Relative expression of insulin like growth factor I (IGFI) and follicle stimulating hormone receptor (FSHR) in follicles and ovarian tissue from Bos primigenius indicus (Nelore)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrasonographic and endocrine aspects of follicle deviation, and acquisition of ovulatory capacity in buffalo (Bubalus bubalis) heifers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Force system evaluation of symmetrical beta-titanium T-loop springs preactivated by curvature and concentrated bends

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Follicle deviation and ovulatory capacity in Bos indicus heifers

The objectives of Experiment I were to determine the interval from ovulation to deviation, and diameter of the dominant follicle (DF) and largest subordinate follicle (SF) at deviation in Nelore (Bos indicus) heifers by two methods (observed and calculated). Heifers (n = 12) were examined ultrasonographically every 12 h from ovulation (Day 0) to Day 5. The time of deviation and diameter of the DF and largest SF at deviation did not differ (P > 0.05) between observed and calculated methods. Overall, deviation occurred 2.5 +/- 0.2 d (mean +/- S.E.M.) after ovulation, and diameters for DF and largest SF at deviation were 6.2 +/- 0.2 and 5.9 +/- 0.2 mm, respectively. Experiment 2 was designed to determine the size at which the DF acquires ovulatory capacity in B. indicus heifers. Twenty-nine heifers were monitored every 24 h by ultrasonography, from ovulation until the DF reached diameters of 7.0-8.4 mm (n = 9), 8.5-10.0 mm (n = 10), or >10.0 mm (n = 10). At that time, heifers were treated with 25 mg of pLH and monitored by ultrasonography every 12 h for 48 h. Ovulation occurred in 3 of 9, 8 of 10, and 9 of 10 heifers, respectively (P < 0.05). In summary, there was no significant difference between observed and calculated methods of determining the beginning of follicle deviation. Deviation occurred 2.5 d after ovulation when the DF reached 6.2 mm, and ovulatory capacity was acquired by DF as small as 7.0 mm. (c) 2008 Elsevier B.V. All rights reserved.

Effect of follicle size on mRNA expression in cumulus cells and oocytes of Bos indicus: an approach to identify marker genes for developmental competence

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

FGF10 inhibits dominant follicle growth and estradiol secretion in vivo in cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biological shape analysis by digital curvature

This paper reports the novel application of digital curvature as a feature for morphological characterization and classification of landmark shapes. By inheriting several unique features of the continuous curvature, the digital curvature provides invariance to translations, rotations, local shape deformations, and is easily made tolerant to scaling. In addition, the bending energy, a global shape feature, can be directly estimated from the curvature values. The application of these features to analyse patterns of cranial morphological geographic differentiation in the rodent species Thrichomys apereoides has led to encouraging results, indicating a close correspondence between the geographical and morphological distributions. (C) 2003 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved.

Follicle profile and plasma gonadotropin concentration in pubertal female ponies

Twelve female ponies were examined daily for 30 days and classified as ovulating (OV; N = 6; 197 ± 6 kg) or prepubertal (PP; N = 6; 196 ± 9 kg). Follicles were detected by ultrasound and gonadotropins quantified by radioimmunoassay. The mean diameter of the largest follicles was significantly larger in OV (38 ± 1 mm) than in PP (26 ± 2 mm) but there was no difference between groups in the size of the second largest follicle. There were more small follicles (<24 mm) in the PP than in the OV group, but PP fillies had a smaller number of follicles >29 mm than the OV fillies. Follicle-stimulating hormone (FSH) levels did not differ between groups but PP fillies had lower luteinizing hormone (LH) peak (8 ± 1 ng/ml) and basal (4 ± 0.5 ng/ml) levels, lower peak magnitude (2 ± 0.2 ng/ml) and period average (5 ± 0.6 ng/ml) than OV fillies (32 ± 4.5, 8 ± 1.2, 17.1 ± 6, and 15 ± 2.3 ng/ml, respectively). The PP group, in contrast to the OV group, showed no relationship between FSH surge and follicle wave emergence. We conclude that an LH concentration higher than 8 ng/ml is needed for follicle growth to a preovulatory size. Wave emergence and FSH secretion seem to be independent events, probably due to an inhibitory neural system in these PP animals. PP fillies may provide a physiological model for the study of follicle wave emergence which apparently does not depend on gonadotropin levels.

Effects of varying curvature and width on the electronic states of GaAs quantum rings

Stationary states of an electron in thin GaAs elliptical quantum rings are calculated within the effective-mass approximation. The width of the ring varies smoothly along the centerline, which is an ellipse. The solutions of the Schrödinger equation with Dirichlet boundary conditions are approximated by a product of longitudinal and transversal wave functions. The ground-state probability density shows peaks: (i) where the curvature is larger in a constant-with ring, and (ii) in thicker parts of a circular ring. For rings of typical dimensions, it is shown that the effects of a varying width may be stronger than those of the varying curvature. Also, a width profile which compensates the main localization effects of the varying curvature is obtained.

Dynamics of follicle populations and gonadotropin concentrations in fillies age two to ten months

Follicle populations and concentrations of circulating gonadotropins were studied during age 2-10 months in 10 spring-born pony fillies. Blood sampling and ultrasound scanning were done every 4 days and daily for four 30 day periods. During 5-12 weeks, FSH concentrations were lower in 6 fillies with follicles greater than or equal to 6 mm (mean +/- s.e. 1.4 +/- 0.1 ng/ml) than in 4 fillies with follicles <6 mm (2.8 + 0.3 ng/ml). The diameters and numbers of follicles and gonadotropin concentrations increased progressively during age 2-4 months. A plateau in follicle activity and reduced levels of gonadotropins occurred during 5-7 months. During 8-10 months, follicles grew to >10 mm and gonadotropin concentrations increased. Waves of follicular growth were identified during the 30 day periods by significant increases in the diameter of the 10 largest follicles. The waves did not partition into dominant and subordinate follicles. Results indicated an initial postnatal period of negative ovarian feedback, temporally related changes in gonadotropins and follicles for months 3-10, and development of follicles in waves.

Reduction in size of the ovulatory follicle reduces subsequent luteal size and pregnancy rate

We hypothesized that reducing the size of the ovulatory follicle using aspiration and GnRH would reduce the size of the resulting CL, reduce circulating progesterone concentrations, and alter conception rates. Lactating dairy cows (n=52) had synchronized ovulation and AI by treating with GnRH and PGF(2 alpha) as follows: Day -9, GnRH (100 mug); Day -2, PGF(2 alpha) (25 mg); Day 0, GnRH (100 mug); Day 1, AI. Treated cows (aspirated group; n=29) had all follicles > 4 mm in diameter aspirated on Days -5 or -6 in order to start a new follicular wave. Control cows (nonaspirated group; n=23) had no follicle aspiration. The size of follicles and CL were monitored by ultrasonography. The synchronized ovulation rate (ovulation rate to second GnRH injection; 42/52=80.8%) and double ovulation rate of synchronized cows (6/42=14.3%) did not differ (P > 0.05) between groups. Aspiration reduced the size of the ovulatory follicle (P < 0.0001; 11.5 +/- 0.2 vs 14.5 +/- 0.4 mm), and serum estradiol concentrations at second GnRH treatment (P < 0.0002; 2.5 +/- 0.4 vs 5.7 +/- 0.6 pg/mL). The volume of CL was less (P < 0.05) for aspirated than nonaspirated cows on Day 7 (2,862 +/- 228 vs 5,363 +/- 342 mm(3)) or Day 14 (4,652 +/- 283 vs 6,526 +/- 373 mm(3)). Similarly, serum progesterone concentrations were less on Day 7 (P < 0.05) and Day 14 (P < 0.10) for aspirated cows. Pregnancy rate per AI for synchronized cows was lower (P < 0.05) for aspirated (3/21=14.3%) than nonaspirated (10/21=47.6%) cows. In conclusion, ovulation of smaller follicles produced lowered fertility possibly because development of smaller CL decreased circulating progesterone concentrations. (C) 2001 by Elsevier B.V.