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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 192 (1961), S. 995-996 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In a second approach, Yushchenko5 freeze-dried spermatozoa suspended in a mixture of 'Freon' and heptane to circumvent the harmful effects of exposure to a eutectic mixture and to eliminate mechanical damage resulting from crystallization. After glycero-lation and equilibration in a ...
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 225 (1989), S. 106-117 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The bovine cervical mucosa was investigated with respect to structure, mucus secretory pattern, and sperm transport. Structural investigation included stereomicroscopic examination of surface-stained tissue blocks and graphic reconstruction of serial sections by using both computer-generated and Plexiglas models. Histochemistry of the mucosa was evaluated in follicular-and luteal-phase animals. Alcian blue, periodic acid Schiff, and high-iron diamine were utilized to distinguish sialomucins, sulfomucins, and neutral mucins. Location and orientation of cervical sperm in follicular phase animals were evaluated 12 h postmating by using light and electron microscopy. Cervical mucosa was characterized by longitudinal primary folds, most of which maintained continuity throughout the cervix. Superimposed on these were secondary folds which varied in length and depth. Abundant, shallow, uniformly spaced, and parallel longitudinal “grooves” covered all surfaces. Grooves had greater continuity in regions distal, as opposed to proximal, to the cervical canal. Blind-ending glands or crypts were not apparent. Follicular-stage cervices exhibited a pronounced sialomucin production in basal areas within grooves while neutral and sulfomucins were predominant in apical areas. In luteal-phase animals, basal sialomicin production was markedly decreased while sulfated and neutral mucins remained abundant. Numerous cranially oriented spermatozoa were observed within the shallow grooves of cervical folds (sialomucin-rich areas) in mated animals and were unidirectionally opposed to ciliary beat. It appeared that privileged paths for transport of viable spermatozoa may originate in the fornix vagina, extend through longitudinal primary folds at the external os, and progress to the uterus within continuous sialomucin-rich channels which are associated with basal areas of the shallow grooves, distal to the cervical canal.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The normal bovine sperm tail consists of the classical 9 + 9 + 2 fiber pattern bound anteriorly by the mitochondrial helix and posteriorly by the fibrous helix except for the last 2 to 3 μ.The outer ring of nine coarse fibers originate as laminated columns, beginning from a common base which is located in a recess at the base of the head. The fibers taper posteriorly ending at different levels in the principal piece. Evidence is presented for the alternate contraction and expansion of the laminated segments of the coarse fibers in the neck  -  the probable mechanism for initiating the flagellar wave.The mitochondrial helix is composed of several mitochondrial strands of different length. Each strand consists of several elongated mitochondria positioned end to end. Apparently the strands of mitochondria may begin or end at various locations along the middle piece. The number of turns in the mitochondrial helix was found to vary from approximately 65 to 75 turns among cells. The helix binds the axial fiber bundle with a pitch of 20 to 25° over most of the middle piece. The mitochondria are double-walled and possess internal cristae that are vesicular or tubular in structure.The fibrous helix consists of dense, circumferential strands of variable thickness and shape with two longitudinal elements on opposite sides of the helix. Both the circumferential strands and the longitudinal elements become thinner as they progress posteriorly.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ultrastructure of the normal bovine sperm head has been studied and particular attention has been given to the morphology and coverings of the nucleus and the formation of the equatorial segment.The bovine sperm head consists of a homogeneous, flattened nucleus which is covered anteriorly by a three-layered head cap and posteriorly by a loose, thin, dense, post-nuclear cap. The nucleus measures approximately 0.2 to 0.3 μ in thickness. It tapers anteriorly to a sharp point along the frontal portion of the head and thickens posteriorly to accommodate an implantation socket for the tail. The nuclear membrane is double and porous. Vacuoles or openings of variable size and shape are present in the nucleoplasm, predominantly in the posterior portion of the nucleus. The head cap measures approximately 350 to 500 Å in thickness. It consists of dense inner and outer membranes which envelop a moderately electron dense middle layer. The head cap thickens across the frontal part of the head forming a ridge on one side of the nucleus.A sequence of structural alterations in the head cap provide evidence for the appearance of the equatorial segment. The anterior portion of the head cap swells and deteriorates leaving the posterior portion intact as a band about the center of the nucleus. This band represents the equatorial segment.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 15 (1986), S. 73-81 
    ISSN: 0148-7280
    Keywords: acrosome morphology ; viability ; live-dead stain ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Dried smears prepared from vitally stained sperm were evaluated as a method of simultaneously determining sperm viability and acrosomal morphology. A combination Fast Green FCF-Eosin B stain was used. The stained smears were examined at × 1, 250 using differential interference contrast microscopy (DIC). For comparison, the percentage of sperm with intact acrosomes was also determined from wet smears using DIC. Acrosomal morphology was not altered by the staining procedure, as the percentage of intact acrosomes was similar whether quantitated from wet or stained smears. Absence of eosinophilic staining in the acrosome was used as an indication of sperm viability. The percentage of sperm with unstained acrosomes was highly correlated with the percentage of intact acrosomes quantitated from stained smears. Thus, vital staining provided an indication of sperm viability comparable to acrosomal integrity, a highly reliable technique. The major advantages of using dried stained smears were more thorough examination of individual sperm without sperm activity interference, simultaneous evidence of sperm viability and morphology, and the opportunity to delay evaluation. In addition, diluting spermatozoa in complex or simple media with or without egg yolk or follicular fluid did not interfere with subsequent staining or acrosomal evaluation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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