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  • Springer  (257)
  • Wiley-Blackwell  (4)
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  • American Geophysical Union
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 40 (1984), S. 1004-1006 
    ISSN: 1420-9071
    Keywords: Rat ; adrenocortical responsiveness ; ACTH ; plasma ; corticosterone ; plasma ; corticotropin releasing factor (CRF)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the course of studying the plasma adrenocorticotropic hormone (ACTH) and corticosterone responses to synthetic corticotropin releasing factor (CRF), we noted some disparity in the responses. A higher dose (20 μg compared with 5 μg per rat i.a.) produced an equal plasma ACTH but greater plasma corticosterone response in adult male rats. Thus, we examined the possibility that CRF increases adrenocortical responsiveness to ACTH. CRF significantly (p〈0.0005) increased the plasma corticosterone response to ACTH in rats pretreated with dexamethasone. Thus, synthetic CRF increases corticosterone secretion in rats not only by stimulating ACTH secretion, but also by increasing the adrenocortical responsiveness to ACTH.
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  • 2
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    Cellular and molecular life sciences 40 (1984), S. 974-975 
    ISSN: 1420-9071
    Keywords: Rat ; prostaglandins ; gastric lesion ; intragastric distension model ; stress model ; indomethacin ; somatostatin preventive effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The inhibition of endogenous prostaglandin synthesis by indomethacin treatment blocks the somatostatin preventive effect on the gastric lesions induced in a stress model and has no preventive effect on an intragastric distension model.
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  • 3
    ISSN: 1420-9071
    Keywords: Rat ; cerebrospinal fluid, human ; analgesia ; naloxone ; pain indifference, congenital ; opiates, endogenous
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary CSF from a patient with congential indifference to pain was found to produce analgesia in the rat following intracerebroventricular injections. The analgesic effect was attenuated by pretreatment with naloxone suggesting the involvement of hyperactive endogenous opiate mechanisms in this patient.
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  • 4
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    Cellular and molecular life sciences 40 (1984), S. 1368-1369 
    ISSN: 1420-9071
    Keywords: Rat ; kidney ; hypertensive ; prostaglandin dehydrogenase ; hexokinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 15-Hydroxyprostaglandin dehydrogenase (PGDH) surged in hypertensive (SHR) and normotensive (WKY) rat kidney at 8 days of age, is greatest in SHR. Hexokinase fell in SHR at 17 days of age, but thereafter was similar to WKY. This suggests multisystem enzymatic abnormalities in SHR kidney during development of hypertension.
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  • 5
    ISSN: 1432-041X
    Keywords: Protein synthesis ; Development ; Antherea pernyi ; Follicles ; Specific ribonuclease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Crude, cell-free protein-synthesizing systems were prepared from follicles of two different stages of development in the ovariole of the silkmothAntherea pernyi. The efficiency of the translation of natural and synthetic mRNAs in these systems was compared with that in a cell-free wheat germ system. A postmitochondrial extract (S-30) from the follicles almost completely inhibited protein synthesis in a polyribosome-dependent, cell-free systems. A specific ribonuclease, obtained from the post mitochondrial extract by ammonium sulphate precipitation, heat denaturation and DEAE-cellulose chromatography, inhibited polyribosome-dependent protein synthesis. The effect of this specific ribonuclease on the structural integrity of radioactive RNAs and ribosomal subunits, which were isolated from Ehrlich ascites tumor cells, was also studied.
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  • 6
    ISSN: 1432-041X
    Keywords: Major haemolymph proteins ; Development ; Cuticle ; Immunocytochemistry ; Ceratitis capitata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The developmental profile of the major haemolymph proteins (ceratitins) inCeratitis capitata was studied. Ceratitin concentration in the haemolymph decreases dramatically during the last days of pupal life, while the amounts of ceratitins in whole organism extracts remain unchanged. By electrophoretic, immunological and immunofluorescence techniques it was revealed that ceratitins are reabsorbed by the fat body and a fraction of them is deposited in the cuticle. The possible role of ceratitins is discussed.
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  • 7
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    Cellular and molecular life sciences 40 (1984), S. 1008-1010 
    ISSN: 1420-9071
    Keywords: Rat ; ethanol preference ; acetaldehyde self-administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peripherally self-injected acetaldehyde in interaction with environmental and nutritional variables significantly enhances alcohol drinking in rats and suggests an involvement of acetaldehyde in voluntary alcohol intake.
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  • 8
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    Springer
    European journal of clinical pharmacology 26 (1984), S. 699-705 
    ISSN: 1432-1041
    Keywords: dihydroergotamine metabolites ; man ; mammals ; pharmacological action ; venoconstriction ; varicose veins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Dihydroergotamine (DHE) and 5 of its main metabolites, namely 8′-hydroxy-dihydroergotamine (8′-OH-DHE), 8′,10′-dihydroxy-dihydroergotamine (8′,10′-OH-DHE), 2,3seco,N(1)formyl,3-keto,8′-hydroxy-dihydroergotamine (8′-OH,N(1)formyl-DHE), dihydrolysergic acid amide (DH-LSA) and dihydrolysergic acid (DH-LS) were investigated on human and canine veins in vitro, on canine veins in situ, and in the ganglion-blocked rat in vivo. Like DHE, the metabolites 8′-OH-DHE, 8′,10′-OH-DHE and DH-LSA caused contriction of human varicose veins and only weak α-adrenoceptor blockade. On canine femoral vein strips the same compounds produced predominantly α-adrenoceptor blockade and only negligible stimulation. 8′-OH,N(1)formyl-DHE and DH-LS were largely inactive. The same compounds, which were agonists on human vein strips in vitro, induced dose-dependent reduction of venous compliance when infused locally into the dog saphenous vein in situ. In the ganglion-blocked rat, only 8′-OH-DHE and 8′,10′-OH-DHE besides the parent drug produced an increase in diastolic blood pressure when injected intravenously. It is concluded that DHE metabolites with considerable venoconstrictor activity may contribute to the selective therapeutic action of DHE.
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  • 9
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    Springer
    European journal of clinical pharmacology 26 (1984), S. 227-232 
    ISSN: 1432-1041
    Keywords: amitriptyline ; kidney function ; uraemics ; biotransformation ; chronic renal failure ; urinary metabolites ; man ; depression ; nortryptyline ; hydroxymetabolites ; unconjugated metabolites ; clinical efficacy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The metabolism of amitriptyline (AMT) has been studied in two groups of depressed in-patients on long term AMT therapy: 11 patients with no other major disease and 8 patients with chronic renal failure, who were being dialysed. The patients with renal insufficiency had decreased concentrations of AMT, nortriptyline (NT) and their unconjugated hydroxymetabolites compared to patients with normal kidney function. The plasma levels of conjugated products were extremely high in the uraemics. The latter metabolites are probably inert. The reduced concentration of unconjugated hydroxymetabolites, which are active compounds, may decrease the clinical effectiveness of the drug.
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  • 10
    ISSN: 1432-072X
    Keywords: Candida tropicalis ; Cell surface ; Hydrocarbon transport ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The surface structure of the hypdrocarbon-utilizing yeast Candida tropicalis was investigated by scanning and transmission electron microscopy (SEM and TEM respectively). The sample preparation technique was based on a rapid cryofixation without any addition of cryoprotectants. In subsequently freeze-dried samples the surface structure was analysed by scanning electron microscopy. Thin sections were prepared from freeze substituted samples. Both techniques revealed hair-like structures at the surface of hydrocarbon-grown cells. The hairy surface structure of the cells was less expressed in glucose-grown cells and it was absent completely after proteolytic digestion of the cells. When cells were incubated with hexadecane prior to cyryofixation a contrast-rich region occured in the hair fringe of thin sections as revealed by TEM. Since these structures were characteristic for hexadecane-grown cells and could not be detected in glucose-grown or proteasetreated cells it was concluded that they originate from hexadecane adhering to the cell surface and are functionally related to hexadecane transport. The structure of the surface and its relation to hydrocarbon transport are discussed in view of earlier results on the chemical composition of the surface layer of the cell wall.
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  • 11
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    Cell & tissue research 236 (1984), S. 373-381 
    ISSN: 1432-0878
    Keywords: Merkel cell surface ; Quinacrine fluorescence ; Lectins ; Vibrissae ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surface carbohydrates on the Merkel cell of the outer root sheath (ORS) were investigated in 1to 4-day-old rat vibrissae by use of rhodamine isothiocyanate (RITC)-conjugated lectins. The red fluorescence of RITC provided a convenient assay for lectin binding to the Merkel cell, which is itself identified by its green fluorescence following selective uptake of the dye quinacrine. In monolayers or suspensions of freshly dissociated ORS cells, the Merkel cell showed high affinity for the α-fucose-specific lectin, Ulex europeus agglutinin I (UEA-I), thus revealing a novel feature for a basally located cell. Other high-affinity lectins included concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and Ricinus communis agglutinin I (RCA-I). In contrast, Dolichos biflorus (DBA), Bandeiraea simplicifolia I and II (BS-I and BS-II), and peanut agglutinin (PNA) virtually excluded the Merkel cell, though PNA-binding sites were unmasked after neuraminidase treatment. Other dispersed ORS cells had varying lectin affinities, and generally binding was inhibited by a competing haptenic sugar. The pattern of lectin binding seen in cryostat and paraffin sections of the vibrissa suggested that the Merkel cells share surface properties with their neighboring basal and/or spinous cells; however, unshared properties are likely to exist since ingrowing mechanosensory nerves recognize the Merkel cells, and not other epidermal cells, as their targets.
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  • 12
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    Cell & tissue research 237 (1984), S. 49-55 
    ISSN: 1432-0878
    Keywords: Axon ; Synapses ; Medulla oblongata ; Gold-fish ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Development of the axon cap neuropil of the Mauthner neuron in post-hatching larval goldfish brains was observed electron-microscopically. The axonal initial segment of newly hatched (day-4) larvae is completely covered with synaptic terminals containing clear spherical synaptic vesicles. Profiles of thin terminal axons, the spiral fibers, containing similar synaptic vesicles, rapidly increase in number around the initial segment and form glomerular neuropil similar to the central core of the adult axon cap by day 7. Three types of synapses are formed in the core neuropil. Bouton-type synapses contacting the initial segment are most abundant in day-4 to-14 larvae; they decrease thereafter and are rare on the distal half of the initial segment of day-40 larvae. Asymmetric axo-axonic synapses are commonly observed between spiral fibers in the core neuropil of day-7 to -19 larvae, but become fewer by day 40. Unique symmetrical axo-axonic synapses showing accumulation of synaptic vesicles on either side of apposed membrane thickenings first appear in day-14 core neuropil, gradually increase in number, and become the predominant type in day-40 core neuropil. Thick myelinated axons, which lose their myelin sheaths in the glial cap cell layer, start to penetrate into the axon cap on day 10. They gradually increase in number and form the peripheral part of the axon cap together with the cap dendrites, which finally grow into the axon cap from the axon hillock region of the Mauthner cell by day 40.
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  • 13
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    Cell & tissue research 236 (1984), S. 711-715 
    ISSN: 1432-0878
    Keywords: Gastric antral mucosa ; Caerulein ; Gastrointestinal hormones ; Cholecystokinin ; Trophic effect ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The growth-promoting effect of caerulein on antral gastric mucosa was explored using Wistar rats. Implanted osmotic minipumps were used to administer submaximal doses of either caerulein or saline to normal rats for up to 4 days. In one group, reflux of bile and pancreatic juice into the stomach was avoided by previous surgical diversion of the distal common bile duct to the jejunum. DNA synthetic and mitotic activity in the antrum epithelium were estimated by 3H-thymidine pulse labelling and autoradiography during the administration of the peptide. The rate of cell migration was determined in animals killed 1, 2 and 3 days after the 3H-thymidine pulse. Administration of caerulein to normal rats provoked significant increases in both labelling and mitotic indices, and a significant acceleration of the upward cell migration in the glandular tubes. In the animals with distal diversion of bile and pancreatic secretions both labelling and mitotic indices were also increased over control values under the effect of the peptide. These data indicate that administration of caerulein stimulates cell proliferation in the antral gastric mucosa. This effect cannot be explained through increased reflux of pancreaticobiliary secretions in the stomach.
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  • 14
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    Cell & tissue research 236 (1984), S. 699-709 
    ISSN: 1432-0878
    Keywords: Testis ; Spermatogenic cycle ; Sertoli cell ; Lipid ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The volume and surface area of lipid inclusions often present in the cytoplasm of rat Sertoli cells was measured directly from semi-thin sections of perfusion-fixed testicular tissues using an image analyser linked to a light microscope. Sertoli cell nuclei were used as a reference for comparing any variations in the measured parameters of lipid inclusions during the rat spermatogenic cycle. Volume density of Sertoli cell lipid inclusions was assessed by morphometric analysis of Sertoli cells photographically reconstructed from electron micrographs. Maximum lipid content in Sertoli cells occurred during stages IX–XIV of the spermatogenic cycle, then declined at stages I–III and remained low from stages IV–VIII. The persistence and increase in number of many large Sertoli cell lipid inclusions beyond the stage where spermatid residual bodies are phagocytosed within the Sertoli cells (stage IX) suggests that the synthesis and lipolysis of Sertoli cell lipid inclusions represents an intrinsic functional cycle of the Sertoli cells. Stage-dependent variations in the lipid content of rat Sertoli cells offers morphological evidence that the metabolic duties of the Sertoli cells are synchronised with the spermatogenic cycle to provide local coordination of the proliferation and maturation of the germ cells.
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  • 15
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    Cell & tissue research 236 (1984), S. 717-724 
    ISSN: 1432-0878
    Keywords: Ovary ; Ovarian follicle ; Atresia ; Immunoregulation ; Immune tolerance ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thy-1+ cells, producing Thy-1+ material, have been demonstrated by the indirect immunoperoxidase technique in the theca of growing ovarian follicles of the rat. OX-2 antigen, known as the minor glycoprotein of rat thymocytes, was detected in granulosa cells of non-growing follicles. Ia+ cells of dendritic type and/or activated macrophages were identified in the granulosa of advanced degenerating follicles, and remnants of the zona pellucida exhibited immunoglobulins. In some ovaries immunoglobulins were also bound to the zona pellucida of oocytes of early degenerating antral follicles. Medium-sized antral follicles with degenerating granulosa were occasionally invaded by cells carrying antigens of cytotoxic T lymphocytes or other T lymphocyte subsets, while degenerating large antral follicles were sometimes invaded by cells exhibiting antigen of cells with natural killer function (but not antigens of T lymphocytes). Granulosa cells of some degenerating antral follicles exhibited class-I antigens derived from the major histocompatibility complex. We suggest that cell-mediated control mechanisms of antigen expression and metabolism of tissue cells during their differentiation and degeneration should be considered in addition to the well-documented hormonal dependence of some tissues.
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  • 16
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    Cell & tissue research 237 (1984), S. 245-252 
    ISSN: 1432-0878
    Keywords: Pineal organ ; Interstitial cells ; Astrocytes ; Immunocytochemistry ; Rat ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antigenic markers characteristic of astrocytes and their differentiative states (i.e., glial fibrillary acidic protein (GFAP), vimentin, and M1 and C1 antigens) were investigated in the pineal gland of mouse and rat using double immunolabeling techniques. In both species the socalled interstitial cells as characterized by TEM were shown to be astrocytes, since they expressed vimentin, but neither fibronectin (a marker for fibroblasts and endothelial cells) nor the neuron-specific L1 antigen or tetanus toxin receptors. Subpopulations of vimentin-positive pineal astrocytes were also GFAP- and C1- antigen-positive. M1- antigenpositive cells were not detected. It is concluded that a considerable proportion of interstitial cells in the pineal gland of rat and mouse are immature astrocytes which, in contrast to other parts of the central nervous system, persist into adulthood.
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  • 17
    ISSN: 1432-0878
    Keywords: Thyroid gland, fetal ; Cytoskeleton ; Cytocha lasin B ; Vinblastine ; Colchicine ; Follicular development (thyroid) ; Tissue culture ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyrotropic hormone (TSH) or cAMP accelerate the formation of follicular cavities in the explanted thyroid gland of the 15-day-old rat fetus. Cytochalasin B or vinblastine and nocodazole or colchicine, which disorganize microfilamental and microtubular structures respectively, inhibit or completely block in vitro-induced folliculogenesis. Exposure of the thyroid tissue to lumicolchicine, a structural isomer of colchicine deprived of antimicrotubular activity, does not inhibit the activation of folliculogenesis induced by TSH. These results are strong evidence for the supposition that microfilaments and microtubules are involved in the TSH-stimulated mechanisms resulting in thyroid folliculogenesis. Folliculogenesis requires the integrity of both microfilaments and microtubules.
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  • 18
    ISSN: 1432-0878
    Keywords: Vitamin D ; Skin ; Autoradiography ; Hair ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tritium-labeled 1,25 (OH2) vitamin D3, when injected into vitamin D-deficient adult and pregnant rats is concentrated and retained strongest in nuclei of cells in the outer root sheath of the hair, followed by the stratum granulosum, spinosum, and basale of the epidermis. In the hair follicle, in addition to the most heavily labeled outer root sheath, nuclear labeling exists also in cells of the hair bulb and of the inner root sheath, as well as in basal cells of the sebaceous gland. In contrast, cells of the dermal papilla and the connective tissue of the dermis are generally unlabeled, except for labeled cells in the outer connective tissue sheath at the infundibulum of vibrissae of 20-day fetal rats and a few scattered labeled cells in the dermis, probably macrophages. In the developing hair, in 18- and 20-day fetal rats, a distinct topographic pattern of labeled cells can be seen, which is characteristic of the different stages of hair follicle development. In the hair germ, heavily labeled cells appear first in the stratum spinosum. In the hair peg, they remain in this position in its juxtaepidermal portion; however, when a dermal papilla develops, heavily labeled cells assume a marginal position. This suggests a sequential epidermal-epidermal and mesenchymal-epidermal receptor induction. Injection of tritium labeled 25 (OH) vitamin D3 did not show nuclear concentration in these tissues and excess unlabeled 25 (OH) vitamin D3 — unlike excess 1,25 (OH2) vitamin D3 — did not prevent nuclear uptake of tritium labeled 1,25 (OH2) vitamin D3. The results indicate differential effects of 1,25 (OH2) vitamin D3 on different structures in the epidermis and dermis.
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  • 19
    ISSN: 1432-0878
    Keywords: CRF-neurons ; Hypothalamus ; Development, ontogenetic ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Appearance of immunoreactive corticotropin-releasing factor (CRF)-containing neurons was studied in developing hypothalamus of the rat by use of antisera against rat- and ovine CRF. These neurons were first recognized in the lateral and paraventricular nuclei on days 15.5 and 16.5 of gestation, respectively, when antiserum against rat CRF was employed. Antiserum against ovine CRF revealed the cells two days later exclusively in the latter nucleus. In both nuclei, the neurons increased in number with development. The neurons in the paraventricular nucleus appeared to project their immunoreactive processes to the median eminence via the periventricular and lateral pathways. In the median eminence, the immunoreaction with antiserum to rat CRF was first recognized in its anterior portion in the form of dots on day 16.5 of gestation but as beaded fibers in the external layer on day 17.5; these structures increased in amount with development in rostro-caudal direction. Although antiserum to ovine CRF was less potent in immunostainability than antiserum to rat CRF, it also revealed the beaded fibers in the median eminence on day 17.5 of gestation. Since evidence is available that the paraventricular nucleus is involved in corticotropin release, it is concluded that, in rats, the hypothalamic regulatory mechanism controlling the release of corticotropin initially appears on days 16.5–17.5 of gestation.
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  • 20
    ISSN: 1432-0878
    Keywords: Caldesmon ; Actin ; Immunocytochemistry ; Small intestine ; Smooth muscle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin-interacting protein) (Sobue et al. 1982) and of actin was studied in the rat's small intestine by means of light-microscopic immunocytochemistry. Positive immunostaining for caldesmon was seen in smooth muscle cells of the intestinal wall, and of blood vessels, and in the apical portion of the absorptive epithelial cells. The immunoreactivity in goblet cells was difficult to recognize. The positive reaction to immunostaining for actin showed almost the same pattern as that for caldesmon. These results suggest that this calmodulin-binding protein may play an important role in the control of actin-myosin interaction in smooth muscle cells and in non-muscle cells.
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  • 21
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    Cell & tissue research 235 (1984), S. 433-438 
    ISSN: 1432-0878
    Keywords: Mammary gland ; Ferritin-concanavalin A ; Concanavalin A ; Endocytosis ; Membrane reuse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ferritin-concanavalin A (Fer-Con A) was used to label the apical plasma membrane of the lactating cell to determine whether membrane internalization takes place. Rat glands were infused in vivo via the teat with 0.2 mg of Fer-Con A in 0.2 ml tris buffer (pH 7.0) containing 0.1% trypan blue, the latter acting as a marker of the infusate. Tissues were obtained from separate animals 5, 10 and 60 min postinfusion. Fer-Con A was seen in alveolar lumina bound to the outer surfaces of apical plasma membrane, microvilli and milk fat globules. It was observed within lactating cells on the inner membrane surfaces of endocytotic vesicles, Golgi cisternae, and secretory vesicles containing casein micelles, and in multivesicular bodies and lysosomes. Internalization of the ferritin-lectin conjugate into casein-containing secretory vesicles was detectable in the 5-min postinfusion tissue. Lysosomes were the only structures in control tissue that contained particles bearing some resemblance to Fer-Con A. The data provide evidence that apical plasma membrane is internalized and distributed to a number of intracellular compartments.
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  • 22
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    Cell & tissue research 235 (1984), S. 449-452 
    ISSN: 1432-0878
    Keywords: Suprachiasmatic nucleus ; Morphometry ; Synapses ; Sexual dimorphism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The suprachiasmatic nucleus (SCN) of male rats was estimated to contain 16×106 synaptic appositions (unilaterally) or 250×106 appositions in 1 mm3 tissue of the nucleus with an average of 1404 appositions per neuron. There are significantly fewer synaptic appositions in the suprachiasmatic nucleus of female rats (15×106 per SCN or 236×106 in 1 mm3 tissue of SCN with 1264 appositions per neuron on an average). Additionally, numbers of various types of synapses (axo-somatic, invaginated, dendrodendritic and optic) are estimated.
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  • 23
    ISSN: 1432-0878
    Keywords: Monosodium-1-glutamate ; Neuropathology ; Rat ; Superior colliculus ; Toxicology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Systemic administration of monosodium-1-gluta-mate by single injections of 4 mg/g body weight in infant rats (2–10 days of age) results in acute swelling of cytoplasm and nuclear pyknosis of neurons in the stratum zonale and stratum griseum superficiale of the superior colliculus. Multiple daily doses of 4 mg/g body weight monosodium-1-glutamate result in an almost complete loss of neurons in these two superficial layers. The deeper layers appear not to be affected. No pathological effects were observed in the lateral geniculate body or pretectal complex. Light-and electron-microscopic studies reveal that the optic nerves are remarkably shrunken and many myelinated as well as unmyelinated axons are lost. Injection of 3Hproline into the vitreous body of one eye results in limited transport to the suprachiasmatic nucleus, lateral geniculate body and to lateral portions of the superior colliculus. The small percentage of intact axons in the optic nerve, as well as the limited proline transport from the eye, suggest that administration of monosodium-1-glutamate leaves intact some optic fibers, a portion of which belongs to the retinohypothalamic tract.
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  • 24
    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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  • 25
    ISSN: 1432-0878
    Keywords: Somatostatin ; Ontogenesis ; Electron-microscopic immunohistochemistry ; Median eminence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of immunoreactive (ir) somatostatin-containing nerve terminals in the rat median eminence (ME) has been examined electron-microscopically. Nerve fibers containing ir particles scattered throughout the axoplasm are first seen in the external layer of the ME on day 18.5 of gestation, and, on day 21.5 appear to terminate on the basement membrane of the perivascular space of the portal vessels. After birth, the fiber terminals contain several membrane-limited granules, which are labeled with ir PAP particles. Ultrathin, Epon-embedded sections of ME, treated by the protein A gold-labeling method for somatostatin, demonstrate positively labeled granules in the nerve fibers in the postnatal ME, but in the prenatal tissue, no specific gold-labeling is found. These findings show that, in the external layer of the ME, somatostatin storing occurs in the granules in the axonal terminals after birth.
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  • 26
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    Cell & tissue research 236 (1984), S. 491-493 
    ISSN: 1432-0878
    Keywords: Brain vessels ; Basal lamina ; Pericytes ; Endothelial cells ; Glial cells ; Argyrophilic staining ; Rat
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    Topics: Biology , Medicine
    Notes: Summary Vibratome sections obtained from perfusion-fixed rat brains were stained by means of silver impregnation and physical development according to Gailyas (1970). Small pieces of the cerebral cortex were postfixed with buffered osmium tetroxide solution and processed for electron microscopy to examine the localization of the silver deposit at the cellular level. The cell surfaces of pericytes and smooth muscle cells were completely outlined by silver grains. Endothelial cells and perivascular astrocytes, however, showed an asymmetric distribution of the silver deposit, i.e., the deposit was restricted to the abluminal endothelial surface and to the astrocytic membrane adjacent to the vessel wall, respectively. The method allowed a clear-cut distinction between perikarya of endothelial cells and pericytes as well as glial cells in perivascular position, even at the light-microscopic level.
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  • 27
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    Cell & tissue research 236 (1984), S. 249-255 
    ISSN: 1432-0878
    Keywords: Oocyte ; Nucleolus ; Silver staining ; Electron microscopy ; Rat
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    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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  • 28
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    Cell & tissue research 237 (1984), S. 103-109 
    ISSN: 1432-0878
    Keywords: Synapses ; Synaptogenesis ; Development fetal ; Olfactory cortex ; Rat
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    Notes: Summary Electron microscopy was used to study synaptogenesis in prepyriform cortex of fetal rat pups during early stages of synapse formation. Of special interest is the frequent occurrence of unapposed, developing synaptic specializations in axon and growth cone profiles. The location and morphology of the unapposed specializations suggests that thay are presynaptic in nature. These presumably immature presynaptic specializations are found in the lateral olfactory tract and subjacent cortex. Intermediate forms between uncontacted presynaptic specializations and definitive synapses suggest a synaptogenic sequence in which initial development of an immature presynaptic specialization begins without apposition of a postsynaptic element at that location. This implies that initiation of presynaptic development is not dependent upon postsynaptic contact and also raises the question of whether synaptic contacts could be established via presynaptic induction of postsynaptic formation.
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  • 29
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    Cell & tissue research 237 (1984), S. 185-186 
    ISSN: 1432-0878
    Keywords: Gap junction ; Cytoskeleton ; Heart ; Ultrarapid freezing ; Rat
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    Notes: Summary Using ultrarapid-freezing techniques and freezefracture electron microscopy, we report here a close association between cardiac gap junctions and specialized membrane domains containing regularly-spaced furrows. These specialized furrowed domains are observed only during periods of gap junction re-organisation (i.e., connexon redistribution) and may reflect the presence of underlying cytoskeletal elements controlling the position of connexons in the membrane.
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  • 30
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    Cell & tissue research 237 (1984), S. 371-373 
    ISSN: 1432-0878
    Keywords: Endothelium ; Transport, intracellular ; Transport vesicles, channels ; Micropinocytosis ; Capillaries ; Endometrium ; Rat
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    Notes: Summary Three types of transendothelial channels are described in the endothelium of blood capillaries in the endometrium of the rat. It is postulated that they may function as pores draining interstitial fluid to the venous blood.
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  • 31
    ISSN: 1432-0878
    Keywords: Thyroid ; Immunocytochemistry ; Caldesmon ; Actin ; Endocytosis ; Rat
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    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin interacting protein; Sobue et al. 1982) and actin was studied in the rat thyroid gland by means of light-microscopic immunocytochemistry, and the fine-structural distribution of actin filaments was examined by use of heavy meromyosin (HMM). Caldesmon and actin were demonstrated in the apical cytoplasm of almost all the follicle epithelial cells in normal as well as TSH-treated animals. Immunoreactivities for both caldesmon and actin showed almost the same pattern in localization. The smooth muscle cells of the blood vessels were also positive for caldesmon and actin. By electron microscopy, numerous actin filaments decorated by HMM and running perpendicularly or randomly to the apical surface were recognized in the apical cytoplasm of the follicle epithelial cell. These results suggest that caldesmon and actin, in conjugation with calmodulin, play a role in the regulation of cellular activity such as exocytosis and endocytosis in the apical portion of the follicle epithelial cell.
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  • 32
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    Cell & tissue research 237 (1984), S. 409-417 
    ISSN: 1432-0878
    Keywords: Mitosis ; Cytokinesis ; Microvilli ; Scanning electron microscopy ; Cell surface
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    Notes: Summary PtK2 cells were studied with scanning electron microscopy to record changes on the cell surface during mitosis and cytokinesis. During prophase, prometaphase and metaphase, the cells remain very flat with few microvilli on their surfaces. In anaphase cells, there is a marked increase in the number of microvilli, most of which are clumped over the separating chromosomes and polar regions of the mitotic spindle leaving the surface of the interzonal spindle region relatively smooth. Microvilli appear over the interzonal spindle region in telophase and the cells also increase in height. At the beginning of cleavage, the distribution of microvilli is roughly uniform over the surface but it becomes asymmetric at the completion of cleav-age when the daughter cells begin to spread. At this time most microvilli are over the daughter nuclei and the surfaces that border the former cleavage furrow. The regions of the daughter cells distal to the furrow are the first to spread and their surfaces have very few microvilli. When chromosome movement is inhibited by either Nocodazole or Taxol, microvilli formation is inhibited on the arrested cells. Nevertheless cell rounding still takes place in the normal time period. It is concluded from these observations that the signal for the onset of chromosome movement in anaphase is accompanied by a signal for the formation of microvilli. It is suggested that there is also a separate signal for the cell-rounding event in mitosis and that microvilli do not play a role in this contractile process.
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  • 33
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    Cell & tissue research 235 (1984), S. 187-194 
    ISSN: 1432-0878
    Keywords: Golgi apparatus ; Monensin ; Small intestine ; Cytochemistry ; Rat
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    Notes: Summary The effect of short-time treatment with the ionophore monensin, administered intraluminally at concentrations of 5 and 10 μM, was studied on the Golgi apparatus of absorptive cells in the small intestine of the rat. At 2–3 min after treatment most of the Golgi stacks exhibited dilated cisternae. At 4–5 min stacked cisternae were absent; they were replaced by groups of smooth-surfaced vacuoles. Dilatation and vacuolization occurred in the entire stacks without preferential effect on any particular Golgi subcompartment. Monensin did not influence the cytochemical Golgi reaction of thiamine pyrophosphatase and acid phosphatase. The characteristic staining pattern of these two enzymes in all Golgi cisternae of absorptive cells in the proximal small intestine, and the reactivity restricted to trans cisternae in distal segments of the small intestine, were unchanged after treatment with monensin. In the distal small intestine, the cytochemical pattern allowed the monensin-induced vacuoles to be attributed to the former cisor trans-Golgi face. Further, the cytochemical results demonstrate that vacuolization is not restricted to the stacked cisternae, but includes the trans-most cisterna. The latter, usually located at some distance from the Golgi stacks, has been defined as belonging to the GERL system in several types of cells. The clear response to monensin, an agent that selectively affects the Golgi apparatus, indicates common properties between trans-most and stacked Golgi cisternae.
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  • 34
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    Cell & tissue research 235 (1984), S. 485-489 
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    Keywords: Ventromedial nucleus ; Hypothalamus ; Ultra-structure ; Nucleoli ; Estrogen effects ; Chromatin ; Rat
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    Notes: Summary Estrogen is accumulated from the blood by nerve cells in the ventromedial nucleus of the hypothalamus and can facilitate female reproductive behavior by acting on this region of the brain. This cell group was examined in ovariectomized female rats, given estrogen or control treatment, by use of light and electron microscopy. A significantly greater portion of the nerve cells in the estrogen-treated animals had protuberances on their nucleolar surfaces, apparent under the light microscope. The fine structure of such protuberances included dense, aggregated material, which is shown to contain DNA by the sodium tungstate staining technique. Because increased numbers of such protuberances were found in nuclei of cells of the experimental group where previous studies demonstrated a significant increase in ultrastructural signs of biosynthetic activity, they may be associated with increased RNA synthesis. Thus, they could indicate, ultrastructurally, increased synthetic rates for RNA in nerve cells through which estrogen promotes reproductive behavior.
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  • 35
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    Cell & tissue research 235 (1984), S. 647-655 
    ISSN: 1432-0878
    Keywords: Classification of chorionic villi ; Fixed stromal cells ; Macrophages ; Placenta (human) ; Scanning electron microscopy
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    Notes: Summary Morphological changes in fixed stromal cells and Hofbauer cells were studied throughout pregnancy in different types of placental chorionic villi by scanning electron microscopy. In the mesenchymal villus the fixed stromal cells were characterized by thin cytoplasmic processes. Hofbauer cells exhibited blebs on their surface. Large sail-like processes with a crescent profile which surrounded well developed stromal channels and a small cell body typified the small reticulum cells of the immature intermediate villus. The Hofbauer cells here displayed blebs, microplicae and large lamellipodia. Short cytoplasmic expansions and a large cell body characterized the fibroblasts present inside the stem villus. Hofbauer cells were rare, having blebs or a few short lamellipodia. The mature intermediate villus contained small and large reticulum cells. The latter had a much larger cell body than the small ones and displayed a few short cytoplasmic processes partly delimiting narrow incomplete stromal channels. Occasional Hofbauer cells with small microplicae and/or blebs were present. The small reticulum cells and fibroblasts present in the terminal villus showed similar morphological features as above. However, the former exhibited less developed cytoplasmic extensions and therefore no stromal channels were observed. In the terminal villus, the morphology of the rare Hofbauer cells was similar to that found in the mature intermediate villus.
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  • 36
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    Cell & tissue research 235 (1984), S. 669-673 
    ISSN: 1432-0878
    Keywords: Liver-cell heterogeneity ; Hepatic venous branches ; Karyometry ; Binucleate cells ; Rat
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    Notes: Summary In untreated adult male albino rats nuclear volume and the percentage of binucleate cells were determined in the first layer of hepatocytes adjacent to hepatic venous branches of varying diameters (〈40 μm, 40 μm–80 μm, 80 μm–120μm, 120 μm–160 μm, 〉160 μm), and in the third and fourth layer of hepatocytes in the remainder of the perivenous parenchyma. In the first layer of hepatocytes adjacent to the vascular structures means of nuclear volume are significantly lower and percentage of binucleate cells significantly higher than in the cells of the remainder of the perivenous parenchyma. Within each area measured distribution curves of nuclear volume classes were homogeneous but showed heterogeneity in comparison with each other. The morphometric data presented in this study strongly support the opinion of the heterogeneity of liver cells in the perivenous zone, as previously postulated on the basis of histochemical investigations.
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  • 37
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    Cell & tissue research 236 (1984), S. 305-315 
    ISSN: 1432-0878
    Keywords: Hepatocytes ; Rat ; Liver ; Circadian rhythm ; Morphometry
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    Notes: Summary Subcellular structures of hepatocytes in periportal and perivenous zones were examined during 24 h. The volume, surface and numerical profile densities of cytoplasmic organelles were analysed morphometrically. Most subcellular structures in periportal and perivenous hepatocytes were subject to strong circadian variations. In hepatocytes from both zones, the volume densities of smooth endoplasmic reticulum (sER), mitochondria, lysosomes, peroxisomes, polysomes and lipid droplets demonstrated peak values at 16.00 h, 20.00 h or 00.00 h; trough values were at 04.00 h, 08.00 h, or 12.00 h, except for peroxisomes (16.00 h). However, the volume densities of glycogen granules and rough endoplasmic reticulum (rER) in periportal and perivenous hepatocytes exhibited maximal values at 04.00 h, 08.00 h or 12.00 h and minimal values at 20.00 h. The surface densities of sER, mitochondria, lysosomes and peroxisomes, and the numerical profile densities of mitochondria, lysosomes and peroxisomes in periportal and perivenous hepatocytes showed similar trends. These events suggest that membranes of the rER show a partial correlation with the sER, mitochondrial and lysosomal membranes during the 24-h span. This may involve the interaction between ribosomes and rER. Almost all cytoplasmic organelles examined displayed significant differences between periportal and perivenous hepatocytes, morphometrically and in fine structure, indicating that the morphofunctional variability of hepatocytes differs depending on the location in the liver acinus.
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    Cell & tissue research 236 (1984), S. 321-325 
    ISSN: 1432-0878
    Keywords: Triiodothyronine ; Radioautography ; Mitochondria ; Liver ; Rat
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    Notes: Summary To assess the distribution of the thyroid hormone triiodothyronine (T3) within intact living cells, freshly prepared dispersed rat hepatocytes were incubated with [125I]-T3 for periods of 5 min and 30 min. Lightand electron-microscopic (EM) radioautography was carried out to determine the distribution of grains over the isolated cells. Both procedures showed the grains distributed almost entirely over the cytoplasmic matrix rather than the nucleus. Grain counts under the EM were compared with expectation based on established quantitative methods. Only the mitochondria showed obvious and statistically significant grain counts, whereas the nucleus failed to accumulate grains in excess of expectations by chance alone based on area. The findings support the existence of mitochondrial binding of T3, presumably a prerequisite for its action in direct stimulation of the mitochondria.
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  • 39
    ISSN: 1432-0878
    Keywords: Lymph node ; Steroids ; Macrophages ; Intercellular junctions ; Rat
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    Notes: Summary Intercellular junctions were often found between macrophages in sinuses of regional lymph nodes of the rat after injection of large doses of cholesterol, cortisone acetate, and estrone at the footpad. They were identified by subplasmalemmal densities, 20–50 nm in width, beneath the plasma membranes of apposed macrophages. No distinct filamentous structures were visible in those dense regions. Electron-dense amorphous materials are lined up at the center of the intercellular space in the junctional regions. Some macrophages form clusters with intercellular junctions. No significant difference in the effect of cholesterol, cortisone acetate, and estrone on the number of intercellular junctions betwene macrophages was found.
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  • 40
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    Cell & tissue research 236 (1984), S. 171-180 
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Ultrastructure ; Supraoptic nucleus ; Neuropil ; Rat
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    Notes: Summary The neuropil located ventral to the SON was investigated by the use of immunoperoxidase staining for neurophysins, oxytocin and vasopressin, and electron miroscopy. The study was performed in six groups of rats: 1) control; 2) infusion of isotonic saline into the CSF; 3) infusion of hypertonic saline into the CSF; 4) drinking hypertonic saline for 4 days; 5) same as group 4 but injection of colchicine into the CSF on second day of dehydration; 6) salt loading for 3 months. In the control rats the ventral neuropil contained a few immunoreactive processes, the general morphology of which was completely different from that of the neurosecretory axons emerging from the SON at its dorsal aspect. In rats of groups 3 to 6 the ventral processes (VP) became loaded with neurosecretory granules, whereas the perikarya and axons were depleted. Based on their general morphology and reactivity pattern it is suggested that the VP are dendrites. Most of these “dendrites” were embedded in a glial cushion formed by the processes of a particular type of marginal glia. Some of these “dendrites” enveloped an arteriole penetrating the optic tract. All VP were rich in synaptic contacts. The possibility that the VP of neurosecretory cells may be functionally related to the subarachnoid CSF and the arteriolar blood flow is discussed.
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  • 41
    ISSN: 1432-0878
    Keywords: Development ; Enterocytes ; Fish ; Mitosis ; Ultrastructure
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    Notes: Summary The processes of proliferation, cell division and differentiation of intestinal epithelial cells have been studied during development of the fish, Barbus conchonius. On the 3rd day, nearly all cells of the presumptive gut proliferate. Once the intestinal epithelium begins to differentiate, a decreasing percentage of proliferative cells can be found. On the 7th day, when intestinal folds start to develop, the proliferative cells become restricted to the future basal parts of the folds. Ultrastructural examination of 3H-thymidine-labeled cells and mitotic cells of 6-day-old larvae shows that functional enterocytes are proliferative. The same feature is suggested for older fish. Proliferating undifferentiated “dark” cells, characterized by many free ribosomes and a few organelles, are also present in the intestinal epithelium of larval fish; they are considered to be stem cells, mainly for goblet cells. Proliferating goblet cells and enteroendocrine cells were not observed. The latter cell type is scarce and has a long turnover time. A common feature of all these dividing cells is the presence of isolated spherical to cylindrical lamellar structures which may have lost contact with the cell membrane during prophase; they probably regain this contact by fusion with the cell membrane at the end of mitosis.
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  • 42
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    Cell & tissue research 236 (1984), S. 561-566 
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars intermedia ; Peptide hormones ; Dopamine ; Corticotropin-releasing hormone ; 6-Hydroxydopamine ; Rat
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    Notes: Summary When rats were injected with 6-hydroxydopamine the catecholaminergic nerve terminals in their intermediate lobes exhibited distinct signs of degeneration. Morphometric examination of the Golgi apparatus in cells of the intermediate lobe of these rats showed significant enlargement of Golgi cisternae. The release of adrenocorticotropin, β-endorphin/lipotropin and α-melanotropin from intermediate-lobe cells in vitro was measured by radioimmunoassay. The high basal peptide release was inhibited by dopamine and stimulated by methyl-isobutyl-xanthine. In contrast, γ-aminobutyric acid, serotonin, histamine and noradrenaline, or corticotropin-releasing hormone, rat hypothalamic extract and vasopressin had no or only very weak effects. These observations indicate that the synthetic apparatus of intermediate-lobe cells is constantly depressed by dopaminergic nerves. We were not able to stimulate peptide release from intermediate-lobe cells by use of the abovementioned endogenous agents.
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  • 43
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    Cell & tissue research 236 (1984), S. 585-591 
    ISSN: 1432-0878
    Keywords: Urinary bladder, toad ; Scanning electron microscopy ; Hypertonicity
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    Notes: Summary Coincident with an increase in the water permeability of toad urinary bladder induced by serosal hypertonicity, a transformation of the ridge-like surface structures of the granular cells into individual microvillous structures occurs. This study was initiated to establish whether the transformation is mediated by the cytoskeletal network and, thus, can be prevented by disruption of microtubulemicrofilament function with colchicine or cytochalasin B (CB). Scanning electron microscopy revealed the characteristic branching ridges on granular cells of control bladder incubated with colchicine or CB. In contrast, transformation of ridges to discrete microvilli was observed in experimental bladders exposed to serosal hypertonicity alone or in combination with either colchicine or CB. These results suggest that the mechanism underlying hypertonicity-induced surface changes which are associated with increased water permeability does not involve either microtubules or microfilaments.
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  • 44
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    Cell & tissue research 237 (1984), S. 181-183 
    ISSN: 1432-0878
    Keywords: Reissner's fiber ; Scanning electron microscopy ; Spinal cord ; Cat ; Rabbit
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    Notes: Summary The caudal portion of Reissner's fiber was examined by scanning electron microscopy (SEM) in the spinal cord of the cat and rabbit. In some preparations of both species the fiber displayed in the sinus terminalis of the central canal either stump-like terminations or structural modifications such as knot-like swellings and convolutions. In the same area homogeneous material could also be found, which obviously originated from the disintegrating fiber.
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  • 45
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    Cell & tissue research 237 (1984), S. 169-179 
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    Keywords: Foetal pancreas ; β Cells ; Insulin ; Fasting mothers ; Morphometry ; Rat
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    Topics: Biology , Medicine
    Notes: Summary After maternal fasting for 72 h the pancreatic β cells of 18-day-old foetal rats show a conspicuous enrichment in secretory material, with an increase of pancreatic insulin concentration and a marked development of the rough endoplasmic reticulum and the Golgi apparatus. The morphometric analysis shows that the intracytoplasmic migration of the secretory granules is inhibited, principally inside the cell web. Consequently the number of secretory granules fused with plasma membrane decreases and this is associated with a decreased foetal plasma insulin. The difference in the ultrastructural aspect of the β cells of foetuses from fasting mothers and of foetuses from fed mothers is less conspicuous at 19 days of gestation and progressively disappears at 20 and 21 days. The modifications in ultrastructural aspect and in functional state are discussed.
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  • 46
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    Cell & tissue research 238 (1984), S. 81-85 
    ISSN: 1432-0878
    Keywords: Retina ; Ibotenic acid ; Toxicity ; Rat
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    Notes: Summary After 2 h intraocular injections of 19 and 190 nmoles ibotenic acid in the rat retina produced an intensive vacuolization of the inner plexiform layer and cellular alterations, in the inner nuclear layer and ganglion cell layer. These alterations consisted of either cytoplasmic swelling accompanied by clumping of the nuclear chromatin or darkening of the cytoplasm along with nuclear condensation. A week later the retinas were thinner than the controls due to the disappearance of the affected cells. Pre-treatment with diazepam prevents the morphological alterations induced by 19 nmoles ibotenic acid; mainly the swelling, which was completely prevented, while the darkening was reduced drastically, although some vacuolization of the inner plexiform layer is still present.
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  • 47
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    Cell & tissue research 238 (1984), S. 159-163 
    ISSN: 1432-0878
    Keywords: Ovary ; Rat ; Cell division ; Luteinizing hormone
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    Notes: Summary The effect of an LH pulse on the rate at which 3H-thymidine is incorporated into cultured ovaries of metestrous rats was studied. In comparison to ovaries cultured with tonic LH, an LH pulse (1) “rescued” follicles from atresia, (2) induced thecal cell proliferation, and (3) increased the rate at which granulosa cells enter mitosis. It is concluded that LH pulses increase follicular growth by first triggering thecal cell proliferation and then inducing mitotic divisions within the granulosa cells of both atretic and non-atretic follicles.
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  • 48
    ISSN: 1432-0878
    Keywords: Choroid plexus ; Immunoglobulin G ; Permeability ; Anti-HRP-IgG ; Rat
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    Notes: Summary The localization of autologous antiperoxidase immunoglobulin G (IgG) was studied in the choroid plexus of Lewis rats immunized against horseradish peroxidase (HRP). This experiment was performed to study the permeability of the choroid plexus to intravascular IgG. It was shown that autologous IgG was present in the extravascular spaces. The transendothelial transfer appeared to occur mainly via the fenestrations and some interendothelial junctions. No transfer of IgG at the level of epithelial cells toward the cerebrospinal fluid was demonstrated. Interstitial spaces in contact with the connective-tissue cells of the choroid stroma were strongly labeled. The significance of these spaces remains hypothetical and raises the question of the fate of IgG from the interstitial space.
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  • 49
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    Cell & tissue research 238 (1984), S. 191-195 
    ISSN: 1432-0878
    Keywords: Glial fibrillary acidic protein (GFAP) ; Pituicytes, neonatal ; Development, ontogenetic ; Immunofluorescence ; Organ culture ; Rat
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    Notes: Summary The appearance and intracellular localisation of glial fibrillary acidic protein (GFAP) in pituicytes in neural lobe cultures of newborn rats aged 7 to 30 days were investigated by use of the indirect immunofluorescence method. GFAP-immunoreactive cells were observed mostly in the outgrowth zone. GFAP was localised in the perikaryal cytoplasm as well as in pituicyte processes. GFAP-positive pituicytes showed considerable morphological polymorphism. The presence of GFAP — astrocytic marker — in pituicytes in vitro and the evident morphological similarity to cultured astrocytes suggest the astroglial character of these cells.
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  • 50
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    Keywords: Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) ; New cytochemical method ; Retina ; Rods, outer segments ; Light perception ; 5′GMPase ; Rat
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    Notes: Summary Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) activity was studied histo- and cytochemically in the retinal rods of the rat with the use of a newly developed technique. Intense activity of cGMP-PDEase was evenly distributed over the outer segments of the rods. Reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A weak reaction product occurred also on the plasmalemma of the inner segments; however, no precipitate was found in the perinuclear and synaptic portions of the rod cells. The enzyme activity was strongly inhibited by 2 mM theophilline and by 2 mM 3-isobutyl-1-methylxanthine (IBMX). To confirm the specificity of this new cGMP-PDEase method, the localization of 5′nucleotidase (5′GMPase) was also studied. In contrast to the activity of cGMP-PDEase, the activity of 5′GMPase was distributed on the plasma membrane of the photoreceptor cells extending over a wide range from the synaptic endings in the outer plexiform layer to the tip of the outer segments.
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  • 51
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    Keywords: S-100 ; Müller cell ; Astrocyte ; Development ; Rat
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    Notes: Summary The rat retina was studied by immunohistochemistry with antibody to S-100 protein during the first three postnatal weeks. Immunoreactive astrocytes are first detected subjacent to the inner limiting membrane close to the optic disc. They gradually increase in number and spread toward the ora serrata along the inner surface of the retina as the development proceeds. S-100-immunostained Müller cells are first identified on the 12th postnatal day although their immunoreactivity is much weaker than that of astrocytes at the same stage. This differential intensity of the immunoreactivity of the two cell types facilitates observation of the entire shape of the astrocyte. This characteristic reveals that cellular investments of blood vessels in the inner retina are formed by astrocytic processes whereas those in the outer plexiform layer are derived from processes of Müller cells. The cellular investment becomes complete by the 18th postnatal day.
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    Cell & tissue research 238 (1984), S. 559-564 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Macrophages ; Ovariectomy ; Rat ; Estradiol administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Macrophages of the adrenal cortex were studied in normal male and female, ovariectomized and estradiol-injected rats. In normal male rats few macrophages with numerous granules were observed in the zona fasciculatazona reticularis border, and in the zona reticularis. Granules, identified as lysosomes, were limited by a single membrane with a heterogeneous matrix; they exhibited acid phosphatase- and aminotriazole-resistant peroxidatic activities. A larger number of macrophages had identical distributions in normal female rats. In ovariectomized and estradiol-injected rats the number and distribution of adrenal macrophages were similar to those in normal females; however, in spayed animals the number of these cells in the zona reticularis was higher than in the other experimental groups. Lysosomes in macrophages of treated animals were more numerous and their contents more complex than in normal male animals. These results indicate that the adrenal macrophage system is stimulated in experimental conditions involving high levels of circulating estrogens.
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  • 53
    ISSN: 1432-0878
    Keywords: Mitochondria ; Heart ; Scanning electron microscopy ; Thin sections ; Freeze-fracturing ; Macaca fuscata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of mitochondria in monkey myocardial cells was investigated by scanning electron microscopy, thin sections and freeze-fracturing. Mitochondria with well-developed cristae were distributed around the nucleus, between the myofibrils and beneath the sarcolemma. Those clustered near the the poles of the nucleus were generally spherical in shape. Interfibrillar mitochondia were arranged in longitudinal rows between the myofibrils, were elongated and usually about the same length as a sarcomere. Subsarcolemmal mitochondria varied in size and shape, being rod-like, spherical, polygonal or horseshoe-like. There were usually two profiles of subsarcolemmal mitochondria in each section of sarcomere, although sometimes one or three occurred, and they were typically oriented perpendicularly to the myofibrils. These morphological differences among mitochondria could reflect functional and/or mechanical properties in the various cellular locations.
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  • 54
    ISSN: 1432-0878
    Keywords: Sympathetic ganglion ; Development, ontogenetic ; Corticosteroid treatment ; Rat
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    Notes: Summary Hydrocortisone injections into rats on postnatal days 3–9 caused an increase in the number of small granulecontaining cells in the superior cervical ganglia. These cells, corresponding to the small, intensely fluorescent cells, showed an extensive rough endoplasmic reticulum, a large Golgi apparatus and a very large number of granular vesicles. In addition to the granular vesicles, 70–160 nm in diameter, in which the dense core filled most of the vesicle, most cells of the hydrocortisone-injected rats contained also larger granular vesicles, up to 350 nm in diameter, in which the dense core was eccentrically located. A minority of the cells contained only granular vesicles 70–100 nm in diameter, which was the only type seen in the saline-treated control rats. Thirty days after discontinuation of the hydrocortisone treatment, most of the cells with large granular vesicles had disappeared, and only two profiles of such cells were seen on day 40. The other small cells contained only granular vesicles 70–160 nm in diameter, and these cells could not be distinguished from the small granule-containing cells of 40-day-old control rats treated early postnatally with saline. Hydrocortisone treatment, first on days 3–9 and subsequently on days 40–46, caused reappearance of the small granule-containing cells with large granular vesicles up to 350 nm in diameter, the dense core of which was eccentrically located. Hydrocortisone treatment on days 40–46 only was not followed by appearance of such cells in rats treated with saline on days 3–9.
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    Cell & tissue research 238 (1984), S. 459-474 
    ISSN: 1432-0878
    Keywords: Meningeal compartment ; Perivascular space ; Brain intercellular compartment ; Cerebral cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intercellular clefts of the brain and the leptomeninges, and the perivascular spaces were studied with reference to the results obtained in a previous study (Krisch et al. 1983). The spatial relationships of these compartments were analyzed at the electron-microscopic level. Horse-radish peroxidase (HRP) was injected into the brain or into the contralateral ventricle. The pattern of distribution of HRP depends on the boundary situation in the individual compartments. The inner and outer pial layers accompany the vessels intruding into the brain. In the Virchow-Robin space the pial funnel obliterates within a short distance. The inner arachnoid layer is continuous with the outer arachnoid layer when it covers the vessels traversing the meningeal space. The perivascular compartment is not in communication with the arachnoid space; moreover, the pial funnel within the Virchow-Robin space is sealed off against the arachnoid space. Thus, blood vessels traversing the meningeal spaces and subsequently penetrating the brain surface are exposed to the common intercellular compartment represented by the intercellular clefts of the brain and the leptomeninges; this compartment does not communicate with the other compartments. The cerebrospinal fluid located in this intercellular compartment is preferentially drained into the upper cervical lymph nodes.
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    Cell & tissue research 238 (1984), S. 635-642 
    ISSN: 1432-0878
    Keywords: Liver ; Endothelium ; Kupffer cells ; Peroxidase ; Cytochemistry ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat liver fixed by perfusion with low glutaraldehyde concentrations was incubated in diaminobenzidine-containing medium to stain for peroxidase. Endogenous peroxidatic activity was found not only in Kupffer cells but also in the endothelial cells lining the sinusoids and central veins. The reaction product was localized in the nuclear envelope and endoplasmic reticulum. The peroxidatic activity in endothelial cells showed a concentration-dependent sensitivity to glutaraldehyde: in liver samples fixed with 0.25% glutaraldehyde, approx. 23% of the sinusoidal endothelial cells and 65% of central vein endothelium were peroxidase-positive; with 0.5% glutaraldehyde, only approx. 8% of the sinusoidal endothelial cells contained detectable amounts of the reaction product; with 1.5% glutaraldehyde all endothelial cells were consistently peroxidase-negative. No peroxidatic activity could be found in liver endothelial cells following isolation by centrifugal elutriation. Endothelial cell peroxidase may possibly be involved in defense responses of liver and/or, as a part of prostaglandin synthase system, in prostanoid production.
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    Protoplasma 123 (1984), S. 152-159 
    ISSN: 1615-6102
    Keywords: Cellular slime mold ; Dictyostelium discoideum ; Development ; Electronmicroscopy ; Golgi apparatus ; Prespore vacuole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When shaken in a glucose-albumin-cyclic AMP medium, dissociated aggregative cells form small clumps in which prespore cells differentiate fairly synchronously (Okamoto 1981). Formation of prespore vacuoles (PSVs) in differentiating prespore cells was examined in these culture conditions, by electronmicroscopy and immunocytochemistry. After 6 hours of culture, a typical Golgi apparatus composed of vesicles and stacked flat cisternae develops near the nucleus. FITC-conjugated antispore serum stains a crescent-shaped region in the cells which seems to correspond to the Golgi area. After 9 hours, flat sacs which contain electron dense lining membrane similar to that of PSVs appear alongside Golgi cisternae. Later, partially and fully round PSVs are observed in this region, suggesting that flat sacs round up to become mature PSVs. After 12 hours, as mature PSVs increase in number, they become dispersed throughout the cytoplasm and a typical Golgi apparatus with cisternae disappears. When cultured in a medium devoid of cyclic AMP, cells develop neither Golgi cisternae nor PSVs. These results strongly suggest that PSVs form from Golgi cisternae.
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    Protoplasma 120 (1984), S. 12-19 
    ISSN: 1615-6102
    Keywords: Development ; Intercellular spaces ; Parenchyma ; Pisum sativum L. seeds
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    Topics: Biology
    Notes: Summary Electron microscopic observations have shown that the intercellular spaces in the storage parenchyma of the cotyledons of pea (Pisum sativum L.) seeds arise schizogenously. The wall segments adjoining future intercellular spaces display a triple zonation and contain regions with electron-dense material. Space formation starts at the central point of contact between several cells and spreads then further up to the electron-dense, intra-wall structures. As a result of this the electron-dense material is found again in the corners of intercellular spaces. It is proposed that the intra-wall structures may have an important function in limiting the schizogenous process. The localization of the intercellular spaces is thus predetermined. The amount of electron-dense material in their corners increases considerably during further development of the embryo. During germination wall segments between two intercellular spaces diverge resulting in a fusion of several spaces.
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    Protoplasma 123 (1984), S. 104-115 
    ISSN: 1615-6102
    Keywords: Constrictive binary fission ; Cyanobacteria ; Development ; Multiple fission ; Septate binary fission ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An ultrastructural examination of cell division in two baeocyte producing cyanobacteria,Pleurocapsa minor andDermocarpa violaceae, reveals two distinct patterns of binary (transverse) fission. Septate binary fission, inPleurocapsa minor, involves centripetal synthesis and deposition of the mucopolymer cell wall layer (L 2). The ingrowth of the cytoplasmic membrane and L 1 cell wall layer, along with the synthesis of the L 2 cell wall layer, results in the formation of a prominent septum. Partitioning of the cell occurs by the constriction of the outer cell wall layers (L 3 and L 4) through the septum. InDermocarpa violaceae, constrictive binary fission occurs by the simultaneous ingrowth or constriction of the cytoplasmic membrane and all cell wall layers (L1, L2, L3, L4). Septate and constrictive binary fission may proceed symmetrically (medially) or asymmetrically (nonmedially). Multiple fission occurs regularly inDermocarpa violaceae and provides for a rapid means of reproduction when compared to binary fission. Successive radial and tangential divisions of the protoplast result in formation of many small daughter cells (baeocytes). The process of multiple fission is similar to septate binary fission with reduced septa being formed. However, constriction of the outer cell wall layers, through the septa, proceeds concurrently with septum formation.
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  • 60
    ISSN: 1573-8221
    Keywords: hypertension ; β-adrenoreceptors ; lymphocytes ; man
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    Bulletin of experimental biology and medicine 97 (1984), S. 635-638 
    ISSN: 1573-8221
    Keywords: diploid cells ; man ; clonal heterogeneity
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    Bulletin of experimental biology and medicine 97 (1984), S. 479-480 
    ISSN: 1573-8221
    Keywords: cloning ; diploid cells ; man ; proliferative potential ; variation
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  • 63
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    Journal of chemical ecology 10 (1984), S. 1007-1018 
    ISSN: 1573-1561
    Keywords: Rat ; Rattus norvegicus sp. ; odorants ; stress ; behavior ; open field ; corticosterone ; fox dropping ; ketone ; sulfur ; compounds ; tans ; mercaptoketones ; repellent ; structure-activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The stress for 12 sulfur-containing synthetized volatiles was evaluated in male Wistar rats and compared to that for fox-dropping extract concentrate. Stress behavior was analyzed by quantifying various stress responses in a standard open field and measuring the increase in plasma corticosterone concentration. Nine compounds induced stress—a dihydrothiazole, two cyclic polysulfides, five mercaptoketones, and a mercaptan. For the mercaptoketones, the following structure-activity relationships were observed. Size can vary considerably; the mercapto group can be either alpha or beta and either secondary or tertiary. The keto group is not essential, since a structurally related mercaptan remains active. The mercapto group is essential for activity in mercaptoketones, since conversion to a methyl sulfide resulted in a neutral response. This type of odorant could function as an allomone and may have potential in rat control as an area repellent.
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    Environmental biology of fishes 10 (1984), S. 89-100 
    ISSN: 1573-5133
    Keywords: Brood size ; Development ; Exotic species ; Feeding ; Gestation period ; Livebearer ; Maturation ; Neonate ; Pike killifish ; Sex ratio ; Viviparity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The pike killifish, Belonesox belizanus, is native to Mexico and Central America and was introduced into Dade County, Florida in 1957. This study reports on the structure and reproduction of the Florida population and compares the species with other members of the family Poeciliidae. The mean standard length (SL) of mature females was about 103 mm. Most females larger than 75 mm SL contained yolked ova, fertilized eggs, or embryos. Mature males averaged about 72 mm SL, and most males larger than 55 mm SL were mature. The sex ratio was significantly skewed in favor of females among adults, but it did not differ significantly from 1:1 among immature fish. Average brood size was about 99, and there was a significant positive correlation of brood size with size of the parent female. There was no evidence of superfetation. Sizes and weights of embryos and neonates were the largest reported for the family. There was a significant decrease in mean embryo weight as development proceeded, indicating that developing embryos received little or no nutrient input from the maternal system after fertilization. The average interbrood interval of aquarium-held females was 42 days, and females stored viable sperm at least 47 days. Reproduction continued year round in the field. Laboratory-born neonates were immediately piscivorous and exhibited distinctive behavior associated with filling the swimbladder and with avoiding detection by predators.
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    Gamete Research 10 (1984), S. 107-118 
    ISSN: 0148-7280
    Keywords: Rat ; fertilization ; in vivo ; in vitro ; topography ; egg ; actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The surface topography of the rat egg was examined during fertilization in vitro and in vivo. Using phase optics, 348 in vitro fertilized and 50 in vivo fertilized eggs were continuously monitored throughout the 7-hour period of sperm incorporation. A myriad of different surface configurations were seen, with each egg exhibiting one or more of the following changes. A small number of eggs (4-6%) formed surface elevations over the sperm head after its detachment from the flagellum, 15-30 min after sperm-egg fusion; 1 to 1.5 hr after fusion, 40-50% of the eggs produced the so-called incorporation cone, a prominent surface elevation over the decondensing sperm nucleus. The vast majority of eggs (74-82%) formed surface elevations over the proximal tip of the flagellum 2-3 hr after sperm-egg fusion. These had no association with the decondensing sperm nucleus. A few eggs (11-12%) exhibited multiple protrusions that were distributed randomly about the egg surface, whereas 14-20% did not manifest any surface elevations and remained spherical throughout the sperm incorporation period. Regardless of the type of surface change, all of the eggs resumed a spherical shape by the time sperm incorporation was complete. These observations are in contrast to the conclusions by previous authors that formation of the so-called incorporation cone over the decondensing sperm nucleus is a ubiquitous event.
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    Journal of Electron Microscopy Technique 1 (1984), S. 331-340 
    ISSN: 0741-0581
    Keywords: Digital image processing ; Laplacin filter ; Scanning electron microscopy ; High-resolution ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Certain digital image-processing methods, which are useful for nonperiodic structural images, have been applied to high-resolution SEM images for the improvement of resolution. Samples utilized in the present study consisted of magnetic tape coated with gold, T4 phage coated with gold-palladium, and uncoated specimens of Prolamellar body (PLB) in Cucurbita moschata. These images were blurred and otherwise disturbed by electronic noise, though the images were taken at the limit of efficiency of intrinsic instrument. The major image-processing tool was the Laplacian filter, which subtracts the Laplacian from the original image. Noise, which is a serious problem in digital processing of high-resolution SEM images, was suppressed by the nonlinear type smoothing method. Also, the noise was evaluated by an autocorrelation function and a power spectrum of the image. By using these methods of “deblurring” and noise removal, we achieved better resolution, and structural details of our biological specimens were revealed.
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  • 67
    ISSN: 0741-0581
    Keywords: Glomerular capillary endothelium ; Vascular perfusion ; Freeze-cracking ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Modern morphological investigation requires the use of a variety of technological approaches and the employment of rigorous morphometric analysis for an adequate evaluation of the structural and ultrastructural features of a tissue or organ. The introduction of the technique of freeze-cracking of tissue to expose new surfaces has made it possible to quantitate the normal surface characteristics of the glomerular capillaries of the mammalian kidney. This report describes the techniques used for the preparation and quantitative assessment of normal glomerular endothelial morphology. The techniques of in vivo and in vitro vascular perfusion of kidneys as a method of fixation and the freeze-cracking of tissue are outlined in detail. In addition, a morphometric analysis of the endothelial surface characteristics are described and values are reported for the control rat and human kidneys from transplant donors.
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    Journal of Electron Microscopy Technique 1 (1984), S. 341-348 
    ISSN: 0741-0581
    Keywords: Vascular casts ; Scanning electron microscopy ; Vascular anatomy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Corrosion casts provide three dimensional replicas that can be examined readily by scanning electron microscopy (SEM). They are prepared by filling vascular networks with polymerizing plastic and then digesting away the tissue. As based on our studies of ocular vessels, this report describes the vascular anatomy, as well as the artifacts, that are encountered during SEM studies of such preparations.
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    Development genes and evolution 188 (1980), S. 55-63 
    ISSN: 1432-041X
    Keywords: Drosophila ; Compound eye ; shibire ts ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analysed the effect of temperature on both developing and adult eye cell clones homozygous forshi ST139, a temperature-sensitive mutant ofDrosophila melanogaster. The mutant gene, autonomous in its cellular expression, causes structural modifications of ommatidial cells when adult clones of cells are exposed to the restrictive temperature (29°C) for several days. However, the mutant phenotype reverses to normal within 4 days at the permissive temperature (20°C). The results of pulse, shift-up and shift-down experiments show that the temperaturesensitive period for developing compound eye cells is from the late second instar up to the early pupa. Cytodifferentiation of compound eye cells is blocked by restrictive temperature treatment during this period, whereas cell proliferation does not seem to be directly affected. These results are discussed with regard to the other known aspects of the phenotype observed in mutant individuals.
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    Development genes and evolution 189 (1980), S. 181-186 
    ISSN: 1432-041X
    Keywords: Xenopus embryo ; Scanning electron microscopy ; Cell shape ; Cilia formation ; Determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Xenopus embryos held inverted from the one cell stage show a partial reversal of the pattern of cleavage: the blastocoel forms towards the new upper pole, and the non-pigmented cells forming the blastocoel roof are smaller than normal endoderm cells. Two properties of the cells from inverted embryos have been studied: their capacity to form cilia when cultured for 48 h, normally a property of ectoderm cells; and their scanning electron microscopical appearance when isolated and cultured for shorter periods, which differs for normal ectoderm and endoderm cells. Groups of the upper, non-pigmented cells from inverted embryos do not form cilia in a longerterm culture, whereas groups of the lower, pigmented cells do. In contrast, the scanning electron microscopical appearance of the upper, non-pigmented cells of inverted embryos is more like that of normal ectoderm cells; the appearance of lower, pigmented cells is more like that of normal endoderm. Thus the determination to form cilia is not reversed by inversion, whereas the control of cell morphology is.
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    Development genes and evolution 188 (1980), S. 205-213 
    ISSN: 1432-041X
    Keywords: Gangliosides ; Development ; Brain ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The developmental profiles of 15 different gangliosides of the optic lobes and cerebrum of the chicken were followed from the 6 th day of incubation to hatching and correlated to morphological development. Five of these gangliosides appearing in both structures between the sixth and tenth day, have not been reported previously in higher vertebrates. Three chromatographed on TLC-plates similarly to GT3, GT2, and GT1c gangliosides, which have been demonstrated in fish brain. One fraction moved just below GQ1b and is suggested, to contain GQ1c. These “novel” gangliosides, which are possibly related to a recently proposed separate and probably phylogenetically older biosynthetic pathway, contained up to 20% of total ganglioside sialic acid. The fifth “novel” fraction, containing up to 16% of total ganglioside-sialic acid, moved below the penta-sialoganglioside GP1 and is suggested to contain hexa-sialogangliosides. There were two main changes in ganglioside synthesis, which were identical in both structures. The first occurred from the sixth to the eleventh day, parallel to decreased proliferation, maximal cell migration and neuroblast differentiation, GD3 and GD2 decreased rapidly in favour of GQ1b, GP1, and to the “novel” fractions, described above. The second occurred from the eleventh to the eighteenth day, parallel to increased growth and arborization of dendrites and axons as well as functional establishment of synaptic contacts, there was a sharp rise in the amount of GD1b, GT1b, and GD1a. Concomitantly the “novel” gangliosides decreased. At hatching GD1a was the predominant ganglioside. GM3, GM2, and GM1 were always minor fractions, each accounting for less than 4% of total ganglioside-sialic acid. GM4 was never detected, indicating neglegible myelinisation until hatching.
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    Development genes and evolution 189 (1980), S. 171-180 
    ISSN: 1432-041X
    Keywords: Amino acyl-tRNA synthetases ; Development ; Nuclear-mitochondrial interactions ; Neurospora
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The specific activities of the branched chain amino acyl-tRNA synthetases from the cytosolic and mitochondrial fractions ofN. crassa were low in dormant conidia and increased during germination, reaching a maximum 8 h after inoculation. This stage of development is characterised by high rates of many other cellular activities. The increases in activity of synthetases of both cytosol and mitochondria are inhibited by cycloheximide indicating that they are synthesized on cytoplasmic ribosomes. The mitochondrial synthetases show a stimulation of their specific activity when mitochondrial RNA and protein synthesis are inhibited by either ethidium bromide or chloramphenicol suggesting that a mitochondrial translation product regulates the synthesis of the mitochondrial synthetases. The activities of amino acyl-tRNA synthetases are dependent on energy production. When respiration is uncoupled from oxidative phosphorylation, synthetase specific activities decrease although the activities of other mitochondrial enzymes like NADH-dehydrogenase increase. This phenomenon suggests that more than one mechanism regulates the synthesis of mitochondrial proteins which are formed on cytoplasmic ribosomes. The synthesis of branched chain amino acyl-tRNA synthetases ofNeurospora is neither repressed by their cognate amino acids, nor is there inhibition by the precursors of these amino acids, as has been observed in other amino acyl-tRNA synthetases of various organism includingNeurospora.
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  • 73
    ISSN: 1432-0827
    Keywords: Rat ; Calvarium ; Electron microscopy ; Preosteoclasts ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.
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    Calcified tissue international 30 (1980), S. 109-119 
    ISSN: 1432-0827
    Keywords: Oxalosis ; Human bone ; Scanning electron microscopy ; X-ray diffraction ; Oxalate titration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Postmortem scanning electron microscopy of human phalanges in a chronic uremic hemodialysis patient with hyperparathyroidism showed the presence of confluent abnormal rounded formations with a radial rosette-like crystalline pattern in the diaphysis as well as in the epiphyseal part of the bones. These fan-shaped configurations were found either as individual formations within bone trabeculae or as numerous aggregated crystalline deposits replacing large parts of the bone structure. The microdissected content of such large areas submitted to X-ray diffraction analysis revealed the predominant presence of calcium oxalate monohydrate or whewellite with some traces of hydroxyapatite. Oxalate titration analysis indicated the presence of 25% of oxalate, corresponding to 45% in weight of whewellite.
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    Calcified tissue international 32 (1980), S. 63-68 
    ISSN: 1432-0827
    Keywords: Rat ; Bone formation ; Fluorochrome ; Microphotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A method for quantitative studies of the formation rate of bone has been developed. After vital staining with calcein, the fluorescence of a bone section was measured with a microphotometer controlled by a mini computer. After staining the bone structure with alizarin red S in a second step, the section was measured in transmitted light. The two data sets were combined and the shortest distances between the bone surface and the fluorescence lines were computed. With this information the distance distribution and the bone area between the label and the surface could be calculated in two different ways: with the single labeling and the continuous labeling techniques. The advantages and disadvantages of the two methods are discussed and compared with those of other techniques.
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    Calcified tissue international 32 (1980), S. 113-122 
    ISSN: 1432-0827
    Keywords: Rat ; Bone ; Metaphysis ; Quantitative ; Aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purpose of this work was to analyze the proximal tibial metaphysis of the 170 g rat in a quantitative histologic fashion which would allow some relation to tissue age to be established. Stained 3 µm thick tissue sections were analyzed with the aid of a Merz grid on an eyepiece reticule and a light microscope. Tissue mass and cell distribution were studied in all areas. The rate of change in tissue mass during aging of the metaphysis was calculated. Two regions of the metaphysis were identified. One, corresponding to the primary spongiosa, less than 4.45 days of age, is a region of high turnover of hard tissue and high numbers of osteoblasts and osteoprogenitor cells. The other, corresponding to the secondary spongiosa, is a region of relatively low net tissue turnover and low numbers of osteoblasts and osteoprogenitor cells. Osteoclasts were found relatively more uniformly distributed through the metaphysis than were osteoblasts and osteoprogenitor cells. The rate of bone formation in the primary spongiosa is 50 times that found in the Haversian bone of the rib of 5-year-old humans and about 500 times that found at the cortical-endosteal surface of ribs of 5-year-old humans. It is argued that both cell distribution and tissue distribution in the metaphysis support the concept that osteoblasts and osteoclasts, rather than osteocytes, are responsible for the maturation of the metaphysis. The inhomogeneous distribution of both cells and tissue in the metaphysis has definite meaning for the interpretation of findings concerning the incorporation of radionuclides into the skeleton.
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  • 77
    ISSN: 1432-0827
    Keywords: Rat ; Hypophysectomy ; Dietary phosphorus deprivation
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    Topics: Biology , Medicine , Physics
    Notes: Summary The demands of growth are known to exacerbate the effect of phosphorus deprivation (PD). We examined whether changes associated with PD could be prevented in young rats in which growth and growth hormone (GH) were eliminated by hypophysectomy (HPX) and whether PD in normal intact rats (INT) was associated with increased secretion of GH. INT or thyroxine- and ACTH-replaced HPX rats were fed one of the three diets: 0.31% P (NP); 0.027% P (LP), and 0.31% P, pair-fed with LP-mates (NP-PF). The results indicate that HPX did not qualitatively alter several physiologic responses to PD: (a) serum and urinary phosphorus (P) decreased and urinary calcium (Ca) increased; (b) net intestinal Ca retention fell and duodenal sac uptake of45Ca rose; and (c) external P balance was restored and duodenal sac uptake of32P-phosphate increased. Only the hypercalcemia seen in INT, LP rats was prevented by HPX. In INT rats serum immunoassayable GH levels, measured in single samples, were not different between different dietary groups while pituitary bioassayable GH was reduced in both LP and NP-PF rats when compared to the NP rats. Thus, except for hypercalcemia, the physiologic responses associated with PD are not prevented by the elimination of growth and GH, and the development of these responses in INT rats was not associated with a consistent or specific alteration in GH secretion.
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  • 78
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    European journal of clinical pharmacology 18 (1980), S. 339-345 
    ISSN: 1432-1041
    Keywords: buprenorphine ; radioimmunoassay ; specificity ; plasma level ; dog ; man
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Antisera to buprenorphine were obtained in rabbits immunised with 3-0-carboxymethylbuprenorphine and N-hemisuccinyl-norbuprenorphine conjugated to obvine serum albumin. Using the latter antiserum and tritium labelled buprenorphine a radioimmunoassay having good accuracy and precision was developed for concentrations as low as 50 picograms in 1 ml of plasma. The N-hemisuccinyl antiserum crossreacted with norbuprenorphine, and the 3-0-glucuronide conjugate with the 3-0-carboxymethyl antiserum. Cross-reactivity of both antisera to other pharmacologically related compounds was negligible. The assay was employed to determine plasma buprenorphine concentration following its parenteral administration to dog and man.
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  • 79
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    European journal of clinical pharmacology 18 (1980), S. 185-187 
    ISSN: 1432-1041
    Keywords: cimetidine ; microsomal drug metabolism ; man ; interaction ; liver microsomes ; antipyrine kinetics
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of cimetidine on human microsomal drug metabolism was studied. In five of six healthy volunteers therapeutic doses of cimetidine prolonged the half-life of antipyrine (range 12–37%; p〈0.05). Its clearance was decreased in five subjects (range 2–18%) and was increased in one subject (15%), the changes not being statistically significant. The volume of distribution increased on average by about 14% (range 9–19%; p〈0.001). Cimetidine in vitro inhibited the hydroxylation of benzo(a)pyrene and coumarin, as well as the O-deethylation of 7-ethoxycoumarin, by homogenised liver biopsies. The in vitro studies suggest that the effect of cimetidine on antipyrine elimination is due to inhibition of microsomal drug metabolism, which may prove an important drug interaction.
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  • 80
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    European journal of clinical pharmacology 17 (1980), S. 243-250 
    ISSN: 1432-1041
    Keywords: digoxin ; atrial fibrillation ; digoxin concentrations in right atrium ; skeletal muscle ; serum ; sinus rhythm ; man
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Serum, right atrial myocardium and skeletal muscle collected from 32 adult patients undergoing open heart surgery were analyzed for digoxin by radioimmunoassay. Preoperatively 20 patients were in sinus rhythm and 12 were in atrial fibrillation. In patients with sinus rhythm, but not in patients with atrial fibrillation, there was a highly significant correlation between digoxin concentration in serum and right atrial myocardium, in skeletal muscle and right atrial myocardium, and in serum and skeletal muscle. The means and variances of the ratios right atrial myocardium/serum and right atrial myocardium/skeletal muscle were significantly higher in patients with atrial fibrillation than in those with sinus rhythm. This, plus the lack of difference in ratios skeletal muscle/serum between these groups of patients, indicate increased right atrial digoxin binding in atrial fibrillation in man. This conclusion is further supported by the finding of similar or higher digoxin concentration in right atrial myocardium than in left ventricular myocardium in atrial fibrillation (6 patients), and a lower digoxin concentration in right atrial myocardium than in left ventricular myocardium in sinus rhythm (3 patients).
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  • 81
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    Environmental management 4 (1980), S. 13-20 
    ISSN: 1432-1009
    Keywords: Planning ; Management ; Natural resource planning ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Since October 1977, the East-West Environment and Policy Institute in Honolulu has been conducting a multinational collaborative project to enhance the preparation and utilization of natural systems assessments in developing countries. This paper presents some of the findings to date: 1. Channels are developing rapidly for transferring ecological knowledge into political and administrative decision making. 2. The systematic approach of ecology is replacing “environmental quality” as the organizing concept for information about natural resources and the environment. 3. Benefit-cost analysis is a promising method for integrating ecological knowledge into economic development decision making. 4. The lack of baseline information, inventories, and predictive capability will not be remedied soon or easily; thus priorities for ecological research are essential.
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  • 82
    ISSN: 1432-072X
    Keywords: Claviceps purpurea ; Ultrastructure ; Development ; Sclerotium ; Oleosomes
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    Topics: Biology
    Notes: Abstract The development of sclerotia of Claviceps purpurea was investigated by light and electron microscopy. During the first days after infection sterigma and conidiospores are formed. The spores show a moderately developed vacuolar system, they are thick walled and contain about 20% lipid (related to the cell volume) embedded in glycogen. The sterigma are cylindrical unicellular hyphae with electron dense cytoplasm and isolated strongly contrasted lipid droplets. In maturing sclerotia the hyphae become septated with increasingly thick cell walls and a large lipid content. The lipid forms small droplets in young cells, while in the mature sclerotium it occurs in the form of very large drops, occupying the major part of the cell. Simultaneously the composition of the lipid is changed. The mature cells have several nuclei. They are partially connected by osmiophilic substances, forming a network of intercellular spaces.
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  • 83
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    Cell & tissue research 209 (1980), S. 95-109 
    ISSN: 1432-0878
    Keywords: Mesonephric nephron ; Scanning electron microscopy ; Rabbitembryo ; Wolffian body
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    Topics: Biology , Medicine
    Notes: Summary The luminal surface ultrastructure of the mature mesonephric nephron in 18 day rabbit embryos was studied in order to classify the nephron segments and to compare them with their metanephric counterparts. The proximal tubule has two slightly different segments. Its brush-bordered cells, with lateral ridges and basal microvilli (revealed in disjoined cells) exhibit structural principles similar to those of metanephric cells. The short distal tubule, starting with an abrupt border, cannot be subdivided. Its surface differs from one specimen to the next; the various cellular patterns are regarded as different functional states rather than evidence of a true cellular heterogeneity. Cells with leaf-like meandering borders correspond to similar metanephric cells favoring a paracellular transport mechanism. The collecting tubule shares common features with the metanephric collecting duct in spite of its different origin. Among principal cells, clearly demarcated by marginal microvillous rows and studded with sparse apical microvilli, non-ciliated and strongly bulging intercalated cells occur in small numbers. The latter have exaggerated, sometimes branched microvilli, and occasional microplicae. In the Wolffian duct, which has no metanephric counterpart, the single cilia dominate the picture of a homogeneous cell population. Apical globular protrusions of the tubular epithelia, which have been depicted in almost every paper on the mesonephros, are all fixation artefacts that can only be avoided by properly perfusing the living embryo.
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  • 84
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    Cell & tissue research 205 (1980), S. 11-17 
    ISSN: 1432-0878
    Keywords: Pineal organ ; Subcommissural organ ; Vasopressin ; Oxytocin ; Vasotocin ; Rat
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    Topics: Biology , Medicine
    Notes: Summary Vasopressin and oxytocin were specifically demonstrated in the rat brain using the unlabelled antibody-enzyme method and purification of the first antiserum. Vasopressin and oxytocin fibres extend via the subcommissural organ or habenular commissure into the pineal stalk and terminate in the anterior part of the pineal organ. In addition, immediately adjacent to the subsommissural organ many vasopressin-containing fibres run caudally toward the central grey. These results are discussed in relation to the proposed presence of vasotocin in the pineal gland.
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  • 85
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    Cell & tissue research 210 (1980), S. 167-170 
    ISSN: 1432-0878
    Keywords: Neuropeptides ; VIP-immunoreactive neurons ; Retina ; Amacrine cells ; Rat
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    Topics: Biology , Medicine
    Notes: Summary Immunoreactive vasoactive intestinal polypeptide (VIP) was detected in a population of amacrine cells in the retina of the rat. Processes of these cells reach both the inner and outer half of the inner plexiform layer where they form sublayers. The VIP neurons are different from previously known amacrine cell types.
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  • 86
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    Cell & tissue research 210 (1980), S. 181-189 
    ISSN: 1432-0878
    Keywords: Catecholamines ; Neurophysin ; Simultaneous demonstration ; Functional interaction ; Rat
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    Topics: Biology , Medicine
    Notes: Summary A method was developed that allows the analysis of neuropeptides and monoamines in a single tissue section by the application of the unlabeled antibody method for peptide staining to tissue sections freeze-dried for formaldehyde-induced monoamine histofluorescence. The hypothalamic magnocellular system of male albino rats served as a model for this study; neurons were stained with anti-neurophysin sera, which mark the vasopressin- and oxytocin-associated proteins. Neurophysin-containing perikarya appeared to be surrounded by catecholamine-containing varicosities. This phenomenon was seen to varying degrees within the supraoptic and paraventricular nuclei. The juxtaposition of varicosities and peptidergic neurons suggests an afferent fiber-target neuron relationship that might favor a functional interaction between monoamines and neuropeptides.
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  • 87
    ISSN: 1432-0878
    Keywords: Rat ; Preovulatory follicle ; Ultrastructure ; Degeneration ; Atresia
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    Topics: Biology , Medicine
    Notes: Summary To identify and describe ovarian follicles committed to undergo follicular degeneration (atresia), immature rats were primed with pregnant mare serum gonadotropin (PMSG). After PMSG treatment, preovulatory follicles develop but subsequently degenerate. Prior to the appearance of pyknotic nuclei (Stage I of atresia), degenerative changes were observed in focal areas of the granulosa cell layer. These changes include “blebbing” of the cytoplasm and alterations in the shape of the granulosa cells. The appearance of these degenerative changes coincides with a decrease in ovarian concentrations of estradiol and testosterone. Since estrogens and androgens maintain the follicle, the decline in estradiol and testosterone could be responsible for the further degenerative alterations that lead to complete deterioration of the preovulatory follicle. In Stage I atretic follicles, lysosome-derived autophagic vacuoles develop and macrophages invade both the thecal and granulosa cell layers. The combined actions of the autophagic vacuoles and macrophages could destroy both the granulosa-cell and thecal layers and thereby transform the preovulatory follicle into an ovarian cyst.
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  • 88
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    Cell & tissue research 211 (1980), S. 117-137 
    ISSN: 1432-0878
    Keywords: Eminentia mediana ; Neurohypophysis ; Development ; Pituicytes ; Tanycytes ; Astrocytic tanycytes ; Oligodendrocytes ; Astrocytes ; Microglia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the glial cells of the rat median eminence (ME), including the supraependymal cells, was investigated from embryonic day (ED) 14 through postnatal day (PD) 7, and pituicyte development from ED 12 through ED 17. The anlage of the ME and neurohypophysis shows a neuroepithelial-like structure at ED 12. From ED 13 to 15, the cells of both regions start to differentiate. At the ultrastructural level, only one cell type appears. At the beginning of ED 16, glioblasts of the oligodendrocyte and astrocyte series migrate laterally (from the region of the arcuate nucleus) into the ME. Also at this time the first distinctive structural features appear in the neurohypophysial anlage, the cells of which later develop into pituicytes. Starting at ED 18, tanycytes and astrocytic tanycytes arise in the ME from local glial cells, and somewhat later oligodendroblasts and astroblasts are formed from immigrant glioblasts. Due to their common features, the pituicytes, tanycytes and astrocytic tanycytes apparently represent different forms of the same parent cell type. Microglial and supraependymal cells are first seen at ED 12. Initially, they resemble the prenatal phagocytic connective tissue cells and mature in the fetus into typical electron-dense microglia and macrophage-like supraependymal cells. Both cell types are apparently of mesodermal origin. The microglial elements of the ME probably migrate from the mesenchyma through the basement into the nervous tissue. The intraventricular macrophages of the infundibular region may originate from microglia, epiplexal cells and subarachnoid macrophages.
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  • 89
    ISSN: 1432-0878
    Keywords: Lymph node ; Macrophages ; Postcapillary high endothelial venules ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The afferent lymphatic vessels of rat popliteal lymph nodes were interrupted, and the histological alterations in the lymph nodes occurring 1 to 14 weeks after operation were studied. One week after operation the number of macrophages was considerably reduced and continued to decrease during the subsequent time periods studied. A 6 weeks most macrophages had disappeared. Simultaneously the immunological activity diminished and had completely disappeared 8 weeks after operation. Three weeks after operation the endothelial cells of the postcapillary high endothelial venules had flattened, and the number of immigrating lymphocytes was greatly reduced. Subsequently the lymph nodes became depleted of both macrophages and lymphocytes, leaving only the reticuloendothelial framework.
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  • 90
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    Cell & tissue research 211 (1980), S. 441-448 
    ISSN: 1432-0878
    Keywords: Somatotroph ; Mammotroph ; Development ; Mouse ; Pituitary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars distalis of the pituitary gland of the C57BL mouse was studied by means of electron microscopy during postnatal stages of males ranging in age from newborn through 24 days, with particular emphasis on the somatotrophs and mammotrophs. During this period, growth curves were plotted in order to correlate postnatal growth patterns with the state of differentiation of the somatotrophs in the pars distalis. In the newborn, the somatotrophs show well developed organelles, including rough endoplasmic reticulum and Golgi complexes. These cells are not as densely packed with granules as the adult somatotrophs; however, from days 5 through 24, they show a progressive accumulation of granules. Although mammotrophs are scarce in the newborn, they are readily distinguishable in the pars distalis at 5 days. Male mice in small litters show a progressive increase in body weight between birth and 11–12 days, at which time the rate slackens until 18–19 days when the rate again increases. Growth curves for mice from large litters are similar to those from smaller litters, except that the transitory decrease in rate is more prominent.
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  • 91
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    Cell & tissue research 209 (1980), S. 1-10 
    ISSN: 1432-0878
    Keywords: Myoepithelial cell ; Exocrine gland ; Scanning electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By removing connective tissue components with enzymatic digestion followed by HCl-hydrolysis, myoepithelial cells (MECs) of the terminal portion in a variety of exocrine glands of the rat were examined with the scanning electron microscope. The profile of MECs varied considerably from gland to gland; MECs in the lactating mammary gland have a few long cytoplasmic processes in close contact with those of adjacent cells forming a continuous network around the terminal portion. Those of the exorbital lacrimal gland are stellate with many thin radiating processes with tapered ends that terminate freely. MECs in the sublingual gland are characterized by a number of broad and extensive cellular processes. MECs in the submandibular gland are similar in appearance to those of the exorbital lacrimal gland, but with more extensive cellular processes that form a more or less continuous network with those of the adjacent cells. No MECs were observed on the terminal portion of the parotid gland where the cells appear to be lodged on the intercalated duct. The relative surface area covered by MECs per terminal portion was also found to vary significantly, being 24% in the lactating mammary, 17% in the exorbital lacrimal, 48% in the sublingual, and 25% in the submandibular glands. The findings are discussed in relation to the physical properties of secretions in different glands.
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  • 92
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    Cell & tissue research 207 (1980), S. 89-107 
    ISSN: 1432-0878
    Keywords: Rehydration ; Nongranular vasopressin ; Intercellular clefts ; Axoplasmic reticulum ; Ultrastructural immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vasopressin system of the rat was examined in the course of the first 12 h of rehydration after prolonged thirst at light and electron microscopic levels and by use of the peroxidase anti-peroxidase (PAP) method. Light microscopically, the median eminence was the only part of the system that not only displayed distinct differences between animals of different rehydration times but also showed a characteristic pattern of immunohistochemical reactivity in its rostro-caudal distribution. Ultrastructurally, in the perikarya a maximal labeling of the rough endoplasmic reticulum was observed after 2 h of rehydration, whereas an extensive labeling of the enlarged Golgi zones was attained after 4 h of resupplying water. A labeling of the intercellular clefts in the basal glial labyrinth of the supraoptic nucleus (and to a lesser degree in the subependymal neuropil adjacent to the paraventricular nucleus) was increased 30 min after the onset of drinking, as compared with water-deprived animals; it decreased slightly after 12 h of rehydration. The filling of the swollen fibers by increasing amounts of labeled axoplasmic reticulum, evident in the nuclear areas already after 30 min of water supply, begins in the median eminence after 2 h of rehydration and is fully developed after 4 and 8 h. Corresponding results hold true for the neural lobe but are somewhat delayed in comparison to the findings in the median eminence. The discussion considers (i) synthesis and transport of nongranular vasopressin within the axoplasmic reticulum, and (ii) release not only from the neural lobe but also from the nuclear areas and from the fibers of the median eminence.
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  • 93
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    Cell & tissue research 210 (1980), S. 383-393 
    ISSN: 1432-0878
    Keywords: Avian skeletal muscle ; Development ; Normal, aneural, paralyzed muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The extent to which the motor innervation regulates the embryonic development of skeletal muscle was investigated by comparing changes in normal, aneural, and paralyzed superior oblique muscle of the duck embryo. The muscle was made aneural by permanently destroying the trochlear motor neurons with electrocautery on day 7 i.e., three days prior to innervation. Embryos were paralyzed by daily application of α-bungarotoxin onto the chorioallantoic membrane from day 10 onwards. The differentiation of myoblasts and myotubes in the aneural muscle was severely affected and did not progress to the myofiber stage. A mass of dead cells in the aneural muscle was replaced by connective tissue. Although the differentiation of myoblasts and myotubes was also retarded in the paralyzed muscle, numerous muscle cells progressed to the myofiber stage. Neuromuscular junctions of normal ultrastructure were seen in all paralyzed muscles. Degeneration of some cells in the paralyzed muscle occurred but there was no evidence of a massive wave of cell death similar to that observed in the aneural muscle. These observations suggest that both the trophic factors from the nerve and the nerve-evoked muscle activity are essential for the execution of the developmental program of the muscle. Trophic factors may play a larger role in differentiation, and maintenance of the muscle than muscle activity.
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  • 94
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    Cell & tissue research 211 (1980), S. 303-316 
    ISSN: 1432-0878
    Keywords: Fish scale ; Fine structure ; Development ; Calcification ; Cyprinodon variegatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scale formation in Cyprinodon variegatus was found to be initiated at about 26 to 30 days after hatching. Ultrastructural investigation revealed that within 4 to 6 h in the first-formed scales the marginal cells begin to flatten and differentiate into osteogenic cells, which later change to osteoblasts and fibroblasts. These cells are separated from the surrounding epithelial cells by a basal lamina. The osteoid is formed by the marginal and osteogenic cells; the osseous layer by the osteoblasts; and the fibrillary plate by the fibroblasts. The osteoid is formed within 2 to 3 h after the initiation of the scale, and within 20 to 24 h the osseous layer is formed. Hydroxyapatite crystals are deposited in the matrix of the osseous layer without apparent association with collagen fibers. No matrix vesicles or dense bodies are evident at the sites of calcification. The fibrillary plate arises 18 to 20 h after the initiation of the scale. It is also partially calcified, but not before the third week of scale formation. The crystals develop almost exclusively between the collagen fibers at the extreme edge of the calcifying front, but solid calcification of the fibers results with further growth of the crystals. The fibroblasts appear to participate in calcification of the fibrillary plate.
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  • 95
    ISSN: 1432-0878
    Keywords: Neuronal grafting ; Dopamine ; Nigrostriatal system ; Rat
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    Topics: Biology , Medicine
    Notes: Summary Dissociated cell suspensions were prepared from the substantia nigra of 15–17 day-old rat embryos and grafted via an intraparenchymal injection into the depth of the neostriatum of adult recipient rats. The survival and fibre outgrowth of the dopamine-containing neurones in the implants were studied by fluorescence histochemistry, and the functional capacity of the grafts was monitored by repeated testing of the amphetamine-induced turning behaviour of the implanted rats. Before transplantation the target neostriatum of the recipient rats was denervated of its normal dopaminergic innervation by an injection of 6-hydroxydopamine into the ipsilateral nigrostriatal dopamine pathway. The completeness of the denervation was ascertained by measurement of the intensity of the amphetamine-induced turning response. After injection of the dissociated cells large numbers of dopamine-containing neurones were found in clusters at the site of injection as well as scattered in the apparently intact neostriatal tissue up to a distance of about 0.5 mm from the site of injection. Extensive dopamine-containing fibre networks had developed around the implant. These newly formed fibres, which were most abundant around the cell clusters at the injection site, extended in a loose network into large areas of the initially denervated caudate-putamen. In all animals with surviving dopamine neurones the amphetamine-induced turning response was reduced, and in the most extensively reinnervated cases even reversed, within 3–5 weeks after transplantation. This strongly suggests that the implanted dopamine neurones are capable of restoring dopaminergic neurotransmission in the denervated neostriatum, probably via reinnervation of the denervated neostriatal tissue. The use of dissociated brain tissue preparations thus permits reliable intraparenchymal grafting of neurones to plausibly any desired site within the central nervous system, and should open entirely new possibilities for investigation of neuronal growth dynamics and functional reconstruction of damaged brain circuits, perhaps even in brains of larger mammals.
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  • 96
    ISSN: 1432-0878
    Keywords: Neocortex ; Evolution ; Development ; Plasticity ; Visual system
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    Topics: Biology , Medicine
    Notes: Summary Recently discovered neocortical equivalents in anamniotes and certain patterns of interspecific variability in brain organization provide new insights into evolutionary and ontogenetic mechanisms of development. The new data suggest that nervous systems become more complex, not by one system invading another, but by a process of parcellation that involves the selective loss of connections of the newly formed daughter aggregates and subsystems. The parcellation process is reflected in the normal ontogenetic development of the CNS in a given species and can be manipulated, to a certain extent, by deprivation or surgically induced sprouting. The parcellation theory allows certain predictions about the range of variation of a given system at all levels of analysis including the cellular and aggregate levels. For example, the interspecific variability in organization of cortical columns, thalamic nuclei, cortical areas and tectal layers can be explained. The findings, summarized here, suggest that diffuse, undifferentiated systems existed in the beginning of vertebrate evolution and that during the evolution of complex behaviors, and analytical capacities related to these behaviors, a range of patterns of neural systems evolved that relate to these functions. One principle underlying the growth, differentiation and multiplication of neural systems appears to be the process of parcellation as defined by the theory.
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  • 97
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    Keywords: Cardiac muscle cells ; Trabeculae carneae ; Fibrillar pattern ; Mouse ; Rat ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cardiac muscle fibers in the trabeculae carneae of mice, rats, and rabbits show a special arrangement of densely interwoven myofibrils. They cross at various angles; however, a preferred orientation of the fibrils cannot be discerned. It is suggested that due to this arrangement the myocytes of trabeculae are not able to contract to the same extent as ventricular myocytes, but thereby gain a high rigidity during contraction. Hence, they may play a principal role as “guiding ridges” for the flow of blood, thereby improving hemodynamics.
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  • 98
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    Cell & tissue research 208 (1980), S. 171-181 
    ISSN: 1432-0878
    Keywords: Microtubules ; Dendritic spine apparatus ; Synapse ; Development ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Using techniques for enhanced microtubular preservation, including albumin pretreatment (Gray, 1975), occipital cortex of rats was studied electron microscopically at various ages of development. A close structural relationship was seen between microtubules, sacs of SER and the postsynaptic “thickening” in primordial spines and with the dense “plate” material of spine apparatuses. Stereoscopic preparations in addition show a more complicated substructure than previously described for the “plate”. Microtubules may contribute to the formation of the “plate” of the spine apparatus which in turn is associated with the postsynaptic “thickening” of the mature spine. Possible functional correlates are discussed.
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  • 99
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    Cell & tissue research 209 (1980), S. 201-216 
    ISSN: 1432-0878
    Keywords: High pressure (2,100 bars) freezing ; Freeze-etching ; Nerve tissue ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vitrification of biological specimens in liquid nitrogen can be achieved under high pressure (2,100 bars). This procedure obviates the use of aldehyde fixation and cryoprotection (glycerol). The present work demonstrates its applicability to the freeze-etching of mammalian brain tissue. Freeze-fracture replicas from rat cerebellar cortex and subfornical organ prepared by this method are compared to conventionally processed material using aldehyde fixation, glycerination and freezing with Freon. The formation of large ice crystals is prevented in tissue blocks up to 0.5 mm thick; deep etching is markedly enhanced. Cytoplasmic microstructures such as mitochondrial cristae, microtubules and microfilaments, are readily observable against a finely granulated cytosol matrix. An additional advantage is the combined application with freeze-substitution.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 206 (1980), S. 477-486 
    ISSN: 1432-0878
    Keywords: Synapse ; Synaptic cleft ; Aldehyde ; PTA technique ; Densitometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synaptic clefts of rat cerebral and cerebellar axodendritic spine synapses were studied after aldehyde-perfusion and subsequent immersion into osmic acid or after processing by the aldehyde-PTA technique. The threedimensional examination of aldehyde-perfused, osmic acid postfixed synapses revealed a double-layered intracleft lamina comparable in dimensions and position to the cleft density of non-osmicated, PTA-stained synapses. The relationship of this lamina to perisynaptic astroglial processes was pointed out. Densitometric analysis of the cleft area suggested the identity of the intracleft lamina of osmicated synapses with the cleft density of non-osmicated, PTA-stained synapses.
    Type of Medium: Electronic Resource
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