The goal of this study was to purify bovine pepsinogen by a simple method allowing the preparatio... more The goal of this study was to purify bovine pepsinogen by a simple method allowing the preparation of large amount of pure protein. The purified protein and antisera are needed to develop diagnostic methods for further investigations in animals susceptible of gastric disorders or helminthosis. Pepsinogen isoforms were separated from extracts of bovine fundic mucosa by ammonium sulfate precipitations and chromatography on DEAE and hydroxyapatite. The isoforms showed a high activity in indirect proteolytic assay. Sequence analysis gave the following amino acid sequence SVVKIPLVKK for fraction 1, 2 and SVVKIPLVKKKSLRQNLIENGKLKE for fraction 3. The Mass spectrometry revealed isoforms with different masses from 39,864 to 40,181 Da. The estimated organic phosphate content ranged from 0.98 to 3.9 moles of phosphate per molecule. The protocol, with few steps, gave consequent quantities of pure and active protein available for further studies including the development of RIA and ELISA as diagnostic tools in gastrointestinal diseases.Peer reviewe
The objectives of this study were to relate the concentrations of plasma urea nitrogen (UN) to pr... more The objectives of this study were to relate the concentrations of plasma urea nitrogen (UN) to pregnancy rate in dairy cows. The cows were grouped, according to their production level and feed rations according to the NRC recommendations for essential nutrients, Holstein-Friesian dairy cows (n=103), randomly selected, were inseminated between Days 39 and 410 after calving. The cows were separated into two groups, where Group 1, was treated with GnRH i.m. injection on Day 12 after At. Group 2, was not treated and served as a control group. Heparinized blood samples were taken from the tall vein, immediately taken after artificial insemination (Day 0) and subsequently on Days 12, 21, 32 and 55 after Al, respectively. Diagnosis of pregnancy and late embryonic mortality was made by ultrasonography and the measurement of pregnancy proteins (PAG) between Days 32 and 55 after Al. Changes in plasma UN concentrations were studied using multivariate repeated ANOVA procedures. Three cows in each group were insemineted in the lutheal phase therefore their data were not used in the calculation. There were no significant differences between the UN concentrations of the pregnant and non-pregnant cows within the groups. However, the time of sampling had a significant effect on the UN concentrations in both the control and the treated groups. The UN concentrations, in pregnant and non pregnant cows of both groups, were significantly decreasing from Day 0 to Day 32. Concentrations of UN (on Day 0) less than 5,8 mmol/l were associated with increased pregnancy rates (53.6%). The pregnancy rates for cows with UN concentrations within the ranges of 5,7-6,75 mmol/l and 6,76-7,82 mmol/l were 47.8% and 46.7%, respectively. The rate of late embryonic mortality was similar in the two groups (treated group: n=2, control group: n=3)
Heterozygotes for Robertsonian translocations have usually a normal phenotype but show variable d... more Heterozygotes for Robertsonian translocations have usually a normal phenotype but show variable decrease in fertility. In humans, meiotic segregation studies carried out in male carriers reveal a majority of balanced spermatozoa. The rate of unbalanced segregation products appears higher in females than in males, but the number of human oocytes analysed so far remains limited (about 100). The occurrence of the t(1;29) translocation in several cattle breeds makes bovines an interesting animal model to study the meiotic segregation in female carrier of Robertsonian translocations. The aim of our project is thus to assess the rates of unbalanced oocytes produced by four cows and to compare these values with those obtained in bulls carriers of the same translocation. The superstimulated cows were subjected to twenty um pick up (OPU) sessions. Dual colour whole chromosome painting probes for BTA1 and 29 were hybridized on oocytes preparations. To date, 649 oocytes have been matured in vitro and 500 successfully spread. Among the 266 oocytes analysed by FISH so far: 201 (75,5%) are balanced, including 105 translocated and 96 normal, 55 are diploid (20.7%), and 10 unbalanced (3.8%). The proportion of balanced oocytes is lower than the average proportion of balanced spermatozoa estimated for two heterozygous bulls (97.1%). This difference is essentially due to a higher rate of diploid oocytes (20.7% vs 0.04% diploid spermatozoa). The origin of observed differences in the segregation profiles of the two sexes, as well as the practical implications of these results for genetic counselling and cattle breeding are discussed.Peer reviewe
At Days 26 to 58 after AI, 138 Holstein-Friesian dairy cows were repeatedly examined by ultrasono... more At Days 26 to 58 after AI, 138 Holstein-Friesian dairy cows were repeatedly examined by ultrasonography, using a 7.5 MHz linear-array rectal transducer. The total calving rate was 37.6% (52/138), and late embryonic mortality occurred 8.6% of the cows (12/138). On the days of ultrasound scanning, blood samples were drawn from the jugular vein for measuring the concentration of bovine pregnancy-specific protein B (bPSPB) and bovine pregnancy-associated glycoprotein 1 (bPAG 1). When compared with calving results, there were no significant differences in accurate diagnosis of pregnant cows were found between the 3 methods. However, when recognition of an embryo proper with a beating heart was used as the criterion for positive ultrasonographic diagnosis significantly fewer (P < 0.001) pregnant cows were correctly identified than by the other 2 tests. When compared with the noncalving cows, significantly fewer (P < 0.001) false positive diagnoses were made by the 2 ultrasonographic tests than by the PSPB and bPAG 1 tests, while significantly fewer (P < 0.001) false positive diagnoses were made by the bPSPB test than by the bPAG 1 test. The accuracy of detecting nonpregnant animals by both protein tests was limited by the relatively long half-life of these proteins after calving and by early embryonic mortality.
The two main groups of placental proteins of ruminants are discussed in this paper: chorionic som... more The two main groups of placental proteins of ruminants are discussed in this paper: chorionic somatomammotropins (placental lactogens) and pregnancy-specific (-associated) proteins. Placental lactogens belong to the prolactin and growth hormone family. They stimulate mammogenesis, fetal growth and maternal metabolism. Pregnancy-specific proteins and pregnancy-associated glycoproteins belong to the aspartic proteinase family like pepsin, cathepsin D and E. These two groups of proteins are secreted in the maternal circulation by the binucleate cells after their migration to and fusion with the uterine cells. Their profiles were determined by radioimmunoassay (RIA). Further investigations are in progress to relate secretory profiles with alterations of the trophoblastic function such as those occurring in embryonic mortality, abortion, and fetal distress. The endocrine function of the primate and equine placenta is also discussed.
Repeated administration of xenogenic gonadotropins in human or animal species may be responsible ... more Repeated administration of xenogenic gonadotropins in human or animal species may be responsible for antibody production and refractoriness. An experiment was conducted in which goats were treated with porcine FSH (p-FSH) at 6-week intervals for a period of 7 months. A sensitive radioimmunoassay (RIA) was used to detect antibodies to p-FSH in plasma samples taken at short-term intervals during a 7-month period. Antibodies appeared after the first injection, and levels increased following booster injections. A high correlation rate existed between antibody level and superovulatory response. Refractoriness in goats was associated with a high level of antibodies.
The goal of this study was to purify bovine pepsinogen by a simple method allowing the preparatio... more The goal of this study was to purify bovine pepsinogen by a simple method allowing the preparation of large amount of pure protein. The purified protein and antisera are needed to develop diagnostic methods for further investigations in animals susceptible of gastric disorders or helminthosis. Pepsinogen isoforms were separated from extracts of bovine fundic mucosa by ammonium sulfate precipitations and chromatography on DEAE and hydroxyapatite. The isoforms showed a high activity in indirect proteolytic assay. Sequence analysis gave the following amino acid sequence SVVKIPLVKK for fraction 1, 2 and SVVKIPLVKKKSLRQNLIENGKLKE for fraction 3. The Mass spectrometry revealed isoforms with different masses from 39,864 to 40,181 Da. The estimated organic phosphate content ranged from 0.98 to 3.9 moles of phosphate per molecule. The protocol, with few steps, gave consequent quantities of pure and active protein available for further studies including the development of RIA and ELISA as diagnostic tools in gastrointestinal diseases.Peer reviewe
The objectives of this study were to relate the concentrations of plasma urea nitrogen (UN) to pr... more The objectives of this study were to relate the concentrations of plasma urea nitrogen (UN) to pregnancy rate in dairy cows. The cows were grouped, according to their production level and feed rations according to the NRC recommendations for essential nutrients, Holstein-Friesian dairy cows (n=103), randomly selected, were inseminated between Days 39 and 410 after calving. The cows were separated into two groups, where Group 1, was treated with GnRH i.m. injection on Day 12 after At. Group 2, was not treated and served as a control group. Heparinized blood samples were taken from the tall vein, immediately taken after artificial insemination (Day 0) and subsequently on Days 12, 21, 32 and 55 after Al, respectively. Diagnosis of pregnancy and late embryonic mortality was made by ultrasonography and the measurement of pregnancy proteins (PAG) between Days 32 and 55 after Al. Changes in plasma UN concentrations were studied using multivariate repeated ANOVA procedures. Three cows in each group were insemineted in the lutheal phase therefore their data were not used in the calculation. There were no significant differences between the UN concentrations of the pregnant and non-pregnant cows within the groups. However, the time of sampling had a significant effect on the UN concentrations in both the control and the treated groups. The UN concentrations, in pregnant and non pregnant cows of both groups, were significantly decreasing from Day 0 to Day 32. Concentrations of UN (on Day 0) less than 5,8 mmol/l were associated with increased pregnancy rates (53.6%). The pregnancy rates for cows with UN concentrations within the ranges of 5,7-6,75 mmol/l and 6,76-7,82 mmol/l were 47.8% and 46.7%, respectively. The rate of late embryonic mortality was similar in the two groups (treated group: n=2, control group: n=3)
Heterozygotes for Robertsonian translocations have usually a normal phenotype but show variable d... more Heterozygotes for Robertsonian translocations have usually a normal phenotype but show variable decrease in fertility. In humans, meiotic segregation studies carried out in male carriers reveal a majority of balanced spermatozoa. The rate of unbalanced segregation products appears higher in females than in males, but the number of human oocytes analysed so far remains limited (about 100). The occurrence of the t(1;29) translocation in several cattle breeds makes bovines an interesting animal model to study the meiotic segregation in female carrier of Robertsonian translocations. The aim of our project is thus to assess the rates of unbalanced oocytes produced by four cows and to compare these values with those obtained in bulls carriers of the same translocation. The superstimulated cows were subjected to twenty um pick up (OPU) sessions. Dual colour whole chromosome painting probes for BTA1 and 29 were hybridized on oocytes preparations. To date, 649 oocytes have been matured in vitro and 500 successfully spread. Among the 266 oocytes analysed by FISH so far: 201 (75,5%) are balanced, including 105 translocated and 96 normal, 55 are diploid (20.7%), and 10 unbalanced (3.8%). The proportion of balanced oocytes is lower than the average proportion of balanced spermatozoa estimated for two heterozygous bulls (97.1%). This difference is essentially due to a higher rate of diploid oocytes (20.7% vs 0.04% diploid spermatozoa). The origin of observed differences in the segregation profiles of the two sexes, as well as the practical implications of these results for genetic counselling and cattle breeding are discussed.Peer reviewe
At Days 26 to 58 after AI, 138 Holstein-Friesian dairy cows were repeatedly examined by ultrasono... more At Days 26 to 58 after AI, 138 Holstein-Friesian dairy cows were repeatedly examined by ultrasonography, using a 7.5 MHz linear-array rectal transducer. The total calving rate was 37.6% (52/138), and late embryonic mortality occurred 8.6% of the cows (12/138). On the days of ultrasound scanning, blood samples were drawn from the jugular vein for measuring the concentration of bovine pregnancy-specific protein B (bPSPB) and bovine pregnancy-associated glycoprotein 1 (bPAG 1). When compared with calving results, there were no significant differences in accurate diagnosis of pregnant cows were found between the 3 methods. However, when recognition of an embryo proper with a beating heart was used as the criterion for positive ultrasonographic diagnosis significantly fewer (P < 0.001) pregnant cows were correctly identified than by the other 2 tests. When compared with the noncalving cows, significantly fewer (P < 0.001) false positive diagnoses were made by the 2 ultrasonographic tests than by the PSPB and bPAG 1 tests, while significantly fewer (P < 0.001) false positive diagnoses were made by the bPSPB test than by the bPAG 1 test. The accuracy of detecting nonpregnant animals by both protein tests was limited by the relatively long half-life of these proteins after calving and by early embryonic mortality.
The two main groups of placental proteins of ruminants are discussed in this paper: chorionic som... more The two main groups of placental proteins of ruminants are discussed in this paper: chorionic somatomammotropins (placental lactogens) and pregnancy-specific (-associated) proteins. Placental lactogens belong to the prolactin and growth hormone family. They stimulate mammogenesis, fetal growth and maternal metabolism. Pregnancy-specific proteins and pregnancy-associated glycoproteins belong to the aspartic proteinase family like pepsin, cathepsin D and E. These two groups of proteins are secreted in the maternal circulation by the binucleate cells after their migration to and fusion with the uterine cells. Their profiles were determined by radioimmunoassay (RIA). Further investigations are in progress to relate secretory profiles with alterations of the trophoblastic function such as those occurring in embryonic mortality, abortion, and fetal distress. The endocrine function of the primate and equine placenta is also discussed.
Repeated administration of xenogenic gonadotropins in human or animal species may be responsible ... more Repeated administration of xenogenic gonadotropins in human or animal species may be responsible for antibody production and refractoriness. An experiment was conducted in which goats were treated with porcine FSH (p-FSH) at 6-week intervals for a period of 7 months. A sensitive radioimmunoassay (RIA) was used to detect antibodies to p-FSH in plasma samples taken at short-term intervals during a 7-month period. Antibodies appeared after the first injection, and levels increased following booster injections. A high correlation rate existed between antibody level and superovulatory response. Refractoriness in goats was associated with a high level of antibodies.
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Papers by Jean-françois Beckers