Interaction of bovine granulosa and theca cells in a novel serum-free co-culture system

The objective of this study was to develop a defined culture system in which bovine follicular and granulosa cells are grown in close contact with each other and with the extracellular matrix (ECM) component laminin. Granulosa and theca cells from follicles 4-6 mm in diameter were cultured on either side of laminin-coated BioCoat cell culture inserts in a serum-free medium containing 10 ng insulin ml(-1) at plating densities of 10(5) and 3 x 10(5) cells per membrane side. The cells adopted a clumped arrangement, maintained steroidogenic activity for at least 7 days and demonstrated paracrine communication by increased steroidogenesis and enhanced cell survival compared with cells in mono-culture. Co-cultured theca cells secreted significantly more androstenedione compared with cells in mono-culture. Granulosa cell viability was doubled by co-culture with theca cells. Co-cultures at both cell plating densities were responsive to treatment with physiological combinations of either FSH, LH and LR3 insulin-like growth factor I (IGF-I) (treatment A) or FSH, LR3 IGF-I and androstenedione (treatment B). Significantly more androstenedione was secreted in the presence of treatment A compared with controls. In contrast, oestradiol secretion was increased only by treatment B. Progesterone secretion was unaffected by treatment and did not increase during culture. Co-cultures at the higher plating density demonstrated higher theca cell survival and better maintenance of the follicular cell phenotype. In conclusion, this novel co-culture system provides a unique model for the study of paracrine communication between ovarian somatic cells and cell-ECM interactions during follicle growth.

The FecB (Booroola) gene acts at the ovary: in vivo evidence

The aim of this study was to differentiate between pituitary and ovarian actions of the FecB gene by measuring the ovarian response to a standardized treatment with gonadotrophins designed to mimic the changes in FSH and LH that occur in the follicular phase of the ovarian cycle in ewes, with (Fec(B/-), n=6) and without (Fec(+/+), n=9) the gene, that were rendered hypogonadotrophic by pretreatment with a potent antagonist of GnRH. Ewes with ovarian autotransplants were used to facilitate the assessment of follicular function by the collection of ovarian venous blood and ultrasonography. The gonadotrophin regimen resulted in concentrations of FSH and LH that were similar to concentrations found in a normal cycle and did not differ between genotypes. Follicular development and ovulation occurred in all animals, and patterns of secretion of oestradiol, androstenedione and inhibin A were normal. Despite these endocrine similarities, the antral follicle population stimulated by FSH infusion retained the characteristic genotypic difference with the ovaries of Fec(+/+) animals containing a range of follicle sizes with decreasing proportions of small (<3.5 mm in diameter) and medium (3.5-4.5 mm in diameter) follicles as well as large follicles (> or =4.5 mm in diameter), whereas the ovaries of Fec(B/-) ewes contained no follicles of >4.5 mm in diameter. This genotypic difference was retained after ovulation with gene carriers having more preovulatory follicles/corpora lutea (3.8+/-0.3) of a smaller diameter (5.3+/-0.3 mm) than did non-gene carriers (1.7+/-0.3; 11.4+/-0.9 mm; P<0.05). As ewes carrying the FecB gene mutation were able to ovulate more follicles than non-gene carriers, despite identical concentrations and patterns of FSH and LH stimulation, the results of this study support the hypothesis that the FecB gene acts at the ovary to enhance ovarian sensitivity to gonadotrophic stimulation.

Mechanisms regulating follicular development and selection of the dominant follicle

Reproductive function is an integrated process encompassing both extra-ovarian signals, such as gonadotrophins, and intrafollicular factors, such as locally produced growth factors. Initiation of primordial follicle growth and the early stages of folliculogenesis can occur without gonadotrophins. However, in vivo and in vitro studies indicate that FSH may stimulate the rate of preantral follicle growth and that it can take only 3 months for a primordial follicle to reach the ovulatory stage. Antral follicle development from 2 and 4 mm in diameter in sheep and cattle, respectively, is gonadotrophin dependent. During the oestrous cycle a transient increase in circulating FSH precedes the recruitment of a group of follicles. Recruited follicles are characterized by induction of expression of mRNAs encoding a range of steroidogenic enzymes, gonadotrophin receptors and local regulatory factors. As follicles continue to mature, there is a transfer of dependency from FSH to LH, which may be part of the mechanism involved in selection of follicles for continued growth. The mechanism of selection of the ovulatory follicle seems to be linked to the timing of mRNA expression encoding LHr and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in granulosa cells. Locally produced growth factors, such as the insulin-like growth factors (IGFs) and members of the transforming growth factor beta (TGFbeta) superfamily (inhibins, activins and bone morphogenetic proteins (BMPs)), work in concert with gonadotrophins throughout the follicular growth continuum. The roles of growth factors in follicular development and survival are dependent on gonadotrophin status and differentiation state, including morphology. In conclusion, it is the integration of extraovarian signals and intrafollicular factors that determine whether a follicle will continue to develop or be diverted into atretic pathways, as is the case for most of the follicles in monovulatory species, such as cattle.

Interactions between nutrition and ovarian activity in cattle: physiological, cellular and molecular mechanisms

The effects of acute changes in dietary intake on ovarian activity can be correlated with changes in circulating concentrations of metabolic hormones including insulin, insulin-like growth factor I (IGF-I), growth hormone and leptin. There is no corresponding change in circulating gonadotrophin concentrations and it is proposed that the dietary induced changes in ovarian activity, resulting from acute changes in dietary intake, are a result of direct actions of these metabolic hormones on the ovary. Changes in the peripheral concentrations of insulin, IGF-I and leptin were also associated with the initiation of a synchronized wave of follicle growth and it is hypothesized that oestrogen secreted by the developing follicle is involved in regulating the secretion of these metabolic hormones. At the cellular level, physiological concentrations of insulin and IGF-I interact to stimulate oestradiol production by granulosa cells. In contrast, leptin inhibits FSH-stimulated oestradiol production by granulosa cells and LH-stimulated androstenedione production by theca cells. At the molecular level, dietary energy intake affects the expression of mRNA encoding components of the ovarian IGF system and these changes can directly influence the bioavailability of intrafollicular IGF. This, in turn, can increase the sensitivity or response of follicles to FSH and is one mechanism through which nutrition can directly affect follicle recruitment. Dietary induced increases in intrafollicular IGF bioavailability also have a negative effect on oocyte quality, and diets that are optimal for follicle growth may not necessarily be optimal for oocyte maturation.

Image stabilization for scanning laser ophthalmoscopy

A scanning laser ophthalmoscope with an integrated retinal tracker (TSLO) was designed, constructed, and tested in human subjects without mydriasis. The TSLO collected infrared images at a wavelength of780 nm while compensating for all transverse eye movements. An active, high-speed, hardware-based tracker was able to lock onto many common features in the fundus, including the optic nerve head, blood vessel junctions, hypopigmentation, and the foveal pit. The TSLO has a system bandwidth of ~1 kHz and robustly tracked rapid and large saccades of approximately 500 deg/sec with an accuracy of 0.05 deg. Image stabilization with retinal tracking greatly improves the clinical potential of the scanning laser ophthalmoscope for imaging where fixation is difficult or impossible and for diagnostic applications that require long duration exposures to collect meaningful information.

The economic impact of foot and mouth disease control and eradication in the Philippines

The authors evaluate the impact of foot and mouth disease (FMD) and control of the disease in the Philippines using cost-benefit analysis. A scenario in which FMD control is maintained at recent levels with continued presence of the disease is compared to scenarios in which a publicly funded programme achieves eradication by 2005 (current policy objective), 2007 and 2010. Under varying assumptions regarding the development of exports of livestock products following eradication, estimated benefit-cost ratios for the investment in eradication range from 1.6 (2010, no exports) to 12.0 (2005, export of 5,000 tons each of low-value and high-value livestock products annually), indicating eradication to be an economically viable investment. The commercial swine sector is estimated to capture 84% of the benefits generated by the public investment in eradication, versus 4% by backyard swine producers. The implications of these results within the context of regional efforts to control FMD in South-East Asia are explored.

Predictors of obstetric intervention rates: case-mix, staffing levels and organisational factors of hospital of birth

We performed a cross-sectional study of all Thames maternity units, 1994-96, including 540,834 live and stillbirths. In contrast to recent media speculation, no association of caesarean section rates with midwifery staffing levels was found after adjustment for confounders. The only association with staffing was with levels of junior obstetric staffing, which could be a reflection of less experienced management of labour. Caesarean section rates were also associated positively with the levels of delivery beds, which could be a reflection of the closer monitoring of labour that may result from increased bed availability. Both caesarean section and instrumental vaginal delivery rates were associated with epidural rates, which was expected from the literature. Variations in epidural rates were mainly associated with variations in demographic case-mix, due possibly to patient demand. Demographic case-mix was also associated with instrumental vaginal deliveries but not the caesarean section rate.

Adjusted mortality rates: a tool for creating more meaningful league tables for stillbirth and infant mortality rates

A number of problems associated with league tables of performance indicators have been discussed in the literature. This paper attempts to address these problems for stillbirth and infant mortality rates in order to produce meaningful and useful information for the government, general public and health professionals. Composite stillbirth and infant mortality rates, low birth-weight and very low birth-weight rates were determined for the 100 English Health Authorities for 1996-1997. Townsend deprivation scores for these districts were also obtained. The mortality rates were adjusted by multiple regression for very low birth-weight and Townsend score separately and together. Confidence intervals were calculated for the dual-adjusted rates. Almost 60% of the variability in mortality rates were explained by Townsend score and very low birth-weight rates together. Adjusted league tables showed how the individual and combined predictors affect the individual mortality rates for each Health Authority. There was considerable overlap in the confidence intervals for the adjusted rates although there were a few Health Authorities whose mortality rates were clearly below most others. We conclude that fairer and more useful information is provided by geographically based league tables which give both crude rates and rates adjusted for single and multiple predictor variables. The inclusion of confidence intervals aids interpretation of annual random variations and knowledge of differences in the effects of the individual predictors enables better resource targeting.

A prospective study of the prevalence of undiagnosed coeliac disease in laboratory defined iron and folate deficiency

AIMS

To determine the prevalence of coeliac disease in a group of patients in the community who have been shown in the laboratory to have iron and/or folate deficiency. To assess the cost efficiency of this laboratory based case finding strategy.

METHODS

The study was undertaken in a large general hospital in the UK serving a population of 300 000. Three hundred and thirty three eligible patients with iron and/or folate deficiency were identified and contacted over an 18 month period. Case finding was by testing for coeliac disease using serological methods and subsequent histological confirmation.

RESULTS

Of the 333 eligible and contactable patients with iron and/or folate deficiency, 258 (77%) consented to coeliac disease antibody testing. Twenty eight patients (10.9%) were positive for coeliac disease antibodies. Of these, 24 patients proceeded to endoscopy and biopsy, resulting in 12 cases of histologically confirmed coeliac disease (4.7% (95% confidence interval, 2.1% to 6.8%) of patients tested for coeliac disease antibodies).

CONCLUSIONS

This laboratory based methodology detected a considerable number of new coeliac disease cases in the community. Many of these patients did not present with clinical findings suggestive of malabsorption and might not otherwise have been diagnosed. Laboratory based methodologies should be considered in conjunction with other strategies for the early identification and treatment of coeliac disease.

Standards for Reporting the Optical Aberrations of Eyes

In response to a perceived need in the vision community, an OSA taskforce was formed at the 1999 topical meeting on vision science and its applications (VSIA-99) and charged with developing consensus recommendations on definitions, conventions, and standards for reporting of optical aberrations of human eyes. Progress reports were presented at the 1999 OSA annual meeting and at VSIA-2000 by the chairs of three taskforce subcommittees on (1) reference axes, (2) describing functions, and (3) model eyes.

Differential effects of leptin on thermoregulation and uncoupling protein abundance in the neonatal lamb

As the role of leptin in energy balance in neonate is unknown, we investigated the effect of acute (2 h) and chronic (7 days) administration of leptin (100 microg/day) on thermoregulation and mitochondrial protein abundance in adipose tissue. The concentration of uncoupling protein (UCP)1 and voltage-dependent anion channel (VDAC) located on the inner and outer mitochondrial membranes, respectively, were measured. Administration of leptin prevented the normal decline in colonic temperature over the first few hours and days after birth. It subsequently accelerated the loss of both mRNA and protein for UCP1 but had no effect on VDAC abundance. At seven days of age, colonic temperature was correlated strongly with both mRNA abundance and thermogenic potential of UCP1 in leptin-treated but not control lambs, indicating more effective use of UCP1 for heat production following leptin administration. Leptin had no effect on weight gain or adipose tissue deposition; at one day of age only, leptin mRNA was correlated positively with adipose tissue weight. In conclusion, leptin administration to neonatal lambs improves thermoregulation and promotes the loss of UCP1 in brown adipose tissue.

Changes in insulin-like growth factor binding protein (IGFBP) isoforms during bovine follicular development

UThe insulin-like growth factor binding proteins (IGFBPs) bind IGFs with high affinity and so regulate their access to the type 1 and 2 IGF receptors. This is the principal mechanism involved in regulating IGF bioavailability during folliculogenesis. IGFBPs undergo a number of post-translational modifications, including proteolytic cleavage, phosphorylation and glycosylation, which can regulate the affinity of IGFBPs for IGFs. However, the post-translational changes to IGFBPs that occur during folliculogenesis have not been fully characterized. The charge and size variants of the IGFBPs in bovine follicular fluid were examined by two-dimensional non-reducing SDS-PAGE followed by non-isotopic western ligand blot analysis, and immunoblot analysis during follicular development. The results demonstrate the presence of at least 51 IGFBP isoforms corresponding to IGFBP-1 to -6 in bovine follicular fluid from subordinate follicles, many of which were phosphorylated. The total number of IGFBPs was reduced in dominant follicles, whereas no gross changes in isoforms were observed during follicular development. These results demonstrate the high degree of conservation of IGFBP post-translational modifications between species, and from the in vitro dephosphorylation of these proteins it is hypothesized that these modifications may result in changes to IGF binding or susceptibility to proteolytic cleavage.

Changes in insulin-like growth factor binding protein (IGFBP) isoforms during bovine follicular development

UThe insulin-like growth factor binding proteins (IGFBPs) bind IGFs with high affinity and so regulate their access to the type 1 and 2 IGF receptors. This is the principal mechanism involved in regulating IGF bioavailability during folliculogenesis. IGFBPs undergo a number of post-translational modifications, including proteolytic cleavage, phosphorylation and glycosylation, which can regulate the affinity of IGFBPs for IGFs. However, the post-translational changes to IGFBPs that occur during folliculogenesis have not been fully characterized. The charge and size variants of the IGFBPs in bovine follicular fluid were examined by two-dimensional non-reducing SDS-PAGE followed by non-isotopic western ligand blot analysis, and immunoblot analysis during follicular development. The results demonstrate the presence of at least 51 IGFBP isoforms corresponding to IGFBP-1 to -6 in bovine follicular fluid from subordinate follicles, many of which were phosphorylated. The total number of IGFBPs was reduced in dominant follicles, whereas no gross changes in isoforms were observed during follicular development. These results demonstrate the high degree of conservation of IGFBP post-translational modifications between species, and from the in vitro dephosphorylation of these proteins it is hypothesized that these modifications may result in changes to IGF binding or susceptibility to proteolytic cleavage.

Search for new physics in photon-lepton events in pp collisions at sqrt[s] = 1.8 TeV

We present the results of a search in pp collisions at sqrt[s] = 1.8 TeV for anomalous production of events containing a photon and a lepton (e or mu), both with large transverse energy, using 86 pb(-1) of data collected with the Collider Detector at Fermilab during the 1994-1995 collider run at the Fermilab Tevatron. The presence of large missing transverse energy (E(T)), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large E(T), for which the observed total is 16 events and the expected mean total is 7.6+/-0.7 events.

Corpus luteum (CL) function: local control mechanisms

LH and PGF(2alpha) are the principal luteotrophic and luteolytic hormones in domestic animals, however, it is becoming increasingly apparent that intra-ovarian factors can modulate luteal function. For example, the insulin-like growth factors (IGF-I and -II) can regulate ovarian function, and have direct effects on ovarian cells. An important role for the IGFs in regulating ovarian function is suggested by the multiple effects of IGFs on both follicular and luteal steroidogenesis. Expression of mRNA encoding IGF-I, IGF-II and the type 1 IGF receptor has also been detected in the ruminant CL and is suggestive of autocrine/paracrine roles for both IGF-I and -II in the regulation of luteal function. The actions of the IGFs are further modulated by their association with specific binding proteins (IGFBPs), which regulate the transport of IGFs and their presentation to specific receptors. IGFBPs have been detected in the CL of domestic animals, and inhibitory effects on IGF-I-stimulated progesterone production have been demonstrated. The rapid cyclical changes in luteal growth and regression are associated with rapid changes in vasculature. The principle angiogenic factors include the fibroblast growth factors (FGFs), vascular endothelial growth factor (VEGF) and the angiopoietins (Ang). Other locally produced factors include cytokines such as TNF-alpha and IL-1beta. One such factor is monocyte chemoattractant protein (MCP-1), which increases after exogenous PGF(2alpha). An influx of macrophages takes place in the CL around luteolysis, possibly in response to MCP-1 release, but these changes are not observed in cattle when luteolysis is inhibited. In conclusion locally produced factors are important in the control of luteal function, although their roles have yet to fully elucidated.

The prevalence of rheumatoid arthritis in the United Kingdom: new estimates for a new century

BACKGROUND

It is 40 yr since the last age- and sex-specific estimates of the prevalence of rheumatoid arthritis (RA) for the UK were published. Since then the classification criteria for RA have been revised and there has been evidence of a fall in the incidence of RA, especially in women.

OBJECTIVES

To estimate the age- and sex-specific point prevalence of RA (defined as fulfilment of a modification of the 1987 ACR classification criteria for RA on the day of assessment). The estimate was made in the primary care setting in Norfolk, UK.

METHODS

A stratified random sample was drawn from seven age and gender bands. The 7050 individuals selected were mailed a screening questionnaire. Positive responders were invited to attend for a clinical examination. The sample was matched against the names in the Norfolk Arthritis Register (NOAR), a register of incident cases of inflammatory polyarthritis which has been in existence since 1990.

RESULTS

The overall response rate was 82%. Sixty-six cases of RA were identified. Extrapolated to the population of the UK, the overall minimum prevalence of RA is 1.16% in women and 0.44% in men. A number of incident cases of RA previously notified to NOAR were not identified as cases in the survey because they had entered into treatment-induced remission. In addition, some cases who failed to attend for examination had significant disability. These prevalence figures are therefore an underestimate.

CONCLUSIONS

The prevalence of RA in women, but not in men, in the UK may have fallen since the 1950s.

Expression of the insulin-like growth factor (IGF) system in the bovine oviduct at oestrus and during early pregnancy

Early mammalian embryo development in vitro can be enhanced by co-culture with oviductal cells and by the addition of insulin-like growth factors (IGFs). This study examined the expression patterns of the oviductal IGF system in cattle in relation to the number of days after oestrus and the presence or absence of embryos. Oviducts were collected from: (i) 66 nulliparous heifers on day 3, day 6 or day 16 after insemination and from (ii) ten non-pregnant, lactating cows on day 0 or day 1 of the oestrous cycle. Oviducts were coiled, frozen whole and sectioned for in situ hybridization. Expression patterns of mRNAs encoding IGF-I, IGF-II, type 1 IGF receptor (IGF-1R), and the IFG binding proteins (IGFBP)-1, -3 and -5 were determined from autoradiographs. Separate measurements were made for the mucosa and muscle layers of the infundibulum, ampulla and isthmus. None of the parameters measured differed between heifers with or without the presence of an embryo. mRNAs encoding IGF-I and IGF-1R were present in the mucosa and muscle of all three oviductal regions, and the highest value of IGF-I mRNA was measured in heifers on day 3. IGF-II mRNA was expressed predominantly in the muscle wall. IGFBP-1 mRNA was not detectable, whereas mRNAs encoding IGFBP-3 and -5 were expressed in both the muscle and mucosa. IGFBP-3 expression was higher in cows on day 0 and day 1 of the oestrous cycle than in heifers on day 3, day 6 and day 16 after insemination. A peak of IGFBP-5 expression was reached on day 6. Locally or systemically produced IGFs, regulated by IGFBPs, may act directly on the embryo or indirectly via modulation of oviductal secretions and muscular activity to influence the success of early embryo development.

Expression of the insulin-like growth factor (IGF) system in the bovine oviduct at oestrus and during early pregnancy

Early mammalian embryo development in vitro can be enhanced by co-culture with oviductal cells and by the addition of insulin-like growth factors (IGFs). This study examined the expression patterns of the oviductal IGF system in cattle in relation to the number of days after oestrus and the presence or absence of embryos. Oviducts were collected from: (i) 66 nulliparous heifers on day 3, day 6 or day 16 after insemination and from (ii) ten non-pregnant, lactating cows on day 0 or day 1 of the oestrous cycle. Oviducts were coiled, frozen whole and sectioned for in situ hybridization. Expression patterns of mRNAs encoding IGF-I, IGF-II, type 1 IGF receptor (IGF-1R), and the IFG binding proteins (IGFBP)-1, -3 and -5 were determined from autoradiographs. Separate measurements were made for the mucosa and muscle layers of the infundibulum, ampulla and isthmus. None of the parameters measured differed between heifers with or without the presence of an embryo. mRNAs encoding IGF-I and IGF-1R were present in the mucosa and muscle of all three oviductal regions, and the highest value of IGF-I mRNA was measured in heifers on day 3. IGF-II mRNA was expressed predominantly in the muscle wall. IGFBP-1 mRNA was not detectable, whereas mRNAs encoding IGFBP-3 and -5 were expressed in both the muscle and mucosa. IGFBP-3 expression was higher in cows on day 0 and day 1 of the oestrous cycle than in heifers on day 3, day 6 and day 16 after insemination. A peak of IGFBP-5 expression was reached on day 6. Locally or systemically produced IGFs, regulated by IGFBPs, may act directly on the embryo or indirectly via modulation of oviductal secretions and muscular activity to influence the success of early embryo development.

Regulation of expression of ovarian mRNA encoding steroidogenic enzymes and gonadotrophin receptors by FSH and GH in hypogonadotrophic cattle

A study was conducted to determine the effects of FSH and bovine somatotrophin on the expression of mRNA encoding the gonadotrophin receptors and steroidogenic enzymes in ovarian follicles of cattle rendered hypogonadotrophic by treatment with a GnRH agonist. Hereford x Friesian heifers were allotted into two pretreatment groups: controls (n = 10) and GnRH agonist-treated (n = 20). Ovaries of control cows were removed on day 2 of the first follicular wave after synchronized oestrus. GnRH agonist-treated heifers were given either FSH or no FSH. FSH was infused at 50 microg h(-1) for 48 h. Ovaries in GnRH agonist-treated heifers were removed at the end of exogenous hormone treatment. The control, GnRH agonist and GnRH agonist plus FSH treatment groups were divided further into bovine somatotrophin or no bovine somatotrophin treatments (n = 5 per treatment). Bovine somatotrophin (25 mg day(-1) by s.c. injection) was administered for 3 days. Ovaries were scanned once a day by ultrasonography. Blood samples for hormone measurements were collected three times a day from oestrus until the time of removal of ovaries. Expression of mRNAs for the FSH and LH receptors and cytochrome P450 side-chain cleavage (P450scc), cytochrome P450 17alpha-hydroxylase (P450c17) and cytochrome P450 aromatase (P450arom) enzymes was localized by in situ hybridization and quantified by image analysis. Ovarian follicular growth was arrested at < or = 4.5 mm in diameter in GnRH agonist-treated heifers. There was no effect of bovine somatotrophin on follicular dynamics, gonadotrophin secretion or expression of mRNA for either the gonadotrophin receptors or steroidogenic enzymes. Infusion of FSH to GnRH agonist-treated heifers increased FSH concentrations in serum to the physiological concentrations observed in controls and stimulated growth of follicles to a size similar (5.5-8.0 mm in diameter) to recruited follicles in control cows. FSH induced mRNA expression of P450scc and P450arom in granulosa cells of follicles at a smaller size (< or = 4.5 mm in diameter) than in controls and increased (P < 0.001) expression in larger (> 4.5 mm in diameter) follicles. Expression of mRNAs for P450scc and P450c17 increased (P < 0.001) with increasing follicle size and was higher (P < 0.01) in theca cells of GnRH agonist plus FSH-treated heifers than in the other groups. There were no treatment differences in expression of FSH receptor in granulosa cells or LH receptor in theca cells, but expression of both receptors increased with follicle size. There was no expression of LH receptor in the granulosa cells of cows from any treatment group. In conclusion, FSH treatment in GnRH agonist-treated heifers induced similar changes in follicular growth to those observed during the first follicular wave, but despite similar peak concentrations, prolonged exposure to high FSH induced precocious expression of mRNAs for P450scc and P450arom in granulosa cells from small follicles and markedly upregulated expression of these enzymes in granulosa cells from recruited follicles. The results of this study demonstrate the key role that FSH plays in the induction of follicular growth and differentiation.

Regulation of expression of ovarian mRNA encoding steroidogenic enzymes and gonadotrophin receptors by FSH and GH in hypogonadotrophic cattle

A study was conducted to determine the effects of FSH and bovine somatotrophin on the expression of mRNA encoding the gonadotrophin receptors and steroidogenic enzymes in ovarian follicles of cattle rendered hypogonadotrophic by treatment with a GnRH agonist. Hereford x Friesian heifers were allotted into two pretreatment groups: controls (n = 10) and GnRH agonist-treated (n = 20). Ovaries of control cows were removed on day 2 of the first follicular wave after synchronized oestrus. GnRH agonist-treated heifers were given either FSH or no FSH. FSH was infused at 50 microg h(-1) for 48 h. Ovaries in GnRH agonist-treated heifers were removed at the end of exogenous hormone treatment. The control, GnRH agonist and GnRH agonist plus FSH treatment groups were divided further into bovine somatotrophin or no bovine somatotrophin treatments (n = 5 per treatment). Bovine somatotrophin (25 mg day(-1) by s.c. injection) was administered for 3 days. Ovaries were scanned once a day by ultrasonography. Blood samples for hormone measurements were collected three times a day from oestrus until the time of removal of ovaries. Expression of mRNAs for the FSH and LH receptors and cytochrome P450 side-chain cleavage (P450scc), cytochrome P450 17alpha-hydroxylase (P450c17) and cytochrome P450 aromatase (P450arom) enzymes was localized by in situ hybridization and quantified by image analysis. Ovarian follicular growth was arrested at < or = 4.5 mm in diameter in GnRH agonist-treated heifers. There was no effect of bovine somatotrophin on follicular dynamics, gonadotrophin secretion or expression of mRNA for either the gonadotrophin receptors or steroidogenic enzymes. Infusion of FSH to GnRH agonist-treated heifers increased FSH concentrations in serum to the physiological concentrations observed in controls and stimulated growth of follicles to a size similar (5.5-8.0 mm in diameter) to recruited follicles in control cows. FSH induced mRNA expression of P450scc and P450arom in granulosa cells of follicles at a smaller size (< or = 4.5 mm in diameter) than in controls and increased (P < 0.001) expression in larger (> 4.5 mm in diameter) follicles. Expression of mRNAs for P450scc and P450c17 increased (P < 0.001) with increasing follicle size and was higher (P < 0.01) in theca cells of GnRH agonist plus FSH-treated heifers than in the other groups. There were no treatment differences in expression of FSH receptor in granulosa cells or LH receptor in theca cells, but expression of both receptors increased with follicle size. There was no expression of LH receptor in the granulosa cells of cows from any treatment group. In conclusion, FSH treatment in GnRH agonist-treated heifers induced similar changes in follicular growth to those observed during the first follicular wave, but despite similar peak concentrations, prolonged exposure to high FSH induced precocious expression of mRNAs for P450scc and P450arom in granulosa cells from small follicles and markedly upregulated expression of these enzymes in granulosa cells from recruited follicles. The results of this study demonstrate the key role that FSH plays in the induction of follicular growth and differentiation.

Upsilon production and polarization in p p macro collisions at square root of s = 1.8 TeV

We report on measurements of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential cross sections (d(2)sigma/dp(T)dy)(/y/<0.4), as well as on the Upsilon(1S) polarization in p p macro collisions at square root of s = 1.8 TeV using a sample of 77+/-3 pb(-1) collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay Upsilon-->mu(+)mu(-). The measured angular distribution of the muons in the Upsilon(1S) rest frame is consistent with unpolarized meson production.

Diffractive dijet production at sqrt[s] = 630 and 1800 GeV at the Fermilab Tevatron

We report a measurement of the diffractive structure function F(D)(jj) of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in pp collisions at sqrt[s] = 630 GeV at the Fermilab Tevatron. The ratio of F(D)(jj) at sqrt[s] = 630 GeV to F(D)(jj) obtained from a similar measurement at sqrt[s] = 1800 GeV is compared with expectations from QCD factorization and other theoretical predictions. We also report a measurement of the xi ( x-Pomeron) and beta ( x of parton in Pomeron) dependence of F(D)(jj) at sqrt[s] = 1800 GeV. In the region 0.035<xi<0.095, /t/<1 GeV2, and beta<0.5, F(D)(jj)(beta,xi) is found to be of the form beta(-1.0+/-0.1)xi(-0.9+/-0.1), which obeys beta-xi factorization.

The effect of increased dietary intake on superovulatory response to FSH in heifers

We have previously shown that the number of ovarian follicles <4 mm in diameter can be increased by enhanced dietary intake in heifers. This study investigated the effect of the same dietary treatment on superovulatory response. The estrous cycles of 24 mature Hereford x Friesian heifers were synchronized by a standard progesterone plus prostaglandin protocol. The animals were fed with either 100% (group M, n = 12) or 200% (group 2M, n = 12) maintenance requirements for a 3-week period. Starting from day 4 of the synchronized estrous cycle, all the animals were superovulated using a standard 4-day FSH regime followed by an injection of GnRH analogue (GnRHa) to induce ovulation. Rectal ultrasound scanning was carried out to assess ovarian follicular populations at the start of FSH treatment and on the day of GnRHa injection, and to determine the number of corpora lutea 5 days after GnRHa injection. The body weight (BW) and body condition score (BCS) were recorded weekly and plasma samples were collected throughout the experimental period. There were no differences in either BW or BCS between two groups at the start of the experiment. The BW and BCS were maintained during the experiment in the group M, whilst animals in the group 2M showed a non-significant (P > 0.05) increase in BW and BCS. Circulating concentrations of insulin were significantly (P < 0.01) higher in heifers from the group 2M throughout the controlled feeding period. The group 2M had significantly (P < 0.05) more follicles 2-4 mm in diameter at the start of FSH treatment and more (P < 0.01) follicles >9 mm in diameter on the day of GnRHa injection, when compared with the group M. Similarly, 5 days after GnRHa injection there were significantly (P < 0.01) more corpora lutea in the group 2M (18.1+/-2.2) than in the group M (10.6+/-3.0). In addition, plasma progesterone concentrations following GnRHa injection were significantly (P < 0.01) higher in heifers from the group 2M. In conclusion, these results confirm that increased dietary intake can enhance the recruitment of ovarian follicles in heifers. This treatment may provide a valuable approach to improving superovulatory response in cattle.

Steroidogenesis in bovine granulosa cells: the effect of short-term changes in dietary intake

The nutritional status of a cow is a key factor in the regulation of both follicle growth and oocyte quality. In this study, the effect of diets designed to increase circulating insulin and insulin-like growth factor I (IGF-I) concentrations on steroid production by granulosa cells in vitro was examined to analyse the mechanisms through which these changes occur. Hereford x Friesian heifers (n = 24) were offered maintenance or twice maintenance diets during the experimental period (17 days). Circulating concentrations of FSH did not differ between the two dietary groups, whereas insulin and IGF-I concentrations showed significant diet x day of oestrous cycle interactions. Ovaries were collected on day 3 of the first follicle wave after synchronization of oestrus. Granulosa cells were isolated from small (1-4 mm) and medium-sized (4-8 mm) follicles and cultured in the presence of long R3-IGF-I or bFSH or both. After 4 days in culture, granulosa cells isolated from small follicles, but not medium-sized follicles, collected from cattle offered the twice maintenance diet secreted significantly higher (P < 0.05) amounts of oestradiol compared with granulosa cells collected from cattle offered the maintenance diet. The effect was apparent in either the presence or absence of FSH and long R3-IGF-I. This nutritional effect on aromatase activity in granulosa cells was not apparent after day 6 of culture. There was no effect of diet on progesterone production by granulosa cells after 4 or 6 days of culture. These results support the hypothesis that dietary-induced changes in circulating insulin and IGF-I concentrations have a direct effect on the steroidogenic potential of bovine granulosa cells from small follicles. The dietary-induced increases in aromatase activity in small follicles combined with the increased concentration of metabolic hormones are possible mechanisms through which short-term changes in nutrition may affect follicle dynamics.