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I De Pauw

Publications and source records attributed to I De Pauw.

6 recordsLinked to original sources
PubMed2004

Storage of fresh bovine semen in a diluent based on the ionic composition of cauda epididymal plasma.

For artificial insemination (AI) in cattle, much lower insemination doses can be applied when fresh semen is used instead of frozen-thawed semen. However, a particular disadvantage of fresh semen is its limited shelf life. As bovine spermatozoa can be stored for several weeks in the cauda epididymis without negative effects on their fertilizing capacity, it is an interesting organ to serve as a model in order to prolong the shelf life of fresh semen. First, the storage capacity of a diluent [cauda epididymal plasma (CEP-1)] with the same ionic composition, pH and osmolarity as the bovine CEP was compared with a Tris diluent for extended preservation of fresh ejaculated bovine semen. Secondly, the ionic composition of the CEP-1 diluent was modified (CEP-2) and its storage capacity was compared with this of the CEP-1 and Tris diluent. Finally, the effect of addition of different polyols (sorbitol, glycerol, mannitol) and egg yolk concentrations (5, 10 and 20%) to the CEP-2 diluent was assessed. Sperm quality decreased rapidly in the CEP-1 diluent. The quality and especially progressive motility of spermatozoa stored in the CEP-2 diluent were better those in the CEP-1 and Tris diluent. No significant effects of different sugars or egg yolk concentrations on the quality of fresh bovine semen in the CEP-2 diluent were observed. In conclusion, the CEP-2 diluent with 10% egg yolk and 1 g/l sorbitol may be used for extended preservation of fresh bovine semen at 5 degrees C up to 6 days.

Animals↗
PubMed2002

Migration of bovine spermatozoa in a synthetic medium and its relation to in vivo bull fertility.

Although sperm migration has been extensively refined and validated in human infertility studies, its application to predict bovine fertility has been very limited, and a clear relation between the sperm migration distance and in vivo bull fertility has never been demonstrated. A synthetic medium based upon methyl cellulose (MC) was tested for its suitability to serve as a migration medium for frozen-thawed bovine spermatozoa. The effects of the concentration of MC, the incubation time, and sperm concentration on sperm migration capacity was determined. The relation between sperm migration capacity at different incubation times of the frozen-thawed spermatozoa of five bulls, and their 56 days nonreturn rates (NRRs) was assessed in order to evaluate its suitability as a tool to predict in vivo bull fertility. The highest repeatability of the sperm migration test (CV = 10.7%) was obtained when the sperm migration distance of the five vanguard motile spermatozoa was determined at 30 min incubation at 37 degrees C in a migration medium with 1.35% MC. No significant difference in migration distance was demonstrated when sperm concentrations of 100 x 10(6) and 150 x 10(6) spermatozoa/ml, respectively, were used. Despite the relatively high repeatability of the migration test, no relation was found between the sperm migration distance and the 56 days NRRs of five sire bulls. Therefore, the sperm migration test in 1.35% MC cannot be used to predict in vivo bull fertility accurately.

Animals↗
PubMed2002

Function of the cumulus oophorus before and during mammalian fertilization.

CONTENTS: Fertilization encompasses a series of different steps which have to be performed in a well-orchestrated way to create a new individual. They include sperm capacitation, sperm binding and penetration of the zona pellucida, traversing the perivitelline space, binding and fusion with the oolemma, activation of the oocyte and decondensation of the sperm head to form the male pronucleus. In most mammalian species, cumulus cells surround the oocyte at the time of fertilization. Removal of the cumulus oophorus at this point of time often leads to a drop in fertilization rates. It is not yet known how cumulus cells interact with the oocyte or with spermatozoa to promote fertilization. There are different possibilities: 1 cumulus cells cause mechanical entrapment of spermatozoa and guide hyperactivated spermatozoa towards the oocyte, while preventing abnormal spermatozoa to enter the cumulus matrix; 2 cumulus cells create a micro-environment for the spermatozoa which favours their capacitation and penetration into the oocyte; 3 cumulus cells prevent changes in the oocyte which are unfavourable for normal fertilization; these changes can be located in the zona pellucida or in the cytoplasm. In this review, studies in several species are listed to prove the importance of these three cumulus cell functions and the current lines of research are highlighted. Moreover, different ways to improve in vitro fertilization of bovine cumulus-denuded oocytes are discussed.

Animals↗
PubMed1990

Lichen planus induced by flunarizine.

A 56-year-old man developed lichen planus while taking flunarizine, a di-fluorinated derivate of cinnarizine. Induction of lichen planus by cinnarizine therapy has been described but the precise etiopathological mechanism is unclear. Although flunarizine is widely prescribed, lichen planus induced (?) by this drug has, to our knowledge, never been reported.

Arteriosclerosis↗