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Biomedical subjects

G Milliken

Publications and source records attributed to G Milliken.

8 recordsLinked to original sources
PubMed2001

Development of porcine embryos in vitro: effects of culture medium and donor age.

We compared development of porcine embryos in three media and evaluated the effect of age of the donor on embryo development in vitro. In Exp. 1, embryos were collected from 35 postpubertal females on d 2 or 3 after onset of estrus. Embryos were cultured 144 h in Whitten's Medium (WM), North Carolina State University Medium-23 (NCSU-23), or Beltsville Embryo Culture Medium-3 (BECM-3) in 95% air: 5% CO2 at 39 degrees C. More (P < 0.01) embryos that were initially one cell or two cells developed to blastocysts when cultured in NCSU-23 (56%) and BECM-3 (43%) rather than in WM (7.5%). More (P < 0.01) embryos that were four cells at recovery developed to blastocysts in NCSU-23 (97%) than in BECM-3 (69%) or WM (69%). Blastocysts that developed from four-cell embryos cultured in BECM-3 had more (P < 0.01) nuclei than blastocysts that developed from four-cell embryos in the other two media. In Exp. 2, ovarian responses, fertilization rates, and in vitro embryo development in NCSU-23 and BECM-3 were compared for postpubertal (approximately 170-d-old) gilts vs gilts given exogenous gonadotropins at 102 d of age. Ovulation rate (P < 0.01), number of eggs recovered, and number of eggs fertilized per gilt (P < 0.001) were greater in the older gilts. The percentage of eggs fertilized, the number of unfertilized eggs, and the number of unclassifiable eggs were similar (P > 0.10) for both age groups. More (P < 0.10) blastocysts developed from embryos recovered from 170-d-old than from 102-d-old gilts, and more (P < 0.05) blastocysts developed in NCSU-23 than in BECM-3. Zona thicknesses and number of nuclei per embryo were similar (P > 0.10) for both ages. We conclude that embryos from prepubertal gilts do not have the same in vitro developmental potential as those from cyclic gilts. However, superior development of embryos in NCSU-23 from both 102-d-old and 170-d-old gilts indicates that media composition did not differentially affect embryos produced by younger vs older gilts.

Age Factors↗
PubMed1997

Effect of stanozolol on body composition, nitrogen balance, and food consumption in castrated dogs with chronic renal failure.

OBJECTIVE: To determine the effect of stanozolol on body composition, nitrogen balance, and food consumption in castrated dogs with chronic renal failure. DESIGN: Blinded crossover trial. ANIMALS: 22 castrated Beagles with experimentally induced chronic renal failure. PROCEDURE: Dogs were divided into 2 groups of 11 dogs each. During each of two 6-week treatment periods, dogs in 1 group received stanozolol, and those in the other group received a control agent. Nitrogen balance, body composition, and food consumption were determined. RESULTS: During administration of stanozolol, the amount of food consumed per dog, lean body mass, and nitrogen balance increased. Stanozolol did not have a significant effect on body fat, bone mineral content, or food consumption per kilogram of body weight. CLINICAL IMPLICATIONS: For dogs with mild-to-moderate, nonuremic, experimentally induced, chronic renal failure, stanozolol had positive effects on nitrogen balance and lean body mass.

Anabolic Agents↗
PubMed1993

Pelvic growth, calf birth weight and dystocia in Holstein x Hereford heifers.

The pelvic area was measured in 129 Holstein x Hereford heifers at 10, 16 and 22 months of age. The heifers were fed an all forage diet. Pelvic growth was not linear over time, changing from an increase of 0.27 +/- 0.2 cm(2)/day during the first 6 months of the study to 0.13 +/- 0.13 cm(2)/day during the last 6 months (P<0.01). The relationship of pelvic area to body weight, height at hooks, and distance from hooks to pins did not change with age, and a moderate correlation between the pelvic area and these other measures (R=0.20 to 0.80) was noted. The pelvic area was measured within 24 hours after calving in 76 of the heifers. The rate of increase of pelvic area/day increased significantly (P < 0.01) in the month prior to calving from 0.14+/-0.13 cm(2) to 1.15 +/- 0.88 cm(2). As a result, the pelvic area at calving had a moderate correlation (R=0.29 to 0.52) to the pelvic area prior to calving. Logistic regression and discriminant analysis techniques were used to model the influence of the pelvic area and calf birth weight on the incidence of dystocia. Ratio of the pelvic area at calving to calf birth weight significantly (P < 0.01) influenced the incidence of dystocia. Logistic regression techniques were not superior to discriminant analysis; both correctly predicted 73% of the cases. Pelvic area measurement at any time other than calving was not associated with dystocia (P >0.05). Pelvic area and calf birth weight are important determinants of dystocia in heifers. The high degree of variation noted in pelvic growth, in particular during the month prior to calving, resulted in low correlation between pelvic area at calving and the precalving measurement. Therefore, we were not able to predict dystocia by measuring the pelvic area prior to calving.

Journal Article↗
PubMed1992

Synthesis of prostaglandins by pig blastocysts cultured in medium containing estradiol or catechol estrogen.

Two experiments were conducted to determine the effects of 2-hydroxy-estradiol-17 beta (2-OH-E2; 0, 50 and 100 microM) and estradiol-17 beta (E2; 0, 25 and 50 microM) on prostaglandin (PG) E and PGF2 alpha synthesis by day-10 pig blastocysts (day 0 is first day of estrus). Blastocysts were incubated in a modified Krebs-Ringer bicarbonate medium, supplemented with bovine serum albumin (4 mg/ml) and the vitamins and amino acids (essential and nonessential) in Minimum Essential Medium (without phenol red or antibiotics). The incubations were conducted at 39 degrees C for three 2-h periods; the second and third periods included an E2 or catechol estrogen treatment. Release of PGF2 alpha into the culture medium decreased (p less than 0.001) linearly with increasing concentrations of 2-OH-E2 in both periods. Release of PGE was not affected by 2-OH-E2, therefore 2-OH-E2 increased (p less than 0.06) the PGE:PGF2 alpha. When E2 was added to the medium, release of PGE was decreased (p less than 0.01) during the second and third periods. Release of PGF2 alpha also was decreased (p less than 0.05) by E2 during period 2, but E2 did not alter the PGE:PGF2 alpha. Content of PGs in blastocysts at recovery was less than 10% of the PGs released in vitro. Therefore, these studies demonstrate effects of both the primary and catechol forms of E2 on the synthesis of PGE and PGF2 alpha. Catechol estrogens and E2 may inhibit PG synthesis and modify the PGE:PGF2 alpha during the establishment of pregnancy in pigs.

Animals↗
PubMed1990

In vitro synthesis of prostaglandin E and F2 alpha by pig endometrium in the presence of estradiol, catechol estrogen and ascorbic acid.

These experiments were undertaken to determine the potential for estradiol-17 beta (E2), 2-hydroxyestradiol-17 beta (2-OH-E2) and 4-hydroxyestradiol-17 beta (4-OH-E2) to regulate prostaglandin (PG) E and F2 alpha synthesis by pig endometrium. Endometrium was collected from pigs on d 10 of pregnancy and incubated (15 to 20 mg/well) for three 2-h periods in 2 ml of medium in 24-well culture plates. At the end of each period, the medium was removed and frozen. Later media were thawed and assayed for PGE and PGF2 alpha. During Periods 2 and 3, the medium contained 0, 25, 50, 100 or 150 microM 2-OH-E2 (Exp. 1); 0, 25 or 50 microM 4-OH-E2 (Exp. 2); or 0, 25 or 50 microM E2 (Exp. 3). Each experiment was a factorial with 2-OH-E2, 4-OH-E2 or E2 as one main effect and 0 or 1 mM ascorbate as a second main effect. Ascorbate decreased (P less than .01) PGE and PGF2 alpha release in all experiments. Two-hydroxyestradiol-17 beta decreased (P less than .01) PGE and PGF2 alpha release into the medium during Periods 2 and 3 in a dose-dependent manner (Exp. 1). In Exp. 2, 4-OH-E2 decreased (P less than .07) endometrial release of PGE and PGF2 alpha in Periods 2 and 3 and increased (P less than .01) the PGE:PGF2 alpha in Period 3. In Exp. 3, E2 decreased release of PGE during Period 3 and PGF2 alpha release during Period 2. The PGE:PGF2 alpha was not altered by E2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Pig blastocyst development in vitro is affected by amino acids.

Pig embryos were removed 5 d after onset of estrus and cultured in modified Krebs-Ringer bicarbonate (mKRB) medium containing bovine serum albumin (BSA; 1 mg/ml). Media in Exp. 1 and 2, but not in Exp. 3, contained 10% heat-inactivated lamb serum (LS). In Exp. 1, embryos were cultured in 1) mKRB + LS or mKRB + LS supplemented with 2) glutamine (2 mM); 3) phenylalanine (.1 mM), methionine (.05 mM) and isoleucine (.2 mM); or 4) phenylalanine, methionine, isoleucine and glutamine. Embryos cultured in media with supplemental phenylalanine, methionine and isoleucine attained larger (P less than .05) volumes during culture and initiated hatching at an increased (P less than .05) frequency compared with embryos cultured without additional amino acids. In contrast, adding glutamine depressed (P less than .05) the maximum volumes observed during culture. In Exp. 2 mKRB + LS was compared with mKRB + LS plus phenylalanine (.1 mM), methionine (.05 mM) and isoleucine (.2 mM); methionine and isoleucine; phenylalanine and isoleucine, or phenylalanine and methionine. Embryos cultured in media supplemented with phenylalanine and methionine attained larger (P less than .05) volumes than embryos cultured in either media without added methionine. Fewer (P less than .05) embryos cultured without methionine initiated hatching (56%) compared with embryos provided methionine (89%). In Exp. 3, we evaluated the addition of glutamine (1 mM) with or without phenylalanine (.1 mM), methionine (.05 mM) and isoleucine (.2 mM) to serum-free mKRB. Adding glutamine alone, but not in combination, increased (P less than .05) blastocyst volumes on d 3 and maximum volume attained during culture compared with embryos cultured in mKRB alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1980

A segmented line regression procedure to describe growth in beef cows.

Three segmented linear regression lines were fitted simultaneously to regress weight of Polled Hereford female cattle on age. Resulting parameter estimates from the procedure measure size and rates of gain. Sire and year of birth had the greatest effects on growth traits before growth rate slowed when heifers were approximately 17 months of age but had less effect in later life. Genetic correlations between weights at all ages were positive, as were genetic correlations between degrees of maturity at all ages. Animals taking longer to reach mature weights had greater mature weights. Degree of maturity and weight were positively correlated at a given age, but changed to negative as the age interval between weight and degree of maturity increased. Animals more mature at any age grew slower until they reached full maturity.

Animals↗