Sperm abnormalities in post-thawed semen of Tunisian Arab stallions.

The study was undertaken in order to evaluate sperm morphology features of post-thawed semen of Tunisian Arab stallions. Forty two ejaculates was collected and frozen, during years 2009 and 2010, from 9 stallions aged between 9 to 24 years. After thawing, sperm morphology was studied after eosin-nigrosin stain. The percentages of abnormal head, mid piece, flagella, sperm with droplets and the total abnormal sperm were determined. Analysis of variance was carried out using SAS software. The results showed that all sperm morphology features varied among ejaculates within stallion and among stallions (p<0.01). The percentage of abnormal flagella and total abnormal sperm varied between young and old stallions (p<0.01). We concluded that freezing and thawing processes increased abnormal sperm that is due to cell alteration for old and young stallions, and consequently, the decrease of the quality of the thawed semen of Tunisian Arab stallions.

Kisspeptin synchronizes preovulatory surges in cyclical ewes and causes ovulation in seasonally acyclic ewes.

We determined whether kisspeptin could be used to manipulate the gonadotropin axis and ovulation in sheep. First, a series of experiments was performed to determine the gonadotropic responses to different modes and doses of kisspeptin administration during the anestrous season using estradiol-treated ovariectomized ewes. We found that: 1) injections (iv) of doses as low as 6 nmol human C-terminal Kiss1 decapeptide elevate plasma LH and FSH levels, 2) murine C-terminal Kiss1 decapeptide was equipotent to human C-terminal Kiss1 decapeptide in terms of the release of LH or FSH, and 3) constant iv infusion of kisspeptin induced a sustained release of LH and FSH over a number of hours. During the breeding season and in progesterone-synchronized cyclical ewes, constant iv infusion of murine C-terminal Kiss1 decapeptide-10 (0.48 mumol/h over 8 h) was administered 30 h after withdrawal of a progesterone priming period, and surge responses in LH occurred within 2 h. Thus, the treatment synchronized preovulatory LH surges, whereas the surges in vehicle-infused controls were later and more widely dispersed. During the anestrous season, we conducted experiments to determine whether kisspeptin treatment could cause ovulation. Infusion (iv) of 12.4 nmol/h kisspeptin for either 30 or 48 h caused ovulation in more than 80% of kisspeptin-treated animals, whereas less than 20% of control animals ovulated. Our results indicate that systemic delivery of kisspeptin provides new strategies for the manipulation of the gonadotropin secretion and can cause ovulation in noncyclical females.

Differential estradiol requirement for the induction of estrus behavior and the luteinizing hormone surge in two breeds of sheep.

For a better understanding of the mechanisms that lead to the preovulatory GnRH/LH surge and estrus behavior, the minimum estradiol (E) requirements (dose and duration) to induce each of these events were determined and compared between two breeds of ewes having either single (Ile de France) or multiple (Romanov) ovulations. The ewes were initially studied during a natural estrus cycle, and were then ovariectomized and run through successive artificial estrus cycles. For these artificial cycles the duration and amplitude of the follucular phase E increase were manipulated by E implants. Under all conditions, the onset of estrus behavior was similar in the two breeds, although its duration was longer in Romanov ewes. While a moderate E signal (6 cm for 12 h) induced an LH surge in 10/10 Ile de France ewes, a larger E signal (12 cm for 12 h) was minimally effective in Romanov ewes (4/10). Additional studies revealed that a small E signal (3 cm for 6 h) induced full estrus behavior in all Romanov ewes but was completely ineffective in Ile de France animals (0/10). Higher doses and mostly longer durations of the E signal (12 cm for 24 h) were required to induce a surge in all the Romanov ewes. These results demonstrate a clear difference in the E requirement for the induction of estrus behavior and the LH surge between breeds of ewes that have different ovulation rates. These data provide compelling evidence that, in one breed, the neuronal systems that regulate both events require different estrogen signals.

Effects of portal triad clamping on haemodynamic conditions during laparoscopic liver resection.

To evaluate the haemodynamic effects of portal triad clamping (PTC) during laparoscopic liver resection, 10 patients without cardiac disease were studied by invasive monitoring including a pulmonary artery catheter and were compared with a control group of 10 patients undergoing liver resection by laparotomy. During laparoscopic surgery, intra-abdominal pressure was kept below 14 mm Hg and minute ventilation was adjusted to prevent hypercapnia. Measurements were made before PTC (T1), 5 min after PTC (T2) and 5 min after clamp release (T3). During clamping with pneumoperitoneum, mean arterial pressure (MAP) remained stable (+2%; not significant), systemic vascular resistance (SVR) increased by 37% (P<0.01, T2 vs T1) and cardiac index (CI) decreased by 19% (P<0.01, T2 vs T1). During laparotomy and clamping, MAP increased by 18% (P<0.01, T2 vs T1), SVR increased by 36% (P<0.01, T2 vs T1) and CI decreased by 9% (not significant). We were unable to demonstrate a difference in haemodynamic changes during clamping with pneumoperitoneum vs the open surgical technique, but in a small number of patients this lack of difference could have been a result of inadequate statistical power. The haemodynamic changes that we found were well tolerated in these patients, who had normal cardiac function.