Biomedical subjects

F W Bazer

Publications and source records attributed to F W Bazer.

At least 37 records · Page 2Linked to original sources

PubMed2001

Cloning of the ovine estrogen receptor-alpha promoter and functional regulation by ovine interferon-tau.

Interferon-tau (IFNtau), the ruminant pregnancy recognition signal, inhibits transcription of the estrogen receptor alpha (ERalpha) gene in the endometrial lumenal epithelium of the sheep uterus, thereby abrogating production of luteolytic PGF(2alpha) pulses. The effects of IFNtau are mediated in part by IFN-stimulated response elements (ISREs) and IFN regulatory factor elements (IRFEs). The promoter/enhancer region of the ovine ERalpha gene was cloned, sequenced, and predicted to contain four IRFEs and one ISRE. Electrophoretic mobility shift assays indicated that the -2110 IRFE bound only IRF-1, whereas the -1877 IRFE and the -1284 ISRE were functional in binding IRF-1 and IRF-2. IFNtau inhibited transcriptional activity of the 2.7-kb ovine ERalpha promoter in transfection assays using ovine lumenal epithelium cells. Analyses of sequential 5'-deletion mutants of the ovine ERalpha promoter indicated that the effects of IFNtau may be mediated by IRFEs as well as other elements. Overexpression of ovine IRF-2, but not IRF-1, inhibited transcriptional activity of several regions of the ovine ERalpha promoter containing an IRFE or an ISRE as well as some, but not all, regions lacking these elements.

Animals↗

PubMed2001

Functional analysis of autocrine and paracrine signalling at the uterine-conceptus interface in pigs.

The complexity of implantation necessitates intimate dialogue between conceptus and maternal cells, and precise coordination of maternal and conceptus signalling events. Maternal and conceptus-derived steroid hormones, growth factors and cytokines, as well as integrins and their ligands, have important and inter-related roles in mediating adhesion between apical aspects of conceptus trophectoderm and maternal uterine luminal epithelium that leads to formation of an epitheliochorial placenta. Integrin receptors appear to play fundamental roles in the implantation cascade and may interact with extracellular matrix molecules and other ligands to transduce cellular signals through autocrine and paracrine mechanisms. Functional in vitro analyses can be used to monitor individual contributions of specific integrin receptors and ligands to the signalling cascades of the maternal-conceptus interface. Integrative studies of implantation in pigs, using in vivo and in vitro approaches, are required to understand conceptus attachment and implantation in this species, and provide valuable opportunities to understand the fundamental mechanisms of implantation in all species.

Animals↗

PubMed2000

Active immunization of ewes against ovine placental lactogen increases birth weight of lambs and milk production with no adverse effect on conception rate.

In two experiments, 16 Booroola-Assaf and 35 Assaf ewe-lambs were actively immunized at 5 months of age against recombinant ovine placental lactogen (oPL). At 9 months of age, the ewe-lambs were mated for the first time and then introduced into a frequent mating-system. Anti-oPL antibody titers, reproductive performance, maternal serum levels of oPL during pregnancy, lamb birth weight and milk production of the ewes were followed in the immunized ewes and in their non-immunized control counterparts. All the immunized ewes developed anti-oPL antibodies, which interfered with oPL bioactivity in an in vitro cell proliferation assay. Conception rates did not differ (P>0.05) between immunized and non-immunized ewes. Abundant antibody-bound non-active oPL detected in sera of immunized ewes by western blotting indicated enhanced oPL production by the placenta following immunization. An increase (P<0.02) in serum oPL bioactivity, but not immunoreactivity, was observed in the immunized ewes in late gestation relative to control ewes. The average litter size was 1.83 and 1.32 lambs born per ewe lambing in the first and second experiments, respectively. Average birth weights of lambs born to the immunized ewes were higher (P<0.01) than for lambs born to control ewes by 10, 17 and 39% for those born as singles, twins and triplets, respectively. Immunized ewes produced 19 and 33% more milk (P<0.02) than the control ewes in the first 3.5 months of the first and second lactations, respectively. These findings do not suggest a role for oPL in maternal recognition of pregnancy, but they strongly suggest important roles for oPL in fetal growth and mammogenesis. Immunization of ewes against oPL may thus represent a novel practical technique for enhancing birth weights of lambs born to prolific sheep, as well as milk production by both dairy and mutton ewes.

Animals↗

PubMed2000

Mechanisms regulating norgestomet inhibition of endometrial gland morphogenesis in the neonatal ovine uterus.

In many species, endometrial gland adenogenesis occurs neonatally in an ovary- and steroid-independent manner. Chronic exposure of the developing neonatal ovine uterus to norgestomet (NOR) from birth permanently ablates endometrial gland morphogenesis or adenogenesis, creating an adult ovine uterine gland knockout (UGKO) phenotype. This study was conducted to determine the mechanism(s) whereby NOR inhibits adenogenesis in the neonatal ewe. Ewe lambs received no implant or a NOR implant at birth and on postnatal day (PND) 14, and they were necropsied on PND28. Histological analyses of the tracts indicated NOR exposure specifically inhibited endometrial adenogenesis, but no histoarchitectural differences were observed in the oviduct, cervix, or vagina. No effect of NOR treatment was detected on proliferating cell nuclear antigen (PCNA) expression in the endometrial luminal epithelium (LE), stroma, or myometrium. In control (CX) ewes, estrogen receptor alpha (ER-alpha) and progesterone receptor (PR) mRNA and protein were expressed strongly in nascent and proliferating glandular epithelium (GE) but were undetected in epithelium of NOR uteri. Expression of c-met and fibroblast growth factor receptor 2IIIb (FGFR2IIIb) mRNA was detected in the LE and GE of CX uteri. In NOR uteri, c-met was expressed in the LE similar to CX uteri, but FGFR2IIIb mRNA levels were lower than in the LE of CX uteri. Uterine hepatocyte growth factor (HGF), the ligand for c-met, and FGFR2IIIb mRNA expression was substantially lower in NOR ewes, but expression of FGF-7 and FGF-10 mRNAs, ligands for FGFR2IIIb, was unaffected. These results indicate that NOR disrupts endometrial adenogenesis by ablating epithelial ER-alpha expression and altering expression of paracrine growth factors and/or receptors involved in epitheliomesenchymal interactions. Likewise, these mechanisms are proposed to be important regulators of normal uterine gland morphogenesis in the neonate.

Animals↗

PubMed2000

Interferon tau-induced hepatocyte apoptosis in sheep.

Clinical applications of Type I interferon (IFN) are limited by adverse side effects mediated largely by unknown mechanisms. This study examined the mechanisms of acute hepatic injury in lambs treated with systemic administration of IFN-tau, a Type I IFN. Liver tissues were collected at 24, 48, or 96 hours after treatment with either IFN-tau or saline. Histopathology revealed acute hepatopathy including cellular swelling, cytoplasmic aggregates, and apoptosis in all IFN-tau-treated lambs, which were accompanied by elevation of aspartate transaminase (AST) (P <.01). The number of apoptotic hepatocytes in IFN-tau-treated lambs was higher than for control lambs (P <.001). Immunohistochemistry for proliferating cell nuclear antigen (PCNA) revealed that IFN-tau induced hepatocyte growth arrest at the G0/G1 phase of the cell cycle and that the majority of hepatocytes in S or G2 phase were eliminated by apoptosis. We investigated expression of bax-alpha and bcl-2, acting as pro- and antiapoptotic molecules, in IFN-tau-induced apoptosis. Northern blot analysis revealed increased expression of bax-alpha messenger RNA (mRNA) in IFN-tau-treated lambs (P <.01) compared with control lambs, consistent with the expression pattern for bax-alpha protein. However, there was no detectable difference in expression of bcl-2 proteins between control and IFN-tau-treated lambs. The levels of bax-alpha associated with the mitochondria also increased during IFN-tau treatment. Bax-alpha immunostaining showed scattered immunoreactive hepatocytes with morphological hallmarks of apoptosis. These results suggest that IFN-tau induces growth arrest as well as apoptosis by regulating bax-alpha expression. These pathological effects of IFN-tau on sheep liver indicate potential mechanisms of Type 1 IFN-induced hepatotoxicity in animals and humans.

Animals↗

PubMed2000

Acute-phase proteins and hematologic values in ovine lentivirus-infected lambs treated with recombinant ovine IFN-tau.

To evaluate changes in complete blood cell (CBC) counts, haptoglobin and fibrinogen in ovine lentivirus (OvLV)-infected lambs treated with recombinant ovine interferon-tau (rOVIFN-tau), 24 lambs were allocated to one of four groups (n = 6 per group): (1) virus + rOvIFN-tau, VI, (2) virus + placebo, VP, (3) no virus + rOVIFN-tau, NVI, and (4) no virus + placebo, NVP. Three lambs in each group were treated once a day for 12 weeks, and the remaining 3 lambs were treated for 33 weeks. Blood was collected at days 0, 7, and 10 and at weeks 2-10, 12, 32, and 33 to determine CBC counts, as well as haptoglobin and fibrinogen levels. Hematologic values remained within normal limits in all groups. However, hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and packed cell volume (PCV) values decreased (p < 0.05) in the two rOvIFN-tau-treated groups (VI and NVI) compared with the placebo-treated (VP and NVP) groups. Both rOvIFN-upsilon and OvLV had a mild negative effect on neutrophil numbers. Although Hb, MCV, MCHC, PCV, and neutrophil values declined in the rOvIFN-tau-treated lambs compared with the placebo-treated lambs, these values remained within the reference range for sheep. Experimental lambs did not show adverse clinical signs associated with OvLV infection or as a result of rOvIFN-tau treatment. The lack of significant side effects of high-dose rOvIFN-tau in sheep and previous reports of broad-spectrum and cross-species antiviral activity suggest that rOvIFN-tau warrants further investigation as an antiviral therapeutic agent.

Acute-Phase Proteins↗

PubMed2000

Ovine uterine gland knock-out model: effects of gland ablation on the estrous cycle.

Ovine endometrial gland development is a postnatal event that can be inhibited epigenetically by chronic exposure of ewe lambs to a synthetic progestin from birth to puberty. As adults, these neonatally progestin-treated ewes lack endometrial glands and display a uterine gland knockout (UGKO) phenotype that is useful as a model for study of endometrial function. Here, objectives were to determine: 1) length of progestin exposure necessary from birth to produce the UGKO phenotype in ewes; 2) if UGKO ewes display normal estrous cycles; and 3) if UGKO ewes could establish and/or maintain pregnancy. Ewe lambs (n = 22) received a Norgestomet (Nor) implant at birth and every two weeks thereafter for 8 (Group I), 16 (Group II), or 32 (Groups III and IV) weeks. Control ewe lambs (n = 13) received no Nor treatment (Groups V and VI). Ewes in Groups I, II, III, and VI were hemihysterectomized (Hhx) at 16 weeks of age. After puberty, the remaining uterine horn in Hhx ewes was removed on either Day 9 or 15 of the estrous cycle (Day 0 = estrus). Histological analyses of uteri indicated that progestin exposure for 8, 16, or 32 weeks prevented endometrial adenogenesis and produced the UGKO phenotype in adult ewes. Three endometrial phenotypes were consistently observed in Nor-treated ewes: 1) no glands, 2) slight glandular invaginations into the stroma, and 3) limited numbers of cyst- or gland-like structures in the stroma. Overall patterns of uterine progesterone, estrogen, and oxytocin receptor expression were not different in uteri from adult cyclic control and UGKO ewes. However, receptor expression was variegated in the ruffled luminal epithelium of uteri from UGKO ewes. Intact UGKO ewes displayed altered estrous cycles with interestrous intervals of 17 to 43 days, and they responded to exogenous prostaglandin F(2 approximately ) (PGF) with luteolysis and behavioral estrus. During the estrous cycle, plasma concentrations of progesterone in intact control and UGKO ewes were not different during metestrus and diestrus, but levels did not decline in many UGKO ewes during late diestrus. Peak peripheral plasma concentrations of PGF metabolite, in response to an oxytocin challenge on Day 15, were threefold lower in UGKO compared to control ewes. Intact UGKO ewes bred repeatedly to intact rams did not display evidence of pregnancy based on results of ultrasound. Collectively, results indicate that 1) transient, progestin-induced disruption of ovine uterine development from birth alters both structural and functional integrity of the adult endometrium; 2) normal adult endometrial integrity, including uterine glands, is required to insure a luteolytic pattern of PGF production; and 3) the UGKO phenotype, characterized by the absence of endometrial glands and a compact, disorganized endometrial stroma, limits or inhibits the capacity of uterine tissues to support the establishment and/or maintenance of pregnancy.

Animals↗

PubMed2000

Interferon-tau and progesterone regulate ubiquitin cross-reactive protein expression in the ovine uterus.

Ubiquitin cross-reactive protein (UCRP) is a functional ubiquitin homolog synthesized by the ruminant endometrium in response to conceptus-derived interferon-tau (IFNtau). Progesterone is required for IFNtau to exert antiluteolytic actions on the endometrium. Therefore, this study was designed to determine whether progesterone is requisite for IFNtau induction of UCRP expression within the ovine uterus. Cyclic ewes were ovariectomized and fitted with intrauterine (i.u.) catheters on Day 5 and treated daily with steroids (i.m.) and protein (i.u.) as follows: 1) progesterone (P, Days 5-24) and control serum proteins (CX, Days 11-24); 2) P and ZK 137.316 (ZK; progesterone receptor antagonist, Days 11-24) and CX proteins; 3) P and recombinant ovine IFNtau (roIFNtau, Days 11-24); or 4) P and ZK and roIFNtau. All ewes were hysterectomized on Day 25. In P-treated ewes, roIFNtau increased endometrial UCRP mRNA and protein levels. However, administration of ZK to ewes ablated roIFNtau induction of UCRP. Recombinant ovine IFNtau induced expression of UCRP mRNA in progestinized endometrial luminal (LE) and glandular (GE) epithelium as well as in both stratum compactum and spongiosum layers of the stroma (ST). Progesterone receptor protein was located in endometrial ST, but not in LE and GE from these ewes. Results support the hypothesis that progesterone is required for IFNtau induction of type I IFN-responsive genes, such as UCRP, in the ruminant uterus.

Animals↗

PubMed2000

Progesterone modulation of osteopontin gene expression in the ovine uterus.

Osteopontin (OPN) is an acidic phosphorylated glycoprotein component of the extracellular matrix that binds to integrins at the cell surface to promote cell-cell attachment and cell spreading. This matrix constituent is a ligand that could potentially bind integrins on trophectoderm and endometrium to facilitate superficial implantation and placentation. OPN mRNA increases in the endometrial glandular epithelium (GE) of early-pregnant ewes, and OPN protein is secreted into the uterine lumen. Therefore, progesterone and/or interferon-tau (IFNtau) may regulate OPN expression in the uterine GE. Cyclic ewes were ovariectomized and fitted with intrauterine (i. u.) catheters on Day 5 and treated daily with steroids (i.m.) and protein (i.u.) as follows: 1) progesterone (P, Days 5-24) and control serum proteins (CX, Days 11-24); 2) P and ZK 136.317 (ZK; progesterone receptor [PR] antagonist, Days 11-24) and CX proteins; 3) P and recombinant ovine IFNtau (roIFNtau, Days 11-24); or 4) P and ZK and roIFNtau. All ewes were hysterectomized on Day 25. Progesterone induced the expression of endometrial OPN mRNA in the GE and increased secretion of a 45-kDa OPN protein from endometrial explants maintained in culture for 24 h. Administration of ZK ablated progesterone effects. Intrauterine infusion of roIFNtau did not affect OPN gene expression or secretion in any of the steroid treatments. Interestingly, OPN mRNA-positive GE cells lacked detectable PR expression, although PR were detected in the stroma. Results indicate that progesterone regulates OPN expression in GE through a complex mechanism that includes PR down-regulation, and we suggest the possible involvement of a progesterone-induced stromal cell-derived growth factor(s) that acts as a progestamedin.

Animals↗

PubMed2000

Keratinocyte growth factor: expression by endometrial epithelia of the porcine uterus.

Keratinocyte growth factor/fibroblast growth factor-7 (KGF/FGF-7) is an established paracrine mediator of hormone-regulated epithelial growth and differentiation. In all organs studied, KGF is uniquely expressed in cells of mesenchymal origin. To determine whether KGF and its receptor, keratinocyte growth factor receptor (KGFR) or fibroblast growth factor receptor-2IIIb, were expressed in the porcine uterus as a potential paracrine system mediating progesterone action, we cloned KGF and KGFR partial cDNAs from the porcine endometrium. KGF and KGFR expression was detected in endometrium by Northern blot hybridization. Interestingly, in situ hybridization results demonstrated that KGF was expressed by endometrial epithelia and was particularly abundant between Days 12 and 15 of the estrous cycle and pregnancy. KGF secretion into the lumen of the porcine uterus was also detected on Day 12 of the estrous cycle and pregnancy. KGFR was expressed in both endometrial epithelia and conceptus trophectoderm. These novel findings suggest that KGF may act on the uterine endometrial epithelium in an autocrine manner and on the conceptus trophectoderm in a paracrine manner in the pig, which is the only species possessing a true epitheliochorial type of placentation.

Animals↗

PubMed2000

Prolactin receptor and uterine milk protein expression in the ovine endometrium during the estrous cycle and pregnancy.

Lactogenic hormones regulate epithelial proliferation, differentiation, and function in a variety of epitheliomesenchymal organs. During pregnancy, the ovine uterus is a potential site for endocrine and paracrine actions of lactogenic hormones in the form of pituitary prolactin (PRL) and placental lactogen (PL). These studies determined temporal and spatial alterations in PRL receptor (PRL-R) and expression of uterine milk proteins (UTMP), a marker of endometrial secretory activity, in the ovine endometrium during the estrous cycle and pregnancy. Slot-blot hybridization analysis indicated that steady-state levels of endometrial PRL-R mRNA increased during pregnancy. In situ hybridization and immunohistochemical analyses indicated that PRL-R mRNA and protein were exclusively expressed in the endometrial glandular epithelium (GE). No PRL-R mRNA expression was detected in luminal epithelium, stroma, myometrium, or conceptus trophectoderm. Reverse transcription-polymerase chain reaction analyses determined that the endometrial GE expressed both long and short alternative splice forms of the ovine PRL-R gene. Slot-blot hybridization analysis indicated that steady-state levels of intercaruncular endometrial UTMP mRNA increased about 3-fold between Days 20 and 60, increased another 3-fold between Days 60 and 80, and then declined slightly to Day 120. In pregnant ewes, UTMP mRNA expression was restricted to the endometrial GE in the stratum spongiosum (sGE), increased substantially between Days 15 and 17, and, between Days 17 to 50 of gestation, was markedly higher in upper than lower sGE. After Day 50, hyperplasia of the sGE was accompanied by increased UTMP mRNA expression by all sGE. Collectively, results indicate that 1) endometrial sGE is a primary target for actions of lactogenic hormones and 2) UTMP mRNA expression is correlated with PL production by the trophectoderm and state of sGE differentiation during pregnancy. It is proposed that activation of PRL-R signal transduction pathways by PRL and PL plays a major role in endometrial GE remodeling and differentiated function during pregnancy in support of conceptus growth and development.

Animals↗

PubMed2000

Expression of hepatocyte growth factor and its receptor c-met in the ovine uterus.

Epithelial-mesenchymal interactions (EMI) are necessary for epithelial cell proliferation, differentiation, and function in the uterus and are mediated, in part, by paracrine growth factors of stromal origin. The objective of this study was to determine if hepatocyte growth factor (HGF, scatter factor) and its receptor c-met were present in the ovine uterus and to characterize their temporal and spatial expression during the estrous cycle and pregnancy. Reverse transcription-polymerase chain reaction was used to clone partial cDNAs for ovine HGF and c-met from endometrial total RNA. Northern blot analysis of endometrial RNA revealed expression of a 6-kb mRNA for HGF and an 8-kb mRNA for c-met in ovine endometrium. In situ hybridization demonstrated that HGF mRNA was expressed by stromal cells of the endometrium, whereas c-met mRNA was localized exclusively to luminal and glandular epithelial cells. In the early conceptus, HGF mRNA was expressed by chorioallantoic mesenchyme, and c-met was expressed by trophectoderm. Steady-state levels of endometrial c-met mRNA increased after Day 9 in both cyclic and pregnant ewes. The HGF mRNA was expressed during both the estrous cycle and early pregnancy. Results indicate that HGF is a stromal-derived paracrine growth factor in the ovine uterus and placenta that is potentially involved in endometrial epithelial-stromal interactions and chorioallantoic stromal-trophectodermal interactions. In the ovine uterus, HGF may stimulate epithelial morphogenesis and differentiated function required for establishment and maintenance of pregnancy, conceptus implantation, and placentation.

Animals↗

PubMed2000

Effects of protease inhibitors and antioxidants on In vitro survival of porcine primordial germ cells.

One of the problems associated with in vitro culture of primordial germ cells (PGCs) is the large loss of cells during the initial period of culture. This study characterized the initial loss and determined the effectiveness of two classes of apoptosis inhibitors, protease inhibitors, and antioxidants on the ability of porcine PGCs to survive in culture. Results from electron microscopic analysis and in situ DNA fragmentation assay indicated that porcine PGCs rapidly undergo apoptosis when placed in culture. Additionally, alpha(2)-macroglobulin, a protease inhibitor and cytokine carrier, and N:-acetylcysteine, an antioxidant, increased the survival of PGCs in vitro. While other protease inhibitors tested did not affect survival of PGCs, all antioxidants tested improved survival of PGCs (P: < 0.05). Further results indicated that the beneficial effect of the antioxidants was critical only during the initial period of culture. Finally, it was determined that in short-term culture, in the absence of feeder layers, antioxidants could partially replace the effect(s) of growth factors and reduce apoptosis. Collectively, these results indicate that the addition of alpha(2)-macroglobulin and antioxidants can increase the number of PGCs in vitro by suppressing apoptosis.

Acetylcysteine↗

PubMed2000

Fibroblast growth factor-10: a stromal mediator of epithelial function in the ovine uterus.

Fibroblast growth factor-10 (FGF-10) is a stromal-derived paracrine growth factor considered to be important during embryogenesis; however, its expression by cells in the female reproductive tract has not been investigated. Therefore, an ovine FGF-10 cDNA was cloned from an ovine endometrial cDNA library to investigate expression and potential paracrine characteristics of FGF-10 in the ovine uterus. The ovine FGF-10 cDNA encodes a protein of 213 amino acids and possesses an unusually long 5' untranslated region (UTR). In situ hybridization demonstrated that ovine FGF-10 mRNA was expressed by endometrial stromal cells and by mesenchymal cells of the chorioallantoic placenta. The mRNA for FGF-7, a homologue of FGF-10, was localized in the tunica muscularis of blood vessels in endometrium and myometrium. In contrast, FGF receptor 2IIIb, the high-affinity receptor for both FGF-10 and FGF-7, was expressed exclusively in luminal epithelium, glandular epithelium, and placental trophectoderm. The in vivo spatial expression pattern suggests that FGF-10 is a novel endometrial stromal cell-derived mediator of uterine epithelial and conceptus trophectodermal functions. The nonoverlapping spatial patterns of expression for FGF-10 and FGF-7 in ovine uterus and conceptus suggest independent roles in uterine function and conceptus development.

Amino Acid Sequence↗

PubMed2000

Neonatal ovine uterine development involves alterations in expression of receptors for estrogen, progesterone, and prolactin.

Effects of age on uterine histoarchitecture, cell proliferation, and hormone receptor expression were determined for neonatal ewe lambs from birth (Postnatal Day [PND] 0) to PND 56. Uteri were histologically evaluated and proliferating cell nuclear antigen (PCNA), estrogen receptor alpha (ER-alpha), progesterone receptor (PR), and prolactin receptor (PRL-R) expression were characterized by in situ hybridization (ISH), immunohistochemistry, or both. The most striking feature of neonatal uterine development was the genesis and development of glands in the intercaruncular areas of endometrium. After birth, endometrial glandular epithelium (GE) budded and differentiated into the underlying stroma from the luminal epithelium (LE) between PNDs 1 and 7. Between PNDs 14 and 56, extensive coiling and branching morphogenesis of nascent endometrial glands occurred. By PND 56, the uterine wall appeared to be histoarchitecturally mature. At birth, nuclear PCNA protein was strongly detected in LE. Between PNDs 7 and 56, high levels of PCNA, ER-alpha, and PR gene expression were detected in both nascent and developing GE. Higher levels of PCNA and ER-alpha expression were detected in GE at the tips of developing glands as well as in the surrounding stroma. Progesterone was below detectable limits in serum. Serum estradiol-17beta levels were high on PND 1, increased from PNDs 14 to 28, and declined from PND 42 to PND 56. Serum PRL levels increased from PNDs 1 to 14 and declined thereafter. Using ISH and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, expression of mRNAs for short and long forms of the ovine PRL-R were first detected in nascent GE on PND 7 and increased between PNDs 7 and 56 in proliferating and differentiating GE. These results indicate that 1) uterine gland genesis is initiated between PNDs 1 and 7 after birth and is essentially completed by PND 56; 2) neonatal uterine morphogenesis involves temporal and spatial alterations in cell proliferation and ER-alpha, PR, and PRL-R gene expression; 3) PRL-R expression is a unique marker of GE differentiation and proliferation; and 4) serum estradiol-17beta and PRL levels increase during the onset of GE tubular branching morphogenesis. Results support the hypothesis that neonatal ovine uterine development involves epithelial PRL-R and ER-alpha activation to stimulate and maintain endometrial gland genesis and branching morphogenesis.

Animals↗

PubMed2000

Arginine nutrition in development, health and disease.

As a precursor of nitric oxide, polyamines and other molecules with enormous biologic importance, L-arginine plays versatile key roles in nutrition and metabolism. Arginine is an essential amino acid in the fetus and neonate, and is conditionally an essential nutrient for adults, particularly in certain disease conditions. L-Arginine administration is beneficial in improving reproductive, cardiovascular, pulmonary, renal, gastrointestinal, liver and immune functions, and in facilitating wound healing. The effect of L-arginine in treating many common health problems is unique among amino acids, and offers great promise for improved health and well-being in the future.

Arginine↗

PubMed2000

Effects of recombinant ovine interferon-tau on ovine lentivirus replication and progression of disease.

The antiviral effects of recombinant ovine interferon-tau (roIFN-tau) were studied in 26 lambs inoculated with ovine lentivirus (OvLV) or mock-infected. Six of the OvLV-infected lambs and three of the mock-infected lambs were treated with 10(6) antiviral units (AVU) per kg roIFN-tau daily for 30 days starting at day 0 post-inoculation (p.i.) and twice a week thereafter (early treatment). Six of the OvLV-infected lambs and three of the mock-infected lambs were treated with 10(6) AVU/kg roIFN-tau daily for 30 days starting at day 150 p.i. and twice a week thereafter (late treatment). Six OvLV-infected and two mock-infected lambs were treated either early or late with placebo. Cell-associated viraemia was quantified by an end-point dilution method. The weekly antibody response against OvLV proteins was studied by ELISA. All experimental animals were killed at 27 weeks p.i. and histological sections of lung were scored for the degree of lymphoid interstitial pneumonia (LIP). A 90% reduction in OvLV titres was detected at 4 weeks post-treatment in lambs that received early roIFN-tau treatment (P<0.01). Differences in virus titres were also found at weeks 2 and 6 (P<0.05). Scores for LIP degree were higher in infected lambs treated with placebo or late roIFN-tau than in the mock-infected lambs or in the infected lambs that received early roIFN-tau (P<0.05). LIP scores were not different between mock-infected lambs and infected lambs that received early roIFN-tau. These results indicate that roIFN-tau curtails OvLV replication in vivo and reduces the likelihood of development of lentivirus-induced LIP when infected lambs are treated during the initial phases of OvLV infection.

Animals↗

PubMed1999

Comparison of naturally acquired parasite burdens among Florida native, Rambouillet and crossbreed ewes.

The response to natural infection by gastrointestinal nematodes was evaluated in three groups of lambing mature ewes: 16 Florida Native; 21 Rambouillet; and 18 1/2 Florida Native x1/2 Rambouillet (F1 generation). Fecal egg counts (FEC), packed cell volume (PCV) and plasma protein levels were determined periodically through a one-year period. The highest FEC was recorded in Rambouillet ewes, with most of the means higher than 1000 eggs per gram (EPG). Florida Native and F1 ewes showed similar trends in FEC, with most of the means below 500 EPG. The highest mean PCV values were recorded in Florida Native ewes, followed in decreasing order by F1 and Rambouillet ewes. F1 ewes showed the lowest plasma protein levels and Florida Natives the highest. Fecal cultures revealed the highest percentages of Haemonchus larvae in Rambouillet ewes (>64%) and the lowest percentages in Florida Native ewes. Florida Native and F1 ewes were more resistant to gastrointestinal nematode infections than were Rambouillet ewes. High negative correlation coefficients between FEC x PCV and FEC x plasma protein levels coincided with peaks in mean FEC of Rambouillet (May and July), Florida Native and F1 ewes (October). This study showed that crossbreeding Rambouillet and Florida Native sheep resulted in the production of F1 ewes resistant against gastrointestinal nematode infections.

Animals↗