the number of Leydig cells in paired testes increased from 53x106 to 113x106. The absolute volume of smooth surfaced endoplasmic reticulum (SER) per Leydig cell amounted in aged rats to 78% of that in young adult rats. The total amount of SER in paired testes increased by 62% with aging. The present analysis suggests that the ability of SER to maintain peripheral testosterone concentration decreases with age. In young adult rats the absolute volume of peroxisomes per Leydig cell correlated significantly with the concentration of testosterone in blood and also with the absolute volume of SER per Leydig cell. These results combined with ultrastructural observations of close apposition of peroxisomes and SER suggest that peroxisomes have a role in testosterone secretion by Leydig cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318610
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  • 34
    Electronic Resource
    Electronic Resource
    Effect of omeprazole-evoked hypergastrinemia on ultrastructure of enterochromaffin-like cells in the stomach of portacaval-shunted rats (1993)
    Springer
    Cell & tissue research 272 (1993), S. 71-77 
    Details
    ISSN: 1432-0878
    Keywords: Enterochromaffin-like cells ; Hypergastrinemia ; Hypertrophy ; Ultrastructure ; Omeprazole ; Portacaval shunt ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The histamine-producing enterochromaffinlike (ECL) cells in the acid-producing portion of the rat stomach responded to long-standing hypergastrinemia (omeprazole treatment daily for 8–10 weeks) with hypertrophy (and hyperplasia) and with a reduced number of granules and vesicles per unit cytoplasm. There was a reduction in the ratio of electron-dense granules versus vesicles and an increase in the profile diameter of the vesicles. Also, portacaval shunting (PCS) induced changes in the ECL cells, manifesting (i) as an increase in cell number and size, and (ii) as a reduced number of granules and vesicles per unit area. The cytoplasmic granules and vesicle profiles were enlarged, and the ratio of granules versus vesicles was reduced. The combination of PCS and long-standing hypergastrinemia (omeprazole treatment) produced a greatly enhanced ECL cell hypertrophy (and hyperplasia) and a marked reduction in the number of granules. The ratio of granules versus vesicles was markedly reduced while the profile diameters of both granules and vesicles were increased. The relative predominance of very large vesicles (vacuoles) was a prominent feature of the ECL cells in these rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323572
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  • 35
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    Electronic Resource
    Ultrastructure of free nerve endings in respiratory and squamous epithelium on the rat nasal septum (1993)
    Springer
    Cell & tissue research 274 (1993), S. 329-335 
    Details
    ISSN: 1432-0878
    Keywords: Intraepithelial axons ; Free nerve endings ; Nasal mucosa ; Ultrastructure ; Enzyme histochemistry ; Immunocytochemistry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of nerve fibres in the mucosa of the nasal septum of the rat was investigated by means of transmission electron microscopy on transverse and tangential ultrathin sections. Near the basement membrane of respiratory and squamous epithelium, a rather dense network of unmyelinated nerve fibres occurs. Some fibres in the respiratory epithelium ascend between the epithelial cells to reach up to the tight junctions. These fibres appeared in transverse sections to end as hooks or boutons, sometimes with branches. These shapes resemble the free nerve endings that are considered to act as nociceptors. The small intraepithelial fibres, with diameters of about 0.5–1 μm, contain both dense granules and clear vesicles comparable to synaptic vesicles. Substance P was found in dense granules in basal fibres; vasoactive intestinal peptide was absent throughout the epithelium. Acetylcholinesterase activity was observed closely associated with the basal fibres; the apical fibres showed little if any activity. Membrane specializations pointing to an efferent function as well as structures usually associated with mechanoreceptive functions were lacking in both respiratory and squamous epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318751
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  • 36
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    Electronic Resource
    The effects of gonadectomy and testosterone treatment on the Harderian gland of the green frog, Rana esculenta (1993)
    Springer
    Cell & tissue research 273 (1993), S. 201-208 
    Details
    ISSN: 1432-0878
    Keywords: Harderian gland ; Castration ; Testosterone ; Ultrastructure ; Rana esculenta (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The effects of gonadectomy and testosterone treatment on the fine structure of the Harderian gland in male and female green frogs were investigated in different periods of the year. Gonadectomy, carried out when the glands are in the lowest secretory phase (September), causes degenerative changes consisting of a reduction of the rough endoplasmic reticulum, the appearance of autolysosomes, and an increase of nuclear heterochromatin. These effects can be prevented by testosterone treatment. No castration effects are found during the recovery (November) and enhancement (April-May) phases of secretory activity. The results suggest that the frog Harderian gland's sensitivity to testosterone changes during the annual cycle. The androgen dependence of the Harderian gland is correlated with the presence of androgen receptors in both male and female forgs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312821
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    Electronic Resource
    Carbamylcholine-induced morphological changes and spatial dynamics of [Ca2+]c in Harderian glands of guinea pigs: calcium-dependent lipid secretion and contraction of myoepithelial cells (1993)
    Springer
    Cell & tissue research 274 (1993), S. 1-14 
    Details
    ISSN: 1432-0878
    Keywords: Harderian gland ; Ultrastructure ; Fura-2/AM digital imaging ; Calcium ion ; Carbamylcholine ; Myoepithelial cells ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract To determine whether lipid-secreting cells have cytosolic Ca2+ concentration ([Ca2+]c)-related secretory mechanisms, morphological changes and intracellular calcium dynamics of Harderian glands of guinea pigs stimulated by secretagogs were studied by electron microspy and Fura-2/AM digital image analysis. Control glandular cells contained large lipid vacuoles that were bordered by multi-layered membranes. Rough-surfaced endoplasmic reticulum, mitochondria, and smooth-surfaced endoplasmic reticulum may be involved in lipid vacuole formation. Myoepithelial cells surrounded alveoli. After carbamylcholine (CCh, 10−6, 10−5, and 10−3 M) stimulation, lipid materials within the membranous structures were frequently discharged by an exocytotic mechanism. Conspicuous deformation of glandular cells caused by vigorous contraction of myoepithelial cells was observed in isolated alveoli after 10−6M CCh stimulation, whereas the deformaties of glandular tissues perfused via vessels were small even after 10−3M CCh stimulation. Connective tissue between glandular alveoli inhibited unbridled myoepithelial-cell contraction. Fura-2/AM digital imaging analysis revealed that CCh stimulation caused an increase in [Ca2+]c in isolated alveoli. The morphological reactions and changes in [Ca2+]c were prevented by atropine. When extracellular calcium ions were absent, enhanced extrusion of lipid vacuoles, myoepithelial-cell contraction, and a rise in [Ca2+]c after CCh stimulation were not observed. Nicotine and catecholamines had no effect on the secretion or on the dynamics of [Ca2+]c. It can be concluded that acetylcholine elicits exocytosis in glandular cells and contraction of the myoepithelial cells of Harderian glands, accompanied by an increase in [Ca2+]c. The dynamics of [Ca2+]c of the gland alveoli are mostly dependent on extracellular Ca2+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327979
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    Electronic Resource
    Electronic Resource
    Electron-microscopic immunocytochemical study of the endocrine pancreas of sea bass (Dicentrarchus labrax) (1993)
    Springer
    Cell & tissue research 274 (1993), S. 303-314 
    Details
    ISSN: 1432-0878
    Keywords: Endocrine pancreas ; Peptides ; Ultrastructure ; Immunogold labeling ; Sea bass ; Dicentrarchus labrax ; (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Insulin (B)-, somatostatin 25 (SST-25) (D1)-, somatostatin 14 (SST-14) (D2)-, glucagon (A)-, and glucagon PP/PYY/NPY (PP-like)-immunoreactive cells in islets of sea bass (Dicentrarchus labrax) were characterized according to their ultrastructure and immunogold labeling. Cells labeled with antisera to bonito and salmon insulin had numerous secretory granules with a small halo and round core, and a few with wide halo and round or crystalloid core. Gold particles were found throughout the granule in tissue labeled with the former but only in the core in tissue labeled with the latter. D1 cells had large granules with a medium electron-dense content and some with a darker core. D2 had smaller medium or high electron-dense secretory granules than D1 cells, located mainly in cell periphery. Glucagon-immunoreactive cells contained some granules with a polygonal core that was heavily labeled and other granules with a round core with no or hardly any labeling. Glucagon and PP-like immunoreactivity were co-localized in secretory granules, in which the gold particles showed no different distribution with the various antisera used. PYY-immunoreactive granules were also found in nerve endings. All the pancreatic endocrine cell types showing involutive characteristics are found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318749
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  • 39
    Electronic Resource
    Electronic Resource
    Cutaneous and subcutaneous sensory receptors of the hagfish Myxine glutinosa with special respect to the trigeminal system (1993)
    Springer
    Cell & tissue research 274 (1993), S. 353-366 
    Details
    ISSN: 1432-0878
    Keywords: Trigeminal nerve ; Mechanoreceptors ; Skin ; Peripheral autonomic ganglia ; Ultrastructure ; Myxine glutinosa ; Cyclostomata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The integument of the hagfish Myxine glutinosa is described with respect to the topography and the fine structural organization of the dermal and hypodermal nerve fiber plexus. Both nerve fiber plexuses contain small ganglion cells with axodendritic and axosomatic synapscs. The six barbels of the head (4 nasal and 2 oral barbels) are supplied with about 5600 afferent trigeminal nerve fibers via the right and left ophthalmic nerve. With respect to the topography of the sensory nerve terminals in the barbels different types of receptors are termed the external cuff receptor, internal cuff receptor, and perichondrial receptor. Free nerve terminals occur within the epidermal layer, especially at the tip region of the barbels and in the glassy membrane of the dermis. The hypodermal edge receptor organ extends from the ventral nasal barbel to the oral barbel. A mechanoreceptive function of the different receptor types is discussed. The innervation pattern of the barbel is similar to the innervation of the mammalian sinus hair. In this context, the barbel is a highly differentiated receptor organ able to explore the nearest surroundings with high stereognostic perception. The ganglion cells of the skin seem to represent a part of the peripheral autonomic nervous system, which is involved in the control of secretion mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318754
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  • 40
    Electronic Resource
    Electronic Resource
    Morphology and distribution of Müller cells in the retina of the toad Bufo marinus (1993)
    Springer
    Cell & tissue research 272 (1993), S. 183-192 
    Details
    ISSN: 1432-0878
    Keywords: Retina ; Müller cells ; Neuron-specific enolase ; Immunocytochemistry ; Quantitative analysis ; Ultrastructure ; Bufo marinus (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have previously shown that an antibody against neuron-specific enolase (NSE) selectively labels Müller cells (MCs) in the anuran retina (Wilhelm et al. 1992). In the present study the light- and electron-microscopic morphology of MCs and their distribution were described in the retina of the toad, Bufo marinus, using the above antibody. The somata of MCs were located in the proximal part of the inner nuclear layer and were interconnected with each other by their processes. The MCs were uniformly distributed across the retina with an average density of 1500 cells/mm2. Processes of MCs encircled the somata of photoreceptor cells isolating them from each other by glial sheath, except for those of the double cones. Some of the photoreceptor pedicles remained free of glial sheath. Electron-microscopic observations confirmed that MC processes provide an extensive scaffolding across the neural retina. At the outer border of the ganglion cell layer these processes formed a non-continuous sheath. The MC processes traversed through the ganglion cell layer and spread beneath it between the neuronal somata and the underlying optic axons. These processes formed a continuous inner limiting membrane separating the optic fibre layer from the vitreous tissue. Neither astrocytic nor oligodendrocytic elements were found in the optic fibre layer. The significance of the uniform MC distribution and the functional implications of the observed pattern of MC scaffolding are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323585
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  • 41
    Electronic Resource
    Electronic Resource
    Structure of the tertiary component of the myenteric plexus in the guinea-pig small intestine (1993)
    Springer
    Cell & tissue research 272 (1993), S. 509-516 
    Details
    ISSN: 1432-0878
    Keywords: Myenteric plexus ; Enteric nervous system ; Intestine, small ; Ultrastructure ; Innervation, of intestinal muscle ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The tertiary component of the myenteric plexus consists of interlacing fine nerve fibre bundles that run between its principal ganglia and connecting nerve strands. It was revealed by zinc iodide-osmium impregnation and substance P immunohistochemistry at the light-microscope level. The plexus was situated against the inner face of the longitudinal muscle and was present along the length of the small intestine at a density that did not vary markedly from proximal to distal. Nerve bundles did not appear to be present in the longitudinal muscle as judged by light microscopy, although numberous fibre bundles were encountered within the circular muscle layer. At the ultrastructural level, nerve fibre bundles of the tertiary plexus were found in grooves formed by the innermost layer of longitudinal smooth muscle cells. In the distal parts of the small intestine, some of these nerve fibre bundles occasionally penetrated the longitudinal muscle coat. Vesiculated profiles in nerve fibre bundles of the tertiary plexus contained variable proportions of small clear and large granular vesicles; they often approached to within 50–200 nm of the longitudinal smooth muscle cells. Fibroblast-like cells lay between strands of the tertiary plexus and the circular muscle but were never intercalated between nerve fibre varicosities and the longitudinal muscle. These anatomical relationships are consistent with the tertiary plexus being the major site of neurotransmission to the longitudinal muscle of the guinea-pig small intestine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318557
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  • 42
    Electronic Resource
    Electronic Resource
    Effects of elastase on contractility and morphology of elastic tissue in isolated guinea pig papillary muscles (1993)
    Springer
    Heart and vessels 8 (1993), S. 71-78 
    Details
    ISSN: 1615-2573
    Keywords: Elastase ; Elastin ; Contractile tension ; Guinea pig papillary muscle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Elastase (ELA) is an enzyme catalyzing the digestion of elastin, an essential constituent of elastic fibers. Using isolated guinea pig papillary muscles, we examined the effect of ELA (3 × 10−7 −3 × 10−4 g/ml) on resting tension (RT) and twitch tension (TT). The effects of ELA on elastic fibers located in the subendocardium were examined histologically. A relatively high concentration of ELA (3 × 10−4 g/ml) increased TT transiently, with progressive decreases in RT. In contrast, a relatively low concentration (3 × 10−5 g/ml) decreased both TT and RT straightforwardly. Much lower concentrations (3 × 10−6 −3 × 10−7 g/ml) did not reveal significant effects. The ELA-induced increases in TT were unaffected in the presence of atenolol (10−5 g/ml), ouabain (10−7M) or ryanodine (10−6M). ELA did not increase the maximum rate of rise of slow action potentials recorded using standard microelectrodes.ELA (3 × 10−5 g/ml) decreased the maximum TT obtained at optimal RT or Lmax, and decreased the slope of the ascending and descending limbs of the TT-RT relation curve (Frank-Starling's). Electronmicroscopic findings revealed that subendocardial elastin was mostly digested at ELA concentrations of 3 × 10−5 −3 × 10−4 g/ml. These findings suggest that the decrease of RT by ELA may be, at least in part, caused by a decomposition of the elastic fibers. On the other hand, the increase of TT by ELA could not be attributed to a release of endogenous catecholamine, an inhibition of Na+, K+-pump, a release of Ca2+ from sarcoplasmic reticulum, or an increase of slow inward current.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01744386
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    Electronic Resource
    Electronic Resource
    Sub-cellular distribution of nitrogen compounds inAzolla andAnabaena by ESI and EELS analysis (1993)
    Springer
    Protoplasma 173 (1993), S. 158-169 
    Details
    ISSN: 1615-6102
    Keywords: Azolla-Anabaena symbiosis ; Ultrastructure ; Nitrogen distribution ; Electron spectroscopic imaging ; Electron energy loss spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The sub-cellular localization of some nitrogen compounds within the leaf cavities ofAzolla filiculoides Lam. was obtained by means of electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS). The analyses were performed on ultrathin unstained sections of differentAzolla leaf cavities which contain epidermal hairs,Anabaena azollae Strasb. and bacteria. Net nitrogen distributions were visualized by image analysis, and nitrogen peaks were evidenced in spectra recorded in the same areas. Different distributions of nitrogen compounds were observed within the leaf cavities along the stem, in particular inside the epidermal hairs ofAzolla and the vegetative cells and heterocysts ofA. azollae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01379004
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  • 44
    Electronic Resource
    Electronic Resource
    Effect of cytochalasin A on actin distribution in the fission yeastSchizosaccharomyces pombe studied by fluorescent and electron microscopy (1993)
    Springer
    Protoplasma 176 (1993), S. 24-32 
    Details
    ISSN: 1615-6102
    Keywords: Actin ; Cytoskeleton ; Schizosaccharomyces pombe ; Freeze substitution ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Actin distribution and ultrastructure of the fission yeastSchizosaccharomyces pombe treated with cytochalasin A (CA) were investigated by fluorescence microscopy using rhodamine-conjugated phalloidin (rh-ph) and freeze substitution electron microscopy. Among the cytochalasins tested, CA was most effective and at 5 μg/ ml inhibited the appearance of the actin ring at the cell equator at the stage prior to septum formation and the accumulation of actin dots at the septum-forming site both in wild-type cells and the mutantcdc 11, which is defective in septum formation at restrictive temperature. Freeze substitution electron microscopy of CA-treated cells revealed the displacement and morphological alteration of cytoplasmic vesicles and dictyosomes within 30 min and the appearance of dense bodies in the cytoplasm. A sub-population of cytoplasmic vesicles and dictyosomes were insensitive to CA and maintained their original structure. An electron less dense layer containing filamentous material was noted beneath the plasma membrane and thought to be the area of heavy actin patches stained with rh-ph at the cells ends. These results suggest that CA disrupted an actin network that normally maintains the organization of the secretory pathway involving dictyosomes and vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01378936
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  • 45
    Electronic Resource
    Electronic Resource
    Membrane coatings on the generative cell surface of freeze-substituted monocotyledon pollen (1993)
    Springer
    Protoplasma 176 (1993), S. 84-88 
    Details
    ISSN: 1615-6102
    Keywords: Pollen (high-pressure freezing) ; Freeze-substitution ; Generative cell ; Plasma membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary High-pressure freezing/freeze-substitution/TEM were employed for studying plasma membrane coatings in mature pollen grains. Data are presented on 6 species belonging to 4 not closely related orders. Two sorts of coatings were observed at the cytoplasmic face of the vegetative plasma membrane bordering the generative cell: (i) A dense, uniform layer with an average thickness of 10 nm (“fluffy coating”). (ii) “Strip-shaped projections” protruding rectangularly into the vegetative cytoplasm. They are 25 to 35 nm in height and set at a constant distance of about 30 nm from each other. Their maximum length, estimated from grazing sections, is about 400 nm. This is the first description of periodically arranged plasma membrane protrusions in freeze-substituted plant cells. Both kinds of membrane coatings are species-and age-dependent features. Especially “strip-shaped projections” are frequently intimately associated with polymorphic endoplasmic reticulum surrounding the generative cell, a hitherto unreported pattern. It is presumed that “strip-shaped projections” are similar to, or even identical with, “ordered ridges” observed in freeze-fracturedPhoenix dactylifera pollen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01378942
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  • 46
    Electronic Resource
    Electronic Resource
    The generative cell and its close association with the endoplasmic reticulum of the vegetative cell in pollen ofCyrtandra pendula (Gesneriaceae) (1993)
    Springer
    Protoplasma 177 (1993), S. 73-81 
    Details
    ISSN: 1615-6102
    Keywords: Cyrtandra pendula ; Generative cell ; Endoplasmic reticulum ; Pollen grain ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of the generative cell (GC) was examined in the bicellular pollen ofCyrtandra pendula. The essential stages are: (1) GC attached to the inline, (2) GC detached and spheroidal in shape, (3) GC mature and elongated. Cisternae of the endoplasmic reticulum (ER) of the vegetative cell are in close contact with the GC at all stages of development. In stages (1) and (2) the entire, slightly undulated surface of the GC is surrounded by tightly appressed, single ER tubules or short stacks. In mature pollen grains (stage 3) the shape of the GC as well as the arrangement of the surrounding ER changes conspicuously. The GC is now spindleshaped and its surface is wrinkled. An ER tubule is present in each invagination. These ER tubules form a cage-like framework around the GC. In the cytoplasm of the generative cell, 6 to 7 microtubular bundles with longitudinal orientation can be observed. They seem to be responsible for maintaining the elongate shape of the GC. During all stages of development vegetative ER cisternae are the only elements intimately associated with the GC wall. This feature indicates that the ER may contribute to the formation of the undulated outer shape of the GC. Also discussed is the possibility that energy-carrying substances are conveyed into the GC through the channels of ER.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01403401
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  • 47
    Electronic Resource
    Electronic Resource
    Microspore development inBrassica napus and the effect of high temperature on division in vivo and in vitro (1993)
    Springer
    Protoplasma 172 (1993), S. 154-165 
    Details
    ISSN: 1615-6102
    Keywords: Brassica napus ; Cell division ; High temperature ; Microspore ; Embryogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Brassica napus cv. Topas microspores isolated and cultured near the first pollen mitosis and subjected to a heat treatment develop into haploid embryos at a frequency of about 20%. In order to obtain a greater understanding of the induction process and embryogenesis, transmission electron microscopy was used to study the development of pollen from the mid-uninucleate to the bicellular microspore stage. The effect of 24 h of high temperature (32.5 °C) on microspore development was examined by heat treating microspore cultures or entire plants. Mid-uninucleate microspores contained small vacuoles. Late-uninucleate vacuolate microspores contained a large vacuole. The large vacuole of the vacuolate stage was fragmented into numerous small vacuoles in the late-uninucleate stage. The late-uninucleate stage contained an increased number of ribosomes, a pollen coat covering the exine and a laterally positioned nucleus. Prior to the first pollen mitosis the nucleus of the lateuninucleate microspore appeared to be appressed to the plasma membrane; numerous perinuclear microtubules were observed. Microspores developing into pollen divided asymmetrically to form a large vegetative cell with amyloplasts and a small generative cell without plastids. The cells were separated by a lens-shaped cell wall which later diminished. At the late-bicellular stage the generative cell was observed within the vegetative cell. Starch and lipid reserves were present in the vegetative cell and the rough endoplasmic reticulum and Golgi were abundant. The microspore isolation procedure removed the pollen coat, but did not redistribute or alter the morphology of the organelles. Microspores cultured at 25 °C for 24 h resembled late-bicellular microspores except more starch and a thicker intine were present. A more equal division of microspores occurred during the 24 h heat treatment (32.5 °C) of the entire plant or of cultures. A planar wall separated the cells of the bicellular microspores. Both daughter cells contained plastids and the nuclei were of similar size. Cultured embryogenie microspores contained electron-dense deposits at the plasma membrane/cell wall interface, vesicle-like structures in the cell walls and organelle-free regions in the cytoplasm. The results are related to embryogenesis and a possible mechanism of induction is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01379373
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  • 48
    Electronic Resource
    Electronic Resource
    Early events in division of the generative cell ofOrnithogalum virens (1993)
    Springer
    Protoplasma 172 (1993), S. 77-83 
    Details
    ISSN: 1615-6102
    Keywords: Ornithogalum virens ; Generative cell ; Mitosis ; Pollen ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ornithogalum virens is a bicellular pollen species. In mature pollen, the generative nucleus is at advanced prophase. Mitosis of the generative cell is resumed just after pollen rehydration and prometaphase occurs within 10 min of germination. Prometaphase is manifested by nuclear envelope breakdown and the appearance of spindle microtubules in the nucleoplasm region. At this stage the number of cytoplasmic microtubules located in the generative cell periphery appears to decrease. Endoplasmic reticulum-like cisternae originating from the nuclear envelope tend to be spaced around the chromosomes, outside the area of the forming mitotic spindle. Some also begin to penetrate the spindle area. The results are discussed in terms of the generative cell cycle in bicellular pollen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01379365
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  • 49
    Electronic Resource
    Electronic Resource
    Ultrastructure of transfer cells in spontaneous nodules of alfalfa (Medicago sativa) (1993)
    Springer
    Protoplasma 172 (1993), S. 64-76 
    Details
    ISSN: 1615-6102
    Keywords: Alfalfa ; Spontaneous nodules ; Development ; Rhizobium meliloti ; Transfer cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Spontaneous nodules were formed on the primary roots of alfalfa plants in the absence ofRhizobium. Histologically, these white single-to-multilobed structures showed nodule meristems, cortex, endodermis, central zone, and vascular strands. Nodules were devoid of bacteria and infection threads. Instead, the larger cells were completely filled with many starch grains while smaller cells had very few or none. Xylem parenchyma and phloem companion cells exhibited long, filiform and branched wall ingrowths. The characteristic features of both types of transfer cells were polarity of wall ingrowths, high cytoplasmic density, numerous mitochondria, abundant ribosomes, well-developed nucleus and nucleolus, and vesicles originated from rough endoplasmic reticulum. These results were compared with normal nodules induced byRhizobium. Our results suggest that xylem parenchyma and phloem companion transfer cells are active and probably involved in the short distance transport of solutes in and out of spontaneous nodules. Since younger nodules showed short, papillate, and unbranched wall ingrowths, and older tissue showed elongated, filiform and branched wall ingrowths, the development of wall ingrowths seemed to be gradual rather then abrupt. The occurrence of both type-A and -B wall ingrowths suggests that phloem companion transfer cells may be active in loading and unloading of sieve elements. Since there were no symbiotic bacteria and thus no fixed nitrogen, it is tempting to speculate that xylem parenchyma transfer cells may be re-transporting accumulated carbon from starch grains to the rest of the plant body by loading xylem vessels. Fusion of ER-originated vesicles with wall ingrowth membrane indicated the involvement of ER in the membrane formation for elongating wall ingrowths. Since transfer cells were a characteristic feature of both spontaneous andRhizobium-induced nodules, their occurrence and development is controlled by the genetic make-up of alfalfa plant and not by a physiological source or sink emanating from symbiotic bacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01379364
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  • 50
    Electronic Resource
    Electronic Resource
    The effects of abscisic acid on the maturation ofBrassica napus somatic embryos (1993)
    Springer
    Protoplasma 174 (1993), S. 147-157 
    Details
    ISSN: 1615-6102
    Keywords: Abscisic acid ; Brassica napus ; Embryo maturation ; Reserves metabolism ; Somatic embryos ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A comparison of embryos, cultured for increasing periods of time with and without abscisic acid (ABA), was undertaken to investigate, at the ultrastructural level, the influence of this growth regulator on the maturation of rapeseed (Brassica napus) somatic embryos. In the absence of ABA, the embryos germinated precociously while lipid bodies (LB), which were not numerous, soon degraded, as revealed by a depletion process associated with the appearance of morphologically mature glyoxysomes and an increase in the number of mitochondria. Moreover, a lack of protein bodies indicated that storage protein accumulation was not initiated under these conditions. On the contrary, the addition of ABA (10 μM) induced marked modification of embryo metabolism. Indeed, ABA completely prevented precocious embryo germination and inhibited lipid reserve catabolism. Moreover, the formation of small vacuoles and proliferation of rough endoplasmic reticulum in their vicinity suggested the onset of storage protein accumulation. After 15 days in the presence of ABA, the embryos contained abundant lipid and protein bodies. Nevertheless, these somatic embryos were not exactly the same as their mature zygotic counterparts since differences were found in chloroplasts, amyloplasts, and nuclear structures. These observations suggest that additional factors might be required to obtain fully mature somatic embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01379047
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  • 51
    Electronic Resource
    Electronic Resource
    Skeletal muscle damage during tourniquet-induced ischaemia (1993)
    Springer
    European journal of applied physiology 67 (1993), S. 342-347 
    Details
    ISSN: 1439-6327
    Keywords: Tourniquet ; Ischaemia ; Skeletal muscle ; Damage ; Lysosomes ; Oedema ; Capillaries ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscle biopsies from the vastus lateralis muscle of patients who had undergone anterior cruciate ligament surgery under conditions of tourniquet-induced ischaemia were examined under the electron microscope at different periods of time up to 90 min of ischaemia. The severity of the alterations in ultrastructure appeared to depend on the period of ischaemia. The pathological changes consisted of accumulation of lysosomes, persistent intrafibre oedema, and some extracellular oedema. Signs of fibre necrosis were found after 90 min of ischaemia. Capillary ultrastructure was only altered with regard to some swelling of the endothelium and marked thickening of the basement membrane. It was concluded that skeletal muscle could be severely affected even during relatively short periods of ischaemia, which might facilitate the development of muscle atrophy during immobilization after orthopaedic surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00357633
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  • 52
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    Electronic Resource
    Ultrastructural changes in salivary glands after different adrenergic and cholinergic stimulations (1993)
    Springer
    European archives of oto-rhino-laryngology and head & neck 250 (1993), S. 33-39 
    Details
    ISSN: 1434-4726
    Keywords: Rat salivary gland ; Ultrastructure ; Adrenergic stimulation ; Cholinergic stimulation ; Sialagogues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have compared four different sialagogues and their degranulating effect on serous and mucous cells, and their long-term effects. From this and earlier experiments, even within the groups of α- and β-adrenergic agents used, the effects varied on the serous and mucous cells. Previous studies have shown that cyclocytidine effectively degranulates serous cells without signs of cellular damage, while carbachol predominantly affects mucous acinar cells but gives early rise to permanent gland damage. Noradrenaline affects both serous and mucous cells, predominantly affecting serous cells with initial mitochondrial damage. Clonidine partially depletes both serous and mucous cells of their granules, producing permanent cellular damage. One month after a single injection of cyclocytidine the early findings described had disappeared. Carbachol showed permanent damage to salivary gland parenchyma, and both noradrenaline and clonidine demonstrated a long-term effect on acinar mucinous cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176946
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    Variations in the distribution of motor end-plates in the avian pectoralis (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 65-88 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Most avian muscles consist of serially arranged, overlapping fibers that do not extend the length of the muscle. This condition appears to be plesiomorphic with respect to diapsid reptiles. The presence of this serialfibered architecture is evidenced by bands of stained motor end-plates (meps) perpendicular to the columns of fibers and dividing each column into a series of “segments.” The avian pectoralis was chosen for a study of variation in the distribution of meps within a single muscle. We report the interspecific variation for 158 specimens in 63 species. We also use additional specimens to examine intraspecific variation.Setting aside hummingbirds, which have an unique and clearly derived condition, the number of mep bands along a column of fibers near the shoulder falls within a remarkably small range. The number of segments is not obviously related to phylogenetic relatedness or to any characteristic of flight or ecology and is only slightly related to size. The largest specimens do average more segments per column, but there are no trends among small to medium-sized species, suggesting that there is an upper limit to fiber length. However, the shape of the sternum and pattern of connective tissue in the pectoralis alleviate the need for additional fibers in many large birds. These findings suggest that the architecture of the avian pectoralis is subject to some as yet unexplained selection that stabilizes the number of myofibers and/or motor neurons. The findings provide few clues as to whether the significant factors are phylogenetic, functional, ontogenetic, or some combination of these. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150105
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993) 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052150201
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    Morphological and functional bases of durophagy in the queen triggerfish, Balistes vetula (Pisces, tetraodontiformes) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 101-118 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tetraodontiform fishes are characterized by jaws specialized for powerful biting and a diet dominated by hard-shelled prey. Strong biting by the oral jaws is an unusual feature among teleosts. We present a functional morphological analysis of the feeding mechanism of a representative tetraodontiform, Balistes vetula. As is typical for the order, long, sharp, strong teeth are mounted on the short, robust jaw bones of B. vetula. The neurocranium and suspensorium are enlarged and strengthened to serve as sites of attachment for the greatly hypertrophied adductor mandibulae muscles. Electromyographic recordings made from 11 cranial muscles during feeding revealed four distinct behaviors in the feeding repertoire of B. vetula. Suction is used effectively to capture soft prey and is associated with a motor pattern similar to that reported for many other teleosts. However, when feeding on hard prey, B. vetula directly bit the prey, exhibiting a motor pattern very different from that of suction feeding. During buccal manipulation, repeated cycles of jaw opening and closing (biting) were coupled with rapid movement of the prey in and out of the mouth. Muscle activity during buccal manipulation was similar to that seen during bite-captures. A blowing behavior was periodically employed during prey handling, as prey were forcefully “spit out” from the mouth, either to reposition them or to separate unwanted material from flesh. The motor pattern used during blowing was distinct from similar behaviors described for other fishes, indicating that this behaviors may be unique to tetraodontiforms. Thus B. vetula combines primitive behaviors and motor patterns (suction feeding and buccal manipulation) with specialized morphology (strong teeth, robust jaws, and hypertrophied adductor muscles) and a novel behavior (blowing) to exploit armored prey such as sea urchins molluscs, and crabs. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150202
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    Early development of the chick embryo (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 165-182 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the early chick embryo was investigated, using scanning (SEM) and transmission electron microscopy (TEM). Eggs were obtained from the shell gland by injecting hens intravenously with a synthetic prostaglandin or arginine vasopressin. Embryos were examined during late cleavage (stages IV-VI, Eyal-Giladi and Kochav, '76), formation of the area pellucida (stages VII-XI), and formation of the hypoblast (stages X-XIV). SEM highlighted the reduction in cell number at the underside of the embryo during formation of the area pellucida although it became apparent that the thickness of the embryo is not reduced to a single layer of cells at stage X. In addition, blastomeres at the perimeter of embryos (stages V-VI) project filopodial extensions onto a smooth membrane that separates the sub-embryonic cavity from the yolk. During hypoblast formation, epiblast cells generate stellate projections at their basal aspect, thus providing a meshwork for the advancing secondary hypoblast cells. By stage XII the epiblast was one cell thick and reminiscent of a columnar epithelium when viewed transversely. Cells of the deep portion of the posterior marginal zone were distinguished morphologically in the stage XII embryo by their many cell surface projections and ruffled appearance. Blastomeres at the perimeter of stage V-VI embryos projected filopodial extensions onto a smooth membrane which separates the sub-embryonic cavity from the yolk. This membrane is presumed to be confluent with the cytolemma. Evidence is presented demonstrating the presence of intracellular membrane-bound droplets which are hypothesised to contain sub-embryonic fluid. © 1993 Wiley-Liss, Inc.
    Additional Material: 41 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150205
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    Land crabs with smooth lungs: Grapsidae, Gecarcinidae, and Sundathelphusidae ultrastructure and vasculature (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 245-260 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The highly terrestrial grapsids and gecarcinids and the amphibious sundathelphusids all have large, expanded branchial chambers. The lining of the branchial chambers is smooth and well vascularized, and it functions as a lung. The respiratory membrane and the cuticle lining the lung are extremely thin (200-350 nm). The blood vessels within the lung are formed from connective tissue cells supported by collagen fibres and lined by a basal lamina. The major vessels in the lung are embedded deep in the branchiostegite and lie just beneath the thick outer carapace. These vessels branch towards the respiratory membrane, where they eventually lose their connective tissue coverings to form thin, flattened lacunae directly below the respiratory epithelium. The lacunae (exchange sites) are bordered by specialized connective tissue cells, which either bear microvilli on their apical surface (fimbriated cells) or are very smooth. The respiratory circulation in the lung is very complex, with two portal systems present between the afferent and efferent systems, producing a total of three lacunal exchange beds. Portal systems increase the surface area available for gas exchange. The major distributing vessel in the lung is the branchiostegal vein, which runs along the inner margin of the branchiostegite. The main venous supplies come anteriorly from the infraorbital and ventral sinuses and posteriorly from the procardial sinus. The main collecting vessel is the pulmonary vein, which arises anteriorly and which runs around the ventral perimeter of the branchiostegite before emptying into the pericardial sinus. © 1993 Wiley-Liss, Inc.
    Additional Material: 25 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150306
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    Naturally occurring diblastodermic eggs in the annual fish Cynolebias: Implications for developmental regulation and determination (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 301-312 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Annual fish development differs from that of other teleosts because a phase of blastomere dispersion-reaggregation spatially and temporally separates epiboly from embryogenesis. The fate of dispersed blastomeres was assessed in diblastodermic eggs of the annual fishes Cynolebias whitei and C. nigripinnis. In typical teleosts, blastomere determination and the events of primary embryonic induction occur prior to or during epiboly, so diblastodermic eggs produce partially or completely duplicated embryos. In the diblastodermic eggs of Cynolebias, the two blastoderms are completely separate from the one cell stage to the high blastula. Blastoderm fusion begins during midepiboly. By the end of epiboly, blastoderm fusion has been completed, and the deep, embryo-forming blastomeres of both blastoderms have completely dispersed and intermingled to form a single cell population. A typical annual fish dispersed blastomere phase ensues. Blastomeres reaggregate into a single mass, in which one embryo develops. When hatched, the young fish have no obvious structural or functional abnormalities. We suggest that the dispersed blastomeres of annual fish eggs are equivalent and that induction or determination takes place within the reaggregate. Alternatively, dispersed cells are partially determined but highly regulative, so that, when two populations fuse, the cells sort out according to tissue type and form a single embryo. In either instance, the formation of a single, normal embryo seems to corroborate the hypothesis that the dispersed cell phase of annual fishes is an adaptation that prevents environmentally induced developmental defects. © 1993 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150309
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    Morphological analysis of tendinous structure in the American alligator jaw muscles (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 171-181 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the American alligator, the jaw muscles show seven bundles of tendinous structure: cranial adductor tendon, mandibular adductor tendon, lamina anterior inferior, trap-shaped lamina lateralis, lamina intramandibularis, lamina posterior, and depressor mandibular tendon (originating from the musculus depressor mandibulae, m. pseudotemporalis, m. adductor mandibulae posterior, m. adductor mandibulae externus, m. intramandibularis, m. pterygoideus anterior, and m. pterygoideus posterior). These tendinous structures are composed of many collagen fibrils and elastic fibers; however, the distributions and sizes of the fibers in these tendinous components differ in comparison with those of other masticatory muscles. The differences of these properties reflect the kinetic forces or the stretch applied to each tendon by the muscle during jaw movements in spite of the simple tendon-muscle junctions. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170206
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    The horizontal septum: Mechanisms of force transfer in locomotion of scombrid fishes (Scombridae, Perciformes) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 183-204 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe the complex shapes of myomeres and myosepta in the mackerels and tunas (Scombridae: Teleostei), and we reveal the orientation of two major systems of collagen fibers in myosepta and horizontal septa with respect to points of attachment to skeleton and skin. Our goal is to identify the likely pathways of the transmission of muscle forces during locomotion. Our primary conclusions are (1) that the collagen fibers of myosepta, horizontal septa, and skin are the organs that transfer locomotor forces from the contraction of myomeres to the backbone and caudal fin during locomotion, and (2) that locomotor muscle pulls against a three-dimensional structure of tendons, septa, and skin that is kept in tension by the radial expansion of the contracting muscle. The main horizontal septum is formed by the convergence of myosepta and is likely to be the major transmitter of muscle force to the axial skeleton. The geometry of the myomeres, the position of red muscle, and particularly the geometric conformation of crossed-fiber arrays of collagen in the main horizontal septum suggest specific mechanisms for the transfer of muscle force to the backbone among scombrid fishes. Morphometrics and the construction of physical models help us to identify musculoskeletal mechanisms of locomotion, and we present two quantitative models of locomotor mechanics in fishes. © 1993 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170207
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    Oviductal morphology and eggshell formation in the lizard, Sceloporus woodi (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 205-217 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Despite a great deal of work in recent years on the structure of reptilian eggshells, few studies have examined the structure and regulation of the female reproductive tract in the formation of eggshell components, and none have examined the entire process from ovulation to oviposition. In this study, we examined oviductal structure in the oviparous lizard, Sceloporus woodi, followed changes in oviductal structure during gravidity, and determined uterine function in the formation of eggshell components. The endometrial glands of the uterus produce the proteinaceous fibers of the eggshell membrane mainly during the first 24 hours following ovulation, and the fibers are secreted intact and subsequently wrapped around the in utero eggs. Eggshell fibers of different thicknesses are layered around each egg, ranging from an inner layer of thick fibers that gradually become thinner medially and finally forms an outer layer of densely packed particulate matter. These changes in the fibrous layer are reflected by the thickness and length of fibers released from the endometrial glands. Calcium deposition occurs from 3 days following ovulation through day 14 (oviposition) and is accompanied by cellular changes in the luminal epithelium suggestive of secretory activity. Deposition of the eggshell components within the uterus occurs on all eggs simultaneously, rather than sequentially. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170208
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    Morphogenesis and ductal development of the prostatic complex of the guinea pig (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 219-227 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphogenesis of glandular architecture of the three lobes of prostate gland of the guinea pig, lateral, dorsal, and coagulating gland was studied from 35 days gestation to 90 postnatal days. Epithelial ductal tubules of various lobes of the gland were microdissected after treatment by collagenase and displayed two dimensionally. The number of ductal tips was counted, and the volume of the ductal network was quantified using a graphic tablet. The results show that the growth and ductal morphogenesis fall into two phases: prenatal and postnatal. The first outgrowth of prostatic buds begins at 35 days gestation (gestational length is 65 days). Ductal growth and branching continues over the next 15-20 days and by 55 days gestation, approximately 60%, 79%, and 71% of the adult number of ductal tips of the lateral and dorsal lobes and coagulating gland respectively, are formed. The figures increase to 89%, 84%, and 106%, respectively, by birth. There is little increase in number of ductal tips thereafter. Postnatal growth is accomplished mainly by elongation of existing ductal network with a little additional branching but with an increase in size (volume) of the tubules. Canalization of ductal tubules occurs prenatally in all lobes but postnatal functional cytodifferentiation takes a slightly different pace among them. Ductal morphogenesis of the guinea pig prostate gland differs significantly in time-course from that of the mouse in which ductal development occurs mainly postnatally. © 1993 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170209
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993) 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052170301
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    Structure of comblike teeth of the ayu sweetfish, Plecoglossus altivelis (Teleostei: Isospondyli): I. Denticles and tooth attachment (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 229-238 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure and tooth attachment of the comblike teeth and denticles of the ayu sweetfish, Plecoglossus altivelis, were examined by light and scanning electron microscopy. The denticle is composed of a spoonlike crown with a spine pointed anteriorly, a triangular plate in the cervical region, and a root that curves laterally and tapers off to a point. The root apex is fused with a long thin pedicle that turns abruptly anteriad toward the jaw bone. Planes of the spine, the spoonlike crown, the triangle plate and the root of the denticle are varied, and the denticle is twisted in the region of the triangle plane.The superficial layer of the dentine is homogeneously calcified and is considered to be enameloid, because some of the inner dentinal epithelial cells in the tooth germ are columnar and possess cellular processes at their apical ends. The dentine is fibrous and fine dentinal tubules are visible in dentine treated with sodium hydroxide and observed by scanning electron microscopy. The upper half of the root is surrounded by a dense layer of collagen fibers running parallel to the tooth axis, and the lower half is encompassed by interlaced collagen fibers. The lower part of the root is open on its lingual side. The pedicle is a long rod which is homogeneously calcified and enmeshed by interlaced collagen fibers, and it curves mediad as it nears the jaw bone. The pedicles are interposed between a layer of gelatinous connective tissue and the jaw bone and terminate on the periosteum. Comparative aspects of ayu tooth morphology are discussed. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052170210
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    Effects of juvenile hormone analogues upon soldier differentiation in the termite Reticulitermes santonensis (Rhinotermitidae, Heterotermitinae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 239-261 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Under the influence of juvenile hormone analogues (JHAs), termite workers are induced to differentiate into soldiers. In Reticulitermes santonensis, such induced differentiation is often incomplete, resulting in intercaste production. The morphology of the structures most affected during differentiation was analyzed descriptively and biometrically in normal workers, presoldiers, and soldiers, and in experimental intercastes. We observed that intercastes form a morphological and biometrical continuum between workers and presoldiers (presoldier intercastes), and between presoldiers and soldiers (soldier intercastes). We also compared the biochemistry of the normal individuals and of the intercastes; in contrast to workers, the intercastes possess a frontal gland secretion which differs from those of the presoldiers and soldiers. Besides intercaste characterization, we consider the mode of action of JHAs in termite differentiation. © 1993 Wiley-Liss, Inc.
    Additional Material: 41 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170211
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    Microtopography of Nippostrongylus brasiliensis (Nematoda: Heligmosomatidae): Free-living larval stages (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 263-271 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtopographic features of the various growth stages of the three free-living larval stages of the rat hookworm Nippostrongylus brasiliensis (Nematoda) were surveyed by scanning electron microscopy. These worms have a rounded anterior end and an elongated tail. Cuticular annulations were observed along the body, which also bore two ribbon-like lateral alae. Two rings of six lip-like lappets were observed around the triradiate oral opening in all larval stages. The cephalic space contained two lateral amphidial pits. The excretory pore in the third anterior part was observed in a ventral view of the larvae. No deirids were observed. The anus with a crescent-shape opening was located posteriorly. Phasmidial apertures, only observed in the third-stage larvae, opened on the lateral alae in the tail region. © 1993 Wiley-Liss, Inc.
    Additional Material: 28 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170302
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    Two different patterns of interrupted spermatogenesis in winter diapause and summer quiescence in the desert beetle, Omorgus freyi (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 347-358 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatogenesis discontinues during both adult reproductive diapause and quiescence in the flightless males of Omorgus freyi. During both types of dormancy, spermatogenesis discontinuity is a dynamic process involving an uninterrupted supply of primary spermatocytes that undergoes partial development and lyses before spermatozoa can be formed. Notwithstanding this common feature, the pattern of discontinuity differs between the two kinds of dormancy. During reproductive diapause, spermatozoa and late spermatids are the first cells that lyse; after diapause break, spermatozoa are produced anew. During quiescence, in contrast, the first indication of discontinuity is the degeneration of late primary spermatocytes; spermatozoa apparently remain intact for a while but eventually degenerate as well. Therefore, males returning to sexual activity after a short period of quiescence may still have spermatozoa capable of fertilization. However, following a long period of quiescence, spermatozoa will be absent and must be produced anew, as in postdiapausing males. The existence of two different patterns of spermatogenesis discontinuity may indicate that each is controlled differently by the endocrine system, in response to the different environmental conditions inducing quiescence or diapause. Dual control of discontinuity may contribute to the high reproductive potential of these flightless beetles, under unpredictable and extreme desert conditions. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052180309
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993) 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052150101
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    Structure of recent and fossil mysid statoliths (Crustacea, Mysidacea) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 31-49 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Statoliths of 61 Recent species representing all subfamilies of Mysidae were studied with special emphasis on internal structure. In addition 5 samples of fossil statoliths from Miocene deposits were examined. Species of Boreomysinae and Rhopalophthalminae show simple roughly spherical organic statoliths, with setae originating from the sensory cushion and anchored in the statolith with distal branches extending shortly below the surface. All other subfamilies possess mineralized statoliths of greater structural complexity, with differentiation in core and mantle, where each part may consist of up to three layers. Habitus is hemispherical to discoidal. External gross structures are dorsal tegmen, ventral fundus, and the ambitus forming the outer toroidal to semi-toroidal circumference. Setae penetrate the mantle through mineralic canals and insert on the surface of the core. As suggested by congeneric species of Schistomysis, there is no principal structural difference between statoliths mineralized with fluorite compared to vaterite. However, vaterite statoliths tend to be more often of moruloid appearance and are exceptional by showing a central conical hole (the hilum) or a central cavity in certain forms. These structures are typical of fossil calcite statoliths. In vaterite and fluorite statoliths, the mantle shows radially arranged (= spherulitic) crystal aggregates. Such arrangements are badly preserved in fossil calcite statoliths. In large extant statoliths, concentric structures, mainly in the form of superficial striation and/or concentric microstrata, are visible in coexistence with radial aggregates. Stratification is possibly due to stratified deposition of the nonmineralized gland product, while the spherulitic structure is indicative of subsequent radial growth of crystal aggregates. The structure of accessory fluorite statoliths in the statocyst of Mesopodopsis slabberi leads to the hypothesis that mantle material is formed by secretions of the caudal statocyst gland. After demineralization of fluorite, vaterite and calcite statoliths, an organic template remains showing most essential morphological features of the statolith. From this we conclude that the structure of the statolith is (almost) entirely matrix mediated. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052150103
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    An ultrastructural study of the dorsal lingual epithelium of the crab-eating frog, Rana cancrivora (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 89-100 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The amphibian tongue contains two types of papilla which are believed to function in gustation and in the secretion of salivary fluid. Scanning electron microscopy reveals that columnar, filiform papillae are compactly distributed over nearly the entire dorsal surface of the tongue of the frog, Rana cancrivora, and fungiform papillae are scattered among the filiform papillae. Microridges and microvilli are distributed on the epithelial cell surface of the extensive area of the filiform papillae. Light microscopy shows that the apex of each filiform papilla is composed of stratified columnar and/or cuboidal epithelium and its base is composed of simple columnar epithelium. Transmission electron microscopy reveals that most of the epithelium of the filiform papillae is composed of cells that contain numerous round electron-dense granules 1-3 μm in diameter. Cellular interdigitation is well developed between adjacent cells. On the free-surface of epithelial cells, microridges or microvilli are frequently seen. Between these granular cells, a small number of ciliated cells, mitochondria-rich cells and electron-lucent cells are inserted. In some cases, electron-dense granules are present in the ciliated cells. At higher magnification, the electron-dense granules appear to be covered with patterns of spots and tubules. Overall, the morphology and ultrastructure of the lingual epithelium of the three species of Rana that have been studied are quite similar, but they can be easily distinguished from those of Bufo japonicus. Therefore, it appears that lingual morphology is phylogenetically constrained among members of the predominantly freshwater genus Rana to produce uniformity of papillary structure and this morphology persists in Rana cancrivora despite the distinct saline environment in which it lives. © 1993 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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    Pigment pattern formation in the larval salamander Ambystoma maculatum (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 151-163 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: As part of an ongoing comparative study of pigment patterns and their formation in embryos and larvae of ambystomatid salamanders, Ambystoma maculatum from two differnt populations, one in the northern (New York) and one in the central (Tennessee) United States, were investigated. Scanning electron microscopy was used to study early neural crest development. Light microscopy in combination with markers for the two pigment cell types (xanthophores and melanophores) made it possible to follow pigment cell migration before the pigment cells were fully differentiated. A bilateral pigment pattern consisting of two horizontal melanophore stripes surrounding an interstripe area populated by xanthophores formed in the larvae. In both populations, some variation was present in the form of a continuum ranging from clear horizontal stripes to extreme cases with a random pattern. Unlike the other ambystomatids that have been investigated, the neural crest cells in A. maculatum do not form aggregates and no vertical bars are formed. Instead, both the pattern and its formation are very similar to what has been reported for salamandrids. If pattern formation mechanisms can act as developmental constraints we would expect the A. maculatum pattern to be the primitive condition in the Ambystomatidae, using the Salamandridae as the outgroup. There is no strong support for this when aggregate formation is used as a character and mapped onto phylogenies for the group. The aggregate formation mechanism, and the pigment pattern that it leads to, have most likely been secondarily lost in A. maculatum. © 1993 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150204
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    A morphologic study of the ductus of the epididymis of Sus domesticus (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 183-193 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The head, body, and tail regions of the epididymal duct (or caput, corpus, and cauda epididymis) in two healthy and sexually mature Sus domesticus males were examined by light microscopy and by scanning or transmission electron microscopy. The epididymal duct is lined with a pseudostratified epithelium with stereocilia and covered by a muscular-connective tissue sheath that is thickest in the tail region. Diameter of the epididymal duct and height of epididymal epithelium are maximal in the head region. Length of the sterocilia and spermatic density are higher in the head and body regions. Somatic cells are abundant in the tail region. The epididymal epithelium is made up of five cell types: basal cells, principal cells, clear cells, narrow cells, and basophilic cells. Abundant secretory units are observed in the supranuclear cytoplasm of columnar principal cells. Each mature secretory unit is constituted by electron-dense secretion granules covered by more than eight layers of cisternae of reticulum between which the mitochondria are intercalated. In the apical cytoplasm the isolated secretion granules become larger and less electron dense. The apical surface is covered by numerous sterocilia. Basal cells are pyramidal and less high than principal cells. The clear cells, arranged between the principal cells, are characterized by the presence of abundant vesicular elements and electron-lucid secretion granules, and by an apocrine secretory process. The narrow cells are characterized by their highly vacuolized cytoplasm. Intermediate cell typologies can be found among basal, principal, clear, and narrow cells, which could be four developmental stages of the same cell type. The basophilic cells are spheroidal and are found at different levels between the epithelial cells and in the connective tissue underlying the epithelium. © 1993 Wiley-Liss, Inc.
    Additional Material: 39 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150206
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    Testicular and androgen dependence of skin gland morphology in the anurans, Xenopus laevis and Rana pipiens (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 195-200 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In anuran amphibians, there is increasing evidence that exocrine glands dispersed throughout the general integument are secondary sex characters (SSC). Following the recent discovery of sexually dimorphic “breeding glands” in the dorsum of male Rana pipiens, we studied the effects of castration and testosterone treatment on the dorsal skin glands of male Xenopus laevis and R. pipiens to determine whether the dorsal breeding glands, or any other dorsal skin glands, are androgen dependent. The dorsal skin glands of X. laevis were unaffected by androgen status. By contrast, in R. pipiens, breeding, mucous, and seromucous glands responded to testosterone stimulation. Mucous glands were significantly (P 〈 0.05) larger in testosterone-treated frogs than in castrates. There was a large, but statistically insignificant, increase in the size of the dorsal breeding glands. Testosterone treatment also increased the epithelial cell height of breeding and seromucous glands (P 〈 0.05). In the skins of castrated and testosterone-treated frogs, there was a reciprocal relationship between the abundance of seromucous and breeding glands: in castrates, seromucous glands were abundant and breeding glands virtually absent, whereas in testosterone-treated frogs, breeding glands were abundant and seromucous glands less common. The total number of the two gland types was similar in both treatment groups. Glands that appeared to be intermediate in form between seromucous and breeding glands were observed in some frogs. These data suggest that seromucous glands may be the regressed form of breeding glands in the dorsal skin of R. pipiens and that the dorsal skin of R. pipiens is a SSC. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150207
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    Development and fine structure of the bony scutes in Corydoras arcuatus (Siluriformes, callichthyidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 225-244 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development and the structure of the bony scutes have been studied in a growth series of the armored catfish Corydoras arcuatus using light and electron microscopy. Fibroblast-like cell condensations appear in the dermis, in the posterior region of the caudal peduncle, and these will constitute the scute papillae. Collagen bundles of the preexisting dermis colonized by the papilla cells are remodeled and incorporated in the papilla to form, in addition to newly synthesized woven-fibered bony material, the initium of the scute. This process of formation differs from that described for the dermal papilla of an elasmoid scale. During growth, the osteoblasts surrounding the scute constitute the scute sac in which the scute grows. Parallel-fibered bone is deposited on both sides of the initium, and osteoblasts are incorporated within the scute matrix. The remodeling and incorporation of collagen bundles of the preexisting dermis is maintained during growth only in the deep, anterior region of the scute. The posterior region and the upper surface of the scute are close to the epidermal-dermal boundary. When growth slows down in the upper part of the scute, a characteristic, well-mineralized tissue, composed of thin vertical fibrils and granules and devoid of typical striated collagen fibrils, is deposited on the scute surface. A new term, hyaloine, is introduced for this nonosseous, highly mineralized layer constituting the upper part of the scute. Hyaloine shows thin electron-dense lines, which probably correspond to periodic growth arrests. The structure and localization of the hyaloine are compared to other well-mineralized, similar tissues found on the surface of the dermal skeleton in lower vertebrates. © 1993 Wiley-Liss, Inc.
    Additional Material: 35 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150305
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993) 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052160101
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    Ultrastructural variations in the spermiogenesis of Triatoma infestans induced by temperature changes (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 17-27 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The reproductive process in insects may be affected by several factors, among which environmental temperature is one of the most important because of the poikilothermic condition of insects. To determine the effect of suboptimal temperature on the spermiogenic process of Triatoma infestans, males were exposed to 12°C for 10 days. In order to determine the reversibility of such alterations, males were returned to 28°C for 10 days after exposure to 12°C. Low temperature caused abnormal changes in the spermiogenic cells such as lack of spermatid orientation, general cyst disorganization, and asynchrony in the development of contiguous cysts. Highly vacuolized areas and pseudomyelinic bodies enclosing isolated or clustered vesicles of different electrodensity were also observed. At the end of the recovery time, cysts with spermatids developed synchronously. However, some presented isolated and clustered vesicles of different size and electrodensity. Some supernumerary organelles were also observed. These abnormal structures were related to processes of autophagy and phagocytosis of degenerating sexual cells. © 1993 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    Regionalization of eccrine and spermiophagic activity in spermathecae of the salamander Eurycea cirrigera (Amphibia: Plethodontidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 161-170 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spermathecae of female Eurycea cirrigera are compound alveolar glands; narrow neck tubules connect the distal bulbs to a common tube that opens onto the roof of the cloaca. The common tube and neck tubules produce apical secretory vacuoles that contain a periodic acid-Schiff (PAS)+ substance for merocrine export into the lumen. This substance is produced throughout the year, although secretory vacuoles are less numerous during the period of reproductive inactivity in the summer. When sperm are present, the product from the secretory vacuoles bathes sperm in the lumen. Sperm are in orderly arrays and never are embedded in the cytoplasm of the common tube or neck tubules. The distal bulbs do not produce PAS+ secretory vacuoles, and are actively spermiophagic as long as sperm are present. Sperm become embedded in the epithelium of the distal bulbs where lysosomes degrade sperm. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170205
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993) 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052180301
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    Ultrastructural study of the ovary of the sessile scyphozoan, Haliclystus octoradiatus (Cnidaria: Stauromedusae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 225-236 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An ultrastructural study of the ovary of the sessible jellyfish, Haliclystus octoradiatus, indicates that it is fundamentally different from that of other scyphozoans and is the most structurally complex within the class. Oocytes develop within a series of spherical, sac-like ovarian follicles consisting of an enlarged intercellular space between two layers of subumbrellar gastrodermis. Developing oocytes are largely restricted to a thin germinal epithelium at the periphery of each follicle and gradually migrate toward the lumen as they mature. Individual oocytes are surrounded by early germ cells and follicle-like accessory cells of presumed somatic origin. Similar folliclelike cells have not been described in the Cnidaria previously. Vitellogenesis appears to involve the combined activity of the Golgi complex and associated rough endoplasmic reticulum. Ovarian morphology may be helpful in deciphering phylogeneitc relationships within the Cnidaria. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052180210
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    Rostrate pedicellariae: A morphologically distinct form of echinoid test appendage (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 237-247 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The term rostrate was introduced by Mortensen ('07) to describe a type of pedicellaria he found in spatangoids. These pedicellariae resemble tridentate ones but have arching valves. Unlike the main categories of echinoid pedicellariae, no clear diagnosis of the rostrate form exists. This work examines the detailed morphology of the valves of rostrate pedicellariae observed by light and scanning electron microscopy and compares the shapes and dimensions of their component parts with tridentate pedicellariae. The data reveal considerable differences between the two, which warrant the recognition of rostrate pedicellariae as a distinct form. A diagnosis is given. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052180302
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    Reproduction, placentation, and embryonic development of the Atlantic sharpnose shark, Rhizoprionodon terraenovae (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 257-280 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Atlantic sharpnose shark Rhizoprionodon terraenovae (Richardson) is a small carcharhinid that is a common year-round resident along the southeast coast of the United States. It is viviparous and its embryos develop an epithelio-vitelline placenta. Females enter shallow water to give birth in late May and early June. Mating occurs shortly after parturition, and four to seven eggs are ovulated. Fertilized eggs attain the blastoderm stage in early June to early July. Separate compartments for each egg are formed in the uterus when the embryos reach 3-30 mm. Embryos depend on yolk for the first 8 weeks of development. When embryos reach 72 mm their yolk supply is nearly depleted and they shift to matrotrophic nutrition. When the embryos reach 40-55 mm, placental development begins with the vascularization of the yolk sac where it contacts the uterine wall. Implantation occurs at an age of 8-10 weeks by which time the embryos reach 70-85 mm. The expanding yolk sac engulfs the maternal placental villi, and its surface interdigitates with the villi to form the placenta. The rest of the lumenal surface of the uterus is covered by non-placental villi that appear shortly after implantation. Histotrophe production by the non-placental villi begins just after their formation. The placenta grows continuously during gestation. The egg envelope is present throughout gestation, separating maternal and fetal tissues. Embryos develop numerous appendiculae on the umbilical cord. Young sharks are born at 290-320 mm after a gestation period of 11 to 12 months. © 1993 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052180304
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    The male reproductive system and mechanism of sperm transfer in Argulus japonicus (Crustacea: Branchiura) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 51-63 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The histomorphology of the male reproductive system and surface morphology of the “peg-and-socket” in Argulus japonicus are described from serial sagittal and transverse sections and scanning electron micrographs. The prostate complex consists of a glandular part, a reservoir for storing the secretion, and an efferent duct opening into the ejaculatory duct. The openings of both the vas deferens and the prostate duct into the ejaculatory duct are guarded by sphincters. The ejaculatory ducts, which are lined by tall columnar epithelial cells, do not open into the cuticle-lined genital atrium but are blind-ending tubes. This observation and results obtained from observing live specimens, as well as the fact that no spermatophores are formed, suggest that semen could leave the ejaculatory duct only after puncturing of its walls. It is suggested that sperm transfer is accomplished in the following manner: during copulation contraction of the muscular walls of the vas deferens and prostate duct causes semen to be pumped into the ejaculatory duct, which is then closed off by sphincters and a high internal pressure is developed. When a spermathecal spine penetrates the walls of the ejaculatory duct, semen flows from the ejaculatory duct into the spermathecal vesicle due to the higher pressure in the ejaculatory duct. This mechanism is analogous to the sucking up of fluid with a hypodermic syringe. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    Anatomy of the larva of Amathia vidovici (Bryozoa: Ctenostomata) and phylogenetic significance of the vesiculariform larva (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 1-29 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Amathia vidovici (Vesiculariidae) has a lecithotrophic coronate larva. The apical disc of A. vidovici larvae is more complex than that of other vesiculariids and includes a new cell type, which may be glial-like in function. A massive nerve nodule consists only of neural processes; as no ganglia or other evidence of interneurons were found, sensory cells apparently innervate their effectors directly. Putative synaptic junctions within the nerve nodule indicate that both receptor and effector cells send processes to this neuropile. Some 44 intercoronal cells of three types, two of which are new, are interspersed among the approximately 40 coronal cells. Juxtapapillary bodies, a unique sensory complex previously known only from Bowerbankia gracilis larvae, also occur in A. vidovici. A large refractile body, which is of uncertain function and is positioned near the center of the larva, is described for the first time.A comparison of vesiculariid larvae that have been studied at the ultrastructural level reveals that larvae of Amathia vidovici and Bowerbankia gracilis are more similar to each other than either is to B. imbricata. Differences between the two Bowerbankia species, however, may reflect relative detail of their study and differences in interpretation rather than intergenic plasticity. Nevertheless. a distinctive suite of larval characteristics are shared by other members of the family Vesiculariidae, justifying a specific name - vesiculariform - for their larvae. A number of the defining characteristics of vesiculariform larvae also appear in the carnosan superfamily Victorelloidae. This finding is consistent with arguments based on adult characteristics that the Victorelloidea are ancestral to the Vesicularioidea. If this geneology is correct, one can predict that those vesiculariform traits which originated in the victorellids are plesiomorphic not only to the Family Vesiculariidae but to all sister taxa placed in the Vesicularioidea. © 1993 Wiley-Liss, Inc.
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    Cranial osteogenesis in Monodelphis domestica (Didelphidae) and Macropus eugenii (Macropodidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 119-149 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pattern of onset and general rate of cranial ossification are compared in two marsupials, Monodelphis domestica (Didelphidae) and Macropus eugenii (Macropodidae). In both species a similar suite of bones is present at birth, specifically those surrounding the oral cavity and the exoccipital, and in both postnatal events follow a similar course. The facial skeleton matures more rapidly than the neurocranium, which is characterized by an extended period of ossification. Most dermal bones begin ossification before most endochondral bones. Endochondral bones of the neurocranium are particularly extended in both the period of onset of ossification and the rate of ossification. These data confirm suggestions that morphology at birth is conservative in marsupials and we hypothesize that the pattern of cranial osteogenesis is related to two distinct demands. Bones that are accelerated in marsupials are correlated with a number of functional adaptations including head movements during migration, attachment to the teat, and suckling. However, the very slow osteogenesis of the neurocranium is probably correlated with the very extended period of neurogenesis. Marsupials appear to be derived relative to both monotreme and placental mammals in the precocious ossification of the bones surrounding the oral cavity, but share with monotremes an extended period of neurocranial osteogenesis. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052150203
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993) 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052150301
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    Falciparum malaria in naturally infected human patients: I. Ultrastructural differences between malaria pigments in intraerythrocytic asexual and sexual forms (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 201-206 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Venous blood samples were taken from patients naturally infected with the human malaria parasite Plasmodium falciparum. Two types of malaria pigment (MP) particles have been demonstrated in intraerythrocytic asexual forms (trophozoites and schizonts), while a single type was detected in gametocytes. Type I MP particles, found in both asexual and sexual forms, are electron-dense. It is suggested that these are proteinaceous and may be intermediate, utilizable metabolic products that serve as a food reserve during development of the parasite in the human host and also during the growth cycle of the sexual form in the mosquito. In asexual forms, type I particles occur within food vacuoles (FV) containing semidigested hemoglobin (Hg), while they are unenveloped in the cytoplasm of the sexual forms. Type II MP particles, found in electron-lucent residual bodies, are crystalloid and of low electron density. It is suggested that these are the final, waste product of Hg digestion in the asexual forms. © 1993 Wiley-Liss, Inc.
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    Falciparum malaria in naturally infected human patients: II. Ultrastructural alterations to erythrocytes infected with asexual forms (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 207-212 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ultrastructural alterations of human erythrocytes infected with asexual forms of Plasmodium falciparum were studied in naturally infected Saudi patients. These included surface knobs and nodules as well as invaginations associated with cytopasmic vesicles observed in erythrocytes infected with asexual forms of the parasites. Such nodules and surface invaginations have been previously described only in erythrocytes infected with P. ovale and P. vivax, respectively. Within the cytoplasm of infected erythrocytes were membrane-bound clefts, similar to those that appear to be a common characteristic in all red cells infected with malaria parasites. Vacuolations were often seen in the peripheral cytoplasm and may represent hemolyzed areas. Collapsed cells with an internal-lucent interior and surrounded by an irregularly folded membrane may represent completely hemolyzed erythrocytes. © 1993 Wiley-Liss, Inc.
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    A microscopic investigation of the lymphoid organs of the beluga, Delphinapterus leucas (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 261-287 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Lymphoid organs from belugas, Delphinapterus leucas, ranging in age from less than one to 16 years, were harvested during a sanctioned hunt to investigate morphology. The spleen is divisible into red and white pulp and a stroma consisting of a reticular network, a collagenous capsule, and trabeculae containing smooth muscle bundles. White pulp areas appear to be devoid of follicles and consist mainly of periarteriolar lymphatic sheaths (PALS), that are larger in younger than in older belugas. Definitive marginal zones between red and white pulp are difficult to discern in older belugas. Lymph nodes are similar to those of other mammals; they possess a follicular cortex surrounding a vascular medulla composed of lymphatic cords and sinuses. Smooth muscle is abundant in the medullary region, usually in close proximity to sinuses. The expansive nodular mass at the root of the mesentery, often referred to as the “pseudopancreas,” is similar to lymph nodes in microscopic architecture. Pharyngeal tonsils and gut-associated lymphoid tissue (GALT) are found along the digestive tract and display an “active” morphology. Tonsils are comprised of lobules of follicles separated by vascular connective tissue. Epithelial-lined crypts communicate with the pharyngeal lumen. GALT consists of diffuse and follicular lymphocytes within the intestinal mucosa and submucosa. The thymus is well developed in the younger belugas, with lobules divisible into densely packed cortical zones of thymocytes and more loosely arranged medullary lymphocytes. Hassall's corpuscles are occasionally visible within the medulla. Cetaceans diverged evolutionarily from other mammals over 55 million years ago. This study investigates changes in lymphoid organ morphology in a species that now inhabits a unique ecological niche. This study also lays the groundwork for functional investigation of the beluga immune system, particularly as it relates to differences between healthy and stranded animals. © 1993 Wiley-Liss, Inc.
    Additional Material: 24 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150307
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    Gliding flight in the American Kestrel (Falco sparverius): An electromyographic study (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 213-224 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electromyographic (EMG) activity was studied in American Kestrels (Falco sparverius) gliding in a windtunnel tilted to 8 degrees below the horizontal. Muscle activity was observed in Mm. biceps brachii, triceps humeralis, supracoracoideus, and pectoralis, and was absent in M. deltoideus major and M. thoracobrachialis (region of M. pectoralis). These active muscles are believed to function in holding the wing protracted and extended during gliding flight. Quantification of the EMG signals showed a lower level of activity during gliding than during flapping flight, supporting the idea that gliding is a metabolically less expensive form of locomotion than flapping flight. Comparison with the pectoralis musculature of specialized gliding and soaring birds suggests that the deep layer of the pectoralis is indeed used during gliding flight and that the slow tonic fibers found in soaring birds such as vultures represents a specialization for endurant gliding. It is hypothesized that these slow fibers should be present in the wing muscles that these birds use for wing protraction and extension, in addition to the deep layer of the pectoralis. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150304
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    Evolution and functional significance of tendon ossification in woodcreepers (Aves: Passeriformes: Dendrocolaptinae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 289-300 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The woodcreepers, a clade of scansorial, neotropical birds, are distinctive among passerines in having extensive tendon ossification. Dissection of 42 of the 50 species indicates that such ossification in the hindlimb is limited almost entirely to tendons of insertion of the crural muscles. Most crural muscles have ossifications, and in all but one the ossified tendons are long and thin. Preliminary dissection revealed a similar pattern among ossified wing tendons. Phylogenetic analysis suggests that extensive tendon ossification is a synapomorphy of the woodcreepers. The species of Dendrocincla, which form a clade, show secondary reduction of ossification in some tendons, which may be correlated with increased intraspecific variation and with an expansion of foraging habits and postures to include nonscansorial behaviors. In contrast, the larger woodcreepers, other than Drymornis bridgesii and Nasica longirostris, form a clade with virtually no loss in ossification or evidence of intraspecific variation, even in large series of two species. Phylogenetic losses do not occur for the primary flexor of the ankle (M. tibialis cranialis), whereas two extensors (Mm. fibularis longus and gastrocnemius pars lateralis) show a complex pattern of derivation and loss. Previous biomechanical studies demonstrate that ossification increases the stiffness of tendons, making them stretch less under a given force. These structural and phylogenetic patterns are consistent with the view that hindlimb tendon ossification in woodcreepers is an adaptation to resist increased forces that act to extend the limb during vertical climbing. © 1993 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150308
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  • 91
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    Follicular dynamics and germinal bed activity during the annual ovarian cycle of the lizard, Calotes versicolor (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 1-7 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Changes in size frequency distribution of extrastromal follicles, atretric follicles (AF), and the number of oogonia, oocytes, and primordial follicles in the ovaries are studied in Calotes versicolor during its annual reproductive cycle. Extrastromal follicles were graded into stages I to VI based on their diemeter. Stage I (0.5-0.75 mm) follicles are found throughout the year. The recruitment of stage II (0.76-1 mm) and stage III (1.10-2 mm) follicles occurs during December and March, respectively. Follicles of stage I-III are found in greater number in May. Stage IV vitellogenic follicles (2.10-3 mm) are recruited in April. Advanced vitellogenic follicles (stage VI) are formed between May and August. From April to August, the ovaries of lizards contain vitellogenic follicles of stages IV or V or VI suggesting that once a set of follicles enters vitellogenic phase there is no recruitment of another set of vitellogenic follicles from previtellogenic follicles until the former ovulates. The presence of vitellogenic follicles and at least two sets of CL in July-August suggest that C. versicolor may oviposit at least three clutches of eggs per season. The clutch size in this lizard varies from a maximum 24 eggs in May to a minimum of 13 eggs in September. The previtellogenic AF are found throughout the year. Atresia is more prevalent in stage III suggesting that these follicles are more prone to become atretic. Interestingly, atresia of vitellogenic follicles occurs rarely. Each ovary in C. versicolor has two germinal beds. The germinal beds contain a greater number of oogonia (536-696), primary oocytes (40-71), and primordial follicles (32-55) during prebreeding and early breeding phases of the ovarian cycle. © 1993 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052160102
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  • 92
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    Ultrastructure of the spermatozoon of the teleost fish Acanthopagrus schlegeli (Perciformes: Sparidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 29-33 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ultrastructurally the spermatozoon of Acanthopagrus schlegeli (Sparidae) has a spherical, homogeneously electron-dense nucleus with a deep axial nuclear fossa, and an unusual notch, shaped like a bowtie, in the nuclear region. The short midpiece contains four spherical mitochondria and encircles the basal body of the flagellum. It is concluded that the spermatozoon is of a primitive type, although it is characterized by several unique features which may provide useful systematic characters. © 1993 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052160105
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  • 93
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    In-series fiber architecture in long human muscles (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 35-45 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fiber architecture of adult human sartorius and gracilis muscles was examined using a combination of fiber microdissections and histological methods. Intact fibers were dissected from fascicles of muscle strips that were digested in nitric acid. All of these fibers terminate intrafascicularly by tapering to a fine strand at one or both ends. They measure 4-20 cm after correction for shrinkage. Systematic dissections of 1 cm long blocks sampled at intervals along the muscle length suggest that tapered fiber endings occur at all locations along the muscle but are most common centrally; here they accounted for up to 14% of dissected fibers in each block. Transverse sections of muscle confirm that fiber profiles with small diameters occur at all levels of the muscle but are especially common in sections more than 5 cm from its origin or insertion. The architectural arrangement demonstrated here suggests that long human muscles, like muscles in other species, are composed of relatively short, in-series fibers. This has many implications for the neural activation and force-developing behavior of these muscles that must be considered when paralyzed muscles are reanimated using electrical stimulation. Further, it may predispose long muscles to certain types of neuromuscular damage and dysfunction. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052160106
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  • 94
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    Suboccipital muscles in the cat neck: Morphometry and histochemistry of the rectus capitis muscle complex (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 47-63 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphometry, histochemistry, and biomechanical relationships of rectus capitis muscles were examined in adult cats. This family of muscles contained six members on the dorsal, ventral, and lateral aspects of the upper cervical vertebral column. Three dorsal muscles (rectus capitis posterior major, medius, and minor) formed a layered complex spanning from C1 and C2 to the skull. Rectus capitis posterior major was composed predominantly of fast fibers, but the other two deeper muscles contained progressively higher proportions of slow fibers. One ventral muscle, rectus capitis anterior major, was architecturally complex. It originated from several cervical vertebrae and appeared to be divided into two different heads. In contrast, rectus capitis anterior minor and rectus capitis lateralis were short, parallel-fibered muscles spanning between the skull and C1. The ventral muscles all had nonuniform distributions of muscle-fiber types in which fast fibers predominated. Dorsal and ventral muscle groupings usually had cross-sectional areas of 0.5 cm2 or more, reflecting a potential capacity to generate maximal tetanic force in excess of 9 N. Biomechanical analyses suggested that one muscle, rectus capitis lateralis, had its largest moment in lateral flexion, whereas the other muscles had large, posturally dependent moment arms appropriate for actions in flexion-extension. The observation that most rectus muscles have relatively large cross-sectional areas and high fast-fiber proportions suggests that the muscles may have important phasic as well as postural roles during head movement. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052160107
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  • 95
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    Organization of hematopoietic tissue in the intermolt lobster, Homarus americanus (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 65-78 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hematopoiesis in the American lobster Homarus americanus, as in most decapod crustaceans, occurs in a thin tissue covering the dorsal surface of the foregut. This tissue is composed of loosely attached, ovoid lobules containing the hematopoietic precursors and maturing hemocytes. Release of hemocytes into the dorsal hemocoel is accomplished by rupture of a portion of the connective tissue capsule covering the lobule. Cross sections of the lobules contain between 6 and 40 hematopoietic cells, of which approximately 90% constitute stages in granulocyte maturation and 10% are intermediates in hyaline cell maturation. Hematopoietic precursors in these two lines are similar to those recently described in a penaeid shrimp Sicyonia ingentis. The mitotic rate averaged 5.1% (range = 0.7% to 15.8%) in intermolt lobsters, 90% comprised granulocyte precursors. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052160108
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    Structural characteristics of marsupial brood pouches of the antarctic sea urchins Abatus nimrodi and Abatus shackletoni (Echinoidea: Spatangoida) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 79-93 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Marsupial spines, tubercles, and pedicellariae of the antarctic brooding spatangoids Abatus nimrodi and Abatus shackletoni have been examined by scanning electron microscopy. Individual brood pouches of A. nimrodi may hold up to 28 embryos and juveniles and those of A. shackletoni may hold up to 38 lecithotrophic embryos and juveniles. Juveniles can be divided into (a) those with early development of external elements and a mean size of 2.0 and 1.6 mm, respectively, and (b) those equipped with fully developed external elements and a mean length of 4.3 and 2.8 mm, respectively. Mean diameters of aboral brood pouch openings of A. nimrodi and A. shackletoni were 6.5 and 4.1 mm, respectively. Brood pouches contain tall, distally enlarged spines, and smaller, layered cover-spines, which form a protective arch over the marsupia. There are also slender brood-pouch-bottom spines, which have an extremely thickened spinal epidermis. A. nimrodi has mainly bidentate, but also triand quadrodentate pedicellariae. A. shackletoni has two forms of tridentate, rostrate, and globiferous pedicellariae. In A. shackletoni, marsupial spine density is significantly lower than in A. nimrodi. These differences may be related to distinct sediment characteristics in their respective habitats. © 1993 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052160109
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    Announcement (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 113-113 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052160111
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993) 
    Details
    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
    URL: http://dx.doi.org/10.1002/jmor.1052160201
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  • 99
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    Ultrastructure of prothoracic glands during larval-pupal development of the tobacco hornworm, Manduca sexta: A reappraisal (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 95-112 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure of Manduca sexta prothoracic glands was investigated using a protocol that preserves membranes. During the last larval stadium, prothoracic gland cells increase in diameter, volume, protein content, and perhaps number, enhancing their capacity to produce ecdysteroids. The glands' strand-of-cells morphology, their in situ location, the presence of gap junctions between cells, and junctional foot-like structures within cells support previous findings that prothoracicotropic hormone stimulates ecdysteroidogenesis via Ca2+-induced Ca2+ release. A different method of tissue fixation from that previously used to investigate the ultrastructure of Manduca sexta prothoracic glands has revealed a significantly different ultrastructure. These new findings begin to define roles for endoplasmic reticulum and mitochondria in ecdysteroid synthesis and support the hypothesis that the glands secrete the steroid hormone via exocytosis. The structural dynamics of the glands are discussed in the context of the glands' function during Manduca sexta larvalpupal development. © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052160110
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  • 100
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    Structure and histochemical organization of the spleen of Agama stellio (Sauria: Agamidae) and Chalcides ocellatus (Sauria: Scincidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 115-120 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spleen of Agama stellio is composed mainly of red pulp; the white pulp is poorly developed, and its clusters are scattered throughout the organ and contain lymphocytes, reticular cells, and some plasma cells. The red pulp consists of clear reticular cells intermingled with blood cells, sinusoids, and pigment cells. The spleen of Chalcides ocellatus is encapsulated by connective tissue and is composed of white and red pulp. The white pulp consists of lymphoid tissue that surrounds the central arterioles, forming the periarteriolar lymphocyte sheath (PALS). The red pulp is composed of a system of venous sinuses and cords. The results of various histochemical procedures designed to demonstrate mucosubstances, proteins, and nucleic acids indicate that the spleen in these species resembles the mammalian spleen. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052160202
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