Biomedical subjects

N Poulin

Publications and source records attributed to N Poulin.

27 records · Page 2Linked to original sources

PubMed1994

Reoperation for recurrent temporal lobe epilepsy.

The indications for the risks and outcome of reoperation for medically refractory temporal lobe epilepsy have not been well documented. A retrospective review is presented of 40 patients who underwent reoperation on the temporal lobe for recurrent seizures. The mean patient age at the first operation was 22 +/- 7 years (+/- standard deviation). Electrocorticography during the first operation showed interictal epileptic abnormalities from surface electrodes in 97% of the cases and from depth electrodes in the mesiotemporal structures in 38%. The seizures recurred with the same pattern within 6 months after the first operation in 60% of patients and within 2 years in 90%. Postoperative neuroimaging studies showed residual mesiotemporal structures in all cases. The mean time between the two operations was 5.5 +/- 5 years and the mean patient age at the second operation was 28 +/- 8 years. The second operation involved focal resection of the mesiotemporal structures in 30 cases. The mean postoperative follow-up period was 4.8 +/- 2.7 years (range 2 to 11 years). After the second operation, 63% of the patients were seizure-free or had rare seizures (one or two per year). There were no permanent neurological complications. Patients who did not benefit from reoperation had electroencephalographic abnormalities in multiple brain areas. Reoperation for temporal lobe epilepsy effectively controls seizures in the majority of patients, and the procedure is safe if rigorous technical rules are observed. More complete resection of mesiotemporal structures during the first operation, even in the absence of intraoperative electrographic abnormalities, could prevent the need for reoperation in defined cases.

Adolescent↗

PubMed1991

In vitro fertilization of sheep oocytes matured in vivo.

Incubating washed ram spermatozoa in a modified Brackett's defined medium buffered with Hepes (DM-H) containing 20% of heat-inactivated sheep serum appears to be a reliable method of capacitating sperm for in vitro fertilization. Raising the Ca(++) concentration in the fertilization medium (DM-H-SS) to 10 mM stabilized the fertilization rate of various rams (2). This study was designed to determine if the developmental competence of the oocytes fertilized under such conditions was normal. Thirty-seven ewes, treated with progestagen sponges, were superovulated with porcine follicle stimulating hormone (pFSH: 16 mg). An intramuscular injection of gonadotropin releasing hormone (GnRH: 100 mug); given 24 to 26 h after sponge removal, induced the synchronization of ovulations 24 h later. Ovulated oocytes (n = 229) recovered with flushing of the oviducts were inseminated in vitro and 17 h later either fixed in acetic/alcohol (n = 115) to evaluate fertilization or transferred (n = 114) into 38 synchronized recipients (three oocytes/recipient) to evaluate their developmental competence. Of the fixed oocytes, 82.6% were fertilized and 61.7% were monospermic. Nineteen of the recipient ewes (50%) were pregnant at Day 18, and 16 ewes produced a total of 26 live young (mean: 1.63/ewe). The results showed a high efficiency of in vitro fertilization of ovulated oocytes in sheep following a pFSH-GnRH treatment and the in vivo developmental competence of oocytes fertilized in the presence of elevated Ca(++) concentration.

Journal Article↗

PubMed1990

Effect of season and duration of FSH treatment on embryo production in sheep.

Thirty-six mature Manchega ewes were used in two experiments to determine the effect of season and of 2- or 3-d FSHp treatment on the ovulation rate and number of transferable embryos produced. During the breeding season, estrus was synchronized with FGA (30 mg for 13 d). Beginning 48 or 24 h before sponge removal, each ewe received two daily injections of 4-4-3-3-1-1 or 5-5-3-3 mg of FSHp. Concurrently with the two last injections both groups were administered 100 microg of LH. Ewes were tested for estrus and 6 or 7 d later were laparotomized and surgically flushed to recover embryos. The number of corpora lutea (CL), the total number of embryos and of viable embryos were recorded. Six months later (nonbreeding season) the design was repeated, with each ewe receiving the opposite treatment to that received in the fall. Response in ovulation rate and number of viable embryos did not differ between seasons. Mean (SEM) numbers of observed CL and embryos recovered were higher (P<0.001) with the 3-d treatment (8.7+/-5.8 and 7+/-4.8) than with the 2-d treatment (5.8+/-3.2 and 4.4+/-3) when pooled over the two seasons. The mean number of transferable embryos was higher (P<0.01) with the 3-d (4.2+/-3.9) than with the 2-d treatment (2.5+/-2.3).

Journal Article↗

PubMed1990

Resumption of gonadotrophin release during the post-partum period in suckling and non-suckling ewes.

The post-partum secretion of LH, FSH and prolactin was monitored in 15 suckling and 6 non-suckling Préalpes du Sud ewes lambing during the breeding season by measuring plasma hormone concentrations daily at 6-h intervals and also weekly at 20-min intervals for 6 h from parturition to resumption of regular cyclic ovarian activity. There was a constant phenomenon in the resumption of normal patterns of FSH and LH secretion: there was a rise in FSH values culminating on average on Day 4 post partum and returning subsequently to values observed during the oestrous cycle, and concurrently an increase in the frequency and amplitude of LH pulses more progressive in suckling than in non-suckling ewes which led to an elevation of LH mean concentrations and occurrence of an LH surge. Since neither the FSH secretory pattern nor FSH mean values differed between suckling and non-suckling ewes, the results suggested that LH pulsatile pattern was a major limiting factor for the resumption of normal oestrous cycles. Before regular oestrous cycles resumed other changes in preovulatory LH surges also occurred: (i) they increased in duration and probably in amplitude; (ii) they were preceded by an acceleration in LH pulse frequency and a large decrease in FSH values as in normal cyclic ewes; and (iii) at least in non-suckling ewes they occurred concurrently with a prolactin surge.

Animals↗

PubMed1989

Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes.

In Préalpes de Sud ewes after an autumn lambing, the mean post-partum interval to first LH surge was 10 +/- 1 days and 17 +/- 1 days for non-suckling and suckling ewes, respectively. Post-partum interval to first luteal phase, estimated from plasma progesterone concentrations, was similar in non-suckling and suckling ewes (27 +/- 1 days and 28 +/- 5 days, respectively). Interval to first oestrus was shorter in non-suckling (22 +/- 2 days) than in suckling ewes (35 +/- 2 days) but these first oestrous periods were followed by short luteal phases in 60% (12/20) of non-suckling ewes and in only 7% (2/29) of suckling ewes. Finally, suckling slightly postponed the resumption of the first oestrus followed by a normal oestrous cycle (37 +/- 1 days versus 31 +/- 2 days) because progesterone, essential for oestrus expression, was secreted mainly during normal luteal phases in 70% (21/30) of suckling ewes and during short cycles in 95% (21/22) of non-suckling ewes. Therefore, the primary consequence of suckling is to regulate the conditions of resumption of cyclic ovarian activity after parturition.

Animals↗

PubMed1988

Ovarian capillary blood flow in seasonally anoestrous ewes induced to ovulate by treatment with GnRH.

The microsphere technique was used to obtain estimates of ovarian capillary blood flow near ovulation, in 8 seasonally anoestrous ewes, which were induced to ovulate by GnRH therapy. Plasma progesterone concentrations were monitored in jugular blood sampled between Days 4 and 7 after the onset of the preovulatory LH surge. The ewes were then slaughtered. Three of the ewes were treated with a single injection of 20 mg progesterone before GnRH therapy. In these ewes and 1 other, plasma progesterone values increased after ovulation and reached 1.0 ng/ml on Day 7 following the preovulatory LH surge (normal, functional CL), whilst in the other 4 ewes progesterone concentrations increased initially then declined to 0.5 ng/ml by Day 7 (abnormal CL). In the ewes exhibiting normal luteal function, the mean ovarian capillary blood flow was significantly greater (P less than 0.01) than that for ewes having abnormal luteal function. Irrespective of the type of CL produced, capillary blood flow was significantly greater (P less than 0.05) in ovulatory ovaries than in non-ovulatory ovaries. These findings indicate that the rate of capillary blood flow in ovaries near ovulation may be a critical factor in normal development and maturation of preovulatory follicles and function of subsequently formed CL.

Anestrus↗

PubMed1984

[Progesterone secretion during male-induced cycle in the Creole goat in anestrus: seasonal effects].

Plasma progesterone levels during male-induced ovarian cycles were measured at three periods (March, July, November) in Creole goats. For the females experiencing a cycle of normal duration, plasma progesterone reached 2.0 ng/ml six days after male introduction. For the females experiencing a short cycle, a brief (one day) and slight (0.5 to 1.0 ng/ml) secretion of progesterone was observed during this cycle. A seasonal variation in the interval between male introduction and maximum level of progesterone during the short cycle was demonstrated (March: 4.7 days; July: 5.6 d. and November: 3.1 d.), but the maximum level reached did not vary with season (0.6; 0.9 and 0.6 ng/ml).

Animals↗

PubMed1980

Mental health.

Explore the source record for details and available documents.

Adolescent↗

PubMedDate not supplied

[In vitro oocyte maturation in domestic ruminants].

In vitro maturation represents the first step towards the in vitro production of embryos in domestic species. This production is of great interest from both zootechnic and basic points of view. Beyond nuclear aspects of maturation (progression of meiosis to metaphase II) cytoplasmic aspects confer to oocytes their potential to be fertilized and to develop normally. The culture medium used for maturation could influence this competence. Furthermore, the origin of oocytes (physiologic and genetic status of the oocyte donor, characteristics of the follicle) could also be determinant. The improvement of in vitro maturation techniques will certainly require a better understanding of these different aspects. Additionally, the maintenance of the oocytes in meiotic block during a pre-maturation in vitro culture will allow them to complete the storage of molecules necessary for fertilization and development.

Animals↗