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  • 1
    ISSN: 0277-5387
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0495
    Keywords: Key words Magnetic susceptibility ; Sea-floor sediments ; Heavy metals ; Hong Kong
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Magnetic susceptibility measurements were conducted on 24 vibrocores obtained from an area located off the northeastern coast of Lantau Island in Hong Kong. High intensities of magnetic susceptibility were detected in the uppermost sections of the majority of the cores. Several magnetic parameters measured for one of the cores suggest that the variations in the magnetic characteristics over depth are mainly due to varying concentrations of the magnetic minerals. Since a strong correlation has been found between magnetic susceptibility and the heavy metals Pb, Cu, Zn and Cr, an anthropogenic contamination origin is thought to be the cause. The present study shows that magnetic susceptibility is a fast, inexpensive and non-destructive method for the detection and mapping of contaminated sediments.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic study was made on the water reabsorption of the epithelial cells of the rat cauda epididymidis. It was shown that when the epididymal duct was reabsorbing water at a maximal rate, widely dilated intercellular spaces were seen. It is suggested that the standing gradient model of water reabsorption first proposed for the gall bladder may also operate in the cauda epididymidis.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1040-452X
    Keywords: Diamide ; dithiothreitol ; CASA ; Sperm kinematics ; Motility maintenance ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A method for objective quantification of hamster sperm movement parameters as an indicator of maturation along the epididymis was established using a computerised system. Analysis of spermatozoa released into medium from five epididymal regions showed that the most drastic increases in percentage motility and curvilinear velocity (VCL) occurred from the distal corpus to the beginning of the proximal cauda and in straight-line velocity (VSL) from the beginning to a more distal site within the proximal cauda region. Both high osmolarity (400 mOsm/kg) and the thiol-oxidising agent diamide (10 μM) increased flagellar straightness of distal corpus spermatozoa, but VSL was increased only with the latter. The thiol-reducing agent dithiothreitol (DTT, 1mM) stimulated and maintained percentage motility and velocities of spermatozoa from the caput, stimulated only percentage motility of distal corpus sperm, but decreased velocities of those from the proximal cauda in prolonged incubation. In rats, diamide increased path straightness but not velocities of caput spermatozoa and yet caused immotility within 15 min, whereas DTT prolonged the maintenance of in vitro motility. The slight increases in kinematic parameters in the presence of DTT were enhanced by a 2-min preincubation with diamide. The finding that the effects of DTT and diamide were not compensatory suggests that the influence of the SH/S-S status on sperm movement is multifaceted, with decreasing sensitivity to stimulation upon sperm maturation. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0878
    Keywords: Key words: Epididymis ; Efferent ducts ; Cell culture ; Immunocytochemistry ; Immunoprecipitation ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The way in which the human epididymis modifies spermatozoa during their sojourn in this structure might be clarified by knowledge of the nature of its secretions. We have examined the presence of several lysosomal hydrolases in human epididymal tissue and fluids, and their synthesis and secretion by monolayer cultures. Tissues were obtained from men undergoing orchidectomy for prostatic carcinoma. The enzymes cathepsin D and acid α-glucosidase were localised in the lysosomes of epithelial cells from the corpus epididymidis, by an immunocytochemical technique. Cathepsin D was also found in epithelial cells of the efferent ducts within lysosomes, apical vesicles and multivesicular bodies. No immunolocalisation of acid glucosidase in the efferent ducts or on the microvilli of the corpus was demonstrable. Cathepsin D, β-hexosaminidase (N-acetylglucosaminidase) and α-glucosidase were measurable in the luminal fluid from the human corpus epididymidis; β-hexosaminidase was secreted into the culture medium by confluent monolayers of epididymal and efferent duct cells. Immunoprecipitation of cell extracts and culture medium of these cultures incubated with 35S-methionine revealed that the precursors of cathepsin D and β-hexosaminidase were synthesized and secreted by such monolayers. Thus, active lytic enzymes are secreted by the human epididymis and could modify sperm membranes.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0878
    Keywords: Luminal perfusion ; Rat epididymis ; Epithelial structure ; Absorption ; Water transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The appearance of the rat epididymal epithelium changed when it was perfused in vivo through the lumen with unphysiologically high sodium ion concentrations; dilatation of intercellular spaces (ICS) at threshold concentrations of 30mM-Na+ in the cauda and about 55mM-Na+ in the corpus was associated with absorption of water from the lumen. Despite the distended ICS, junctional complexes appeared intact, and their integrity was confirmed by the exclusion of luminal horseradish peroxidase (HRP) from the ICS, and by demonstrating that circulating [3H]inulin did not enter the lumen. Smooth ER and lipid droplets in the principal cells of the corpus epididymidis were well maintained, and the preservation of granular ER in principal cells of the cauda epididymidis lent morphological support to the continued secretion of protein in this segment. However, occasional distension or involution of inner Golgi cisternae was evident in principal cells after 3–6 h perfusion. In contrast to multivesicular bodies of principal cells, the apical and basal vacuoles characteristic of clear cells changed in size with different perfusing solutions. When low Na+ concentrations were perfused large translucent vacuoles were frequently found in the apical cytoplasm of clear cells in the corpus and cauda epididymidis, and filled vacuoles became larger and showed a decrease in content density in the cauda epididymidis. These large vacuoles were absent from tissue perfused with high Na+ concentrations. Normal pinocytotic activity of both cell types was demonstrated by perfusing HRP which was taken up by the normal route in principal cells, with some transfer to the Golgi cisternae. By far the most HRP was accumulated in clear cell vacuoles irrespective of the composition of the perfusing solution.
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  • 8
    ISSN: 1432-0878
    Keywords: Epididymal ultrastructure ; Transcytosis ; Protein transport ; Fluid-phase endocytosis ; Epididymal arterial perfusion ; Rat (Sprague-Dawley) ; Golden hamster ; Mouse (CB6/F1)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The transport of protein across the cells of the epididymal epithelium was studied using horseradish peroxidase. Transient vascular perfusion of the epididymis of the rat and golden hamster was achieved by pulsatile retrograde infusion into the testicular artery. Peroxidase was found in the interstitium and in the epithelium, located in vesicles, vacuoles and multivesicular bodies of principal, clear and apical cells. Similar findings were obtained in mice after systemic injection of the tracer. In the rat, discharge to the lumen was confirmed by the appearance of enzyme activity in luminal fluid from the caput epididymidis after local injection. The extent of transport amounted to no more than what has been considered leakage in physiological experiments, and the time-course of appearance complemented that found by electron microscopy. The level of transcytosis after pulsatile administration of peroxidase in vivo, as judged from the occurrence of tracer in the epithelium, was much less than that obtained during constant immersion in vitro. The protein was present in multivesicular bodies of principal cells and in vesicles of clear cells at short times after presentation in vitro, when it could not have arrived by endocytosis from the lumen. This suggests that routing of basal endocytic vesicles to the lysosomal apparatus occurs.
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  • 9
    ISSN: 1432-0878
    Keywords: Epididymis ; Monolayer culture ; Directed secretion ; Phosphatases ; Glucosaminidase ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A cell culture system is characterised for monolayers of immature rat epididymal epithelial cells grown on permeable supports. Cover of the filters was achieved by days 4–5 and was maintained for 9–12 days. The secretion of acid phosphatase (ACP), alkaline phosphatase (AKP) and N-acetylglucosaminidase (NAG) into apical and basal compartments of culture chambers was monitored with time in culture for cells from the proximal and distal epididymis of 37-day-old animals. There was independent secretion of the three enzymes: secretion of NAG and AKP was mainly apical, that of ACP basal; daily secretion of ACP and AKP was constant throughout culture, that of NAG declined; there was greater secretion of NAG and AKP by cells from the proximal than the distal region. The initial high apical secretion of NAG is thought to reflect loss of enzyme from unattached cells, whereas the later AKP secretion is truly directional. Secretion was not influenced by the enzymes used in cell preparation. The cytotoxic agent Thimerosal inhibited secretion of all enzymes when placed beneath the cultures, indicating that secretion depended on viable cells, but initially stimulated release of AKP when applied above the cells possibly reflecting release from the cell membrane.
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  • 10
    ISSN: 0148-7280
    Keywords: cyclic AMP ; epididymal spermatozoa ; sperm motility ; sperm maturation ; reactivation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Hamster spermatozoa from the caput and cauda epididymides were demembranated with 0.04% Triton X-100 and reactivated with 1 mM ATP. Motility parameters were analysed by video recording and stroboscopic photography. In the absence of added cAMP, reactivated cauda sperm showed percentage motility and forward swimming patterns similar to those of intact cells, but velocities were lower. When 2 or 20 μM cAMP was present, the velocities were increased but there was no effect on beat frequencies or percentage of forward progressing sperm. Cyclic AMP also markedly increased the percentage of cauda sperm which at first displayed nonprogressive “looping” movement. Addition of cAMP to the reactivation medium greatly improved the otherwise feeble and irregular motility of the demembranated caput sperm by increasing the percentage motility and beat frequencies of nonprogressive cells. It also induced forward motility with beat frequencies and velocities similar to cauda sperm reactivated in the absence of cAMP, but looping was never seen, indicating a change in the flagellar apparatus with maturation. The time required for the exhibition of the cAMP effects was reduced when caput sperm were reactivated in extracts of another previously maximally reactivated caput sperm preparation. The results suggest the production of some potent compound(s) by the axonemes for the manifestation of the cAMP effects.
    Additional Material: 11 Ill.
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