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  • 1
    Electronic Resource
    Electronic Resource
    Electrophysiological properties of the follicle wall in the pig ovary (1988)
    Springer
    Cellular and molecular life sciences 44 (1988), S. 212-214 
    Details
    ISSN: 1420-9071
    Keywords: Pig ovary ; follicular fluid ; active transport ; trans-epithelial potential difference ; short-circuit current ; specific resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The transmural potential difference and short-circuit current of the porcine Graafian follicle have been measured in an attempt to test whether antral fluid accumulates as a result of active transport of salt. The values obtained by mounting explants of follicle wall in Ussing chambers were close to zero and the specific electrical resistance was only 59 Ω·cm2. The elemental composition of the follicular fluid was similar to that of ovarian venous plasma with the exception of follicular Na+ which was slightly more abundant. Bicarbonate concentrations were slightly lower in follicular fluids. These findings were interpreted as evidence that the follicular wall is a leaky epithelium and, therefore, any charge resulting from net ion transport will be shunted along low resistance paracellular pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01941708
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of ovarian follicular fluids of sheep, pigs and cows using proton nuclear magnetic resonance spectroscopy (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1012-1015 
    Details
    ISSN: 1420-9071
    Keywords: Ovary ; follicular fluid ; NMR spectroscopy ; sheep ; pig ; cow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Proton NMR spectra were produced for Graafian follicular fluids obtained by aspiration from sheep, pig and cow ovaries. The following low molecular mass, non-protein-bound metabolites were detected at concentrations exceeding 0.1 mM: acetate, alanine, creatinine/creatine, glycine, D-3-hydroxybutyrate, lactate, valine. Glucose was difficult to quantify and N-acetyl sugars gave a broad resonance at 2.06 ppm, presumably representing side-chains of glycoproteins. Ethanol was detected at up to millimolar concentrations in some specimens, though the physiological significance of this finding was not clear. The concentrations of all metabolites were comparable to those of plasma. These results have therefore shown that NMR spectroscopy is useful for gaining a broad and semiquantitative impression of the more abundant metabolites in the fluids of preovulatory Graafian follicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01940658
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  • 3
    Electronic Resource
    Electronic Resource
    Oviduct function in pigs, with particular reference to the pathological condition of polyspermy (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 29 (1991), S. 385-391 
    Details
    ISSN: 1040-452X
    Keywords: Fertilisation ; Spermatozoa ; Insemination ; Progesterone ; Glycoprotein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Because the exceptionally high incidence of polyspermic fertilisation has been emphasised as a major defect in systems of in vitro fertilisation in pigs, the aetiology of the condition has been analysed in a series of experiments in vivo in the search for a common underlying cause and possible means of mitigation. Whereas the defense mechanism against polyspermy in pig oocytes is classically viewed as a zona reaction, more recent evidence suggests a secondary block at the vitelline surface. Both blocks may be compromised in situations leading to polyspermy, although deleterious influences seem to be expressed principally in an inadequate zona block, as judged by the presence of perivitelline spermatozoa.Postovulatory aging of mammalian oocytes prior to sperm penetration leads to polyspermy, as can be demonstrated in pig eggs. The primary lesion may concern the cortical reaction, owing to a delayed and incomplete exocytosis of the vesicular contents. Eggs ovulated after gonadotrophin treatment during the luteal phase of the cycle show a high incidence of polyspermic penetration (60.6%), as do those shed at estrus in animals treated with progesterone systemically (40%) or by local microinjections in the oviduct wall (32.3%). Whereas progesterone may be modifying interactions of the gametes and responses of the egg organelles in all four above experimental situations, enhanced numbers of spermatozoa ascending a more patent isthmus appear to be the principal cause of polyspermy. Support for this hypothesis comes from isthmus resection with re-anastomosis of remaining portions of the oviduct (32.4% polyspermy), and surgical insemination directly into the oviducts (33.8% polyspermy). Recent experiments draw attention to a role for oviduct epithelial glycoproteins in modulating the extent of polyspermy in vitro. The role of such oviduct macromolecules in gamete interactions in vivo is considered.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080290411
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  • 4
    Electronic Resource
    Electronic Resource
    Sperm: Egg ratios and putative molecular signals to modulate gamete interactions in polytocous mammals (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 35 (1993), S. 324-327 
    Details
    ISSN: 1040-452X
    Keywords: Activation ; Oocyte ; Spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Reasoning from the premises that 1) the sperm:egg ratio at the time of activation of the secondary oocyte in mammals is close to unity under conditions of spontaneous mating, 2) a majority of eggs within the cumulus oophorus of a polytocous species is fertilized in a reasonably short interval of time, and 3) spermatozoa would find it difficult to reverse their approach to the zona pellucida, it is proposed that molecular gradients exist to divert spermatozoa penetrating the cumulus mass away from eggs already activated and towards eggs as yet unfertilised. Possible sources of such molecular cues are considered, as is the event that triggers their release. © 1993 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080350315
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  • 5
    Electronic Resource
    Electronic Resource
    Capacitation potential of the fallopian tube: A study involving surgical insemination and the subsequent incidence of polyspermy (1988)
    New York, NY : Wiley-Blackwell
    Gamete Research 21 (1988), S. 255-266 
    Details
    ISSN: 0148-7280
    Keywords: pig ; fertilization ; vitellus ; chromatin aggregates ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In an attempt to demonstrate limitations in the capacitating potential of the Fallopian tube, ejaculated boar spermatozoa were introduced directly into the isthmus at varying intervals before ovulation. The incidence and degree of polyspermy subsequently observed were taken as indicators of the population of capacitated spermatozoa confronting the newly ovulated eggs: the more extensive the condition of polyspermy, the greater the number of capacitated spermatozoa presumed to have been available at the site of fertilization. Results are based on 673 eggs from 53 animals.When suspensions containing 2.21-3.87 × 108 sperm per ml were introduced 36-40 hours and 26-30 hours before ovulation, 85% and 61% respectively of the eggs were polyspermic, such eggs exhibiting mainly dispermy and trispermy. By contrast, when comparable sperm suspensions from the same boar were instilled 17-18 hours before ovulation, 70% of the eggs were polyspermic but the degree of polyspermy had increased dramatically: most eggs contained 40 or more sperm heads in the vitellus, invariably forming swollen chromatin aggregates rather than male pronuclei. Surgical insemination at times closer to ovulation significantly reduced the incidence and degree of polyspermy, reaching a low of 2% with insemination 1-2 hours before ovulation. These results therefore support the concept of a limited capacitation potential of the Fallopian tube.In a separate series of observations, mating animals shortly before surgical insemination with sperm suspensions from the same boar markedly reduced the incidence of polyspermy. This latter observation may be of clinical significance in procedures of laparoscopic or transcervical insemination into the tubes to alleviate human infertility. The manner whereby myosalpingeal physiology could be modified in response to coital stimulation is discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120210307
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