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  • 1980-1984  (5,247)
  • 1970-1974  (2,803)
  • 1880-1889  (50)
  • Life and Medical Sciences  (7,347)
  • Electron microscopy  (757)
  • Nuclear reactions
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 402 (1984), S. 289-296 
    ISSN: 1432-2307
    Keywords: Epithelium ; Chorion laeve ; Diabetes mellitus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The epithelium of human chorion laeve from pregnancies complicated by diabetes mellitus was examined under the light and electron microscopy. In comparison with normal chorion laeve, the epithelium of chorion laeve in diabetes mellitus shows the following morphological changes: 1. The trophoblast cells display more microvilli and cell processes on their surface. 2. Trophoblast cells with different cytoplasmic characteristics can be seen. Some display few organelles and large glycogen depositions; other are rich in organelles. Furthermore, some cells with electron dense filaments and few cell organelles can be found. 3. Necrotic cells are frequently present in the outer epithelial layers. 4. The intercellular spaces in the epithelial layers near the basement membrane are narrower. Since vasculopathy of the decidual arteries with disturbance of blood circulation is often found in pathological pregnancies, we assume that the morphological changes found are due to deficiency in nutrient and oxygen supply.
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  • 2
    ISSN: 1432-2307
    Keywords: Alloxan ; Culture ; Electron microscopy ; 6-Hydroxydopamine ; Pancreaticβ-cells ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stereological techniques on electron microscopy micrographs were used to evaluate the morphological changes of cultured isletβ cells that had been exposed to alloxan or 6-hydroxydopamine. Trypan Blue exclusion by cells cultured for 3 days indicated that the cells were 100% viable. Electron microscopy revealed that nearly all of the surviving cultured cells wereβ cells. Exposure to 5 mmol/l alloxan or 1–5 mmol/l 6-hydroxydopamine for 10 or 30 min caused a general swelling of the cultured cells with a concomitant swelling of mitochondria and nuclei. The size of the secretory granules was not affected by the drugs. Only 3–10% of the cells excluded Trypan Blue after exposure to 5 mmol/l alloxan or 6-hydroxydopamine. The data conform with the hypothesis that a primary action of alloxan and 6-hydroxydopamine is at the plasma membrane level ofβ cells.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 404 (1984), S. 213-221 
    ISSN: 1432-2307
    Keywords: Oat cell carcinoma ; Male breast ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of small cell neuroendocrine (oat cell) carcinoma of the breast in a 52-year old male is presented. Oat cell carcinomas have been reported in various extrapulmonary sites, but this is the second case of a primary oat cell carcinoma of the breast and the first one to have been documented in a male. The tumor was investigated histologically, immunocytochemically and ultrastructurally. The relationship to so-called “carcinoid” mammary tumors is discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 404 (1984), S. 427-434 
    ISSN: 1432-2307
    Keywords: Elephantiasis neuromatosa ; Neurofibromatosis ; Electron microscopy ; Immunohistochemistry ; S-100 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An example of elephantiasis neuromatosa, an unusual variant of neurofibromatosis, coexistent with lipomatosis is presented. This dual cell population produced a diffuse swelling of the gluteal sulcus of a young female. The neurogenous origin of the spindle cell component was substantiated by immunoreactivity for S-100 protein as well as by the fine structural observation of a regular basement membrane coating and a profusion of Luse bodies. As far as can be ascertained, this is the first reported immunohistochemical and ultrastructural study of this particular variant of peripheral nerve sheath lesion.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-2307
    Keywords: Calcifying epithelial odontogenic tumor ; Electron microscopy ; Histoenzymology ; Ameloblast ; Amyloid-like substance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A calcifying epithelial odontogenic tumor, simultaneously located in the two jaws (maxilla and mandible) was examined by histochemical and electron microscopic methods. Squamous tumor cells without secretory polarity were different from those of common ameloblastoma. High activities of alkaline phosphatase and ATPases were demonstrated by light and electron microscopy on the cytoplasmic membrane, findings similar to those in the stratum intermedium cells of the normal dental germ from which these tumor cells seem to arise. The tumor cells, like preameloblasts of the dental germ, also produce a granulo-filamentous material in intracytoplasmic vesicles and discharge it into the stroma. This “pseudo-amyloid” substance represents an abnormal protein of the enamel matrix and calcification, mainly occurring in that substance, might be an attempt at mineralization.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 403 (1984), S. 391-400 
    ISSN: 1432-2307
    Keywords: Immunohistochemistry ; Electron microscopy ; Light microscopy ; Granular cell tumour ; Mammary gland neoplasm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Primary granular cell tumours of the breast in 35 2and 55 year old women were studied by light microscopy, transmission electron microscopy and immunohistochemistry. Light and electron microscopy revealed a neural origin of the tumours and this was further substantiated by immunohistochemical studies, with positive S-100 protein reaction and negative reactions for surface heavy and light chains, CEA, alfa-1-antitrypsin, muramidase and GFA-protein. Granular cell tumour of the mammary gland is a very rare tumour. Clinically it sometimes simulates carcinoma because of its fibrous consistency, fixation to pectoral fascia and skin retraction. The diagnosis of granular cell tumour should be included in the differential diagnosis of carcinoma of the breast. The granular cell tumour is derived from neuro-ectodermal tissue. Whether it represents a neurogenic cell-confined metabolic disturbance with lysosomal activation, or a true neoplasm remains to be elucidated.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Urological research 12 (1984), S. 17-22 
    ISSN: 1434-0879
    Keywords: Urinary calculi ; Electron microscopy ; X-ray microanalysis ; Artefacts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Material in urinary calculi is prone to irradiation damage during electron microscopy and this suggests the need for care in the interpretation of data. It is shown, however, that minimum-dose transmission microscopy is feasible for single-crystal electron diffraction work, and that although internal damage in severe, morphological artefacts are unlikely in the SEM unless the incident electron flux is greater than 10-13 A nm-2. During EDX micro-analysis, the detection of light elements is impaired by irradiation effects unless a minimum-dose procedure is used. For the preparation of SEM samples, artefacts can be created by cleaving air-dried material-and it is therefore important to consider more lengthy preparation methods such as cryogenics.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1434-0879
    Keywords: Concanavalin A ; Lectin receptors ; Bladder tumor ; Electron microscopy ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We used concanavalin A (con A)-peroxidase-iron dextran-diaminobenzidine (DAB) technique for the electron microscopic detection of con A binding sites on cell membranes. Normal bladder mucosa showed a sparse distribution of con A binding sites with both transmission (TEM) and scanning (SEM) electron microscopy, but bladder tumors showed a higher concentration in the distribution of con A binding sites in proportion to the histopathological grade of transitional cell carcinoma. Quantitative estimation of the con A binding sites was attempted using scanning X-ray pulse analysis of iron elements contained in the reaction complexes. Con A binding sites were quantitatively the smallest in normal mucosa, increasing proportionate to the grade of the bladder tumor. Some specimens were compared by the ferritin-labelled method and the pattern of ferritin conjugates distribution was similar to that seen with the con A-peroxidase-iron dextran method.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1434-0879
    Keywords: Urinary calculi ; Stone ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A study of urinary stones obtained from patients after surgery in the Medical College Hospital, Trivandrum, under the scanning electron microscope showed the presence of calcium oxalate and calcium biphosphate crystals as the main constituents. However, the pattern of the different phases of crystal growth was not uniform. Within the crystal lattice, fibrous structures, possibly of protein matrix, were invariably observed. Electron microscopy may be usefully adapted as a particularly suitable method for ultramicroscopic investigation of the fine structure of urinary stones including single crystal surface structure, section of urinary calculi and for possible presence of hitherto unknown components within the calculus.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 169 (1984), S. 9-20 
    ISSN: 1432-0568
    Keywords: Peroxisomes ; Marginal plates ; DAB-Cytochemistry ; Electron microscopy ; Freeze-etching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the canine circumanal gland, the morphological alterations of peroxisomes during differentiation and maturation of the glandular cells were studied by electron microscopy, cytochemistry and freeze-etch technique. Each of the following three cell types has its own characteristic peroxisomal population: 1) The basal cell contains only a few small peroxisomes, which appear as spherical and tubular profiles showing strong DAB reaction. In the differentiating basal cells, these are joined by a few dilated, hemispherical organelles with intensely stained small marginal plates. 2) In the intermediate cell, additional to spherical and tubular peroxisomes, numerous clongated organelles with distinct marginal plates are observed, displaying weak catalase activity. 3) In the mature cell, dumbbell-shaped peroxisomes with enlarged marginal plates predominate. Serial section analysis and freeze-etching studies reveal that these dilated particles are of erythrocyte-like shape. They exhibit very weak catalase activity or do not contain any visible DAB reaction product. In their flattened, thin central portions, the memoranes enclose the marginal plates and form straight cisternae, which are closely associated with adjacent fenestrated cisternae of ER on both sides, referred to as paramarginal cisternae. Dumbbell-shaped peroxisomes with their corresponding paramarginal cisternae form large peroxisome-ER-complexes. Furthermore, three to five dumbbell-shaped particles are often stacked in parallel. Only at their flat poles are the organelles in close contact with paramarginal cisternae. The observation of continuities, in particular between erythrocyte-like organelles and tubular peroxisomes in mature glandular cells, indicates the existence of a peroxisomal compartment composed of two segments in the mature stage. In freeze-etch replicas of mature glandular cells, only the dilated segments of the peroxisomal compartment can be easily recognized because of their unusual size and erythrocyte-like shape. Additionally, on the E-face of their central portion, a straight, square or rectangular area with a distinct crystalline pattern is seen, which corresponds to the marginal plate. These findings indicate that the circumanal gland of the dog offers unique possibility to analyze the biological properties of a well-defined peroxisomal compartment.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 62 (1984), S. 225-229 
    ISSN: 1432-0533
    Keywords: Dandy-Walker syndrome ; Dandy-Walker cyst ; Ependymal cell ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the wall of the Dandy-Walker cyst has been described rarely. A boy aged 2 years was confirmed clinically, neuroradiologically, and operatively as having a Dandy-Walker cyst in the posterior fossa. The cyst wall obtained during surgery consisted of an outer arachnoid cell layer, intermediate interwoven neuroglial strands, and an inner layer of cells which lacked the characteristic appearance of ependyma. An unusual finding was a small, buried island of ependymal cells in the intermediate layer of the neuroglial tissue. Ultrastructural study of the cyst wall provides a better understanding of the pathogenesis of the Dandy-Walker syndrome.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 63 (1984), S. 96-107 
    ISSN: 1432-0533
    Keywords: Hereditary coproporphyria ; Hereditary hepatic porphyrias ; Sural nerve biopsy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In spite of several cases reported in the literature, the exact pathogenetic mechanism of neuropathic changes in porphyric neuropathy remains uncertain. Various authors have ascribed the neuropathologic findings to either a dying-back axonal degeneration or segmental demyelination. In recent years, the hypothesis of an axonal and myelinic disorder has received support by the demonstration of a combined and simultaneous involvement of both these structures. Such different opinions are also a consequence of the reduced number of detailed bioptic observations in the different forms of acute porphyria not only during acute phases but also between attacks. In this paper we report the results of light- and electronmicroscopic examination of two sural nerve biopsies from subjects with hereditary coproporphyria. The first was performed 6 months after an acute attack, the second specimen was obtained from a patient without acute attacks, who had clinical and electrophysiologic signs of a chronic progressive neuropathy. In both cases a dying-back axonal degeneration is considered the primary change. The pathogenetic mechanism of peripheral nerve lesions in porphyric neuropathy will be discussed finally.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 62 (1984), S. 324-331 
    ISSN: 1432-0533
    Keywords: Human skeletal muscle ; Hemiplegia ; Cerebral vascular disease ; Histopathology ; Electron microscopy ; Rehabilitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Anterior tibial muscle biopsies of the hemiplegic side of 16 patients with a cerebrovascular accident in the middle cerebral artery region were analyzed qualitatively and quantitatively by enzyme histochemistry and electron microscopy. Patients grouped according to the time lapsed as from the occurrence of the accident (1–17 months) demonstrated a progressive decrease in the fiber diameter and changes in fiber type distribution with predominant type II atrophy and type I predominance. Nuclear internalization, myopathic alterations, and perifascicular fatty infiltrations were observed constantly. In the affected fibers the ultrastructural findings were myofibrillar alterations with the formation of rods and cytoplasmic bodies. There was accumulation of lipofuscin, glycogen, and lipid droplets. Microvascular changes were observed frequently. Biopsies from the asymptomatic legs were either normal or showed age-related muscle alterations. Correlation was noted between the clinical and functional status of the patients and the morphological aspects seen in muscle biopsies.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 63 (1984), S. 255-263 
    ISSN: 1432-0533
    Keywords: Carbon disulphide ; Electron microscopy ; Giant axonopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adult Wistar rats were exposed to carbon disulphide (CS2) vapour at a concentration of 2.4 mg/l of air for 5 days a week (6h a day), and the ultrastructure of peripheral nerves, neuromuscular junctions and muscles was investigated after 6 months of exposure to CS2. Numerous giant axons, i.e. paranodal or internodal swellings, were seen in the peripheral nerves. At the swollen paranodes, the myelin sheath was thinned, in other regions large intramyelinic vacuoles indicative of more dramatic demyelination were observed at axonal enlargements. Axonal enlargements consisted essentially of whorls of tightly packed neurofilaments. A number of nerve fibres underwent complete degeneration, but at the same time there was evidence of nerve regeneration. Nerve terminals were affected in a similar way following CS2 exposure. At neuromuscular junctions, filamentous swellings of nerve terminals preceded their degeneration and eventual denudation of synaptic gutters. As a rule, the postsynaptic part of neuromuscular junctions remained unimpaired by CS2 treatment. Muscles were affected by both atrophy and degeneration. Clusters of dense and lamellar bodies and numerous autophagosomes indicative of direct myotoxic effect of CS2 were frequently encountered in the investigated muscles. Some muscle fibres apparently underwent necrosis judging from the occurrence of myotubes characteristic of muscle degeneration and regeneration. The pathomorphology of CS2 neuropathy resembles that of other toxic neuropathies which presumably have a common origin in impaired energy metabolism.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 169 (1984), S. 261-270 
    ISSN: 1432-0568
    Keywords: Peroxisomes ; DAB-cytochemistry ; Electron microscopy ; Three-dimensional reconstruction ; Preputial gland ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of peroxisomes in partially differentiated cells of the mouse preputial gland was investigated using serial thin sections and three-dimensional reconstruction as well as the alkaline diaminobenzidine technique for visualization of the peroxidatic activity of catalase. An analysis of serial sections indicates that the different types of intensely stained peroxisomal profiles, classified according to their shape, represent random planes through highly complex peroxisomes. These organelles exceed 4 μm in length and exhibit a focal heterogeneity with respect to their size, shape and enzyme distribution. The graphical three-dimensional reconstruction demonstrates that the most intricate peroxisomes are characterized by tortuous, elongate, and branched tubular segments of varying diameter equipped with enlarged terminal hollow-spherical structures which engulf areas of cytoplasm. A close spatial relationship is established between adjacent peroxisomes and peroxisomes and mitochondria, the latter two of which synchronously develop into highly complex structures. A close association is also observed between peroxisomes and the endoplasmic reticulum, whereby membrane continuities between the two compartments cannot be demonstrated. These observations are inconsistent with traditional concepts concerning peroxisomal shape and size, the number per cell, as well as their biogenesis from the endoplasmic reticulum. The functional significance of individual highly complex peroxisomes and their assemblage forming an extensive netlike membraneous system throughout the cell is discussed with respect to intracellular energy transport and trans-membrane electron exchange.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1432-0568
    Keywords: Implantation ; Blastocyst ; Zona pellucida ; Decidual reaction ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural studies were undertaken to investigate the temporal relationship between loss of the zona pellucida around the blastocyst and the appearance of decidual changes in the endometrial stroma during normal implantation in rats. Blastocyst-free and blastocyst-containing sites of pregnant uterine horns were studied and compared with control sites from contralateral salpingectomized horns and horns of pseudopregnant animals from 24.00 h on Day 4 and onwards. There were no membrane contacts between the blastocyst and the uterine epithelium at 10.00 h on Day 5 and earlier because of an intervening zona pellucida. From 14.00 h onwards, however, such contacts were present and at 18.00 h, the zona pellucida had disappeared and the blastocyst had attached onto the uterine epithelium. The stromal cells of pregnant and control horns were indistinguishable from each other at 24.00 h on Day 4, but from 06.00 h on Day 5 onwards specific changes were noted in the stromal cell nucleoli of the pregnant horns. The results therefore suggest that the first morphological sign of decidualization occurs about 12 h before the Pontamine Blue reaction and is initiated by the blastocyst early on Day 5 while it is still encased by the zona pellucida.
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  • 17
    ISSN: 1432-0568
    Keywords: Meconium corpuscles ; Apoptosis ; Foetal intestine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During the embryonic development of the intestine, programmed deletion of epithelial cells plays a vital role in the formation of secondary lumina and of villi. Electron microscopy shows that this deletion is effected by apoptosis, a distinctive mode of cellular death recently recognised as being implicated in normal tissue involution in the adult, as well as during intrauterine development. The process involves cellular condensation and budding to form membrane-bounded apoptotic bodies containing well-preserved organelles. These are then either engulfed by neighbouring principal cells or sloughed off into the intestinal lumen. Engulfed apoptotic bodies that show various degrees of lysosomal degradation have previously been reforred to as “meconium corpuscles”.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 64 (1984), S. 108-113 
    ISSN: 1432-0533
    Keywords: Image analysis ; Electron microscopy ; Muscle fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Based on a fixed number of EM photomicrographs a semiautomatic image analysis is made of normal gastrocnemius muscle fibers to obtain reference values for comparison with pathologic data. Z disc, mitochondria, tubular system, and sarcoplasmic reticulum are measured. It is stated that no definite fiber type differentiation is possible based on these quantitative data. However, measurements of Z disc and mitochondria are suggestive of such a differentiation. On the other hand, all data reach a Gaussian distribution on a logarithmic scale after a 5% correction factor is introduced.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 64 (1984), S. 122-128 
    ISSN: 1432-0533
    Keywords: Hydrocephalus ; Blood-brain barrier ; Tight junctions ; Paracellular pathway ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Considering the possibility of a paracellular route for edema resolution we studied the microvasculature of the subependymal and subcortical white matter in hydrocephalic rats. Normal adult rats were used as controls. After injection of kaolin suspension into the cisterna magna, the animals were killed at intervals of 1, 2, 4, and 8 weeks. In hydrocephalic rats at 1 week after kaolin injection, widening of the interendothelical cleft between the tight junction (dehiscence) was seen in 27 of 76 (35%) vessels. At 2 weeks after kaolin injection, the number of the dehiscences had increased (39/7:56%) and some were enlarged, forming interendothelial blisters. At 4 weeks in hydrocephalic rats, both dehiscences and blisters were still prominent (45/73∶63%) and at 8 weeks the dehiscences were still prominent, but the number of the blisters had decreased (25/81∶31%). The blisters and dehiscences were most pronounced in the corpus callosum and occipital regions. Following i.v. injection of horseradish peroxidase, the interendothelial dehiscences and blisters were completely devoid of the marker substance. These findings indicate that in obstructive hydrocephalus the tight junctions may constitute part of a paracellular pathway for the resorption of interstitial edema fluid.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 276 (1984), S. 2-11 
    ISSN: 1432-069X
    Keywords: Photochemotherapy ; Freckles ; Electron microscopy ; Melanocytes ; Langerhans cells ; Retinoid therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Photochemotherapy (PUVA)-induced freckles were found in 25 patients (41%) who had received more than 1,000 J/cm2 of PUVA. The patients had been treated with PUVA for more than 2 years, with more than 150 exposures before PUVA lentigines appeared on the thighs, the upper arm, the mid-lower arm, the waist, and the buttocks. The histopathology of these freckles was analyzed by light and electron microscopy. Light microscopy showed an increased amount of pigment and melanophages and increased numbers and size of melanocytes. The keratinocytes often displayed atypical features such as enlarged nuclei, giant size, or fibrillar degeneration. Homogenization of the papillary dermis was observed in 11 patients. The activation of melanocytes was confirmed electron microscopically, and pathological features such as large amounts of lipid droplets and lysosome-melanosome complexes within the melanocytes were seen. The Langerhans cells were mostly normal, whereas the keratinocytes showed cytolytic changes, fibrillar degeneration, and vacuolization. A close follow-up of patients with prolonged PUVA treatment is recommended.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 277 (1984), S. 44-54 
    ISSN: 1432-069X
    Keywords: Birbeck granule ; Birbeck granule-like structure ; Electron microscopy ; Langerhans cell ; Lymph node
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To understand contact hypersensitivity, it is important to know the kinetics of Langerhans cells (LC) and related cells in the lymph node (LN), as well as in the skin. For this purpose, we tried experimentally to induce increased numbers of LCs, Birbeck granule-like structure (BgS)-containing cells, and interdigitating reticulum cells (IDC) in DNCB-sensitive mice and studied them by means of electron microscopy with the following results: (1) cytologically, LC, BgS-containing cells and IDC were closely related; (2) BgS seemed to arise from rough-surfaced endoplasmic reticulum (r-ER), and BgS-containing cells were midway in nature between LC and IDC from the morphological view point. From these findings, it appears that IDC, BgS-containing cells, and LCs were simultaneously involved in the contact hypersensitivity reactions of LNs.
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  • 22
    ISSN: 1432-0533
    Keywords: Polyneuropathy ; Hereditary disease ; Chiloren ; Sural nerve biopsy ; Electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ten autosomal recessive/sporadic cases of hereditary motor and sensory neuropathy type I (HMSN I), nine of which originated from the northern part of Sweden, were included in the study. Parents were free from neurologic symptoms. Motor and sensory conduction velocity was normal when recorded, i.e., in 19 and 17 parents, respectively. Sural nerve biopsies from the ten cases revealed a varying degree of onion bulb formation. In eight of the cases the onion bulbs consisted of abundant basement membranes, whereas the Schwann cells were few and sometimes lacking. There were in some cases considerable differences between separate fascicles as to the loss of myelinated nerve fibers. In the six biopsies in which teasing was performed signs of present and previous demyelination were noticed. Numerous internodal segments were abnormally thin with reference to their length. In many such segments there were marked local thickenings of the nerve fiber. In cross sections the probable counterparts to these thickenings were nerve fibers with unduly thick myelin sheaths and complex folding of the myelin. Ultrastructural axonal changes were seen in the majority of the cases. The pathogenetic and diagnostic implications of the present findings are discussed.
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  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 65 (1984), S. 128-137 
    ISSN: 1432-0533
    Keywords: Quantitative ; Electron microscopy ; Microangiopathy ; Pi granules ; Schwann cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A significant reduction in the myelinated nerve fiber population was observed during quantitative electron-microscopic examination of peripheral nerves in chronic alloxan diabetic rats. Dystrophic axonal abnormalities and regenerating fibers were more numerous in diabetics than age-matched controls. Schwann cells showed reactive changes including prominent pi granules of Reich and intracytoplasmic filament accumulation. Enumeration of these alterations, however, revealed no singificant difference from controls. Endoneurial macrophages in diabetic rats were also filled with lamellar intracytoplasmic inclusions characteristic of a chronic neuropathy. Quantitation of pathologic lesions in teased nerve fibers confirmed the preponderance of axonal over demyelinative disease and showed demyelination to be segmental. Microangiopathy was noted throughout the vasa nervorum of diabetic rats, and quantitative electron microscopy showed endothelial proliferation with doubling of the number of endothelial cells and proportional capillary mural thickening. Swollen, reactive endothelial cells appeared to effece the vascular lumen and may impair capillary perfusion. These microcirculatory changes, in the presence of biochemical and rheologic disturbances may contribute to tissue hypoxia and underly the loss of axons in experimental diabetic neuropathy.
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  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 138 (1984), S. 273-277 
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Secondary metabolite ; Allelopathy ; Photosynthesis ; Electron transport ; Thylakoids ; Herbicides ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyanobacterin is a secondary metabolite produced by the cyanobacterium, Scytonema hofmanni. Highly purified cyanobacterin was found to inhibit the growth of many cyanobacteria at a minimum effective dose of 2 μg/ml (4.6 μM). The antibiotic had no effect on eubacteria including the photosynthetic Rhodospirillum rubrum. The site of action of cyanobacterin was further investigated in the unicellular cyanobacterium, Synechococcus sp. Electron micrographs of antibiotic-treated Synechococcus cells indicated that cyanobacterin affects thylakoid membrane structure. The antibiotic also inhibited light-dependent oxygen evolution in Synechococcus cells and in spheroplasts. These data support our conclusion that cyanobacterin specifically inhibits photosynthetic electron transport. This activity is similar to herbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU). The anhydro analog of cyanobacterin had no biological activity.
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  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 140 (1984), S. 265-270 
    ISSN: 1432-072X
    Keywords: EcoRI ; EcoRI-DNA complexes ; EcoRI* activity ; Recognition sites ; Frequency of binding ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electron microscopy of negatively stained isolated restriction enzyme EcoRI revealed particle projections with triangular or square outlines, indicating that the enzyme, in its tetrameric state, is tetrahedron-like. The two dimers making up the tetramer appear to be arranged in two planes orthogonal to each other. Complexes formed by EcoRI with the plasmids pBR322 or pGW10 were investigated by electron microscopic spreading techniques. In the presence of Mg2+, EcoRI was bound to the DNA molecules to form pearl necklace-like aggregates. The number of bound EcoRI particles was much higher as the sum of EcoRI-and 5′..AATT..3′ sites (with exceptions, the 5′..AATT..3′ sites may function as one type of EcoRI* sites) along the DNAs, indicating unspecific binding. In the absence of Mg2+, EcoRI was bound to the DNA only at the recognition site for EcoRI and the sites where the tetranucleotide sequence 5′..AATT..3′ was present. A direct correlation of the local concentrations of the bases A and T within the flanking sequences of the binding sites with the frequency of EcoRI to the DNA was observed. Dimers and tetramers of the enzyme was found to bind to the DNA. Tetramers occasionally exhibited two binding sites for DNA as indicated by the observation of DNA loops originating at the sites of bound tetrameric EcoRI particles.
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  • 26
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    Journal of cancer research and clinical oncology 107 (1984), S. 242-244 
    ISSN: 1432-1335
    Keywords: Phospholipase ; Plasma membrane ; Cytochemistry ; Electron microscopy ; Human tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Phospholipase activity was localized for the first time by cytochemical staining at the plasma membrane of malginant cells in gastric adenocarcinomas by electron microscopy. This activity was not found in benign cells of the same tumor, e.g., in components of the connective tissue underlying the glandular epithelium, or in cells beyond the margin of the same tumor. Neither benign nor maligant cells of colorectal tumors, nor those in malignant melanoma, had any phospholipase activity that could be demonstrated by the method.
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  • 27
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    Journal of cancer research and clinical oncology 107 (1984), S. 229-232 
    ISSN: 1432-1335
    Keywords: Prolymphocytic leukemia ; Cytoplasmic inclusions ; X-ray microanalysis ; Chronic lymphocytic leukemia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A patient with prolymphocytic leukemia is described. The peripheral blood and bone-marrow cells contained nuclear pockets, bridges, and appendices, as well as cytoplasmic inclusions that were not membrane bound or connected with the endoplasmic reticulum. X-ray microanalysis of the cells showed them to contain large amounts of phosphorus, sulfur, chlorine, and calcium, as well as a smaller amount of sodium and magnesium in comparison with control lymphocytes. When compared with lymphocytes of a patient with chronic lymphocytic leukemia (CLL), the patient's cells showed higher amounts of magnesium, sulfur, and chlorine, while the sodium content was decreased. The usefulness of electron microscopy and X-ray microanalysis in the diagnosis of this type of leukemia is discussed.
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  • 28
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    Virchows Archiv 403 (1984), S. 27-40 
    ISSN: 1432-2307
    Keywords: Spleen ; Ellipsoids ; Morphometry ; Electron microscopy ; Lymphocyte traffic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A study of ellipsoids (EL) in the human spleen was done on 25 surgically resected specimens in order to assess the number of EL, their structure, the nature of the cuff cells and the problem of lymphocyte traffic through their wall. The results show that an average spleen of 200 g contains 1.6 × 107 EL. They are localized in a constant segment of the vascular tree, just at the transition of the penicillary arterioles into capillaries and they consist of a capillary (not an arteriole) surrounded by a cuff of cells. These cells are neither endothelial nor smooth muscle cells, display lysosomal activity and are considered as fixed specialized pericapillary cells capable of cytoplasmic expansion. Since their number is inconstant in different individuals and in different species they are considered to be dynamic histological structures. Because of the constant presence of lymphocytes in their walls we consider the EL to be a transit system for lymphocytes and the splenic equivalent of the high endothelial venules in the lymph nodes.
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  • 29
    ISSN: 1432-2307
    Keywords: Gastric carcinoma ; Scirrhous carcinoma ; Collagen ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Collagen types I and III were examined immunohistochemically in 32 cases of gastric carcinoma classified as poorly differentiated adenocarcinoma with scirrhous stroma, well differentiated adenocarcinoma with intermediate stroma, or poorly differentiated adenocarcinoma with medullary stroma. In the stroma of scirrhous carcinoma, types I and III collagens were distributed abundantly in fibrillar or granular patterns with little difference in the intensity of staining. In well differentiated adenocarcinoma, type I collagen was diffusely distributed in the stroma with type III collagen distributed sparsely. In poorly differentiated adenocarcinoma with medullary stroma, the two types of collagen were only found around capillaries, constituting the tumor interstitium. Electron microscopic examination of scirrhous carcinoma showed tumor cells partially covered with fibroblasts, and discontinuous basal lamina, collagen fibers and microfibrils present between tumor cells and fibroblasts. In well differentiated carcinoma, tumor cells were surrounded by fibroblasts, and well developed basal lamina was observed beneath the tumor cells. In poorly differentiated carcinoma with medullary stroma, the stroma consisted of capillaries and very few fibroblasts with discontinuous basal lamina occasionally being present between tumor cells and fibroblasts.
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  • 30
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    Cell & tissue research 237 (1984), S. 219-226 
    ISSN: 1432-0878
    Keywords: Spermatogonia ; Spermatocytes ; Carbohydrates ; Guppy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of guppy (Poecilia reticulata) spermatogonia and spermatocytes has been studied using electron microscopy. The spermatogonia, situated at the apex of the seminiferous tubule, are almost all surrounded by a network of Sertoli cells; they have very diffuse chromatin and one or two large nucleoli. The cytoplasm contains relatively few organelles, although annulate lamellae are found. The mitochondria have few cristae and are concentrated at one pole of the cell; they are sometimes found with intermitochondrial cement. These spermatogonia are separated from each other, having no intercellular bridges or inclusion in Sertoli cells, and are relatively undifferentiated; they correspond to stem cells. The spermatogonia beneath the apex are organized into cysts. First-generation spermatogonia are more dense and heterogeneous, their nuclei becoming smaller and their chromatin becoming denser during successive generations. In spermatocytes, the synaptinemal complex exists as a modified form until metaphase. The concentration of organelles in the cytoplasm increases and the organelles become more diversified as spermatogenesis progresses. Many cytoplasmic bridges are observed (several per cell), indicating that the cells remain in contact after several divisions. These changes in germ cell structure have been related to some of the characteristic features of spermatogenesis in guppy, e.g. the large number of spermatogonial generations and the complexity of spermiogenesis.
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  • 31
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    Cell & tissue research 238 (1984), S. 413-416 
    ISSN: 1432-0878
    Keywords: Peroxisomes ; DAB-cytochemistry ; Electron microscopy ; Liver, amphibian ; Gymnophiona ; Ichthyophis glutinosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of hepatic peroxisomes was investigated in Ichthyophis glutinosus (Amphibia: Gymnophiona), employing perfusion fixation and the diaminobenzidine (DAB) technique for the visualization of catalase. The majority of peroxisomes is circular or rod-shaped, although elongated particles occasionally occur. They contain a finely granular matrix, lightly stained after the DAB procedure. Their mean diameter is approximately 0.25 μm. Serial sections reveal that the circular and rod-shaped peroxisomal profiles are cross and oblique sections of highly tortuous, tubular organelles exceeding 2 μm in length. In addition to tubular profiles, elongated, rectangular particles, as well as straight dumbbell-shaped organelles with distinct marginal plates are observed. They range from 900 to 1650 nm in length (mean = 1200 nm). In the flattened, thin central portion of the dumbbell-shaped particle, the peroxisomal membranes form a cisterna enclosing one or two uniformly thick marginal plates, which display a definite substructure with a periodicity of 10 nm. These findings indicate that peroxisomes in the liver of Ichthyophis exhibit a complex organization. It is suggested that the organelles undergo a specific differentiation process, morphologically characterized by the formation of enlarged segments of unusual shape.
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  • 32
    ISSN: 1432-0878
    Keywords: Ovulation (rabbit) ; Graafian follicle ; Perfusion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Isolated ovaries from untreated, sexually mature rabbits were introduced into an in vitro perfusion system and perfused with a chemically defined medium containing albumin. The ovaries were perfused for up to 15 h (mean 11.5 h) and then processed for morphological investigation. Both at the light- and electron-microscopical levels, most of the ovaries exhibited a normal structure comparable with ovaries in situ. In two cases, however, marked accumulations of bacteria were found, although not inside the follicles. Since ovulation in the rabbit normally occurs between 9.5–13 h after mating or human chorionic gonadotrophin treatment, this model seems adequate for studies of ovulation in vitro. It is, however, important to study the ovaries microscopically after the perfusion to detect artifacts, e.g., bacterial infection, that may have influence on the process of ovulation.
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  • 33
    ISSN: 1432-0878
    Keywords: Tannic acid ; Acetylcholine receptors ; Tissue culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spinal cord neurons from 9-day chick embryos were maintained in culture for up to 35 days and then fixed in 4% cacodylate-buffered glutaraldehyde containing 2% tannic acid. After about 15 days in culture a small percentage of the synaptic specializations present were characterized by striking electron-dense striations averaging 15 nm in width, oriented perpendicular to the postsynaptic membrane. These structures increased in frequency with time in culture (to a maximum of about 10% of all synapses in the oldest cultures); they were asymmetrical, protruding approximately 8 nm into the synaptic cleft, and more deeply (approximately 15–18 nm), into the postsynaptic cytoplasm. On the basis of earlier work by Sealock (1980) they are interpreted as concentrations of acetylcholine receptors. Similar membrane differentiations were also seen associated with active-zone areas of a few presynaptic membranes, and the possibility that these represent presynaptic acetylcholine receptors is discussed. Additional observations reported are (1) the presence of striations resembling those seen at the postsynaptic membrane in the membranes of some postsynaptic vesicles, and (2) filamentous links between the striations and cytoskeletal elements of the postsynaptic cell.
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  • 34
    ISSN: 1432-0878
    Keywords: Monoamine-containing cells ; Taste bud ; Paracrine cells ; Mechanoreceptors ; Electron microscopy ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The taste buds on the barbels in three species of teleosts (Cyprinus carpio, Misgurnus anguillicaudatus, Parasilurus asotus) were studied by means of fluorescence and electron microscopy. Intensely yellow-fluorescent cells, which are disk-shaped and located exclusively in a basal position, are observed in the barbel-buds of all fishes examined. The basal cells contain a large number of small clear vesicles approximately 40–60 nm in diameter, which show a tendency to aggregate in the cytoplasm facing the junction of the nerve terminals; chemically transmitting synapses are seen in the latter region. It is suggested from the present observations that the basal cells in the barbel-bud may originate from Schwann cells and have a dual function both as mechanoreceptors and paracrine elements. Since the administration of 5,6-DHT results in an appearance of small dense vesicles among the small clear vesicles, the possibility exists that the basal cell may be capable of taking up monoamines and storing them in the small clear vesicles.
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  • 35
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Calcium pool ; Calcium release ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to identify a cellular Ca2+-pool, from which calcium is released when secretagogues are applied, tissue fragments of the rat exocrine pancreas were incubated and fixed with glutaraldehyde in the presence of calcium. By means of this procedure electron-dense deposits were found on plasma membranes. X-ray microanalysis showed that these deposits contain calcium. Stimulation of tissue fragments with the use of the secretagogues carbachol or cholecystokinin reduced the number of deposits by about 80%. When the antagonist atropine was applied after carbachol stimulation, deposits reappeared on cell membranes, which then disappeared again after a second stimulation with cholecystokinin. In the presence of procaine, carbachol was inhibited and only slightly reduced the Ca2+-deposits on the plasma membranes. These results suggest that a calcium pool, from which calcium is released to induce enzyme secretion on stimulation, is located in the cell membrane
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  • 36
    ISSN: 1432-0878
    Keywords: Chloride cells ; Acid stress ; Gill ; Electron microscopy ; Fathead minnow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fathead minnows, Pimephales promelas, were exposed for 129 days to Lake Superior water acidified with sulfuric acid by means of a flow-through toxicant injection system. The effects of chronic acid stress (pH 6.5, 6.0, 5.5, 5.0) on gill histology were examined. Most of the histological effects were seen at pH 5.5 and 5.0 and were confined primarily to changes in numbers, distribution, and morphology of chloride cells. At low pH levels there tend to be more chloride cells in the gill epithelium and an increased percentage of these cells in the secondary lamellae. In contrast to normal chloride cells, chloride cells from fish exposed to low pH frequently had apical pits while some had bulbous apical evaginations. The occurrence of structural changes in chloride cells during exposure to acid water suggests that chloride cells may be involved in acclimation to acid stress.
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  • 37
    ISSN: 1432-0878
    Keywords: Lactating cell ; Lipid droplets ; Secretory vesicles ; Mitochondria ; Intracellular associations ; Electron microscopy ; Milk secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The size, cellular location, and identity of surface-associated components were determined for lipid droplets in lactating cells. Transmission electron-microscopic measurements were made involving 3801 droplets in approximately 211 cells from three rats and 1197 droplets in 66 cells from a mouse. For the purposes of droplet evaluation, cells were divided into seven locations ranging from basal to secreting positions. Droplets were also categorized with respect to contact with other droplets, basolateral plasma membrane, mitochondria, Golgi apparatus, secretory vesicles, and endoplasmic reticulum-cytoplasm (ERC). Data on droplet size showed that droplet growth occurs mainly in the secretory position, confirming previously published findings. Lipid droplets from mouse tissue, although somewhat smaller in size showed similar growth trends to those of the rat. Data on numbers of droplet contacts and percentages of droplet circumferences involved in associations with other cell components showed that the dominant interaction of lipid droplets was with the ERC. However, intimate association of droplets with mitochondria was noted in all cellular locations. In addition, nursed animals exhibited a greater proportion of droplet surface association with secretory vesicles and less in contact with mitochondria in comparison to those not nursed. The significance of these relationships to milk synthesis and secretion is discussed.
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  • 38
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    Cell & tissue research 236 (1984), S. 249-255 
    ISSN: 1432-0878
    Keywords: Oocyte ; Nucleolus ; Silver staining ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The nucleoli of dictyate-stage growing oocytes in rat ovaries were examined both with routine electron microscopy and electron microscopy after silver nitrate and ammoniacal silver nitrate (Ag-AS) staining. The nucleoli of the unilaminar follicular oocytes consist of twisted strands of dense fibrillar components, aggregates of granular components, and small fibrillar centers. After Ag-AS staining, silver grains are numerous on the dense fibrillar strands, fewer on the fibrillar centers, and very sporadic on the granular aggregates. The same stainability of three nucleolar components with the Ag-AS method was also confirmed in the nucleoli segregated by actinomycin D. During the transition of growing oocytes from bilaminar to plurilaminar follicle stage, the nucleolar dense fibrillar strands gradually conglomerate and are transformed into large and compact spherules. The stainability of dense fibrillar components with the Ag-AS method was lost along with this nucleolar transformation. These results may provide some new clues on the functional significance of AgAS-positive proteins in the nucleoli.
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  • 39
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    Cell & tissue research 235 (1984), S. 51-58 
    ISSN: 1432-0878
    Keywords: Parathyroid glands ; Electron microscopy ; Light microscopy ; Quantitative histology ; Mongolian gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stereology and semi-automatic image analysis were used with the aim of comparing the structure of parathyroid glands from untreated adult Mongolian gerbils fixed by immersion with those fixed by perfusion. Subclassification of the chief cells based upon the staining affinity or electron density of the cytoplasm was readily performed only in glands fixed by immersion, and so-called atrophic cells were observed only in these glands. The atrophic cells were often surrounded by “light” chief cells. In glands fixed by perfusion, “light” chief cells were only rarely encountered. A significant difference between glands fixed by immersion and those fixed by perfusion was found only with regard to the form of cells and nuclei, those fixed by perfusion being more spherical. When comparing individual cells within glands fixed by immersion, “light” chief cells were more spherical and had a significantly larger nuclear and cellular size, and a lower mitochondrial volume density than the “intermediate”/“dark” chief cells. Otherwise there were no significant differences in any of the parameters investigated. These data indicate that occurrence of socalled “light” chief cells and atrophic cells is a result of improper fixation. The results of this study do not favour the concept of a functional cycle with a simultaneous occurrence of active and inactive cells within parathyroid glands.
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  • 40
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    Cell & tissue research 235 (1984), S. 153-158 
    ISSN: 1432-0878
    Keywords: Bovine ; Interdigitating cell ; Lymphoid tissues ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-microscopic studies of lymphoid tissues from bovine fetuses and from calves disclosed a non-lymphoid cell type in the thymus-dependent zones of secondary lymphoid tissues and in the thymus that is distinguishable from reticulum cells, epithelial and endothelial cells, and macrophages. Based on morphological and topographical criteria, the cell is identified as the interdigitating cell. In addition, studies of the tissues of normal and virus-challenged fetuses, and of conventionally reared calves, indicated that the interdigitating cells originate from monocytoid cells, which undergo differentiation in the thymus-dependent zones during an immune response.
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  • 41
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    Cell & tissue research 235 (1984), S. 243-249 
    ISSN: 1432-0878
    Keywords: Gap junction ; Electron microscopy ; Freeze fracture ; Cell-to-cell communication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gap junctions exist in the septa between the segments of the lateral giant axons in the ventral nerve cord of the crayfish Procambarus. A large increase in the resistance (uncoupling) of these gap junctions was brought about by mechanical injury to the axonal segments. Both thin sections and freeze-fracture preparations were used to monitor the morphological changes which occurred up to 45 min after injury. There was no apparent change in the organization (a loose polygonal array) of the intramembrane particles which make up the junctional complex up to 45 min after injury. In some instances, however, the intramembrane particles appeared to have moved away from the junctional area. Other junctional regions were internalized and appeared similar to what have been called annular gap junctions. Also at this time (20–25 min after injury), a dense cytoplasmic plug formed in uninjured axon near the junctional region. It is concluded that the gap junctions that exhibit a loose polygonal organization of the intramembrane particles may be either in a state of low resistance (coupled) or a state of high resistance (uncoupled).
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  • 42
    ISSN: 1432-0878
    Keywords: Ovulation ; Perfusion ; Graafian follicle (rabbit) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ovulation was induced in rabbits by intravenous administration of human chorionic gonadotrophin (HCG), and 4–5 h later the ovaries were isolated and introduced into an in-vitro perfusion system containing synthetic medium with albumin. Rupture of follicles occurred in vitro within the physiological time range (mean 11.3 h after injection of HCG), although with a reduced frequency. Preovulatory and ruptured follicles were studied in detail by light and electron microscopy. In the granulosa layer of ruptured or preovulatory follicles cytoplasmic blebbing activity, disappearance of CallExner bodies and differentiation toward luteinized cells were found. Perhaps the most important sign of normal preovulatory development in vitro was that the basement membrane surrounding the granulosa layer was penetrated by projections of granulosa cells. In the absence of this penetration phenomenon the granulosa layer prolapsed out of the follicle. Immediately before rupture, follicles showed marked degeneration, restricted to the outer layers of the apical wall, which is compatible with the hypothesis that degradative enzymes are released close to the surface of preovulatory follicles. Although the majority of follicles that ovulated under in-vitro conditions showed the same kind of morphological alterations as can be seen in vivo, occasional atypical ruptures occurred without any overt signs during perfusion. Also technical manipulations of the perfusion system, e.g., nonphysiological increase of perfusion pressure, could force follicles to rupture. This illustrates the importance of careful morphological study of all ovaries perfused in vitro before conclusions are drawn.
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  • 43
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    Cell & tissue research 237 (1984), S. 149-154 
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars distalis ; Innervation ; Synaptoid contacts ; Electron microscopy ; Rana temporaria L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pars distalis of the hypophysis of adult Rana temporaria, three types of nerve-fiber profiles were found at two distinct sites, in both lateral parts of the bordering regions of the anterior lobe with the intermediate lobe of the hypophysis. The first type of nerve-fiber profile consists of bundles of very fine axonal elements (diameter: 〈0.7 μm). The second type is formed by larger nerve fibers (diameter up to 4 μm) containing a few neurosecretory granules of approximately 100 nm. The third type of nervefiber profile resembles the second type but these nerve fibers make synaptoid contacts on at least two different types of glandular cells. The possible functional significance of these nerve fibers in the pars distalis is discussed. No nerve fibers were found (1) in the central part of the bordering region of the pars distalis with the intermediate lobe, (2) at the bordering region with the median eminence and (3) with the neurohypophysial stalk, and (4) in all other parts of the pars distalis.
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  • 44
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    Cell & tissue research 238 (1984), S. 165-175 
    ISSN: 1432-0878
    Keywords: Mesonephros ; Pig embryo ; Glomerulus ; Microvasculature ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vascularization of the pig mesonephros was investigated in embryos 5–8 cm in length. Vascular injections with microfil were cleared and dissected; corrosion casts were studied under the scanning electron microscope (SEM). Perfusion-fixed tissue was used for SEM and transmission electron microscope (TEM) studies, including freeze-fracture specimens. The branches of one mesonephric artery carry up to 15 glomeruli. Several glomeruli occupy the same arterial branch, with very short afferent arterioles proper. The efferent vessels, frequently 2–5, leave the extensive vascular pole opposite the entering arteriole and split into peritubular capillaries radiating towards the superficial veins. These capillaries form vascular regions in the shape of flattened pyramids. Along its course, one nephron is supplied by vessels derived from 4–7 glomeruli. The nephrons have less vascular contact than in the definitive kidney. The ultrastructure of the single mesonephric vessels matches the metanephric counterparts. Epithelioid cells with renin granules are common in afferent arterioles, larger arteries, and efferent vessels. The lobulated glomeruli are up to 750 μm long and flattened, showing the usual features of podocytes, mesangial cells, and an attenuated endothelium with fenestrations between 50 and 250 μm. It partially retains its own basement membrane. There is no proximal mesangium.
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  • 45
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    Cell & tissue research 238 (1984), S. 387-394 
    ISSN: 1432-0878
    Keywords: Pacinian corpuscles, cat ; Denervation ; Atrophy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Pacinian corpuscles of the cat located in the crural region and innervated by the interosseous nerve was studied 1 to 14 months after denervation. Both the Pacinian inner core and capsule remained well preserved one month after denervation. However, the denervated inner cores underwent progressive atrophy and wasting, which resulted in a gradual reduction of the amount of inner-core cells and lamellae, widening of interlamellar clefts, formation of empty spaces in the axial region and a considerable increase in the number of collagen fibrils. In spite of the wasting, the inner core still survived 14 months after denervation, but at least half of its volume became occupied by collagen fibrils which surrounded the remaining inner-core cells and lamellae. Collagen fibrils assembled in the denervated core were markedly thinner than those found in the capsule, as is also the case in normal Pacinian corpuscles. In the capsule, discrete focal degeneration, occasional pyknosis of the innermost capsular cells and macrophage infiltration were observed from the first month after nerve section onward, but the number of capsular layers remained within the normal range (30–40) up to 14 months after denervation.
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  • 46
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    Protoplasma 119 (1984), S. 48-54 
    ISSN: 1615-6102
    Keywords: Electron microscopy ; Marine alga ; Membrane contrast ; Osmium-azole complexes ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Addition of certain heterocyclic nitrogen-carbon compounds to standard osmium tetroxide solutions used as secondary fixative resulted in an enhanced general membrane contrast in cells of the marine algaEmiliania huxleyi (Lohmann) Kamptner. Ultrastructural cell morphology and the contrast distribution were compared between cells treated according to a standard secondary fixation procedure and cells post-fixed when above mentioned heterocyclic compounds were introduced; in both cases some of the ultrathin sections were post-stained. Different compounds were tested: 1,2,4-triazole (TRA), 3-amino-1,2,4-triazole (A-TRA), 5-amino-tetrazole (A-TEA) and 2,4,6-tri-amino-1,3,5-triazine (melamine). The results were interpreted to indicate the possible bonding types arising from interaction of the heterocyclic compounds with osmium tetroxide and with membrane constituents. Interpretations were partly inspired by considerations from coordination chemistry. All above tests which did not include post-staining of thin sections could be performed at alkaline pH, and consequently calcified structures were preserved. The enhanced osmium accumulation at membranes was verified with X-ray microanalysis, which also showed that in the cases where membranes were visibly contrasted, localization of probable sites of intracellular non-crystalline calcium was facilitated.
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  • 47
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    Plant and soil 76 (1984), S. 127-137 
    ISSN: 1573-5036
    Keywords: Adenylate pool ; Biomass volume ; CO2 evolution ; Chitin ; DNA ; Electron microscopy ; Enzymes ; Fluorescent antibody ; Fumigation-respiration ; Fungi Histochemistry ; Imunofluorecence ; Jones-Mollison technique ; Microcosms ; Monoclonal antibodies ; Nitrogen ; Nutrients ; Oxygen consumption ; Phosphorus ; Phytotoxins ; Plate counts ; Rhizobium ; Rhizosphere ; Sulphur ; Xenobiotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary There is an immense literature on biological and biochemical analyses of soils. Such analyses have revealed the enormous richness of species in soil and their vast range of metabolic potentials and ecological diversity. Accordingly, the approaches used to investigate the soil biota and its biochemistry usually have to be modified or adapted depending upon the purpose of the investigation. Studies of micro-organisms in the soil environment, are complicated because microbial cells are commonly attached to surfaces where they live side-by-side with other populations in consortia usually containing different morphological and physiological types. Such assemblages of organisms cannot be described quantitatively using cultural techniques, such as plate counts, which underestimate both cell numbers and viable biomass. The development of more powerful observational and staining techniques has improved our knowledge of the diverse morphological and biochemical composition of soil micro-communities. Such findings have been amplified at a grosser level by laboratory studies with multi-component systems (microcosms) to mimic field situations and to assess the range of biochemical potentials of microbial consortia. But despite notable advances in analytical methods we are still, with a few exceptions, unable to detect or identify those microorganisms which carry out specific biochemical transformations or determine whether particular cells are alive, dormant or dead at the time of observation. Considerable work has been done to define some of the fundamental ecological attributes of microbial assemblages in soil. Productive work on the metabolic activities of the soil microbiota, specially geochemical transformations of C, N, S and P, has been under way for more than a century. But only in more recent years have more sensitive and reproducible analytical methods become available to measure viable biomass in soil. This will enable some insight to be gained into the role that microbial biomass plays as a labile source and sink for plant nutrients.
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    Plant and soil 76 (1984), S. 319-337 
    ISSN: 1573-5036
    Keywords: Aggregates ; Aluminium ; Bacterial mucilage ; Binding agents ; Calcium ; Cation bridges ; Complexing agents ; Dispersion ; Electron microscopy ; Electrophoretic mobility ; Fungal hyphae ; Glues Iron ; Management Periodate ; Polysaccharides ; Rhizosphere ; Roots ; Slaking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The stability of pores and particles is essential for optimum growth of plants. Two categories of aggregates macro- (〉 250 μm) and micro- (〈250 μm) depend on organic matter for stability against disruptive forces caused by rapid wetting. Dispersion of clay particles from microaggregates is promoted by adsorption of complexing organic acids which increase the negative charge on clays. The acids are produced by plants, bacteria and fungi. However, the dispersibility of clay in microaggregates is offset by the binding action of polysaccharides, mainly mucilages produced by bacteria, but also by plant roots and fungal hyphae. The stability of microaggregates is also enhanced by multivalent cations which act as bridges between organic colloids and clays. Macroaggregates are enmeshed by plant roots, both living and decomposing, and are thus sensitive to management, and increase in number when grasses are grown and the soil is not disturbed. Lack of root growth,i.e. fallow, has the opposite effect. Various implications for management of soil structure are discussed.
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  • 49
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    European archives of oto-rhino-laryngology and head & neck 240 (1984), S. 55-61 
    ISSN: 1434-4726
    Keywords: Inner ear ; Adenylcyclase ; Ouabain-insensitive endothelial ATPase ; Cytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cytochemical localization of adenylcyclase in the lateral cochlear wall was studied using a modification of the Reik-Howell method. All the cell membranes of the stria vascularis and spiral prominence cells, except the vascular endothelium, showed a low enzyme activity. In the marginal cell and spiral prominence epithelium facing the endolymph, this activity was limited to the perilymphatic membrane sections. The results are discussed.
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  • 50
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    Journal of Morphology 179 (1984), S. 229-242 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Wild-collected adults of Bombina orientalis are bright green dorsally and red to red-orange ventrally. As a prelude to an analysis of the differentiation of pigment cells in developing B. orientalis, we describe structural and chemical aspects of the fully differentiated pigment pattern of the “normal” adult.Structurally, differences between dorsal green and ventral red skin are summarized as follows: (1) Dorsal green skin contains a “typical” dermal chromatophore unit comprised of melanophores, iridophores, and xanthophores. Red skin contains predominantly carotenoid-containing xanthophores (erythrophores), and skin from black spot areas contains only melanophores. (2) In ventral red skin, there is also a thin layer of deep-lying iridophores that presumably are not involved in the observed color pattern. (3) Xanthophores of red and green skin are morphologically distinguishable from each other. Dorsal skin xanthophores contain both pterinosomes and carotenoid vesicles; ventral skin xanthophores contain only carotenoid vesicles. Carotenoid vesicles in dorsal xanthophores are much larger but less electron dense than comparable structures in ventral xanthophores.The presence of carotenes in ventral skin accounts for the bright red-orange color of the belly of this frog. Similar pigments are also present in green skin, but in smaller quantities and in conjunction with both colored (yellow) and colorless pteridines. From spectral data obtained for xanthophore pigments and structural data obtained from the size and arrangement of reflecting platelets in the iridophore layer, we attempt to explain the phenomenon of observed green color in B. orientalis.
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  • 51
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    Journal of Morphology 180 (1984) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 52
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    Journal of Morphology 180 (1984), S. 29-35 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study describes intercellular bridges in the ovaries of neonatal gerbils. Electron microscopy has revealed the presence of true intercellular bridges, connecting oogonia or oocytes, in ovaries of newborn gerbils. The cytoplasm of the intercellular channels is similar to that of the connected cells, with mitochondria, smooth and rough endoplasmic reticulum, and free ribosomes present. Lysosomes are also occasionally present in the intercellular bridges and they may be involved in early waves of oocyte atresia. An electrondense substance, 350-500 Å thick, is located immediately beneath the unit membrane of the intercellular bridges. Accumulation of electron-dense material increases the thickness of the walls of the intercellular bridges, supporting and maintaining the patency of the channels. It is suggested that the intercellular channels probably allow the interchange of nutrients, organelles, and possibly regulatory materials as well.
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  • 53
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    Journal of Morphology 180 (1984), S. 55-68 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A comparative study of the forelimbs of the semifossorial prairie dog, Cynomys gunnisoni, and the scansorial tree squirrel, Sciurus niger, was focused on the musculoskeletal design for digging in the former and climbing in the latter. Based on lever arm mechanics, it was expected that the forelimb of the prairie dog would show features appropriate to the production of relatively large forces and that of the fox squirrel to relatively great velocity. Force and lever arm measurements were made of select forelimb muscles at the shoulder, elbow, and wrist joints for a series of angles in both species. Contraction time and fatigue indexes were determined for the same forelimb muscles. Contrary to expectation, in the few cases in which significant (P 〈 .05) differences were found, the forces, lever arms, and torques (force times its lever arm) were greater in the smaller fox squirrel. The observed variation in the torques produced fits the demands on the forelimb during climbing and digging as estimated from films. Several forelimb muscles of the fox squirrel show significantly higher mean contraction times than do the homologous muscles of the prairie dog. There were no significant differences between the two species in the fatigability of the selected forelimb muscles, although the mean fatigue index was always higher (less fatigable muscle) in the prairie dog. Similarities in the forelimbs of these two sciurids suggest that only minor modifications may have been required of the ancestral forelimb in order for descendent forms to operate successfully as climbers and diggers.
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  • 54
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    Journal of Morphology 180 (1984), S. 105-124 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy of neurons of the stomatogastric nervous system of Ascheta domesticus was studied using heavy metal iontophoresis through cut nerve ends followed by silver intensification. Nineteen categories of neuron are described and compared with neurons known from the stomatogastric nervous system of other insects. Possible functions for the neurons are suggested. Motor neuron candidates are suggested for all parts of the gut served by the stomatogastric nervous system, and axons of sensory neurons of the anterior pharynx are located. There are four neuron types that cannot readily be assigned motor, sensory, or interneuron functions: large dorsal cells of the frontal ganglion; the two neurons of the nervus connectivus, and two categories of neurons in the median neurosecretory cell group of the pars intercerebralis, the axons of which are contained in the stomatogastric nerves.
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    Journal of Morphology 180 (1984), S. 159-169 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the pedicellar segment of the fly antenna there is a large campaniform sensillum. The central projection of the sensory cell (LCC) of this large campaniform sensillum is described from labeling with horseradish peroxidase (HRP) and cobalt. The LCC projects bilaterally to several regions of the brain and subesophageal and thoracic ganglia. The LCC processes in these termination areas were analyzed in relation to other neural processes, including the remaining antennal sensory and motor projection. This analysis was aided by combining HRP labeling with Golgi silver impregnation. Based on earlier findings and the present data we suggest that the LCC, with its various outputs in, e.g., antennal and leg motor centers, serves as a multifunctional sensory path involved in control functions necessary in flight.
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  • 56
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    Journal of Morphology 180 (1984) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 57
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    Journal of Morphology 180 (1984), S. 173-180 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During the long starvation period (November to June) of the lizard (Varanus exanthematicus), pancreatic B cells undergo profound modification. The degeneration of β granules observed in electron microscopy appears correlated with the diminution of the immunoreactive insulin-like content of the pancreas. The analogy between the phenomena observed here and those reported in animals treated with alloxan is discussed.
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  • 58
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    Journal of Morphology 180 (1984), S. 195-211 
    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 crystallography of the internal shell of the pulmonate gastropod slug Limax maximus were studied at the levels of light and scanning electron microscopy, revealing patterns of shell ontogeny and morphogenesis. The calcified portion of the slightly convex ovoid shell is composed of a single palisade layer of calcitic crystals. Numerous projections, 100 μm in width at the dorsal tip, are found on the dorsal surface of the shell and coincide with local nucleation sites of primordial calcium salt deposition onto the periostracum. With continued calcification these projections coalesce ventrally, forming the single crystalline shell layer. The organic portion of the shell includes the periostracum and an extensive PAS-staining conchiolin. In EDTA-etched preparations, conchiolin appears as a spongy network of fibers throughout the shell. Both horizontal and vertical components of the conchiolin are present, the former of variable thickness and occurring in an intercrystalline manner, the latter always occurring normal to the horizontal set. Macromorphogenic growth is characterized by three distinct temporal stages. Primary growth occurs radially from the umbonal region. Secondary growth is synonymous with shell thickening. Tertiary growth is characterized by both a lateral component, in which the shell extends beyond the primary growth boundaries, and a ventral component, in which the shell continues to grow in thickness. SEM of the ventral shell surface reveals a pattern of growth at the crystalmatrix interface. Proteinaceous fibers of the conchiolin occur unidirectionally in horizontal rows. Zones of incipient calcitic crystallization onto these hypostracal fiber bundles are contrasted by zones of increasing crystallization until the fibrous template (reduced hypostracum) is completely covered by crystals.
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  • 59
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    Journal of Morphology 180 (1984), S. 271-296 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electron microscopy shows that the pharyngeal lining of the larval lamprey Petromyzon marinus is a structurally complex epithelial system that can be separated into eight epithelial types: gill lamellar, gill interlamellar, goblet cell, protective, terminal (taste) bud, preciliated, ciliated in tracts, and ciliated in grooves. Furthermore, these epithelial types encompass at least sixteen different cell types based on ultrastructure and, in some cases, correlative histochemistry (PAS, Alcian blue). Common to nearly all the epithelial types are basal cells and intermediate cells. These two cell types are seen as undifferentiated. Among mature cells, structural specialization as proceeded in three directions: (1) elaboration of mitochondria, probably related to molecular transport (ion-uptake cells, chloride cells); (2) ciliogenesis (preciliated and ciliated cell types); and (3) production of mucous secretory granules (mucous-platelet cells, goblet cells, superficial protective cells, columnar mucous cells, “cobblestone” cells, and marginal and dark cells in the terminal buds). Many of the functions of the cell types relate to the process of suspension feeding in this animal.
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  • 60
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    Journal of Morphology 180 (1984), S. 243-252 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A small short muscle frequently acts across a joint in parallel with a vastly larger and longer muscle; therefore it should play a minimal role in the mechanical control of that joint. This study provides evidence suggesting that the small member of such a “parallel muscle combination” (PMC) may serve an important sensory feedback role. The spindle densities of large and small members of PMCs in man and the dog were determined and compared. Epaxial PMCs controlling canine intervertebral joints were dissected and tissue samples were embedded in paraffin, sectioned transversely to the muscles' long axis and, stained with hematoxylin-periodic acid-Schiff (PAS). Representative tissue sections were projected on to stereological grids and the percentage volume of spindles was determined. Data existing in the literature were used to ascertain spindle densities in human PMCs controlling joints in the cervico-occipital region and the extremities. The spindle density for each muscle in a group of PMCs controlling a particular motion was listed, and the mean spindle densities were determined for both the large and the small members of the group. Student's unpaired t test was used to determine the significance of the differences between mean spindle densities. Linear regression was calculated and the data were plotted graphically.In all PMCs examined, the spindle density of the small muscles was significantly higher than that of their large counterparts. It is therefore proposed that the small muscles of PMCs may function as “kinesiological monitors” generating important proprioceptive feedback to the central nervous system.
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  • 61
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    Journal of Morphology 181 (1984), S. 1-8 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The internal reproductive apparatus of female Platynotus punctatipennis is composed of the paired ovaries, paired lateral oviducts, common oviduct, spermatheca associated with its accessory gland, and a bursa copulatrix. The accessory (colleterial) glands are absent. The ovary is made up of a large number of telotrophic ovarioles which are covered by a double-layered peritoneal sheath. The terminal filament is separated from the germarium by the basement membrane of the latter and consists of a syncytial core surrounded by the peritoneal sheath. Nutritive cords are absent. The pedicel shows highly eosinophilic and PAS-positive secretion of obscure origin. The spermatheca reveals a number of interesting features. It is composed of a pair of sperm-storing tubules, enclosed in a very thin muscle layer. A winecup-like structure, provided with a thick coat of circular muscles, connects the spermathecal gland with thespermathecal duct. Four types of intimal linings occur in the spermatheca and its associated structures. The wine-cup-like connection and four types of intima are entirely new features observed. Histology of the various parts of the reproductive apparatus is described.
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  • 62
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    Journal of Morphology 181 (1984), S. 29-47 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The formation of somites, coelomic sacs, splanchnic mesoderm, fat bodies, circular system, gonads, and musculature in the embryo of the primitive moth, Neomicropteryx nipponensis Issiki, is described. The following paired somites are formed: the labral, antennal, intercalary, mandibular, maxillary, labial, three thoracic, and 11 abdominal. Small but distinct coelomic cavities appear in all these somites. Labral somites differentiate into the labral muscles, stomodaeal muscles, and dorsal dilator muscles of the pharynx. Antennal somites differentiate into the antennal muscles, aorta, and the ventral dilator muscles of the pharynx. Intercalary somites are short-lived, disintegrating to liberate many free cells into the yolk. The suboesophageal body is not formed. Mandibular somites differentiate into the mandibular flexor and extensor muscles. Maxillary and labial somites differentiate into the splanchnic mesoderm, fat bodies, and into muscles of the maxillolabial region. Three pairs of thoracic and ten pairs of abdominal somites split into the splanchric and somatic mesoderm. The 11th abdominal somites merge into the proctodaeal mesoderm, and differentiate into the musculature of the hindgut. The heart is formed by the fusion of the cardioblasts derived from the first thoracic to the tenth abdominal segment. The aorta arises from the antennal median mesoderm. Blood cells are derived from the median mesodermal cells of the maxillary to the tenth abdominal segment. Germ cells appear at the mediodorsal corner of each somite in the fifth abdominal segment. They become enclosed with a mesodermal sheath to form a pair of rudimentary gonads in this segment. Major muscles in the head, thorax, and abdomen of the fully grown embryo are described.
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  • 63
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    Journal of Morphology 181 (1984) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 64
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    Journal of Morphology 181 (1984), S. 155-160 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The architectural and histochemical properties of the anatomically distinct compartments of the semitendinosus muscle (ST) of mice, rats, guinea pigs, and rabbits show that the ST is composed of two separate compartments aligned in series - a destal compartment (STd) and a proximal one (STp). The STp is further subdivided into a ventral head (STpv) and a dorsal head (STpd). The muscle fibers were arranged in parallel to the line of muscle pull within each compartment. The STd has the longest and the STpv the shortest fibers in all species. The physiological cross-sectional area and the estimated tetanic tension was greatest in the STd. Based on the staining pattern for myosin ATPase (alkaline preincubation) and an oxidative indicator (NADH or SDH), the STpv has the highest percentage of slow-oxidative (SO) or SO plus fast-oxidative-glycolytic (FOG) fibers of any portion of the muscle. The differences in fiber-type distributions and architectural designs of the separate compartments suggest a specialization of function of the individual compartments.
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  • 65
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    Journal of Morphology 181 (1984), S. 97-131 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The three-dimensional structure of the organ of Bellonci in the marine amphipod Gammarus setosus and the relationship between its sensory cells and concretion are described using light, transmission, and scanning electron microscopy, with chemical treatment for cell lysis, calcium chelation, glycogen staining, and lanthanum labelling. The organ is encapsulated and has three units called fuselli. Each is enclosed by two fusellar cells which generate and release calcium granule strands into the cores of the fusellar concretions, which are united in the center of the organ. The surface of each fusellus is traversed by spiral dendrites entering dorsally and ending ventrally. The spiral dendrites arise from sensory neurons contained in a palm-shaped ganglion in the center of the capsule, beyond which they are twisted like a rope before reaching the concretion. The spiral dendrites are linked in pairs by gap and tight junctions and each gives origin to two pairs of 9+0 sensory cilia 30 μm apart. The ciliary distal segments give rise to long tubules which are in contact with the calcium granule strands. The ciliary proximal segments are expanded by many long mitochondria which interdigitate with the branched striated ciliary rootlets. The concretion is suspended in the capsule cavity by axons originating from four neurons of a remote mechanoreceptor. The structure of the organ suggests that it is a sensory organ involved in the reception and integration of a variety of stimuli.
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the kidney and the bladder of the bullfrog (Rana catesbeiana), the bullfrog tadpole, and the mudpuppy (Necturus maculosus) were studied with special attention to the innervation of renal tubule cells and bladder epithelial cells. In the bullfrog kidney, nerve terminals and varicosities were frequently associated with the tubule cells, apparently in an increasing order from the proximal tubule to the connecting tubule. Although these terminals and varicosities did not directly contact the tubular cell membrane, an aggregation of synaptic vesicles on the side facing the tubule was considered as morphological evidence that neurotransmitter can be released here and can affect the transport activity of the tubule cells. The association of nerve varicosities with canaliculi cells in the connecting tubule was also demonstrated. In the bullfrog tadpoles, renal tubule cells were occasionally innervated. In the mudpuppy, renal tubule cells were only poorly innervated. The epithelium of the bullfrog bladder was commonly innervated. Nerve terminals with synaptic vesicles were located very near basal cells and even contacted them directly on rare occasions. In the mudpuppy, the innervation of the bladder epithelium was observed infrequently. The bullfrog tadpoles did not possess an apparent bladder. In all materials studied, renal arterioles and bladder smooth muscle cells were innervated.
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  • 68
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    Journal of Morphology 179 (1984) 
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  • 69
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    Journal of Morphology 179 (1984), S. 13-19 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytoplasmic microtubules can be divided into two subpopulations: (1) those adjacent to the nucleus (perinuclear), and (2) those distributed between the myofilament bundles (nonperinuclear). Previous observations (Cartwright and Goldstein, '83) indicate total cytoplasmic microtubule numeric density increases to a maximum at 5-9 days and decreases to the steady value of the adult muscle. We have examined the numeric density (mean numbers of microtubule profiles per μm2 cross-sectional area) of the perinuclear subpopulation and compared it to the numeric density of the total cytoplasmic microtubule population in postnatally developing rat papillary muscle ages 1, 3, 5, 9, 21, and 42 days, and adult. The perinuclear region was defined as the area around the nucleus which extends to the 0.273 μm from the nuclear envelope. The density of perinuclear microtubules did not change with postnatal development. Our study suggests that perinuclear microtubules are a separate and relatively stable subpopulation of the total population of cytoplasmic microtubules and may serve a function different from that of the more variable nonperinuclear microtubules.
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    Journal of Morphology 180 (1984), S. 19-28 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Each antenna of both sexes of adult Rhodnius prolixus has approximately 570 mechanosensitive neurons that innervate five morphologic types of cuticular mechanosensilla: campaniform sensilla, tapered hairs, trichobothria, and type I and type II bristle sensilla. Each campaniform sensillum and tapered hair is presumably innervated by one mechanosensitive bipolar neuron and probably functions in proprioception. The campaniform sensilla being located at the base of the scape could monitor the position of the antenna. Tapered hairs are found at the distal margin of flagellar segment I and projecting laterally from the bases of the pedicel and scape. They probably provide information about the relative positions of the antennal segments. Seven trichobothrium are located on the pedicel and three on flagellar segment I. Each trichobothrium has a long filamentous hair inserted into the base of a socket that extends inwardly as a cuticular tube and is innervated by one bipolar neuron with a tublar body, a parallel arrangement of microtubules associated with electron-dense material. The trichobothria may respond to small variations in air currents.Type I bristles occur at the base of the antenna and are the most numerous type of mechanosensillum; an average of 452 occur on each antenna of females and 440 on males. The bristle is curved toward the antennal shaft and is serrated distally. Type II bristles are located distally and are the second most numerous type of mechanosensillum; an average of 88 were counted on each antenna of females and 94 on males. The type II bristle is straight with small, longitudinal, external grooves and projects laterally from the antennal shaft. Each type I and II bristle sensillum is innervated by a bipolar neuron whose dendrite is divided into an inner and outer segment. The outer segment is encased by a dendritic sheath which may be highly convoluted and distally contains a tubular body. Two sheath cells are associated with each sensillum. Both types of bristle sensilla have a tactile function.The tubular bodies of both types of bristle sensilla have a complex structure indicating that they are very sensitive. Variations in the amount and arrangement of the electron-dense material at the tip of the tubular bodies may reflect differences in viscoelastic properties that underlie functional characteristics.
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    Journal of Morphology 180 (1984), S. 69-79 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fine structural study indicates that the neuromuscular system of stage I polyps of Aurelia aurita is exclusively ectodermal.The three major muscle fields are the radial muscles of the oral disc, the longitudinal muscles of the tentacles, and the muscle cords of the septae and the column; the muscle fields are in physical continuity at the peristomial pits and share a common innervation and type of myofibril. The myofibril is striated in the tentacle base, in the outer oral disc, and in the upper part of the muscle cord; it grades into a smooth muscle toward the tentacle tip, the mouth, and the lower part of the cord. There is a fourth field of longitudinal smooth muscle in the pharynx.The nervous system consists of an epithelial sensory cell in the tentacle and a single type of neuron found in the subepithelial layer of the tentacle, oral disc, and muscle cord. The lack of gap junctions suggests that there is no nonnervous conduction system. The subepithelial layer also contains three types of fibers and a type of soma which cannot be characterized as neuronal. The soma is identified as the “neurosecretory cell” described in Chrysaora. The absence of neuromuscular elements in the column and stolon distinguishes the Aurelia aurita collected from Washington, USA, from English polyps previously described.
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  • 72
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    Journal of Morphology 180 (1984), S. 125-144 
    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 interrelationships of the mouthparts and of the food canal and its accessory cephalic structures of the females of Simulium venustum are described through microscopic observations. The mouthparts that enter the would during feeding are the mandibles, maxillary laciniae, hypopharynx, and labrum and collectively form a “syntrophium.” The labium and labellar lobes, which do not enter the wound, ensheathe the syntrophium distally and must be retracted to allow biting.We present an interpretation of mouthpart function during biting that emphasizes how biting steps are accomplished and what sensory structures are used to monitor the process. Four phases of biting are identified: (1) initial penetration of the skin effected by the mandibles; (2) consolidation of mouthpart position involving anchoring the syntrophium into the wound by means of the barbed laciniae; (3) diet sampling and active feeding - food (blood) is pumped by three groups of muscles forming two functional pumps, one located in the cibarium, the other in the pharynx. These pumps are separated from each other and from surrounding regions of the food canal by valve muscles making the pumping process a complex and highly coordinated series of muscular contractions; and (4) mouthpart disengagement involving removal of the laciniae, thus releasing the syntrophium from the wound.
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  • 73
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    Journal of Morphology 180 (1984), S. 37-54 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The external morphology of contact-chemoreceptive hairs (taste hairs) of six fly species, Calliphora vicina, Lucilia caesar, Musca domestica, Phormia terranovae, Sarcophaga carnaria and Stomoxys calcitrans, is described. The species can be distinguished by the differences between the patterns of taste hairs at the ventral side of their prothoracic tarsi. Taste hairs can be subdivided into morphological types, using the shape of the cuticle around the apical pore as criterion, even though this shape changes slightly on opening and closing of the pore. Light microscopical studies reveal that the nature and osmolarity of stimuli are decisive for the effect stimuli have on the shape of the top of the labellar hairs. The motions of the apical cuticle appear to be reversible.Gentle ultrasonic treatment preserves the shape of the cuticle of the top and the diameter of the pores on fluid stimulation. This technique makes it possible to study the effect of a previous stimulation on both tarsal and labellar hairs with the scanning electron microscope. It is supposed that stimuli can affect cuticular components around the pore, producing volume changes in that cuticle which alter the diameter of the pore.
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  • 74
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    Journal of Morphology 180 (1984) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 75
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    Journal of Morphology 180 (1984), S. 297-308 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During the breeding season, male anurans display clasping behavior by holding females with their forelimbs. This behavior is peculiar to males, and may require specializations in forelimb musculature. The present study revealed that five kinds of forelimb muscles were heavier in the male Japanese toad than in the female: the flexor carpi radialis (FCR), the flexor antibrachii medialis caput superius (FAMsup), the abductor indicis longus (AIL), the extensor carpi radialis caput superius (ECRsup), and the flexor antibrachii lateralis superficialis caput superius (FALSsup). In addition, one breast muscle, the coracoradialis (CR), was also heavier in males than in females. A quantitative analysis of muscle fibers processed for myosin ATPase activity showed that, in such “sexually dimorphic muscles” of the female, both fast (twitch) and slow (tonic) muscle fibers were of smaller diameter than in other forelimb muscles of both sexes (all male muscles plus “nondimorphic muscles” of the female). Moreover, both types of fibers were less numerous than in the corresponding muscles of the male. These results suggest that the “sexually dimorphic muscles” are used especially for clasping by the male and are degenerative or subnormal in the female. Slow muscle fibers were neither peculiar to, nor abundant in, these clasping muscles, although they may well be necessary for tonic and prolonged contractions of the forelimb muscles during clasping. The mechanism of sexual dimorphism may be a direct action of androgens on clasping muscles or an indirect action on clasping muscles via the innervating motoneurons.
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  • 76
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    Journal of Morphology 181 (1984), S. 21-28 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Shells from eggs of the turtle Kinosternon flavescens were examined during different stages of development with light and scanning electron microscopy. Prior to initiation of the calcareous layer, organic spheres or cores appear on the outer surface of the shell membrane. Presumably, these cores nucleate deposition of the mineral layer of the eggshell. Growing shell units of the mineral layer are rounded and nodular in shape, crystallites of adjacent shell units do not interlock, and numerous spaces occur between shell units. As growth continues, most of the spaces between shell units are obliterated, and shell units become more elongate in form. The calcareous layer of partially shelled eggs resembles the calcareous layer of flexible-shelled eggs of emydids and chelydrids. Eggshells assume the morphology typical of rigidshelled chelonian eggs only at an advanced stage of shell formation. These observations indicate that rigid and flexible eggshells may form by fundamentally similar mechanisms, with length of shell growth being the primary determinant of whether shells are flexible or rigid.
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  • 77
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    Journal of Morphology 181 (1984), S. 69-86 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hymenopteran venom glands are epidermal glands that have evolved from female accessory reproductive glands. In the honey bee, Apis mellifera L., the venom gland shows many of the fine structural features of primitive glands. A honey bee venom gland is a simple, long, thin, distally bifurcated structure, opening into an ovoid reservoir. Along most of the length of the gland are similar secretory units that have four major components (secretory cells, duct cells, ducts, and end apparatuses), except in the part of the gland proximal to the venom reservoir, where the secretory units resemble those around the venom reservoir. In the latter secretory units a funnel structure occurs between the duct (which is shorter than that of the secretory units of the gland) and the end apparatus. This funnel may be important in protecting the secretory cells around the reservoir from the cytolytic activity of the complex chemical mixture constituting the venom.
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  • 78
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    Journal of Morphology 181 (1984), S. 175-204 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anatomical studies of cephalic bones and muscles combined with cine and high-speed videographic analyses of feeding demonstrate that Amphiuma tridactylum uses two distinct types of suction feeding. Small or relatively immobile prey generally elicit a stationary capture mode in which mouth opening precedes buccal expansion and there is no forward movement of the head of the salamander. Actively moving prey are captured by a rapid strike during which mouth opening and buccal expansion are synchronous and the extent of buccal expansion is greater than in stationary feeding. Differences between these feeding modes may be due to differences in the timing of contraction of the rectus cervicis muscle. Synchronous hyoid and mandibular excursions during the strike are probably generated by simultaneous contractions of the depressor mandibulae and rectus cervicis, whereas delay of hyoid excursions during stationary capture suggests sequential contraction of the depressor and rectus cervicis.
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  • 79
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    Journal of Morphology 181 (1984), S. 161-173 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Silver impregnation of serial histological sections of the tubeworm Chaetopterus variopedatus revealed the presence of a subepidermal nervous system. The anterior nervous system is delimited by the first 11 segments and comprises (1) two dorsolateral cerebral ganglia and lateral instead of ventral nerve cords which are widely separated and thus connected by unusually long commissures, (2) a pharyngeal ganglion in the fourth segment which is connected to the cerebral ganglia by pharyngeal nerves and constitutes along with the pharyngeal plexus a stomatogastric or enteric nervous system, and (3) small, presumably segmental ganglionic swellings along the lateral nerve cords from which emerge commissures and parapodial nerves. No subesophageal ganglion or periesophageal connective could be identified. The lateral nerve cords converge toward the midline in the 12th segment to form the posterior nervous system comprising a pair of ventromedian nerve cords with their repetitive segmental ganglia from which emerge numerous short commissures and three segmental nerves coursing toward the dorsal and ventral regions of parapods and toward the neuropod. Light and electron microscopic investigations of cerebral and segmental ganglia showed an arrangement of inner neuropile and of unipolar neuron somata at the periphery. The neuropile comprises numerous neurites ranging in diameter from 0.5 to 10 μm and making polarized or symmetrical synaptic junctions with each other. The pharyngeal ganglion consists of a similar neuropile and of a large mass of cell bodies which is traversed by an elaborate network of sinuses and harbors three types of neurosecretory cells in addition to the conventional neuron somata. These findings are interpreted in the framework of the highly specialized morphological features and habits of Chaetopterus, and the welldeveloped stomatogastric system is considered to be related to control of the feeding activities.
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  • 80
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    Journal of Morphology 181 (1984), S. 297-303 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Whenever individuals of the freshwater sponge Ephydatia fluviatilis belonging to different strains come into contact, they reject each other by building a nonmerging front. The present work describes the development, the structure, and the nature of the barrier secreted between two individuals. The observations reported give unequivocal data about the collagen nature of the incompatibility barrier. First, ultrastructural investigations reveal the presence of fibrils and microfibrils which are, respectively, typical of collagen and spongin. Second, incorporation of tritiated proline, a characteristic precursor of collagen and related products, is particularly intense in the front. The involvement of several cell types in the barrier formation is discussed. The allogeneic incompatibility reaction between E. fluviatilis individuals appears very close to the process of allograft chronic rejection that we formerly described for some marine sponges. Both phenomena are basically analogous to the process which fixes to and isolates the sponges from their substrate.
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  • 81
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    Notes: Motor units of the medial gastrocnemius (MG) and the single lateral gastrocnemius/soleus (LG/S) muscles of the opssum (Didelphis virginiana) were found to have uniformly slow contraction times relative to homologous muscles of the cat. Though a broad range of peak tetanic tensions was found among motor units from both muscles, most of the motor units were quite large relative to tension of the whole muscle. Comparison of the relative sizes of motor units showed that those of LG/S are significantly larger and slower than the units of MG. This suggests that the motor units of the two muscles may be differentially recurited during different behaviors.All of the MG and LG/S motor units were highly or moderately resistant to fatigue. Histochemical staining for NADH-diaphorase activity indicated consistently high levels of the enzyme in all of the fibers of both muscles. Apparently, all of the fast motor units consist of fast oxidative/glycolytic (FOG)-type muscle fibers. Our data provide functional evidence that the types of myofibrillar ATPase demonstrated by Brooke and Kaiser ('70), are not necessarily correlated to physiological classification of fiber types as slow oxidative (SO), fast oxidative/glycolytic (FOG), and fast glycolytic (FG) (Peter et al., '72).Perhaps compartmentalization of muscle fiber types may be a first step in the separation of muscles into multiple heads during the evolution of specialization to diverse locomotor habits among the mammals.
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  • 82
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    Notes: Sensory epithelia of the oral tube, a fungiform body anterior to the tentacles and of the terminal knob of tentacles, were studied in Ovatella myosotis by electron microscopy. All three epithelia consist of columnar support cells, sensory cells, and, except in the oral tube, numerous goblet cells. The epithelia differ significantly in their apical differentiations. In the oral tube an outer layer is formed by irregularly bent villi of support cells completely embedded in a surface coat. Cilia and cytofila of the dendrites of sensory cells intertwine throughout the entire depth of the villous layer. In the fungiform sensory body some of the villi of support cells are singly branched. Their basal region is free of a surface coat. In this region cytofila and cilia of dendrites form a spongy layer, some cytofila extending into the surface coat. In the tentacular terminal knob the villi of the support cells branch dichotomously once or twice, a single villus thus ending with 2-4 tips. Only these terminal twigs are invested with the surface coat. The cytofila and dendritic cilia are confined to a broad spongy layer underneath. Three types of dendrites are present. They differ in their number of cilia, structure of basal bodies and occurrence in the three epithelia. Dendritic cytofila are most abundant in the tentacular terminal knob and least numerous in the oral tube. The observations are discussed with respect to corresponding epithelia in other pulmonates, the homology of the fungiform body, and possible functional correlates of structural features.
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  • 83
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    Journal of Morphology 182 (1984), S. 63-69 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Renal tubules in the dog shark, leopard shark, and red skate were examined histologically and analyzed histochemically for enzymes. Cells of the distal and collecting tubules exhibit extensive interdigitations and large intercellular spaces, suggesting that these tubules are sites of sodium reabsorption. Although Na-K-ATPase is very scarce to nonexistent in the distal and collecting tubules, very intense carbonic anhydrase activity in these segments indicates that they secrete large amounts of hyrogen ion and reabsorb sodium by H+/Na+ exchange process. Epithelial cells of the necks are not interdigitated, tightly join adjacent cells, and have low enzyme activities. They seem to be passively permeable to the water. Necks are attached to the distal tubules with scant intervening stroma. It seems likely that the stroma has a high osmotic pressure resulting from absorption of solutes in the distal tubules. Water may be reabsorbed from necks to stroma because of a concentration gradient of the solutes distributed between these sites.
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  • 84
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    Notes: Light and electron microscopy were used to examine the morphology of the mucosa of the diverticulum, anterior intestine, and transition zone in prefeeding and spontaneously feeding adult lampreys (Petromyzon marinus L.). Absorptive (either types A or B), ciliated, and enteroendocrine cells are present in all regions but the diverticulum and anterior intestine also possess zymogen (secretory) cells. Type A absorptive cells are restricted to the diverticulum and the rostral one-third of the anterior intestine and are characterized by abundant mitochondria and an extensive smooth tubular network. Type B absorptive cells, in the remainder of the anterior intestine and the transition zone, possess small numbers of these organelles but in the transition zone also have inclusion bodies. During feeding, abundant lipid droplets and lipoprotein (VLDL) accumulate in the cytoplasm of both types of absorptive cells and in the lateral intercellular and the perivascular spaces. Lipid is present to a limited extent in ciliated cells and is encountered only rarely in enteroendocrine and zymogen cells. Although the animals are obligate sanguivores, there is little evidence of iron within these mucosal cells. It is suggested that intestinal efficiency displayed by this animal is due in part to ion transport in osmoregulation in type A cells, lipid absorption in types A and B cells, and digestion through enzymes in zymogen cells.
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  • 85
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    Journal of Morphology 182 (1984), S. 71-83 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fourteen species of leiognathid fishes (Perciformes, Leiognathidae) from the Philippine Islands, Thailand, Japan, Indonesia, and Palau were examined for accessory secondary sexual dimorphism. Thirteen species exhibit either external dimorphism (a clear patch of skin on the flanks of males, a large clear patch of skin on the opercular margins of males, or a flank stripe in males) or internal dimorphism (large light organs in males) or both. Eight of the 14 species (and possibly as many as 11) exhibit both forms of sexual dimorphism. Two species show only internal light organ volume dimorphism, and one species shows neither external nor internal dimorphism. Sexual dimorphism is thus very common in leiognathids. The externally dimorphic skin patches are closely associated with the internally dimorphic light organ system in seven species (and possibly as many as ten), indicating a potential for light emission through the clear patches. A bioluminescent signaling function by males is therefore suggested for the sexual dimorphism in leiognathids, which may play an important role in the schooling behavior as well as in species and sexual recognition of these coastal fishes.
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  • 86
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    Journal of Morphology 182 (1984), S. 1-37 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Among egg-brooding hylid frogs there is much interspecific variation in the degree of development of the young at hatching. In certain species of Gastrotheca the eggs hatch into free-living tadpoles, whereas in others (and in the genera Amphignathodon, Cryptobatrachus, Stefania and Hemiphractus) the eggs hatch directly into frogs. We examined the oral anatomy of tadpoles and embryos of 22 species of egg-brooding hylids in order to determine the morphological differences between free-living larvae and embryos of species having direct development. All free-living Gastrotheca larvae are morphologically similar and have a large array of oral structures directly associated with a suspension feeding way of life. Among those egg-brooding hylids without free-living larvae there is a complete gradation from those with all of the free-living tadpole oral structures to those with none. Different lineages retain different vestiges of free-living larval morphology, suggesting that direct development has evolved multiple times among these frogs. All of the morphological patterns in the direct-developing embryos can be accounted for by simple truncation or acceleration of the normal tadpole developmental program. We explore the possibility that certain Gastrotheca species with tadpoles may have evolved from species that lack larval stages. The development of oral structures in egg-brooding hylids provides insight into the phylogenetic significance of these charactes in other groups of anurans. Most significantly they reinforce the idea that microhylids evolved from ranoidlike ancestors.
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  • 87
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    Journal of Morphology 182 (1984) 
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 88
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: With the use of rabbit antisera against crustacean hyperglycemic hormone (CHH), it is possible to describe a distinct immunopositive reaction in a group of neurosecretory cells in the medulla terminalis ganglionic X-organ2 (MTGX2), in the MTGX-sinus gland tract, and in a considerable part of the sinus gland from several species of prawns belonging to the Palaemonidae. By introductory studies on the CHH system in Palaemon serratus, we can postulate a sequence in the activity cycle of the CHH-producing cells on the basis of differences in staining intensity of the immunoreaction and such morphometric parameters as cellular and nuclear diameter. By studying the CHH-producing system in combination with variations in the glucose level of the blood, an “inverse relationship” is observed between the number of immunoreactive cells and the blood glucose level during different periods of the year as well as during different stages of the molting cycle. A “shift in phase” of this correlation during the diurnal cycle suggests that several rhythmical phenomena may play a role in the regulation of glycemia in Crustacea.
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  • 89
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    Journal of Morphology 182 (1984), S. 115-123 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A large mechanosensory campaniform sensillum (LCS) is found close to the flagellum/pedicellus joint in the antennae of the blowfly Calliphora erythrocephala. The LCS possesses a single sensory cell, enveloping cells and a cuticular stimulus-conducting structure. The distal part of the sensory process is developed as a tubular body and is connected to the two parts of the stimulusconducting apparatus. The sensory cell is characterized by the complete absence of ciliary structures in the transition zone between dendrite and sensory process.
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  • 90
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    Journal of Morphology 182 (1984), S. 95-113 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A three-dimensional muscle model with complex geometry is described and tested against experimental data. Using this model, several muscles were constructed. These muscles have equal optimum length but differ in architecture. The force exerted by the constructed muscles, in relation to their actual length and velocity of shortening, is discussed. Generally speaking, the constructed muscles with considerable pennation have great fiber angles, a great physiological cross section, a narrow active and steep passive length-force relation, and a low maximal velocity of shortening. The maximal power (force times velocity) delivered by the constructed muscles is shown to be almost independent of the architecture of the muscles. The steepness of the passive length-force relation is determined mainly by the shortest fibers within the group of constructed muscles, wheras maximal velocity of shortening and the width of the active length-force relation are determined mainly by the longest fibers.The validity of the three-dimensional muscle model with respect to some morphological and functional characteristics is tested. Length-force relations of constructed muscles are compared with the actual length-force relations of mm. gastrocnemii mediales and mm. semimembranosi of male Wistar rats. Moreover, actual fiber angle, fiber length, and muscle thickness of three mm. gastrocnemii mediales are compared with values found for constructed muscles. It is concluded that the three-dimensional muscle model closely approximates the actual muscle form and function.
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  • 91
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    Journal of Morphology 182 (1984), S. 125-136 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Horseradish peroxidase histochemical studies of afferent and efferent projections of the trigeminal nerve in two species of chondrostean fishes revealed medial, descending and ascending projections. Entering fibers of the trigeminal sensory root project medially to terminate in the medial trigeminal nucleus, located along the medial wall of the rostral medulla. Other entering sensory fibers turn caudally within the medulla, forming the trigeminal spinal tract, and terminate within the descending trigeminal nucleus. The descending trigeminal nucleus consists of dorsal (DTNd) and ventral (DTNv) components. Fibers of the trigeminal spinal tract descend through the lateral alar medulla and into the dorsolateral cervical spinal cord. Fibers exit the spinal tract throughout its length, projecting to the ventral descending trigeminal nucleus (DTNv) in the medulla and to the funicular nucleus at the obex. Retrograde transport of HRP through sensory root fibers also revealed an ascending bundle of fibers that constitutes the neurites of the mesencephalic trigeminal nucleus, cell bodies of which are located in the rostral optic tectum. Retrograde transport of HRP through motor root fibers labeled ipsilateral cells of the trigeminal motor nucleus, located in the rostral branchiomeric motor column.
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  • 92
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    Journal of Morphology 182 (1984), S. 153-168 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two types of nerve cells, sensory and ganglion cells, were identified in the epidermis of the hypostome of Pelmatohydra robusta by light and electron microscopy. In the study of distribution of these cells, the presence of a circumhypostomal nerve ring in the epidermis was revealed, although hydras have been considered to possess only a diffuse nervous system or socalled nerve net. The nerve ring, which encircled the hypostome, was constituted by several clusters of ganglion cells, thick bundles of many neurites connecting these clusters, and a small number of individual ganglion cells located along the bundles. In the nerve ring, some of the lamellae protruding from the ganglion cells were frequently myelinated and wrapped the cell bodies of neighboring ganglion cells, and other lamellae were arranged in concentric circles.
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  • 93
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    Journal of Morphology 182 (1984), S. 137-152 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The epithelium of the posterior intestine and hindgut of recently metamorphosed adult lampreys (Petromyzon marinus L.) prior to and during spontaneous feeding was examined using light and electron microscopy. These two regions differ slightly in their general morphology but possess the same mucosal cell types. Included are caveolated absorptive and mucous cells, which are not present in more cephalic regions of the intestine, and ciliated and enteroendocrine cells. During feeding, the caveolated cells undergo dramatic transformation in their structure, namely, through the acquisition of numerous heterophagic vacuoles. Due to their morphology and to the fact that there are low amounts of lipid, it is suspected that caveolated cells are primarily involved in the absorption of protein components from the ingested host blood and body fluids. Iron in caveolated cells may result from the degradation of ingested heme or reflect the excretion of bile products at this location in the intestine. Mucous cells are likely responsible for lubrication of the luminal surface and may be important as a stem cell for the mucosal epithelium.
    Additional Material: 23 Ill.
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  • 94
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984), S. 169-178 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This investigation describes the morphogenesis of the type I pneumocyte from the neonatal stage to the age of 3 months. Cells lining subpleural air spaces were photographed from electron microscopic serial sections and a three-dimensional representation of each cell was obtained by transferring the contours of the cell membranes from micrographs to transparent plastic sheets which were then spaced to scale and stacked. The portion of the reconstructed cell surface taking part in the formation of the blood-airbarrier increased extensively in postnatal stages when compared with reconstructed cells of prenatal stages. Reconstructed cell-surface irregularities decrease during distension. A cytoplasmic plate seen in the last stage studied may represent a forming alveolar pore.
    Additional Material: 14 Ill.
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  • 95
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984), S. 179-196 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three hypothetical models of tongue movement of the walrus during suction feeding are examined. These models encompass the entire range of simple tongue retraction movements possible by examining 1) movement of the tongue directly to the rear following the curvature of the palate, 2) to the rear and ventrally in a straight line, and 3) ventrally in a straight line. The percent of muscular force available from the hyoglossus, genioglossus, and styloglossus that could be applied toward retraction as predicted by each model is calculated. The resistance that the tongue would provide during retraction is calculated using projected tongue areas and is combined with the above data from the muscles to provide an estimate of the percent of the total available force that is needed to retract the tongue for each model. A separate examination of the direction of tongue-induced wear striations on the palatal and lingual aspects of the teeth is used to help support or reject the three models.The model where the tongue is moved directly to the rear is supported by studies of both muscle force and tooth wear. In the mammalian groups that were compared to the walrus, there is a great deal of interspecific variation in movements of the tongue during suction feeding; no two groups can be considered to have identical stereotyped tongue movements.
    Additional Material: 8 Ill.
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  • 96
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984), S. 221-225 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The retina of the chick contains retinal cells of a morphology very similar to that of the horizontal cells, but the perikarya, axons, and axon terminals lie in the inner plexiform layer. The discovery of this neuronal ectopia appears to support the idea that some horizontal and amacrine cells derive from a common, freely migrating cell.
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  • 97
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 98
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984), S. 227-244 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cranial and cervical osteology of the European oystercatcher, Haematopus ostralegus L. is completely described from both whole skeletons and spirit specimens. Contrary to previous reports, the postorbital ligament shows variability in bifurcation and attachment, with the posterior branch, where present, attaching either to the suprameatic process or the zygomatic process. In addition, the quadrate ligament, which had been described as originating from the suprameatic process, appears instead to attach to the zygomatic process in some specimens. The caudal mandibular fenestra, earlier considered absent in oystercatchers, is present in all specimens examined. The cranium is additionally distinguished by a number of features which may be unique to oystercatchers. A fourth, previously unrecorded, division of the maxillopalatine strut is present, while the palatine process of the premaxilla is reduced to a thickening along the edge of the premaxillary process of the palatine. The distinctiveness of the oystercatcher cranium is particularly evident in the area of the quadratomandibular articulation, which possesses features potentially important for stabilizing the joint. A deep retroarticular notch is present, guiding a large medial jugomandibular ligament along the posterior margin of the articulation. A lateral mandibular tuberosity, which is received dorsally by an emargination of the jugal arch and quadrate, may act as an osteological brace, preventing posterior shifting of the closed mandible. The 15 cervical vertebrae are divided on the basis of structural criteria into three sections.
    Additional Material: 10 Ill.
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  • 99
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984), S. 197-219 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Many climbing mammals are able to reverse normal hind foot posture to effect the grip necessary to descend headfirst or to hang upside down. Such hind foot reversal is known in sciurids, procyonids, felids, viverrids, tupaiids, prosimians, and marsupials. The joint movements involved, however, have never been documented unequivocally although various interpretations (some contradictory) have been made. We report here radiographic data from species of the genera Didelphis, Felis, Nasua, Nycticebus, Potos, Sciurus, and Tupaia. In the six eutherians studied, three joints are involved, and there is a common pattern in the mechanism: crurotalar plantarflexion, subtalar inversion, and transverse tarsal supination. Hind foot reversal represents the development of an unusual degree of excursion at these joints, rather than the appearance of any new type of movement. In Didelphis the mechanism is quite different: a bicondylar, spiral tibiotalar joint is the principal site of inversion/abduction movements. This specialization is characteristic of didelphids and phalangerids, and occurs in the extinct multituberculates as well; it is not found in macropodids (which are like eutherians in crurotalar joint structure) or other marsupial families. This diversity in pedal structure and function is evidently the result of parallel evolution from the type of tibiotalar joint of cynodonts and early mammals. In Morganucodon the bulbous, hemispheroidal proximal surface of the talus bears two tibial facets. These facets are represented in didelphids and multituberculates as sulci, whereas in macropodids and eutherians they developed as the proximal and medial surfaces of the talar trochlea. Among living mammals, the primitive hemispheroidal joint is retained among monotremes as a ball and socket joint.
    Additional Material: 14 Ill.
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  • 100
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984), S. 245-255 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The sequence of appearance of the 17 different skull bones in the oriental fire-bellied toad, Bombina orientalis, is described. Data are based primarily on samples of ten or 11 laboratory-reared specimens of each of 11 Gosner developmental stages (36-46) representing middle through late metamorphosis. Ossification commences as early as stage 37 (hind limb with all five toes distinct), but the full complement of adult bones is not attained until stage 46 (metamorphosis complete). Number of bones present at intermediate stages is poorly correlated with external morphology. As many as four Gosner developmental stages elapse before a given bone is present in all specimens following the stage at which it may first appear. The modal ossification sequence is frontoparietal, exoccipital, parasphenoid, septomaxilla, premaxilla, vomer, nasal, maxilla, angulosplenial, dentary, squamosal, quadratojugal, pterygoid, prootic, interfrontal, sphenethmoid, and mentomeckelian. Most specimens are consistent with this sequence, despite the poor correlation between cranial ossification and external development as assayed by Gosner stage.The timing of cranial ossification in Bombina orientalis differs in many respects from that described for two other, distantly related anurans, the leopard frog (Rana pipiens) and the western toad (Bufo boreas). These include the total number and sequence of appearance of bones, and the timing of ossification relative to the development of external morphology. Interspecific variation may reflect differences in the timing of the tissue interactions known to underlie skeletal differentiation and evolution.
    Additional Material: 4 Ill.
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