Survey on the concentrations of hormones (estradiol-17 beta, progesterone, testosterone) in bovine muscles

Natural sex hormones, estradiol-17 beta (EST), progesterone (PRO) and testosterone (TES), in sixty domestic bovine muscles and forty bovine muscles imported from USA and Australia were determined by radioimmunoassay. The EST, PRO and TES levels (mean +/- standard deviation) in domestic samples (n = 60) was 1.15 +/- 1.87 ppt, 3.19 +/- 5.80 ppb and 30.9 +/- 122.1 ppt on a whole basis, respectively. The hormone levels in muscles was presumed to reflect sex, estrous cycle, and so on. The hormone levels in imported bovine muscles (n = 40) were 3.33 +/- 2.83 ppt (EST), 0.52 +/- 0.50 ppb (PRO) and 8.8 +/- 13.0 ppt (TES), respectively.     

Use of concentrations of progesterone and estradiol-17 beta in milk in monitoring postpartum ovarian function in dairy cows

Data from artificial insemination, rectal palpation, and hormone assays were used to characterize postpartum reproductive activity in 54 dairy cows. Progesterone and estradiol-17 beta were measured in milk samples collected for 120 d (Trial 1) or 65 d (Trial 2). Progesterone was higher and estradiol was lower in milk than in serum. Values for both hormones in milk were highly correlated with those in serum. Most cows (64%) had short first luteal phases (less than or equal to 12 d). First rise (28 d) in progesterone was later (33.4 vs. 24.9 d) for cows having short rather than normal (greater than 12 d) luteal phases. Cows were classified as having a short luteal phase followed by a normal luteal phase or as having normal luteal phases for the first two estrous cycles. Estradiol for the 6 d prior to each luteal phase was higher preceding the second phase than the short phase or those preceding both phases of cows with normal phases. Follicular function prior to ovulation, as measured by estradiol, was not responsible for short-lived corpora lutea. Concentrations of progesterone in milk in the late luteal phase prior to insemination were related to fertility.     

Effects of ovarian follicle ablation on FSH, oestradiol and inhibin A concentrations and growth of other follicles in sheep

The aim of this study was to examine the effect of removal of the largest follicle or all visible follicles during the first follicle wave on subsequent follicular growth, steroid, inhibin A and gonadotrophin secretion in sheep. On day 4.5 of a synchronized oestrous cycle, ewes (n = 18) were assigned to one of three groups which underwent either no treatment (control), ablation of the largest follicle (largest follicle aspirated and cauterized via laparotomy) or ablation of all follicles (all visible follicles ablated). Between day 0 and day 10 of the oestrous cycle, blood samples were collected every 8 h and ovaries were examined daily using transrectal ultrasonography. The lifespan of the second largest follicle (number of days > 3 mm in diameter) was longer (6.7 +/- 0.9 days; P < 0.05) and the maximum diameter tended to be greater (4.8 +/- 0.3 mm; P = 0.07) in ewes in which the largest follicle was ablated than in the control ewes (3.8 +/- 0.4 days; 4.2 +/- 0.3 mm). There was no difference in the day of emergence of the second follicular wave between groups (day 6.9 +/- 0.4). However, the peak of the transient increase in FSH concentrations after ablation was earlier (day 5.67 +/- 0.15; P < 0.05) in ewes in which all follicles were ablated than in control ewes (day 6.72 +/- 0.36); the timing in ewes that had only the largest follicle ablated was intermediate (day 6.11 +/- 0.28). Serum inhibin A concentrations were about three-fold lower (P < 0.05) in both follicle ablation groups than in the control group. The numbers of follicles 2-3 mm in diameter during the first 3 days of the second follicular wave were greater in 'ablated ewes' (both groups had 2.6 +/- 0.2 follicles day-1) than in control ewes (1.7 +/- 0.3 follicles day-1). It is concluded that: (i) transient increases in FSH concentrations precede the emergence of follicle waves; (ii) ablation of all follicles on day 4.5 after oestrus advanced the timing of the next peak in FSH concentrations and the numbers of small follicles associated with the development of the second follicular wave; and (iii) ablation of the largest follicle resulted in an increase in the lifespan of the second largest follicle, indicating a regulatory role of large dominant follicles over smaller subordinate follicles.     

Expression and localisation of extracellular matrix degrading proteases and their inhibitors during the oestrous cycle and after induced luteolysis in the bovine corpus luteum

The corpus luteum (CL) offers the opportunity to study high proliferative processes during its development and degradation processes during its regression. We examined the mRNA expression of matrix metalloproteases (MMP)-1, MMP-2, MMP-9, MMP-14, MMP-19, tissue inhibitor of MMP (TIMP)-1, TIMP-2, tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), uPA-receptor (uPAR), PA-inhibitors (PAI)-1, PAI-2 in follicles 20 h after GnRH application, CLs during days 1-2, 3-4, 5-7 and 8-12 of the oestrous cycle as well as after induced luteolysis. Cows in the mid-luteal phase were injected with Cloprostenol and the CLs were collected at 0.5, 2, 4, 12, 24, 48 and 64 h after PGF2alpha injection. Real-time RT-PCR determined mRNA expressions. Expression from 20 h after GnRH to day 12: MMP-1, MMP-2, MMP-14 and tPA showed a clear expression, but no regulation. TIMP-1 and uPAR mRNA increased when compared with the follicular phase. TIMP-2, MMP-9, MMP-19 and uPA increased from the follicular phase to days 8-12. PAI-1 and PAI-2 expression increased from days 1-7 and decreased to days 8-12. Induced luteolysis: MMP-1, MMP-2, MMP-9, MMP-14, MMP-19 and TIMP-1 all increased at different time points and intensities, whereas TIMP-2 was constantly decreased from 24 to 64 h. The plasminogen activator system and their inhibitors were up-regulated from 2 to 64 h, tPA was already increased after 0.5 h. Immunohistochemistry for MMP-1, MMP-2, MMP-14: an increased staining for MMP-1 and MMP-14 was seen in large luteal cells beginning 24 h after PGF2alpha application. MMP-2 showed a strong increase in staining in endothelial cells at 48 h.     

Expression and localization of apelin and its receptor APJ in the bovine corpus luteum during the estrous cycle and prostaglandin F2alpha-induced luteolysis

Angiogenesis, changes in blood flow, and extracellular matrix remodeling are the processes associated with the development and demise of the bovine corpus luteum (CL) during the estrous cycle. APJ (putative receptor protein related to angiotensin type 1 receptor) is a G-protein-coupled receptor, and its ligand, apelin, has been identified as a novel regulator of blood pressure and as an angiogenic factor. We hypothesized that the apelin-APJ system is involved in luteal function. This study investigated whether apelin-APJ exists in bovine CL and determined their expression profiles and localization during luteal phase and prostaglandin F(2)(alpha) (PGF(2)(alpha))-induced luteolysis. During the luteal phase, apelin mRNA expression increased from early to late CL and decreased in regressed CL. APJ mRNA expression increased from early to mid-CL and remained elevated in late and regressed CL. Apelin and APJ proteins were immunohistochemically detected only in the smooth muscle cells of intraluteal arterioles during the luteal phase. PGF(2)(alpha) stimulated apelin and APJ mRNA expression at 0.5-2 and 2 h respectively, and then the mRNA expression of apelin-APJ was inhibited from 4 h during PGF(2)(alpha)-induced luteolysis. Additionally, apelin mRNA and protein were stimulated at 1 h after PGF(2)(alpha) injection only in the periphery of mid- but not early CL. The present study indicated that the apelin-APJ was localized in the smooth muscle cells of intraluteal arterioles, and responded to PGF(2)(alpha) at the periphery of mid-CL in the cow. Thus, the apelin-APJ system may be involved in the maturation of CL and the luteolytic cascade as a regulator of intraluteal arterioles in cow.     

Effects of synchronization treatments on ovarian follicular dynamics, corpus luteum growth, and circulating steroid hormone concentrations in lactating dairy cows

Lactating dairy cows (n=57) ≥45 d postpartum at first service were enrolled in a randomized complete block design study to evaluate treatments to synchronize estrus and ovulation. At 10 d before artificial insemination (AI), animals were randomly assigned to 1 of 3 treatments: (1) d -10 GnRH (GnRH1; 10 μg of buserelin, i.m.) and controlled internal drug release insert [CIDR, 1.38 g of progesterone (P4)]; d -3 PGF(2α) (PGF; 25 mg of dinoprost, i.m.); d -2 CIDR out; and AI at observed estrus (CIDR_OBS); (2) same as CIDR_OBS, but GnRH (GnRH2) 36 h after CIDR out and timed AI (TAI) 18 h later (CIDR_TAI); or (3) same as CIDR_TAI, but no CIDR (Ovsynch). Transrectal ultrasound was used to assess follicle size before ovulation and on d 4, 8, and 15 after the presumptive day of estrus (d 0) to measure the corpus luteum (CL). Blood samples were collected to determine concentrations of estradiol (E2; d -10, -9, -3, -2, -1, and 0) and P4 (d -10, -9, -2, -1, 0, 1, 4, 6, 8, 11, and 15). No treatment differences were observed in either circulating concentrations of P4 or the ovulatory response to GnRH1 at the onset of synchronization treatments. Circulating concentrations of P4 were greater for CIDR_OBS and CIDR_TAI compared with Ovsynch at 24 h after CIDR insertion (5.34 and 4.98 vs. 1.75 ng/mL) and immediately before CIDR removal (1.65 and 1.48 vs. 0.40 ng/mL). Peak circulating concentrations of E2 were greater for CIDR_OBS compared with Ovsynch (3.85 vs. 2.39 pg/mL), but CIDR_TAI (2.82 pg/mL) did not differ from either CIDR_OBS or Ovsynch. The interval from PGF injection to peak circulating E2 did not differ between CIDR_TAI and Ovsynch (52.1 vs. 49.8 h). Both CIDR_TAI and Ovsynch, however, had shorter intervals from PGF injection to peak circulating E2 concentrations compared with CIDR_OBS (67.8 h). The diameter of the dominant follicle before ovulation was greater for CIDR_OBS compared with Ovsynch (18.5 vs. 16.0 mm) but CIDR_TAI (17.1 mm) did not differ from either of the other treatments. The mean interval from PGF to ovulation was longer for CIDR_OBS (100.0 h) compared with CIDR_TAI and Ovsynch (84.4 and 83.2 h, respectively). Use of CIDR_OBS resulted in increased preovulatory follicle size and greater circulating concentrations of E2 due to a longer period of preovulatory follicle growth. Progesterone supplementation during synchronization and GnRH on the day before TAI affected ovulatory follicle size, and periovulatory circulating concentrations of P4 and E2. No differences, however, in postovulatory P4 or luteal volume profiles were observed.     

Effect of number and diameter of follicles on plasma concentrations of inhibin and FSH in mares

The role of the number of follicles and circulating immunoreactive inhibin in the decrease in plasma FSH concentrations that occurs during development of a follicular wave was studied in mares. All follicles > or = 6 mm in diameter were ablated by ultrasound-guided transvaginal aspiration of follicular fluid on day 10 after ovulation. During the subsequent wave, all follicles, the three largest follicles (three follicle group), the largest follicle (single follicle group) or no follicles were retained and the remaining follicles were ablated before they reached > 10 mm in diameter (n = 10-11 mares per group). Ablation of new follicles was continued until the day on which the largest follicle of the new wave reached 25 mm in diameter (day 18 after ovulation in the 'no follicle' group). Diameters of retained follicles were measured once a day by transrectal ultrasonography. Plasma samples were taken once a day and analysed by radioimmunoassay for concentrations of FSH and immunoreactive inhibin (includes dimeric inhibin as well as free alpha-subunit forms). Data were normalized to the day of the expected start of the decrease in plasma FSH concentrations (day 0: largest follicle 13 mm in diameter in the follicle-retained groups). A simultaneous increase in circulating concentrations of FSH (P < 0.05) and immunoreactive inhibin (P < 0.05) occurred before the largest follicle reached 13 mm in diameter, which indicates that immunoreactive inhibin produced by follicles < 13 mm in diameter did not suppress FSH. Plasma concentrations of FSH decreased (P < 0.05) and immunoreactive inhibin concentrations increased (P < 0.05) after day 0 in the follicle-retained groups. A slower decrease in FSH concentrations was associated temporally with a delay in the increase in immunoreactive inhibin concentrations in the 'single follicle' group relative to the 'three follicle' and 'all follicle' groups. All follicle-retained groups had similar plasma concentrations of FSH and immunoreactive inhibin after the expected beginning of deviation in growth rates between the two largest follicles (largest follicle 22-23 mm in diameter). These results indicated that the decrease in plasma FSH concentrations from the start of the decrease until the expected day of deviation was a function of multiple follicles of a wave and was attributable to the secretion of inhibin. Thereafter, the largest follicle alone accounted for the continued FSH suppression.     

Induction of lactation in nonpregnant cows by estradiol-17 beta and progesterone from an intravaginal sponge

An intravaginal sponge impregnated with 500 mg estradiol-17 beta and 1000 mg progesterone to induce lactation in nonpregnant dairy cattle was investigated. Sponge retention (greater than 95%) was achieved by its attachment to a nylon collar. Treatment with the sponge for 10 days resulted in lactogenesis in 25% of treated cows compared with an 89% success rate when an adjunct injection of dexamethasone esters (20 mg intramuscular) was given on day 6 or a 96% success rate when reserpine injections (2.5 mg intramuscular) were given on days 6, 8, and 10 10 after sponge insertion. Milking was begun 12 days after sponge insertion (2 days after removal). Peak milk yield was unaffected by adjunct treatments but was greater in spring (mean 11.5 kg/day) than in autumn treated cows (mean 3 and 6 kg/day) in 2 yr of trials. Concentration of estradiol-17 beta in plasma rose rapidly after sponge insertion to a peak similar to that in cows in late pregnancy. Measurement of estradiol-17 beta concentration in milk indicated less, even at first milking than in commercially distributed pasteurized milk. Milk fat and protein content were higher in milk from induced lactations compared with that from normally calving cows on the same day.     

Effect of follicular aspiration just before ovulation on corpus luteum characteristics, circulating progesterone concentrations and uterine receptivity in single-ovulating and superstimulated heifers

The aim of this study was to investigate, in unstimulated and superstimulated heifers, the effect of follicle aspiration just before ovulation on corpus luteum (CL) development, circulating progesterone (P(4)) concentrations and the ability of the uterus to support embryo development. Following follicle aspiration or ovulation timed from GNRH administration, CL development was assessed by daily ultrasonography, and CL function was assessed in terms of the capacity to produce P(4) and the expression of genes involved in steroidogenesis in luteal tissue. The capacity of the uterine environment to support conceptus development was assessed following transfer and recovery of in vitro-produced embryos. Follicular aspiration just before the expected time of ovulation leads to a significant reduction in CL diameter, CL area and area of luteal tissue. This was associated with a decrease in circulating P(4) in both unstimulated and superstimulated heifers. Follicle aspiration leads to a reduction in conceptus length and area on day 14 in unstimulated heifers only. Follicle aspiration leads to a reduction in the expression of LHCGR in luteal tissue from unstimulated heifers compared with those in which the CL formed after ovulation. Superstimulation significantly reduced the expression of STAR in luteal tissue in both ovulated and follicle-aspirated heifers. In conclusion, in stimulated and unstimulated heifers, aspiration of the preovulatory dominant follicle(s) just before expected ovulation interferes with the subsequent formation and function of the CL, in terms of size and P(4) output and this, in turn, is associated with a reduced capacity of the uterus to support conceptus elongation in unstimulated heifers.     

High feed intake increases liver blood flow and metabolism of progesterone and estradiol-17beta in dairy cattle

Increased liver blood flow (LBF) resulting from elevated feed intake in lactating dairy cows may increase steroid metabolism. Continuous infusion of bromosulphthalein (BSP; specifically metabolized in liver) was used to measure LBF. Similarly, progesterone (P4) and estradiol-17beta (E2) were administered by continuous infusion. Circulating concentrations at steady state were used to calculate the metabolic clearance rate (MCR) of BSP, P4, and E2. Experiment 1: Variation in LBF was determined in thee nonlactating and four lactating cows over 3 d at 3 to 5 h after feeding. Coefficients of variation ranged from 14 to 31% among cows within day and from 4 to 8% within cows across days. Experiment 2: Six nonlactating cows were used in a 3 x 3 Latin-square design with three feed regimens: no feed, 0.5 maintenance diet (M), and 1.5 M. Experiment 3: Eight lactating cows were used in a 4 x 4 Latin-square design with four feed regimens: no feed, 0.5 M, 1.5 M, and 2.2 M. In experiments 2 and 3, LBF and MCR of P4 increased immediately after feed consumption and increases persisted longer at higher intakes. The LBF reached a maximum at 2 h after feeding and MCR of P4 reached maximum at 3 h after feeding with a positive correlation (r = 0.92) between LBF and MCR for P4. Experiment 4: A crossover design was used to determine MCR of E2 in unfed or full-fed lactating dairy cows. The MCR of E2 increased immediately after feeding and stayed elevated throughout the 4.5-h infusion period. Thus, LBF and steroid metabolism were acutely elevated by feed consumption in lactating and nonlactating cows. Higher rates of LBF and steroid metabolism in lactating than in nonlactating cows may indicate chronic effects of higher feed intakes as well.     

Sequence of interleukin 1beta actions on corpus luteum regression: relationship with inducible cyclooxygenase and nitric oxide synthase expression

Corpus luteum regression has been described in terms of: (i) functional luteolysis - a reversible decline in serum progesterone concentration; and (ii) structural luteolysis - irreversible morphological changes and tissue remodelling events within the cellular membrane. In rats, PGF(2alpha) and interleukin 1beta (IL-1beta) are involved in structural luteolysis, PGF(2alpha) by increasing ovarian lipid peroxidation, and IL-1beta by reducing progesterone and increasing PGF(2alpha) concentrations. The aim of the present report was to determine whether by an early action IL-1beta is able to regulate functional luteolysis. Thus, ovarian explants from rats at the mid-stage of corpus luteum development were incubated during short periods with either 15 or 25 ng IL-1beta ml(-1). At 15 ng ml(-1), IL-1beta inhibited progesterone after 4 and 8 h of culture without affecting PGF(2alpha) production, and a longer incubation (21 h) was needed to increase PGF(2alpha) production. In contrast, IL-1beta enhanced PGF(2alpha) concentrations at 8 h only at the higher dose (25 ng ml(-1)). The observed reduction in progesterone synthesis at the lower dose of IL-1beta before the increase in PGF(2alpha) concentrations led to the hypothesis that IL-1beta regulates functional luteolysis (progesterone diminution) before it affects structural luteolysis (PGF(2alpha) increase). The fact that the early IL-1beta action was described at 4 h but no effects on inducible nitric oxide synthase and inducible cyclooxygenase expression were found before this time led to the suggestion that these inductions were not necessary for the early IL-1beta action described.     

The effects of IGF-I on bovine follicle development and IGFBP-2 expression are dose and stage dependent

This study aimed to determine the effect of insulin-like growth factor-I (IGF-I) on early antral bovine follicular development, and the expression of insulin-like growth factor-binding protein-2 (IGFBP-2). Antral follicles separated into three different size groups were cultured for 6 days in medium supplemented with either a low (10 ng/ml) or high (1 microg/ml) dose of human recombinant IGF-I. Oestradiol production by follicles in all size ranges, cultured in the presence of the high concentration of IGF-I, significantly increased by day 6 (P < 0.05). Follicles in the smallest size range, 165-215 microm, cultured in a high dose of IGF-I, were found to be significantly increased in size (P < 0.01). Oocyte health of the largest follicles (281-380 microm) was significantly improved by the addition of IGF-I to the culture medium. mRNA expression of IGFBP-2 was decreased in the granulosa cells of follicles, size range 216-280 microm, cultured with a high dose of IGF-I (P < 0.05). Granulosa cells (P < 0.05) and oocytes (P < 0.01) of the largest follicles (281-380 microm) showed a decrease in IGFBP-2 expression (protein) when cultured in the control and low-IGF-I treatment groups. Therefore, the response of a bovine follicle to IGF-I is both dose and stage dependent. This work supports a role for IGF-I in modulating somatic and germ-cell maturation and development in early antral follicles. Furthermore, the inverse relationship between the level of IGF-I stimulation and IGFBP-2 expression suggests a local regulatory system modulating IGF-I availability.     

Influence of cultivar,maturity stage and geographical location on the juice pigmentation of Tunisian pomegranates

The anthocyanin pigmentaion of the juices obtained from six Tunisian pomegranate cultivars harvested at commercial maturity was studied by HPLC. The anthocyanin content in the juice ranged between 6 μg/ml and 120 μg/ml. Six anthocyanins, namely the 3-O-glucosides and the 3,5-diglucosides of pelargonidin, cyanidin and delphinidin, were detected in all samples. Differences in the relative amounts of each anthocyanin were found for the different cultivars. The total amount of anthocyanin pigmentation of pomegranate juice was largely affected by the variety, the maturation stage and the geographical location of the fruit, but the anthocyanin profile remained quite stable under the different conditions. The anthocyanin profile constituted by the six pigments seems to be identical to those reported previously for Californian, Spanish and Italian pomegranates, and only differences in the relative amounts of the individual anthocyanins could be related to the variety and other climatic and cultural variables. These data suggest that the HPLC anthocyanin profile of pomegranate juice could be used as an adjunct in its analytical characterization, and in the differentiation with other anthocyanincontaining juices in food authenticity studies.     

Energy balance and size and number of ovarian follicles detected by ultrasonography in early postpartum dairy cows

Multiparous Holstein cows (n = 52) were fed one of six diets consisting of a totally mixed ration (corn silage, corn grain, soybean meal, dried distillers grains, and whole cottonseed) plus either alfalfa hay, alfalfa cubes, or bermuda-grass hay fed chopped as a component in the mixed ration or separate as long hay. Predicted energy balance was calculated from DM intake, milk yield and composition, and BW. On d 25 postpartum, ovarian status was programmed by injecting 25 mg of prostaglandin F2 alpha and treating cows for 15 d with an intravaginal device containing 1.9 g progesterone. Before d 25, number of class 1 follicles (3 to 5 mm; detected by ultrasonography) decreased with increasing days postpartum, and number of class 3 (10 to 15 mm) and class 4 (greater than 15 mm) follicles increased. The number of class 1 and 2 follicles (6 to 9 mm) decreased with increasing energy balance, and number of class 3 follicles increased with energy balance. Before d 25, predicted energy balance explained treatment differences in the number of follicles within each size class. After d 25, energy balance did not affect the average number of follicles per cow, but diet affected the number of follicles within each class. Predicted energy balance and dietary treatments influenced number of follicles at different times after calving. These results identify the importance of diet and energy balance to follicular and ovarian function in postpartum lactating dairy cows.     

Historical perspective of turnover of dominant follicles during the bovine estrous cycle: key concepts, studies, advancements, and terms

This review chronicles the key concepts, studies, advancements and terms that have led to our current understanding of turnover of dominant follicles (growth and atresia) during the bovine estrous cycle. The "two-wave" concept of follicular development was first proposed in 1960, but remained controversial for the next 28 yr. The concept of the "dominant" follicle was adapted to cattle in 1987. By 1988, ultrasound analysis of individual follicles had demonstrated that heifers usually had two or three distinct waves of turnover of dominant follicles during an estrous cycle. From 1992 to 1993, it was established that a transient rise in serum concentrations of FSH initiated each follicular wave, and a decreased episodic secretion of LH was associated with loss of dominance and the end of a nonovulatory follicular wave. In the past decade, numerous intrafollicular growth factors, such as inhibins, activins, and insulin-like growth factors and their binding proteins, have been identified in follicular fluid of individual bovine follicles. In addition, in vitro studies demonstrate that these growth factors could have endocrine, autocrine, or paracrine actions that modify gonadotropin-stimulated follicular growth and differentiation. However, the precise role of intrafollicular growth factors in turnover of dominant follicles has not been defined. We concluded that two or three FSH-stimulated waves of follicular growth usually occur during the bovine estrous cycle, and each follicular wave culminates in development of a single nonovulatory or ovulatory dominant follicle.     

Measurements of particle number and mass concentrations and size distributions in a tunnel environment

Particulate matter emissions were measured in two bores of the Caldecott Tunnel in Northern California during August and September 2004. One bore (Bore 1) is open to both heavy- and light-duty vehicles while heavy-duty vehicles are prohibited from entering the second bore (Bore 2). Particulate matter number and mass size distributions, chemical composition, and gaseous copollutants were recorded for four consecutive days near the entrance and exit of each bore. Size-resolved emission factors were determined for particle number, particle mass, elemental carbon, organic carbon (OC), sulfate, nitrate, and selected elements. The size distributions in both the bores showed a single large mode at roughly 15-20 nm in mobility diameter, with occasional smaller modes around 100 nm. The PM10 mass emission factor for heavy-duty vehicles was 14.5 times higher than that of light-duty vehicles. The particles derived from diesel are more abundant in elemental carbon, 70.9% of PM10 emissions, as compared to the light-duty vehicles. Conversely, a greater percentage of OC was found in light-duty emissions than heavy-duty emissions. In comparison to previous studies at the Caldecott Tunnel, less particle mass but more particle numbers are emitted by vehicles than was the case 7 years ago.     

Effects of follicle size and electrolytes and glucose in maturation medium on nuclear maturation and developmental competence of bovine oocytes

The concentrations of electrolytes (Na, K, Cl, Mg and Ca) and glucose in small follicle (SF) follicular fluid (SFF) and large follicle (LF) follicular fluid (LFF) from slaughterhouse-derived ovaries were studied. Oocytes were matured in medium based on synthetic oviductal fluid. The effects of various concentrations of electrolytes (Na, K, Ca and Mg) and glucose in the maturation medium on the progression of nuclear maturation and subsequent development were also studied. K in SFF was significantly greater than that in LFF. The Mg concentration in follicular fluid (FF) is 2.0-2.3 mM, which is greater than the concentration present in medium generally used for culture. The glucose concentration in FF is about 3.5-3.9 mM and rapidly decreases during the preservation of ovaries. LF oocytes resumed nuclear maturation and progressed to the M2 stage significantly faster than those collected from SF oocytes. In addition, more LF oocytes developed to blastocysts than did SF oocytes. Changing the Na/K ratio in the maturation medium from 16 to 24 did not affect either the progression of nuclear maturation or the rate of development. A low concentration of Mg (0.5 mM) combined with a low Ca concentration (0.5 mM) inhibited the rate of development, but did not affect the progression of nuclear maturation. On the other hand, increasing the Mg concentration to 2.0 mM from 0.5 mM hastened the progression of nuclear maturation and improved the rate of blastulation, irrespective of the Ca concentration. The progression of nuclear maturation was faster and the rate of development was greater with 5.56 mM glucose than with 1.5 mM glucose. The difference in time needed to progress to M2 among the experiment was about 2-3 h. Therefore, prolonging the maturation periods from 21 to 24 h did not change the rate of development. Our results show that the concentrations of Mg and glucose in the maturation medium and the follicle size enveloping the oocyte affect the progression of nuclear maturation and subsequent development. The time requirement for oocytes to reach M2 is strongly related to the developmental competence of the oocytes.     

Influence of 17beta-estradiol, progesterone, and dexamethasone on diapedesis and viability of bovine blood polymorphonuclear leukocytes

The aim of the current study was to investigate whether polymorphonuclear leukocyte (PMN) diapedesis and viability are influenced by steroid hormones. Using an in vitro model with different types of cell layers (bovine mammary epithelial cells and fibroblasts), we investigate whether steroid hormone treatments (17beta-estradiol, progesterone, and dexamethasone) have an influence on the diapedesis capacity and viability of PMN. In addition, we studied apoptosis of PMN in the in vitro model and evaluated the influence of different types of cell layers and steroid hormone treatments on this process. A significant decrease in the number of viable PMN in the lower compartment of the in vitro model (i.e., number of migrated PMN x viability after migration) was found after 17beta-estradiol treatment, whereas no influence was detected after progesterone or dexamethasone treatment. The effect of 17beta-estradiol was not due to a lower viability before migration as none of the treatments caused a significant effect on the viability before diapedesis. This treatment effect was not influenced by endogenous 17beta-estradiol or progesterone levels before isolation because there was no correlation between these plasma levels and PMN diapedesis capacity or viability. Furthermore, migration through epithelial cells caused a significant decrease in viability of PMN due to increased apoptosis but not necrosis.     

Prostaglandin F2alpha increases endothelial nitric oxide synthase in the periphery of the bovine corpus luteum: the possible regulation of blood flow at an early stage of luteolysis

Prostaglandin F(2)(alpha) (PGF(2)(alpha)) released from the uterus causes alterations in luteal blood flow, reduces progesterone secretion, and induces luteolysis in the bovine corpus luteum (CL). We have recently discovered that luteal blood flow in the periphery of the mature CL acutely increases coincidently with pulsatile increases in a metabolite of PGF(2)(alpha) (PGFM). In this study, we characterized changes in regional luteal blood flow together with regional alterations in endothelial nitric oxide synthase (eNOS) expression during spontaneous luteolysis and in response to PGF(2)(alpha). Smooth muscle actin-positive blood vessels larger than 20 microm were observed mainly in the periphery of mature CL. PGF(2)(alpha) receptor was localized to luteal cells and large blood vessels in the periphery of mid-CL. PGF(2)(alpha) acutely stimulated eNOS expression in the periphery but not in the center of mature CL. Injection of the NO donor S-nitroso-N-acetylpenicillamine into CL induced an acute increase in luteal blood flow and shortened the estrous cycle. In contrast, injection of the NOS inhibitor l-NAME into CL completely suppressed the acute increase in luteal blood flow induced by PGF(2)(alpha) and delayed the onset of luteolysis. In conclusion, PGF(2)(alpha) has a site-restricted action depending on not only luteal phase but also the region in the CL. PGF(2)(alpha) stimulates eNOS expression, vasodilation of blood vessels, and increased luteal blood flow in periphery of mature CL. Furthermore, the increased blood flow is mediated by NO, suggesting that the acute increase in peripheral blood flow to CL is one of the first physiological indicators of NO action in response to PGF(2)(alpha).