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  • Articles  (136)
  • paleolimnology  (54)
  • Biomagnetism (including magnetocardiography)  (46)
  • Rat  (36)
  • Springer  (136)
  • 1980-1984  (136)
  • 1925-1929
  • 1983  (136)
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  • Articles  (136)
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  • Springer  (136)
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  • 1980-1984  (136)
  • 1925-1929
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  • 101
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    Hydrobiologia 103 (1983), S. 303-308 
    ISSN: 1573-5117
    Keywords: paleolimnology ; acid waste-water ; liming ; diatoms ; heavy metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Sysmäjärvi is located inside the municipal boundary of Outokumpu in North Karelia, Finland. Since 1928 metalliferous, and at a later stage highly acid waste-water, has been discharged into the lake. Neutralization of the lake water by liming was introduced, and by the end of 1966 the pH of the water had become neutral to alkaline. Two sediment cores (0.5 m and 5 m long, respectively) were analyzed for pollen, diatoms, loss-on-ignition, organic carbon, Fe, Cu, Ni, Pb, Zn and Hg. The maximum concentrations of organic matter and heavy metal content occur 30 cm below the sediment surface. Evidence of the liming and of accelerated eutrophication appear close to the surface of the sediment (0–10 cm), indicated by an increase in Nitzschia plana.
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  • 102
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    Hydrobiologia 103 (1983), S. 309-318 
    ISSN: 1573-5117
    Keywords: paleolimnology ; heavy metals ; polluted lake ; sedimentary chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Macro nutrients N, P, K, Ca, Mg, Na and S as well as heavy metals Pb, Cu, Zn, Co, Cr, Ni, Fe and Mn were analysed from a sediment core representing a 7000-year long history of a lake including the preceding brackish (Litorina Sea) and freshwater (Ancylus Lake) stages. Sediments were also analysed for sedimentary pigments, algal growth potential (AGP) of the interstitial water, phosphorus fractions, pH, specific conductivity and redox potential. The annual accumulation values of several chemical elements were interpreted in light of other paleolimnological data from the same core. In the uppermost sediment stratum the influence of sewage pollution is clearly reflected by increases in total electrolyte content, pH, AGP and sedimentary pigments including myxoxanthophyll. Nickel, copper and manganese only slightly increase in the recent sediment, whilst other heavy metals (especially Cr and Zn) and sulphur, phosphorus, nitrogen and total organic matter are heavily concentrasted in the polluted surface sediment. The interpretation of the chemostratigraphy of the lake accords with evidence of lake development based on biological analyses.
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  • 103
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    Hydrobiologia 103 (1983), S. 15-19 
    ISSN: 1573-5117
    Keywords: paleolimnology ; dating ; radioactive fallout ; sediment ; 137Cs ; 239,240Pu ; varves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution of 137Cs and 239,240Pu in sediment core samples of the Finnish lakes Laukunlampi, Lovojärvi and Pääjärvi were determined. The sediment samples were collected using dry ice and liquid nitrogen freezing methods. The sediments of these lakes are annually laminated. A clear maximum concentration of 137Cs and 239,240Pu was found in sediment layers formed during 1962–1964, the years of maximum fallout, and the middle of the 1950's can be estimated from the 137Cs and 239,240Pu profiles. The highest concentrations, 11 500 and 820 pCi kg−1 dry wt for 137Cs and 239,240Pu, respectively, were found in the sediment of Laukunlampi. The vertical distribution was similar for 137Cs and 239,240Pu in the lakes investigated. A slight migration of 239,240Pu and 137Cs was found and the migration of 137Cs seems to be higher than that of 239,240Pu. The advantages of 137Cs dating method are rapidity and simplicity. 239,240Pu is preferable when the sample size is small. The agreement found between 137Cs and 239,240Pu dates and the annual laminae show that these fallout radio isotopes can be used for dating sediments formed during the past 25 years.
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  • 104
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    Hydrobiologia 103 (1983), S. 29-35 
    ISSN: 1573-5117
    Keywords: paleolimnology ; 210Pb ; sediment accumulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The last few years have seen a dramatic growth in the use of 210Pb sediment dating. Despite this, considerable doubt still surrounds the nature of the processes by which 210Pb is deposited in lake sediments, and this has lead to a situation where there is a choice of dating models offering different interpretations of 210Pb data. In assessing 210Pb data it is therefore essential to first of all determine whether data is consistent with the assumptions of the dating model, and to then compare the 210Pb chronology with independent dating evidence. We have tested 210Pb data from a wide variety of sites, and our calculations indicate that the crs (constant rate of 210Pb supply) model provides a reasonably accurate chronology when the total 210Pb contents of cores from neighbouring locations are comparable.
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  • 105
    ISSN: 1573-5117
    Keywords: paleolimnology ; caesium-137 ; perched lake ; meromictic ; diffusion ; bioconcentration ; sediment accumulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hidden Lake is a perched, brown-water lake located in the centre of Great Sandy Island (Fraser Is.), S.E. Queensland. It is highly acid (pH 4.0), oligotrophic and is thermally and chemically stratified for most of the year. The sediments revealed a 137Cs profile which departed from the temporal pattern of 137Cs fallout in Brisbane and was represented by an exponential increase of 137Cs towards the surface sediments from ca. 32 cm depth. The possible causes of the divergent profile are discussed, including physical and biological mixing, lag in the transport of catchment material to the sedimentary basin, diffusion, recycling and biological concentration. It is hypothesised that a combination of the last four processes, with diffusion facilitated by the highly acid conditions, are the major causes of the observed 137Cs profile. Possible recycling and bioconcentration of 137Cs raises questions as to the validity of this method of dating in similar environmental conditions, and as to the interpretation of other palaeochemical data. These hypotheses are to be tested against profiles obtained from 14C, 210Pb, 239/240Pu analyses of the sediment, and the measurement of 137Cs activity in the water and biota of the lake.
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  • 106
    ISSN: 1573-5117
    Keywords: paleolimnology ; pollen analysis ; land drainage ; sediment accumulation ; 210Pb dating ; 14C reservoir effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous measurements of the 14C activity of lake sediments and Potamogeton plants from Säynäjälampi, collected in 1970, indicated a severe hard-water effect (Donner et al. 1971). Samples from new cores, collected in 1977, were sliced into thin sections down to 18 cm. The 14C concentration in samples down to 7 cm was similar to that obtained by the Helsinki Laboratory. The corresponding apparent 14C age is almost 2 000 years. Light-coloured layers, apparently due to catchment drainage, were used together with density diagrams to correlate the cores. The drainage history gives a time-scale showing that the lowest samples dated to correlate the cores. The drainage history gives a time-scale showing that the lowest samples dated were just old enough to be pre-bomb sediments. Three samples of submerged plants were also examined, indicating some exchange with the air and an appreciable reservoir age. The activity of the plants was significantly lower in 1978 than in 1970. One sample, well below the lowest drainage stratum, indicates a reservoir age of ca. 1 100 years. This sample yielded an apparent age of the INS fraction which was significantly different from that of the SOL fraction. The difference was determined to ca. 600 years. Total 210Pb was determined via 210Po using isotope dilution while 226Ra was measured with the help of radon emanation. The 226Ra was used to estimate the supported 210Pb. The unsupported 210Pb showed a higher sediment accumulation rate for the top nine cm of one core (the length investigated was 16.5 cm). The varying accumulation rate was explained by human activities, as could be seen from the heterogenous sediment composition of the cores. Recent vegetational change is described from direct observations since 1957. Pollen analysis does not give any reliable indication of agriculture.
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  • 107
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    Cell & tissue research 229 (1983), S. 269-280 
    ISSN: 1432-0878
    Keywords: Uterus ; Implantation ; Blood vessels ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the blood vessels of the endometrium was analysed during implantation of the blastocyst in rats, at the time of appearance of the Pontamine Blue Reaction. Vessels from implantation sites and from interimplantation sites were compared. In vessels from implantation sites the endothelial cells showed fenestrations covered by diaphragms. In addition, small interruptions (gaps) between the endothelial cells were observed. These features were present in vessels larger than 5 μm in diameter and more than 100 μm away from the uterine epithelium, both in the mesometrial and antimesometrial wall of the endometrium. Vessels from interimplantation sites displayed neither fenestrations nor interruptions. The endothelial cells of the implantation sites displayed morphological signs of metabolic activation. These consisted of increased numbers of polyribosomes, well developed Golgi complexes and prominent nucleoli. The fenestrations and gaps in the vessel wall were interpreted as constituting the morphological basis for the increase in vascular permeability and the consequent edema which characterize the Pontamine Blue Reaction.
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  • 108
    ISSN: 1432-0878
    Keywords: CRF ; Oxytocin ; Vasopressin ; Immunohistochemistry ; Median eminence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Conspicuous differences in the distributional pattern of nerve fibers containing corticotropin-releasing factor (CRF) or posterior lobe hormones, respectively, were shown in the median eminence of the adult male rat by means of immunoperoxidase histochemistry, with the use of anti-CRF, anti-oxytocin, and anti-vasopressin sera. In the rostral and central divisions of the median eminence, a high concentration of CRF-immunoreactive nerve fibers was found in the median portion of the external layer; these fibers terminated on the capillary loops of the hypophysial portal system. In the caudal division of the median eminence, the CRF-immunoreactive nerve fibers were located in the median to paramedian portions of the external layer. Numerous oxytocin- and vasopressin-immunoreactive nerve fibers were observed evenly distributed throughout the internal layer of the median eminence. In the external layer, a small number of the oxytocin- and vasopressin-containing nerve fibers was found around the capillary loops, particularly in the median to paramedian portions. The distributional patterns of the CRF and the posterior lobe hormones in the hypothalamo-hypophysial system and their functional interrelationship are discussed.
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  • 109
    ISSN: 1432-0878
    Keywords: Prolactin ; Somatostatin ; Estrogen priming ; Adenohypophysis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Apart from the known hypothalamic controls, which have been well documented, a myriad of compounds both endogenous and exogenous have proved effective in influencing secretion of prolactin (PRL). Recent studies have shown that somatostatin (SRIF), when injected intra-atrially as a bolus, is able to inhibit PRL secretion in vivo. However, the inhibitory effect of SRIF occurs only in adenohypophyses previously primed with estradiol. This research was undertaken to examine the ultrastructural effects of that inhibition using male Sprague-Dawley rats primed for three weeks with subcutaneous implants of estradiol. Within 2 min of injection of SRIF (1 mg/kg), the adenohypophyses were removed and processed for electron microscopy. We found dramatic changes in the estradiol-primed mammotrophs, including 1) an apparent rearrangement of rough endoplasmic reticulum (RER) into concentric cisternae, and 2) the appearance of intracellular bodies closely associated with granules. These changes were not observed in non-estradiolprimed male rats injected with SRIF which is consistent with the fact that in the normal male rats, SRIF failed to inhibit PRL secretion. These findings suggest that SRIF causes reorganization of cellular organelles so that PRL granules are sequestered thereby inhibiting secretion of PRL.
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  • 110
    ISSN: 1432-0878
    Keywords: Splenic implants ; Immunoperoxidase technique ; Lymphocyte homing ; Interdigitating cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The localization of T-and B lymphocytes and interdigitating cells (IDC) was investigated during the regeneration process of splenic implants. For this purpose a two-step immunoperoxidase technique was used to visualize T-cell antigen, immunoglobulins and Ia-antigen on cryostat sections. The specific localization of the repopulating lymphocytes occurred simultaneously with the development of non-lymphoid elements characteristic for the different compartments of the white pulp, i.e., the periarteriolar lymphocyte sheaths (PALS) and follicles. The marginal zone (MZ) developed after the PALS and primary follicles, but before germinal center reactions were found. During ontogeny, however, the development of a broad MZ precedes the formation of follicles. This difference in sequence of events is discussed.
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  • 111
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    Cell & tissue research 228 (1983), S. 451-457 
    ISSN: 1432-0878
    Keywords: Bone matrix vesicles ; Parathyroid hormone ; Mineralization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The enzymatic activity of bone matrix vesicles from parathyroidectomized rats was determined and compared to the activity of vesicles from sham operated and normal animals. The vesicles were isolated from the alveolar bone by collagenase digestion and differential centrifugation and further purified on a discontinuous sucrose density gradient. The amount of extractable protein and the activity of alkaline phosphatase, acid phosphatase, and ATPase in the vesicle fractions thus obtained did not differ significantly from the values characteristic of preparations from control rats. It may therefore be suggested that parathyroid hormone depletion and the associated hypocalcemia have no significant effect on the occurrence and phosphatase activity of bone matrix vesicles.
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  • 112
    ISSN: 1432-0878
    Keywords: Pineal organ ; Melatonin ; Pineal protein secretion ; Rat ; Hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hypothesis that melatonin (aMT) is implicated in the regulation of the secretory process involved in the synthesis and release of protein/peptide “hormones” of the pineal organ has been tested in the present study by the use of an in vitro system in two mammalian species. In these species the secretory process studied is characterized by either large (hamster) or very small (rat) numbers of granular vesicles. In both species, aMT clearly participates in the regulation of the process of protein/peptide secretion. However, the effect of aMT varies with the presence of noradrenaline (NA) in the medium and is not identical in both species. Melatonin, in the absence of NA, induces the formation of granular vesicles by the Golgi apparatus in pinealocytes of the rat but not in those of the hamster, while in the presence of NA, aMT provokes a decrease in the number of these vesicles in both species. The present experiments show (i) that the pineal is one of the target organs for aMT, and (ii) that aMT is implicated in the control of protein/ peptide secretion in the pineal organ.
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  • 113
    ISSN: 1432-0878
    Keywords: Pituitary gland ; S-100 protein ; Castration ; Thyroidectomy ; Postnatal development ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pituitary folliculo-stellate cells and associated cells were studied immunohistochemically throughout the life of male and female rats. The marginal layer cells of the pars distalis and intermedia as well as the folliculo-stellate cells were immunostained with anti-S 100 protein serum. The immunostained folliculo-stellate cells in one section were identified as themselves by their ultrastructural properties on the adjacent section. Corticotrophs, thyrotrophs and prolactin cells, characterized by the stellate shape, were not immunostained with anti-S 100 protein serum. Reactivity for S-100 protein appeared on postnatal Day 6 in the marginal layer cells of the pars intermedia, and appeared on Day 10 in those cells of the pars distalis. No immunostained folliculostellate cells appeared before Day 6, but a few of them appeared on Day 10. Thereafter they increased in number, having more intense immunostaining with advancing age. In castrated rats, the immunostained folliculo-stellate cells appeared quite numerously, with branched cytoplasmic processes surrounding the gonadotrophs. In the thyroidectomized rats, however, folliculo-stellate cells lacked ramified cytoplasmic processes, and their topographic affinity for thyrotrophs was negligible.
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  • 114
    ISSN: 1432-0878
    Keywords: Carotid body ; Rat ; Glomus cells ; Exocytosis ; High ; K fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Extensive secretion by exocytosis was demonstrated in the glomus (type I) cells of the adult rat after perfusion of carotid bodies with a potassium-rich (high K) glutaraldehyde fixative. Similar secretory profiles were very rare with a glutaraldehyde fixative containing a low concentration of potassium (low K). The increase in the incidence of exocytotic profiles in glomus cells with the high K fixative was highly significant, whereas no statistical difference could be observed in the incidence of coated pits with the different fixatives. Exocytotic profiles were characterized by the following features: (1) they predominated in non-synaptic regions, but were occasionally observed near synapses between two glomus cells; they were not observed near synapses between glomus cells and nerve terminals; (2) extruded electron-dense material associated with coating of the cell membrane was frequent; (3) different stages of dissolution of the extruded granule material was evident. The possible role of exocytosis as a mode of secretion in the glomus cells and the characteristics of the new high K-glutaraldehyde fixative are discussed.
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  • 115
    ISSN: 1432-0878
    Keywords: CRF neurons ; Hypothalamus ; Immunohistochemistry ; PAP ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A specific rabbit anti-CRF serum and the immunoperoxidase technique were used to show that CRF-containing neurons are mainly distributed in the paraventricular and supraoptic nuclei of the rat hypothalamus. In addition, immunoreactive neurons are scattered in other hypothalamic regions. These neurons are 20–30 μm in diameter. From the present and previous investigations it may be concluded that the hypothalamic magnocellular nuclei, i.e., paraventricular and supraoptic, and other hypothalamic accessory nuclei, are the producing sites not only for vasopressin and oxytocin, but also for corticotropin-releasing factor.
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  • 116
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    Cell & tissue research 230 (1983), S. 309-336 
    ISSN: 1432-0878
    Keywords: Neural ectopia ; Cerebellum ; Granule cells ; Development ; 6-Hydroxydopamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present report describes the genesis, development and topographical distribution of ectopic cells of the external granular layer in the subarachnoid space covering the rat cerebellum. Following one intracisternal injection to newborn rats of 100 μg 6-hydroxydopamine (6-OHDA), the meningeal cells degenerate and are removed by phagocytosis within 24 h post injection (p.i.), leaving the cerebellar cortex without a pia-arachnoid cover. Defects appear in the basal lamina investing the cerebellar cortex 3 to 5 days p.i., and both external granule cells and ‘sprouts’ from Bergmann-glia endfeet grow into the subarachnoid space. The latter form large, flat glial lamellae and cover extensive areas of the denuded cerebellar surface, although they do not form a glial scar over the exposed neuropil of the cerebellar cortex. The numbers of ectopic external granule cells increase within the subarachnoid space both by proliferation and a continuous efflux of cells from the cerebellar cortex. They migrate, aggregate, and ultimately develop into granule, stellate and basket cells, the morphology of which is indistinguishable from their counterparts in situ; they make specific afferent and efferent connections, both among themselves and with the underlying cerebellar cortex and brainstem. The distribution of ectopic external granule cells and their derivatives is restricted to the anterior vermal fissures and the vermal-hemispheric junctions. The present results indicate that external granule cells and their derivatives are capable of both differentiating normally and surviving in the subarachnoid space if they become associated with glial cells and establish synaptic connections.
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  • 117
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    Cell & tissue research 230 (1983), S. 367-375 
    ISSN: 1432-0878
    Keywords: Rat ; Testis ; Protein ; Endocytosis ; Microperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary As luminal fluid moves from the seminiferous tubule and enters the rete testis, its protein concentration declines from approximately 6 mg/ml to 1 mg/ml. It was therefore suggested that protein is either 1) utilized by the spermatozoa, 2) transported across the epithelium of the terminal segment of the seminiferous tubule, the tubuli recti or rete testis, or 3) absorbed and degraded by the epithelium. Horseradish peroxidase (HRP), a protein marker, was microperfused into single seminiferous tubules or perfused directly into the rete. After fixation, the HRP was localized histochemically and the tissue observed under the light- and electron microscope. HRP was taken up via pinocytotic vesicles into the cytoplasm of the Sertoli cells and germ cells but did not permeate extracellularly beyond the tight junctions. Similar results were obtained in the cells lining the terminal segment and the tubuli recti. The rete epithelium showed uptake of HRP into coated and noncoated vesicles, while some cells additionally revealed diffuse cytoplasmic distribution of HRP. The terminal segment, tubuli recti, and rete testis may be important routes by which proteins may leave the testicular fluid either to be degraded or to enter the blood.
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  • 118
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    Cell & tissue research 233 (1983), S. 125-132 
    ISSN: 1432-0878
    Keywords: Osteoclasts, origin of ; Macrophages ; Sex chromatin (Barr body) ; Ossification ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When the resorption zones of the distal femoral and proximal tibial epiphyseal plates of rats are examined with the electron microscope, numerous macrophages can be seen surrounding degenerated chondrocytes. Macrophages are also found in the neighbourhood of the invading sinusoids and in close proximity to multinucleate osteoclasts. Cell fusion, however, could not be observed. Repeated transfusions of female leukocytes to isohistogeneic growing male rats caused an increase in the number of nuclei containing a Barr body in the osteoclasts of the males. The result suggests that leukocytes — of which only the monocytes come in question — are the source of multinucleate osteoclasts in endochondral ossification.
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  • 119
    ISSN: 1432-0878
    Keywords: Development ; Somatostatin neuron ; Hypothalamus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ontogeny of the somatostatin-containing neuron system was investigated by light-microscopic immunohistochemistry. During development, immunoreactive somatostatin-containing neurons arise from three discrete regions of the neuroepithelium of the third ventricle and show a chronological difference. The neurons are first evident within the third ventricle floor on day 12.5 of gestation; they move thereafter to the arcuate nucleus. The second generation occurs in the dorsal region of the arcuate nucleus during days 17.5–19.5; these neurons migrate sequentially into the arcuate-ventromedial nuclear region. The third generation is recognized in the neuroepithelial cell layer of the rostral hypothalamus on day 17.5 of gestation; these cells move to the periventricular area. This latter generation is most prominent during days 3–6 after birth, and some of the cells are seen sporadically even up to day 20. The first two generations give rise to the somatostatin neuron system in the arcuate-ventromedial nuclear region, while the latter gives rise to that in the rostral periventricular region in the adult rat hypothalamus.
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  • 120
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    Cell & tissue research 232 (1983), S. 457-469 
    ISSN: 1432-0878
    Keywords: Sex differences ; Adrenal cortex ; Rat ; Maturation ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This paper reports a stereological study of the cellular aspects of development of the adrenal cortex of male and female rats in the course of maturation. Rats of the Wistar strain were studied at weekly intervals from day 21 to day 77 of postnatal life. From day 42 homogenates of adrenals from female rats produced more corticosterone than homogenates from males of corresponding age. In the strain of rats studied sex differences in adrenal weight appeared at about day 49. From this day onward relative, and subsequently absolute adrenal weights were higher in females than in males. In the course of maturation the total volume of all adrenocortical zones gradually increased. From day 70 the zona glomerulosa and from day 49 the zona fasciculata were larger in female than in male rats, while no distinct sex difference was observed in the volume of the zona reticularis. The appearance of sex-related differences in the adrenal cortex depends mainly on changes in the zona fasciculata, the cells of which markedly increased in volume in female rats by comparison with males. The total number of all adrenocortical cells increased from ca 13 million on day 21 to ca 25 million on day 77 and at all intervals studied adrenal glands of male and female rats contained a similar number of parenchymal cells.
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  • 121
    ISSN: 1432-0878
    Keywords: TRH ; Immunocytochemistry ; Autoradiography ; Arcuate nucleus ; Median eminence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical and autoradiographic localization of thyrotropin-releasing hormone (TRH)-and 3H-TRH-binding sites was studied in the arcuate nucleus-median eminence region of the rat. TRH-like immunoreactivity was found in dense granular vesicles (90–140 nm in diameter) in TRH-like immunoreactive nerve fibers and terminals. In the median eminence, the immunoreactive terminals were observed to be in direct contact with the perivascular basal lamina of the portal vessel and to form synaptoid contacts with tanycytes. In the arcuate nucleus, the immunoreactive terminals were often found to form axosomatic and axo-axonic, and/or axo-dendritic synapses. The uptake of tritiated TRH into the nerve fibers and terminals of the median eminence was also observed by autoradiography and the distribution and localization of silver grains in them were analyzed quantitatively by circle analysis. Thirty minutes after intraventricular infusion of 3H-TRH, radioactive labeling occurred in type-2 and 3-nerve fibers and terminals containing dense granular vesicles in the median eminence. It is therefore suggested that the neurons labeled after 3H-TRH infusion possess certain functions as physiological recognition sites or receptors for TRH.
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  • 122
    ISSN: 1432-0878
    Keywords: Rat ; Parathyroid ; Freeze-fracture ; Storage granule ; Exocytosis ; Endocytosis ; Discharged secretory granule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Freeze-fracture images of the parenchymal cells in the parathyroid gland of rats were observed after vitamin D2 plus calcium chloride-suppression and EGTA-activation of secretion. In cells of the suppressed glands, large bulges protruded from the Golgi cisternae, and large granules with a stalk, which are identified as storage granules, suggest that, during maturation, some storage granules may be connected by long tubules with the Golgi cisternae and supplied with secretory products from the Golgi cisternae via these tubules. In the activated glands, presumptive exocytotic and endocytotic specializations of intramembranous particles of the parenchymal cell plasma membrane were frequently observed. In addition, elevations and complementary shallow depressions of various shape and extent were occasionally encountered in the intercellular space. From their morphological characteristics it was concluded that these originated from secretory granule cores, which are discharged from the parenchymal cells into the intercellular space by exocytosis, and it was suggested that discharged granule cores may retain their spherical shape until they fuse to form a flat conglomerate.
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  • 123
    ISSN: 1432-0878
    Keywords: Vomeronasal neuroepithelium ; Olfactory epithelium proper ; Cell coat ; Ruthenium red ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The apical cell coat of the olfactory epithelium proper and the vomeronasal neuroepithelium of the rat was investigated electronmicroscopically by means of the Ruthenium-red reaction. In the olfactory epithelium proper, the cilia of receptor cells and microvilli of supporting cells possess a cell coat measuring approximately 10 nm in thickness. In the vomeronasal neuroepithelium, the apical cell coat is thicker than in the olfactory epithelium proper. On microvilli of vomeronasal receptor cells the cell coat varies in thickness from 15 to 20 nm, and on microvilli of supporting cells it measures approximately 75 nm. The functional implications of these findings are discussed.
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  • 124
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    Cell & tissue research 231 (1983), S. 289-299 
    ISSN: 1432-0878
    Keywords: Enterocytes ; Microtubules ; Colchicine ; Cell membrane ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The function of the microtubules that are present in the villus enterocytes of the mammalian small intestine is virtually unknown. In order to advance our knowledge about enterocyte microtubules, a quantitative ultrastructural comparison was carried out on enterocytes from rats injected intraperitoneally with colchicine (0.5 mg/100 g body weight) in saline and from rats injected with saline alone. Our morphometric and stereologic study demonstrates that colchicine treatment results in 1) an absolute decrease in microtubules, 2) a reduction in microvilli, essentially in length, 3) an increased thickness of the terminal web, 4) an increase in total lysosomal volume, apparently by an increased number of smaller lysosomes, and 5) a decrease in the number of Golgi lamellae. These results along with those from other studies suggest to us that enterocyte microtubules are involved in the biogenesis of microvillus plasma membrane. Our morphometric data from the saline-treated rats essentially agree with comparable data from other studies. However, comparison with comparable data from hamster enterocytes demonstrates species differences.
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  • 125
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    Cell & tissue research 231 (1983), S. 337-346 
    ISSN: 1432-0878
    Keywords: Annulate lamellae ; Neuromuscular junction ; Muscles Cell nucleus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pseudointranuclear inclusions resulting from invaginations of the nuclear envelope, characteristic of myopathic muscles, were found in the soleplate nuclei of normal soleus muscles of rats. Such inclusions had annulate lamellae (AL), nemaline or rod bodies, lamellar structures, a concentric system of membranes, as well as tightly packed sarcoplasmic organelles. An accumulative origin of such included structures was suggested. The AL were sometimes connected directly to the outer membrane enclosing the inclusions, dilated into cisterns and positioned perpendicularly against the nuclear surface. AL, some of which were welldeveloped, were observed in the same loci as above during the course of denervation atrophy.
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  • 126
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    Cell & tissue research 232 (1983), S. 257-264 
    ISSN: 1432-0878
    Keywords: Pars intermedia ; Rat ; Porphyrins ; Microspectrofluorometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cells emitting orange-red autofluorescence have been found in the pars intermedia of aging rats. The fluorescence maximum of the emission is localized in an area of the spectrum where the most intense band maxima of porphyrins are located. The fluorescence fades when the excitation wavelength is about 400 nm, which is specific (Soret band) for the absorption spectra of porphyrins. The fluorescence is emitted by coarse inclusions in the cytoplasm of a few cells. These inclusions are also stainable with paraldehyde-fuchsin and exibit a high endogenous peroxidase activity. The inclusions observed have morphologic features similar to those of porphyrin-containing astrocytes from the periventricular area of the hypothalamus. The inclusion-bearing cells of the pars intermedia also contain debris that might be due to the phagocytic activity of these cells.
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  • 127
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    Cell & tissue research 228 (1983), S. 597-640 
    ISSN: 1432-0878
    Keywords: Meningeal compartments ; Median eminence ; Cortex ; CSF-and hemal milieu ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intervascular segments of the leptomeninges of the rat were studied by the use of horseradish peroxidase (HRP) in short-term experiments. HRP was injected (i) intravenously, (ii) into the lateral ventricle, (iii) into the cortex, and (iv) into the meninges. The composition of the meninges covering the median eminence (ME) was analyzed in comparison to the results obtained with the parietal cortex. The meninges covering the cortex show the following pattern of layers and compartments: The intercellular compartment comprises the intercellular clefts of the neuropil, the subpial space, and the intercellular clefts of the leptomeninges. The pial space establishes a second compartment. The third compartment is the arachnoid space. The intercellular clefts of the dura form the fourth compartment. At the border of the ME, the neurothelium and the outer arachnoid layer are rolled up to form a tissue frame around a hollow pit that is covered by a diaphragm consisting of meningeal cells; the latter separate the hemal milieu of the ME from that of the dura. The hemal and the cerebrospinal fluid (CSF) milieus may communicate to a limited extent only within the subpial space adjacent to the ME. The CSF-containing compartments of the pial and arachnoid spaces terminate at the brain-facing insertion of the tissue frame. According to the present results, an anatomical basis for a short-loop feedback from and to the neurohemal region of the ME via the CSF does not exist.
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  • 128
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    Cell & tissue research 229 (1983), S. 85-95 
    ISSN: 1432-0878
    Keywords: Amoeboid microglial cells ; Brain macrophages ; Immunohistochemistry ; Macrophage antiserum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunohistochemical studies with the use of the peroxidase-antiperoxidase (PAP) method revealed that “amoeboid microglial cells”, in the brains of neonatal rats and “brain macrophages” in lesioned brains of adult rats react positively to an antiserum raised against macrophages. In brains of neonatal rats, “amoeboid microglial cells” stained by means of the PAP-method were observed in the corpus callosum, internal capsule, dorso-lateral region of the thalamus, subventricular zone of the lateral ventricle, and the subependymal layer of the ventricular system. These cellular elements were not detected in brains of rats aged 21 days or older. Resting microglial cells displaying a typical ramified structure were not specifically stained. Cells reacting positively to the macrophage antiserum appeared (i) in the cerebral cortex of adult rats following placement of a stab wound, or (ii) in the hippocampal formation after kainic acid-induced lesions; in the damaged areas immunoreactive cells exhibited the typical features of “brain macrophages”. “Brain macrophages” and “amoeboid microglial cells” are considered to belong to the class of exudate macrophages derived from blood monocytes. Thus, elements of hematogenous origin do exist in the intact brain parenchyma of neonatal rats and in lesioned brains of adult rats. The relationship between brain macrophages and resting microglial cells is discussed.
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  • 129
    ISSN: 1432-0878
    Keywords: Vasopressin ; Oxytocin ; Neurophysin ; Neurohypophysis ; Adrenalectomy ; Osmotic stress ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of adrenalectomy and administration of hypertonic saline on the amount of vasopressin, oxytocin, and neurophysin contained in the median eminence and the neural lobe of rats was studied by means of the following methods: (i) morphometric and microphotometric analyses of aldehyde fuchsin-stained histological sections of the neurohypophysis; (ii) immunohistochemical demonstration of vasopressin, oxytocin, and neurophysin in the neurohypophysis, and (iii) radioimmunological measurement of vasopressin and oxytocin in extracts of the median eminence and the neural lobe. Adrenalectomy increases the amount of vasopressin and neurophysin in the external layer of the median eminence but does not change the content of oxytocin. It has no influence on the amount of vasopressin, oxytocin, and neurophysin demonstrable in the inner layer of the median eminence and in the neural lobe two weeks after the operation. Hypertonic saline markedly diminishes the vasopressin, oxytocin, and neurophysin content of the inner layer of the median eminence and the neural lobe but reduces only slightly, if at all, the amount of vasopressin and neurophysin in the outer layer of the median eminence. The findings support the concept that osmotic stress reduces only the vasopressin and oxytocin content of the hypothalamus-neural lobe system and has no or only little influence on the vasopressin content of the outer layer of the median eminence.
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  • 130
    ISSN: 1432-0878
    Keywords: Rat ; Lymph node ; Steroid ; Reticular cell ; Macrophage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of macrophages and reticular cells of regional lymph nodes of the rat after administration of large doses of cortisone acetate, estrone, progesterone, and cholesterol in aqueous suspensions was investigated. A large number of vacuoles, most of which were surrounded by unit membrane, and lipid droplets not surrounded by unit membrane were observed in the cytoplasm of both macrophages and reticular cells. They were not seen in these cells of control animals and in experimental animals that had received smaller doses of these steroid hormones. After cholesterol injection, many lipid droplets were observed in the cytoplasm of macrophages. These observations suggest that steroids injected in suspension accumulate in macrophages and reticular cells of the regional lymph nodes. Electron-dense material was often present in vacuoles of macrophages but not in those of reticular cells.
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  • 131
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    Cell & tissue research 229 (1983), S. 451-456 
    ISSN: 1432-0878
    Keywords: Preimplantation development ; Rat ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ability of ova collected from mated middle-aged rats (9–10 months of age) to undergo preimplantation development in vitro was compared to that of younger controls (3–4 months of age). The majority of ova from young rats underwent at least one cleavage division for every 24 h of the 96 h culture period. Seventy-two percent reached the morula/blastocyst stage at the termination of the culture. Aged ova had a reduced capacity to undergo preimplantation development in vitro with the number of fragmented and/or degenerated ova increasing after each day in culture. At the end of the culture period, 81.6% of the ova had degenerated. It is concluded that middle-aged rats ovulate defective ova and that these defective ova account, in part, for the preimplantation losses that characterize middle-aged rats.
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  • 132
    ISSN: 1432-0878
    Keywords: LHRH, effect of ; Pineal gland ; Synaptic ribbons ; Synaptic spherules ; Melatonin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies have shown that LHRH or LHRH-like substances are present in the pineal gland. In order to investigate whether exogenous LHRH may affect the pineal gland, in the present study the effects of a single dose of LHRH (1 μg, i.p.) on pineal “synaptic” ribbons and spherules as well as serum melatonin levels were examined in diestrous Wistar rats. One hour after the injection both ribbons and spherules exhibited a statistically significant decrease in number. Serum melatonin levels were not affected. It is concluded that humoral feedback mechanisms may exist between the hypothalamus and the pineal gland.
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  • 133
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Autonomic nervous system ; Gut innervation ; Neuropeptide Y ; Pancreatic polypeptide ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunoreactive neuropeptide Y (NPY) was demonstrated in neuronal elements in the gut and pancreas of the rat. Immunoreactive endocrine cells could not be detected. The occurrence of NPY containing nerve-cell bodies in the submucosal and myenteric ganglia indicates an intrinsic origin of the NPY fibers. However, an additional extrinsic supply of NPY fibers is suggested by the finding that abdominal sympathectomy caused the disappearance of some NPY fibers, notably those around blood vessels. The distribution of NPY fibers in all layers of the gut wall suggests multiple functions of NPY, including a role in the regulation of intramural neuronal activities, smooth muscle tone, and local blood flow.
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  • 134
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    Cell & tissue research 230 (1983), S. 649-660 
    ISSN: 1432-0878
    Keywords: Hypothalamo-hypophysial system ; Capillaries ; Permeability ; Ontogenesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscopic study has been carried out in order to examine the permeability of the blood-brain barrier in the median eminence of perinatal rats. After several minutes, intravascularly injected electron-dense tracers (lanthanum nitrate; horseradish peroxidase, 40000 MW MW: molecular weight , ferritin, 500000 MW) pass the capillary wall, the perivascular space, and become incorporated into neurosecretory axons and basal processes of tanycytes both in fetuses and young rats. In the case of immature capillaries, the materials diffuse freely through the endothelial cells, and to a lesser extent are transferred via occasional plasmalemmal vesicles and fenestrae. As the maturation of capillaries proceeds, their permeability via plasmalemmal vesicles and fenestrae increases considerably due to a gradual rise of the number of these structures. The plasmalemmata of the differentiated endothelial cells become impermeable to all of the tracers. Only ionic lanthanum appears to penetrate through transendothelial channels and intercellular junctions between adjacent endothelial cells.
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  • 135
    ISSN: 1432-0878
    Keywords: Satellite cells ; Skeletal muscle ; Snake-venom toxin ; Muscle regeneration ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Satellite cells were studied in the undamaged part of the rat soleus muscle rendered partially necrotic by a subcutaneous injection of notexin, the myotoxic toxin purified from the venom of the Australian snake Notechis scutatus scutatus. Nuclei of satellite cells were twice as numerous as in the controls, with a decreasing gradient in the number of satellite cells with distance from the necrotic area. The cells were in an activated state with an increased cytoplasmic volume and prominent organelles. Occasionally, mitosis of some satellite cells was observed. Between the satellite cell and the muscle fibre, an unusually wide space was frequently seen, within which a “new” basal lamina was often visible. It is suggested that the role of the satellite cells of undamaged muscle fibres in the regeneration of necrotic muscle is worthy of more detailed investigation.
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  • 136
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    Cell & tissue research 233 (1983), S. 183-196 
    ISSN: 1432-0878
    Keywords: Retrograde transport ; Neurosecretory material ; Neurosecretory granules ; Hypothalamo-neurohypophyseal neurons ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The axonal transport of neurosecretory material was studied in neurosecretory axons of the supraoptico-posthypophyseal system after in-situ transection of the median eminence. Two hours, 8 h, and 18 h after the lesion, both vasopressin and oxytocin antibodies revealed progressive accumulations of immunoreactive material not only in the proximal but also in the distal stumps of the transected axons. The electronmicroscopic examination of these axonal portions revealed that such intense immunopositive labelings could be correlated, in both stumps, to a conspicuous accumulation of neurosecretory granules. It is concluded that, under normal physiological conditions, a significant amount of axoplasmic neurosecretory material is transported in retrograde direction and that such a retrograde transport mainly involves neurosecretory granules.
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