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Biomedical subjects

B Colenbrander

Publications and source records attributed to B Colenbrander.

At least 19 recordsLinked to original sources
PubMed1997

[Equine arteritis virus: clinical symptoms and prevention].

Sero-epidemiological surveys have revealed that equine arteritis virus (EAV) is prevalent in most European countries. The virus causes sporadic cases of respiratory disease and abortion in horses, the incidence of which has increased in recent years. Mares and geldings eliminate virus after acute infection, but 30% to 60% of stallions become persistently infected. In these animals, EAV is maintained within the reproductive tract and is shed continuously in the semen. Persistent infection with EAV in stallions has no negative consequences for fertility but mares inseminated with virus-contaminated semen can have an acute infection. These mares shed large amounts of virus in respiratory secretions and urine, leading to lateral spread of the virus to other susceptible horses. Acute infection at later stages of gestation can lead to abortion. Effective control of the spread of EAV infection depends on the identification of virus-shedding stallions. Persistently infected stallions should not be used for breeding or should be bred only to seropositive mares. Mares bred to shedding stallions should be isolated from other animals for a period of 3 weeks following insemination to prevent the lateral spread of EAV.

Abortion, Veterinary↗
PubMed1996

In vitro maturation of bovine oocytes in the presence of growth hormone accelerates nuclear maturation and promotes subsequent embryonic development.

Regulatory effect of GH on follicular growth and development in the cow is well documented. The aim of this study was to investigate the role of GH on in vitro bovine oocyte maturation. Therefore bovine cumulus oocyte complexes (COCs) were cultured in M199 without FCS and gonadotropins and in the presence of 10, 100, or 1,000 ng/ml bovine GH (NIH-GH-B18). The COCs were incubated at 39 degrees C in a humidified atmosphere with 5% CO2 in air and nuclear stage was assessed after 2, 4, 8, 16, 22, and 24 hr of incubation using DAPI staining. To assess the effect of GH on developmental capacity of the oocytes, COCs were incubated in the presence of GH for 22 hr, followed by IVF and in vitro embryo culture. Cultures without GH served as controls. For subsequent development, the embryos were cultured in M199 supplemented with 10% FCS on a monolayer of BRL cells. Embryos were scored morphologically and the efficiency of the culture system was evaluated as (1) the percentage of cleaved embryos 4 days after IVF, (2) the percentage of blastocysts on day 9 expressed on the basis of the number of oocytes at the onset of culture, and (3) the percentage of hatched blastocysts on day 11 expressed on the basis of the total number of blastocysts present at day 9. GH (100 and 1,000 ng/ml) significantly accelerated nuclear maturation (P < 0.001). At 4 and 8 h the percentage of oocytes in GV stage after GH treatment (54% and 19%) was significantly lower than the control (64% and 41%). Similarly at 16 and 22 h the percentage of oocytes in MII stage was significantly higher in the GH-treated group; (58% and 77%) and (46% and 62%) for GH and control respectively. The number of oocytes in MII beyond 22 hr of culture did not differ; 100 and 1,000 ng/ml GH induced significant cumulus expansion (P < 0.05), which was not observed in the absence of GH. Addition of 100 and 1,000 ng/ml GH during maturation significantly (P < 0.01) enhanced subsequent cleavage rate from (64% and 67%) in control to (75% and 81%) in GH-treated group; embryonic development in terms of day 9 blastocyst formation was also significantly increased in the presence of GH (29% and 34%) compared to the control (18% and 24%). The hatchability of the blastocysts was not influenced by GH. From the present data, it can be concluded that GH present during IVM has a beneficial effect on subsequent development.

Animals↗
PubMed1996

Equine arteritis virus: a review of clinical features and management aspects.

Sero-epidemiological surveys have revealed that equine arteritis virus (EAV) is prevalent in most European countries. The virus causes sporadic cases of respiratory disease and abortion in horses, the incidence of which has increased in recent years. Mares and geldings eliminate virus after acute infection, but 30% to 60% of stallions become persistently infected. In these animals, EAV is maintained within the reproductive tract and is shed continuously in the semen. Persistent infection with EAV in stallions has no negative consequences for fertility but mares inseminated with virus-contaminated semen can have an acute infection. These mares shed large amounts of virus in respiratory secretions and urine, leading to lateral spread of the virus to other susceptible horses. Acute infection at later stages of gestation can lead to abortion. Effective control of the spread of EAV infection depends on the identification of virus-shedding stallions. Persistently infected stallions should not be used for breeding or should be bred only to seropositive mares. Mares bred to shedding stallions should be isolated from other animals for a period of 3 weeks following insemination to prevent the lateral spread of EAV.

Abortion, Veterinary↗
PubMed1995

Glycolipid migration from the apical to the equatorial subdomains of the sperm head plasma membrane precedes the acrosome reaction. Evidence for a primary capacitation event in boar spermatozoa.

In order to extend the static information of immunolabelling sulphogalactolipids in fixed boar spermatozoa, a fluorescent sulphogalactolipid analogue, galactose(3-sulphate)-beta 1-1'[(N-lissamine rhodaminyl)-12-aminodode-canoyl]-sphingosine, was incorporated into plasma membranes of living spermatozoa and its lateral distribution over the sperm head was studied. The fluorescent lipid was enriched in the apical ridge subdomain of freshly ejaculated sperm cells. After sperm binding to the zona pellucida the lipid redistributed to the equatorial segment of the sperm surface. A similar shift occurred during capacitation in vitro with 2 mM CaCl2 or with 4% (w/v) bovine serum albumin. The desulphated derivative galactose-beta 1-1'[(N-lissamine rhodaminyl)-12-aminododecanoyl]-sphingosine was also incorporated into the plasma membrane of freshly ejaculated sperm cells and clearly stained the apical ridge subdomain and the (pre)-equatorial subdomains of the sperm heads. The desulphogalactolipid analogue showed a slightly faster migration to the equatorial segment of the sperm plasma membrane than did its sulphated counterpart. The measured fluorescence intensity distributions correlated linearly with the spatial probe distribution, which was checked by fluorescence lifetime imaging microscopy. The observed migration of the incorporated glycolipids precedes the acrosome reaction and is one of the underlying molecular events likely to be important in the process of sperm capacitation. The results of this study suggest that lipid phase segregation is an important driving force for the organization of the sperm head plasma membrane into subdomains.

Acrosome↗
PubMed1994

Development and evaluation of PCR test for detection of Taylorella equigenitalis.

A PCR for the detection of Taylorella equigenitalis, the causative agent of contagious equine metritis, was developed and evaluated. A genus-specific primer-probe set was derived from the 16S ribosomal DNA sequences. The PCR was specific and amplified a 585-bp product from all 64 available T. equigenitalis isolates. This PCR product hybridized with a specific probe in a dot spot assay. A variety of microorganisms from the genital tracts of horses or with a close phylogenetic relationship to T. equigenitalis did not yield a visible PCR product and were all negative in the dot spot hybridization assay. The results of the PCR assay were compared with those of culture by using 191 genital swabs from horses of several breeds. We demonstrate that the sensitivity of the PCR assay is superior to that of culture. The assay is most sensitive when DNA from culture plates incubated for at least 2 days is used. Of the tested samples, 1.5% were positive in the culture assay, whereas 35% were positive in the culture PCR assay. PCR-positive samples were obtained from all breeds tested. This means that many T. equigenitalis-carrying horses go unidentified by the current culturing technique. This affects current views about the spread and control of T. equigenitalis.

Animals↗
PubMed1994

Visualization and quantification of glycolipid polarity dynamics in the plasma membrane of the mammalian spermatozoon.

Seminolipid (sulphogalactosylalkylacylglycerol), the glycolipid that is specific for mammalian germ cells, is located exclusively in the outer leaflet of the sperm plasma membrane. In this study the lateral distribution of seminolipid on sperm heads has been investigated by indirect immunofluorescence labelling and detection with digital imaging fluorescence microscopy. In freshly ejaculated sperm cells this glycolipid was present primarily at the apical ridge subdomain of the plasma membrane of the sperm head. After binding the sperm cells to zona-coated coverslips seminolipid migrated, in 40 minutes, from the apical ridge to the equatorial subdomain of the plasma membrane. A similar redistribution of seminolipid was observed during capacitation of sperm cells in vitro induced by Ca2+ or bovine serum albumin. Comparable migration of seminolipid was also found after prolonged storage of ejaculated sperm cells, albeit at a much slower rate. Addition of arylsulphatase A, an enzyme present in seminal plasma that desulphates seminolipid, significantly enhanced the migration of seminolipid during storage of sperm cells. Its breakdown product desulphoseminolipid (galactosylalkylacylglycerol) appeared highly specifically at the equatorial segment. The measured fluorescence intensity over the sperm head surface correlated linearly with the spatial probe distribution as was checked by fluorescence lifetime imaging microscopy. This paper demonstrates and quantifies for the first time the polarity of seminolipid on the surface of the sperm cell and the dynamic alterations that occur in this polarity during post-ejaculatory events.

Animals↗
PubMed1994

Reproductive characteristics and semen quality in maiden Dutch Warmblood stallions.

The semen characteristics and testicular size of 398 3-year-old maiden Dutch Warmblood stallions were studied during February and March. Mean values (+/- SD) of age (1030 +/- 88 days) and testicular size (9.8 +/- 0.9 cm) of the maiden stallions were determined as well as the following semen characteristics (mean of two ejaculates, taken 1 h apart): volume (65 +/- 26 ml), sperm concentration (2.061 +/- 1.685 x 10(8) ml-1), total number of spermatozoa (1.129 +/- 0.71 x 10(10)), percentage of progressively motile spermatozoa (68 +/- 9%), percentage of live spermatozoa with normal morphology (66 +/- 15%), total number of progressively motile morphologically normal spermatozoa (5.307 +/- 3.833 x 10(9)) and pH (7.5 +/- 0.2). The morphology of the spermatozoa was studied and data on the most common abnormalities are presented. The first and second ejaculates show significant differences (P < 0.05) in volume, motility, number of spermatozoa, sperm morphology, total number of progressively motile morphologically normal spermatozoa and pH. The original breed has been split up into two different lines. There was a significant difference (P < 0.05) in semen characteristics between the types (riding and carriage horses). The semen quality and quantity of semi-siblings were compared and a significant sire effect (P < 0.05) was shown for the following characteristics: volume, motility (%) and sperm concentration. These results indicate that there are differences of heritability of those factors, which makes it possible to select on semen quality.

Animals↗
PubMed1993

Development of a sperm zona pellucida binding assay for bull semen.

Assays based on sperm zona pellucida binding have been developed as diagnostic tests to predict the fertilisation potential of human spermatozoa. The aim of this study was to establish a similar assay for bull sperm. The results showed differences between established fertile bulls in the relative numbers of sperm cells bound to the zona pellucida of a batch of oocytes. These differences suggest that there may be a relationship between the sperm zona pellucida binding capacity and the fertility of bulls.

Animals↗
PubMed1993

Effects of various cryoprotective agents and membrane-stabilizing compounds on bull sperm membrane integrity after cooling and freezing.

In this study attempts were made to improve the survival rates of bull spermatozoa after freezing/thawing and to clarify the importance of certain agents to the cryopreservation of spermatozoa. For that purpose the standard freezing extender was modified by the addition of different concentrations of various cryoprotectants and membrane-stabilizing agents: glycerol, 1,2-propanediol, polyvinylpyrrolidone, sucrose, egg yolk, lipid vesicles, and bovine serum albumin (BSA). Sperm membrane impermeability toward H33258 was employed as the parameter for sperm integrity during cooling and after freezing/thawing. Exclusion of glycerol from the extender did not significantly affect sperm integrity. Replacing 6% glycerol by 6% 1,2-propanediol resulted in reduced sperm survival, whereas replacement of glycerol by 62.5 mM sucrose slightly improved survival rates. Addition of 5 or 10% polyvinylpyrrolidone (either or not in combination with 0.5 M sucrose) significantly reduced sperm integrity. Excluding egg yolk from the extender caused a serious decrease of sperm survival after both cooling and freezing. The cryoprotection offered by egg yolk could not be mimicked by dioleoylphosphatidylcholine (DOPC) vesicles or DOPC/phosphatidic acid/cholesterol vesicles in concentrations up to 29 or 9 mM, respectively. However, the freezing extender containing 6.5 mM DOPC vesicles in combination with 6% BSA yielded results which did not significantly differ from those obtained with the standard extender; higher vesicle concentrations combined with BSA might produce even better results. Further research on the cryopreservation of bovine spermatozoa should focus on membrane stabilization since the membrane-stabilizing compounds yield more promising results than the ice-preventing agents.

Animals↗
PubMed1993

Boar seminal vesicles secrete arylsulfatases into seminal plasma: evidence that desulfation of seminolipid occurs only after ejaculation.

The presence and composition of arylsulfatases in secretions of various glands of the boar genital tract were studied. Arylsulfatase A was present in seminal plasma but not in extracellular fluids of the testis and epididymis nor in blood serum of boars. On the other hand, arylsulfatase B was present in both seminal plasma and extracellular fluids of the testis but was completely resorbed in the epididymis. The acrosomal arylsulfatase A did not leak out of spermatozoa before ejaculation. We conclude that arylsulfatases A and B present in seminal plasma are secreted by the seminal vesicles, for three reasons: 1) secretions from seminal vesicles contained 2.3-fold higher arylsulfatase activities than did those from seminal plasma, but had an identical composition; 2) cauda epididymal fluids did not contain arylsulfatase; and 3) other accessory glands of the boar genital tract did not secrete arylsulfatase. When intact boar spermatozoa were incubated with arylsulfatase A, complete desulfation of seminolipid was observed. The most important arguments favoring our hypothesis that desulfation of seminolipid does not start before ejaculation are the following: 1) desulfoseminolipid is not detectable in epididymal or freshly ejaculated sperm samples; 2) the acrosomal arylsulfatase A cannot desulfate seminolipid present at the surface of the plasma membrane of intact spermatozoa because of its intracellular localization; 3) extracellular arylsulfatase A is stored in seminal vesicles and thus can interact with spermatozoa during and after ejaculation.

Animals↗
PubMed1993

Optimizing semen production for artificial insemination in swine.

Efficient production of high quality semen is of major importance to artificial insemination (AI) organizations. The semen produced should be free of contagious organisms, be of high quality, have good storage properties, fertilizing capacity and be of high genetic value. The best approach to prevent the spreading of microorganisms via semen in the process of AI is to collect semen from boars free from specific diseases, for example pseudorabies virus or leptospirosis. Antibiotics are added to the semen to suppress proliferation of microorganisms or even reduce their number. Sperm production is influenced by many factors such as season, collection frequency, breed and age. The average number of sperm cells produced per boar per week can vary more than 30% within one AI station, depending on the breed. Boar selection and boar management markedly influence the efficiency of sperm production. Sperm quality should be evaluated by fertility results obtained at breeding farms related to both farrowing rate and litter size to ensure a good quality monitoring system. A quality control system should be established to provide maximum reliability to customers.

Animals↗
PubMed1993

Liquid storage and freezing of semen from New Forest and Welsh Pony stallions.

Two experiments were conducted to examine the effects of liquid storage extender and of a modified freezing protocol on motility and morphology parameters of 3-year-old pony stallions. In experiment 1 ejaculates were diluted 1 + 1 (v+v) with glycine-egg-yolk extender (D11) or skim milk extender (SME), centrifuged, resuspended in the corresponding extender and kept at +5 degrees C. Concerning motion characteristics, both progressive motility and average path velocity of semen stored in SME was significantly superior to semen stored in D11 after 6, 18 and 42 hrs. However, over time of storage the D11 seemed to have more beneficial effect on sperm morphology and acrosome integrity compared to SME. In experiment 2 ejaculates--after centrifugation in D11--were resuspended in lactose-egg-yolk-glycerol extender, packaged in 0.5 ml straws and frozen at computer controlled cooling rates. There was a significant decrease from fresh to post thaw motility, velocity and percentage of morphologically normal spermatozoa, whereas acrosome morphology not seemed to be affected by freezing/thawing.

Animals↗
PubMed1992

Characterization of three arylsulfatases in semen: seminolipid sulfohydrolase activity is present in seminal plasma.

Sperm cells and seminal plasma of various mammals contain high levels of arylsulfatase. In the present study, we investigated the composition of soluble AS in these compartments of boar semen by analysing sperm cells and seminal plasma using anion-exchange chromatography. Seminal plasma contained both arylsulfatase B (2.4 units per ml), an enzyme which desulfates sulfoglycosaminoglycans and probably sulfoglycoproteins, and arylsulfatase A (10.2 units per ml), an enzyme which desulfates sulfogalactolipids. Sperm cells contained only arylsulfatase A, which differed biochemically from the extracellular arylsulfatase A of seminal plasma (2.6 units per ml). Both types of arylsulfatase A desulfate seminolipid, the natural sulfolipid substrate in sperm, as well as two brain sulfatides. The possible physiological consequences of the presence of extracellular arylsulfatases in seminal plasma for spermatozoa are discussed.

Animals↗