Quantification of the uterine involution and dimensions, hormonal response and reproductive performance of pyometric and healthy dairy cows treated with Dinoprost

The aim of the present study was to investigate the effects of a PGF2α analogue (Dinoprost) on involution of the puerperal uterus, especially with pyometra during 35 to 45 days postpartum in multiparous high yielding Holstein dairy cows. At days 40 ± 5 postpartum, 1250 cows were ultrasonographically examined. Fifty cows were diagnosed as pyometric. Fifty pyometric and 50 clinically healthy cows were assigned randomly to one of four groups. Groups were: 1.) Pyometric+Dinoprost cows (PD, n = 25 treated with 25 mg of Dinoprost), 2.) Pyometric+Saline cows (PS, n = 25 treated with saline), 3.) Healthy+Dinoprost cows (HD, n = 25 treated with 25 mg of Dinoprost), and 4.) Healthy+Saline cows (HS, n = 25 treated with saline). All treatments were given intramuscularly. Ultrasonography was performed at the time of examination and 7 days later to evaluate changes in uterine diameter. Treatment with Dinoprost significantly reduced gross uterine diameter in PD in comparison to the PS group in the presence or absence (P4 concentrations <1 ng/ml) of an active corpus luteum. Dinoprost treatment did not decrease gross uterine diameter in groups HD and HS. Luminal diameter was significantly smaller in the PD than in the PS group. Pregnancy rate of PD was greater than PS cows (36% vs 20%, respectively). Days to first service (110 d vs. 140 d) and open days (160 d vs. 190 d) were shorter in PD cows than PS cows. It was concluded that injection of 25 mg of Dinoprost to pyometric cows had uterotonic effects in presence or absence of functional corpus luteum. Therefore, this treatment can help uterine involution in puerperal dairy cows affected by pyometra and consequently improved reproductive performance.Keywords: Cattle, Dinoprost, pregnancy rate, pyometra, uterine healt

Scattering functions of knotted ring polymers

We discuss the scattering function of a Gaussian random polygon with N nodes under a given topological constraint through simulation. We obtain the Kratky plot of a Gaussian polygon of N=200 having a fixed knot for some different knots such as the trivial, trefoil and figure-eight knots. We find that some characteristic properties of the different Kratky plots are consistent with the distinct values of the mean square radius of gyration for Gaussian polygons with the different knots.Comment: 4pages, 3figures, 3table

Effect of oral administration of pioglitazone on follicular dynamics in Holstein dairy cows

This study investigated the effects of oral administration of pioglitazone (PGT), a specific and synthetic ligand of peroxisome proliferator-activated receptors gamma (PPARγ), on follicular dynamics and corpus luteum (CL) functionality in dairy cows. Cows exhibiting strong signs of estrus after 2 injections of PGF2α (given14 d apart) at d 30 postpartum (n = 28) were allotted to four groups (n = 7 cows/treatment) and orally received 6 mg PGT/kg body weight/day according to the following protocol: no PGT (control); PGT for 14 d from 7 d before expected estrus (10 d after 1st injection of PGF2α) to 7 d after observed estrus (PGT14); PGT for 21 d after observed estrus (PGT21); and PGT for 28 d, 7 d before expected estrus to 21 d after observed estrus (PGT28). During the first follicular wave, number of follicles (total and small) increased in PGT14 and PGT28 cows compared to the control group (P < 0.05). During the ovulatory wave, number of total and small follicles increased in PGT28 (P < 0.05) and PGT21 (P < 0.10) compared with PGT14 and control cows. Size of the largest follicle at first wave was greater in PGT28 (P < 0.05), PGT14 (P < 0.05) and PGT21 (P < 0.10) compared to the control cows. Maximal size of the ovulatory follicle was greater in PGT28 (P < 0.05) and PGT21 (P < 0.10) groups compared to the control group. Growth rate of the largest follicle at first wave was higher (P < 0.05) in PGT-treated cows, while growth rate of the ovulatory wave was higher in PGT28 and PGT21 groups, leading to shorter days from luteolysis to ovulation. Pioglitazone administration did not affect CL size, but increased progesterone (P4) concentration. The PGT14 and PGT28 cows had higher maximal plasma P4 concentration and shorter intervals to reach maximal plasma P4 compared to the control group. In conclusion, oral administration of PGT had some positive effects on follicular development and circulating P4 levels which may be conducive to better reproductive performance

Myristoylated peptides potentiate the funny current (If) in sinoatrial myocytes

The funny current, If, in sinoatrial myocytes is thought to contribute to the sympathetic fight-or-flight increase in heart rate. If is produced by hyperpolarization-activated cyclic nucleotide sensitive-4 (HCN4) channels, and it is widely believed that sympathetic regulation of If occurs via direct binding of cAMP to HCN4, independent of phosphorylation. However, we have recently shown that Protein Kinase A (PKA) activity is required for sympathetic regulation of If, and that PKA can directly phosphorylate HCN4.1 In the present study, we examined the effects of a myristoylated PKA inhibitory peptide (myr-PKI) on If in mouse sinoatrial myocytes. We found that myr-PKI and another myristoylated peptide potently and specifically potentiated If via a mechanism that did not involve PKA inhibition and that was independent of the peptide sequence, Protein Kinase C or phosphatidylinositol-4,5-bisphosphate. The off-target activation of If by myristoylated peptides limits their usefulness for studies of pacemaker mechanisms in sinoatrial myocytes