The effect of maternal nutrition level during the periconception period on fetal muscle development and plasma hormone concentrations in sheep.

The effect of maternal nutrition level during the periconception period on the muscle development of fetus and maternal-fetal plasma hormone concentrations in sheep were examined. Estrus was synchronized in 55 Karayaka ewes and were either fed ad libitum (well-fed, WF, n=23) or 0.5×maintenance (under-fed, UF, n=32) 6 days before and 7 days after mating. Non-pregnant ewes (WF, n=13; UF, n=24) and ewes carrying twins (WF, n=1) and female (WF, n=1; UF, n=3) fetuses were removed from the experiment. The singleton male fetuses from well-fed (n=8) and under-fed (n=5) ewes were collected on day 90 of gestation and placental characteristics, fetal BWs and dimensions, fetal organs and muscles weights were recorded. Maternal (on day 7 after mating) and fetal (on day 90 of pregnancy) blood samples were collected to analyze plasma hormone concentrations. Placental characteristics, BW and dimensions, organs and muscles weights of fetuses were not affected by maternal feed intake during the periconception period. Maternal nutrition level did not affect fiber numbers and the muscle cross-sectional area of the fetal longissimus dorsi (LD), semitendinosus (ST) muscles, but the cross-sectional area of the secondary fibers in the fetal LD and ST muscles from the UF ewes were higher than those from the WF ewes (P<0.05). Also, the ratio of secondary to primary fibers in the ST muscle were tended to be lower in the fetuses from the UF ewes (P=0.07). Maternal nutrition level during the periconception period did not cause any significant changes in fetal plasma insulin and maternal and fetal plasma IGF-I, cortisol, progesterone, free T3 and T4 concentrations. However, maternal cortisol concentrations were lower while insulin concentrations were higher in the WF ewes than those in the UF ewes (P<0.05). These results indicate that the reduced maternal feed intake during the periconception period may alter muscle fiber diameter without affecting fiber types, fetal weights and organ developments and plasma hormone concentrations in the fetus.

The effect of maternal nutritional status during mid-gestation on placental characteristics in ewes.

The aim of this study was to determine the effects of maternal nutritional status during mid-gestation on placental characteristics in ewes. Time of estrus of 3-5 years old Karayaka breed ewes was synchronized and mating was monitored to determine the day 0 of gestation. The ewes had similar body weights (47.8±0.7kg) and loin eye muscle values (thickness; 20.9±1.0mm and fat thickness; 4.7±0.5mm) at mating. The ewes were allocated into two treatment groups at day 30 of gestation; under-fed (UF; n=12) and well-fed (WF; n=13) groups. The ewes in UF group were fed with a diet to provide 50% of their daily requirement from day 30 to day 80 of gestation and 100% of their daily requirement during the rest of the gestation period. The ewes in WF group were fed at least 100% of their daily requirement throughout gestation. The singleton bearing ewes in the UF group had a lesser (P<0.05) placental weight (354.1 compared with 378.3g), average cotyledon weight (1.50 compared with 1.82g) and lamb birth weight (3.8 compared with 4.2kg) than singleton bearing ewes in the WF group. There were positive correlations between placental weight and lamb birth weight (r=.469; P<0.05), placental weight and average cotyledon weight (r=.695; P<0.01), average cotyledon weight and lamb birth weight (r=.742; P<0.01) and placental efficiency and cotyledon density (r=.853; P<0.01) for ewes in WF group. Additionally, the pattern of weight gain/loss was different (P<0.05) between the two groups. Ewes in UF group lost body weight progressively from day 30 of gestation until day 80. The results of present study show that under-feeding of ewes during mid-gestation may cause an insufficient placental development and hence alter fetal development resulting in a reduced birth weight from singleton pregnancies.

Development, amino acid utilization and cell allocation in bovine embryos after in vitro production in contrasting culture systems.

The effects of protein-supplemented and protein-free media on amino acid uptake, protein synthesis and cell differentiation in bovine blastocysts were investigated. Four formulations of synthetic oviduct fluid were used. Each formulation was identified by the principal supplement: bovine serum albumin (0.4%, w/v); polyvinyl alcohol (0.3%, w/v); or either of two steer sera (10%, v/v). After zygote culture, blastocyst yields (day 7.5) were lowest in protein-free medium and highest in albumin-supplemented medium. Subsequent 12 h incubation in the presence of both essential and non-essential amino acids was used for the measurement of amino acid flux. All blastocysts released alanine but consumed aspartate (P < 0.001) and the extent was influenced by prior culture conditions. Aspartate uptake was lower in blastocysts produced in protein-free conditions (P < 0.05) than in blastocysts produced in albumin-supplemented conditions. Consumption indices for 16 other amino acids were not influenced by blastocyst source. Cell counts and hatching incidences were highest for albumin-supplemented blastocysts, but were similar among blastocysts from the protein-free and serum-dependent treatments. Crucially, the use of protein-free medium for zygote culture did not compromise resultant blastocysts in terms of either de novo protein synthesis ([3H]phenylalanine incorporation) or trophectoderm function (phenotype based on interferon-tau detection). Thus, although blastocyst yields were compromised after zygote culture in a protein-free (vis-à-vis albumin-supplemented) medium, amino acid flux was qualitatively conserved, and only quantitatively modified in the case of alanine and aspartate. Moreover, vital properties of blastocysts that were produced, including de novo protein synthesis and trophectodermal cell function, apparently were not adversely affected by protein deprivation.

Development and de novo protein synthetic activity of bovine embryos produced in vitro in different culture systems.

In vitro matured (IVM) and fertilized (IVF) putative Day 1 zygotes (Day 0 = IVF) were allocated randomly to culture in formulations based on Synthetic Oviduct Fluid (SOF) medium and identified on the basis of their contrasting principal supplements, which were 10% v/v steer serum (SS; n = 558) or 4 mg/mL crystalline BSA (SBSA; n = 531) or 3 mg/mL polyvinyl alcohol (SPVA; n = 607) in 9 replicates. SBSA and SPVA also contained 10 microg/mL non-essential amino acids, while the former was further supplemented with 20 microL/mL essential amino acids and the latter with 0.5 mmol/L sodium citrate and 5 ng/mL epidermal growth factor. Zygotes were cultured in 20 microL drops (4 zygotes per drop) until Day 8 in an atmosphere of 5% CO2, 5% O2 and 90% N2 at 39 degrees C and droplets were renewed every 48 hours. The incidence of zygote cleavage was lower (P < 0.05) in SS (mean +/- SEM = 61 +/- 3%) than in SBSA (76 +/- 3%) but not in SPVA (72 +/- 4%) up to Day 3. The SPVA generated a lower yield of blastocysts on Day 7 (12 +/- 2%; P < 0.001) and by Day 8 (21 +/- 4%; P < 0.01) than did SS (33 +/- 3%; 40 +/- 3%) and SBSA (30 +/- 3%; 37 +/- 4%). Cell numbers (n) and diameters (d) of blastocysts on Day 8 were greater (P < 0.001; Replicates 1 to 5) in embryos from SBSA (n, 156 +/- 9; d, 203 +/- 4 microm) than in those from SS (n, 81 +/- 4; d, 177 +/- 3 microm) and SPVA (n, 76 +/- 5; d, 167 +/- 3 microm). Embryos produced in SS incorporated less 3H-phenylalanine into PCA-precipitable protein (replicates 6 to 9; log10 dpm = 3.03 +/- 0.04) than did embryos cultured in SBSA (3.21 +/- 0.03; P < 0.001) or in SPVA (3.14 +/- 0.03; NS). In conclusion, blastocyst yield was poor in SPVA, but the embryos had metabolic activities similar to those of embryos produced in SBSA. Blastocyst yields from SS were not compromised but their capacity for de novo protein synthesis was reduced significantly.

Nitrogen metabolism and fertility in cattle: II. Development of oocytes recovered from heifers offered diets differing in their rate of nitrogen release in the rumen.

In vitro blastocyst production was determined for oocytes recovered postmortem from 48 beef x dairy heifers offered low (Low NH3) or high (High NH3) plasma ammonia-generating diets during the period of late antral follicle development. Following the establishment of a reference estrus (d 0), the experimental diets were offered for an 18-d period starting on d 3 and during which a second estrus was induced (d 16) 4 d before the animals were slaughtered. Blood samples collected at varying intervals were analyzed for ammonia, urea, progesterone, and LH. Ovarian folliculogenesis was monitored daily by transrectal ultrasonography. Ovaries were collected at slaughter and cumulus-oocyte complexes were aspirated from small (1 to 4 mm) and medium-sized (> 4 to 8 mm) sized follicles. In vitro-matured and -fertilized putative d-1 zygotes were cultured for a further 7 d in vitro and embryo development and metabolism were assessed. Relative to the low-NH3-generating diet, the high-NH3-generating diet increased peak postprandial levels of plasma ammonia (326.1 +/- 43.3 vs 52.1 +/- 7.4 micromol/L; P < .001), mean levels of plasma urea (7.0 vs 5.7 mmol/L; SED = .2; P < .001), peak levels of plasma progesterone prior to induced luteolysis (8.9 +/- .4 vs 6.8 +/- .3 microg/L; P < .001), and follicular fluid levels of ammonia (267 +/- 18 vs 205 +/- 20 nmol/mL; P < .05) and progesterone (351 +/- 69 vs 199 +/- 26 ng/mL; P < .05). The timing and level of the preovulatory LH surge was not affected by dietary treatment. Of oocytes cultured, cleavage (47.4 vs 62.4%; P = .02) and blastocyst production (10.9 vs 20.6%; P = .06) rates were reduced when the oocytes were derived from heifers offered the high- rather than the low-NH3-generating diets. There were interactions between dietary treatment and follicle size class, which indicated that fewer blastocysts were produced from cleaved oocytes derived from medium-sized follicles of heifers offered the high-NH3 treatment but that de novo protein synthesis was increased in such embryos. In conclusion, exposure to high levels of ammonia and(or) urea in vivo can significantly compromise the subsequent capacity of oocytes to develop to blastocysts in vitro, and oocytes recovered from medium-sized follicles are particularly sensitive to this effect.

The response of bovine granulosa cells to different gonadotrophins in culture.

Previous studies with bovine granulosa cells cultured in vitro indicated that follicle-stimulating hormone (FSH) stimulated differentiation and progesterone production of granulosa cells in a dose-dependent manner, this was due mainly to an increase in the number of differentiated cells. The objectives of the present study were to investigate (1) whether the response of bovine granulosa cells in culture to luteinising hormone (LH) and equine chorionic gonadotrophin (eCG) was similar to the response to FSH, and (2) whether granulosa cells derived from different cattle breeds responded similarly to gonadotrophin stimulation. Pairs of ovaries were recovered postmortem from Charolais (38) and Hereford (41) crossbred post-pubertal heifers, and granulosa cells were aspirated from 5-8 mm follicles. In two simultaneous experiments, granulosa cells (2-3 x 10(5) viable cells) were cultured with different gonadotrophins (oFSH or oLH in Experiment 1; oFSH or eCG in Experiment 2). Cell culture was for 4 days at 37 degrees C in a humidified atmosphere of 5% CO2 in air in 1 ml of serum-free culture medium. Progesterone production, total DNA and the protein content of granulosa cells on Day 4 of culture were determined. Log10 data were analyzed by analysis of variance and multiple linear regression. In Experiment 1, both FSH and LH stimulated progesterone production (ng microgram-1 DNA) and protein content (microgram microgram-1 DNA) of granulosa cells in a dose-dependent manner (P < 0.01). The relative potencies of FSH to LH (milli micron/milli micron) were found not to be different from unity. In Experiment 2, progesterone production and the protein content of granulosa cells were stimulated by both FSH and eCG in a dose-dependent manner (P < 0.001). The progesterone response curves (log/log) were linear up to 1-10 milli microns FSH and 1-10 iu eCG, and were Y = 1.67 + 0.093 FSH and Y = 1.60 + 0.091 eCG for progesterone production. Calculated on a milli micron/iu basis, FSH was found to be 5.8 times more potent than eCG (P < 0.05) in terms of stimulating progesterone production. Granulosa cells derived from Hereford crosses were more sensitive (P < 0.001) than those from Charolais crosses to gonadotrophin stimulation (31 and 42 times for FSH and eCG, respectively, in terms of progesterone production, and 4.8 and 3.1 times for FSH and eCG, respectively, in terms of protein content). The response curves for both FSH and eCG were similar within each breed. The slopes of the progesterone response curves, and the protein responses were similar for all the gonadotrophins. In conclusion, these results imply that FSH; LH and eCG have similar effects on the differentiation and progesterone production of bovine granulosa cells from 5-8 mm follicles cultured in vitro. Furthermore, granulosa cells from different breeds cultured in vitro had different sensitivities to gonadotrophin stimulation.

Bovine granulosa cell culture for assessment of potency and specificity of antibodies to pregnant mares' serum gonadotrophin.

Antibodies to pregnant mares' serum gonadotrophin (PMSG) neutralize the effect of PMSG in vivo and increase the number of transferable embryos when administered at the optimum time relative to the preovulatory luteinizing hormone (LH) surge in PMSG-stimulated cows. The objective of the present study was to investigate the possible use of bovine granulosa cells in a serum-free culture system as a bioassay for antibodies to PMSG. Granulosa cells (2-3 x 10(5) viable cells) were cultured with varying doses of PMSG and/or an anti-PMSG for 4 days. Whilst progesterone production (ng/micrograms DNA) of granulosa cells was stimulated by PMSG (p < 0.01) in a dose-dependent manner, increasing amounts of anti-PMSG neutralized (p < 0.01) this stimulatory effect of either follicle-stimulating hormone or LH on progesterone production of bovine granulosa cells in vitro. The bovine granulosa cell culture system is a potential in vitro bioassay method for testing the specificity and the neutralizing capacity of different anti-PMSG preparations.

[Nurses' role in primary health care]. / Temel saglik hizmetlerinde hemsirenin rolü.

PIP: 2 nurses describe the duties which nurses should assume in primary health care, particularly as practiced in rural areas, in prize-winning articles from a contest sponsored by the Turkish Ministry of Health and Social Services. Both articles argue that primary health care, an internationally recognized human right, is an indispensible factor in national development. As a national investment, it helps reduce clinical treatment costs. The ministry-appointed health care nurses, who are in the forefront of the development of primary health care programs, must be well-trained and skilled in problem solving in order to be able to effectively recruit local cooperation. They might try to cultivate the interest of locally elected or appointed leaders in their objectives. This, in turn, might expedite the process of stimulating popular awareness of the problems. However, both writers agree that nurses receive insufficient material means and legal authority. The quality and effectiveness of the services nurses could provide depend on stable, predictable and sufficient funding. In general, nurses and related health care professionals need to be better equipped. They need the skills to communicate with local people in an accurate and helpful manner and the knowledge to set examples which contradict traditional practices; they must also conduct research into the causes of regionally occurring illnesses and refer people to proper medical institutions. Both writers conclude that nurses should be spared the many obstacles impeding their efforts at making a population aware of preventive medicine practices, and capable of implementing health care solutions.^ieng