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R M Roberts

Publications and source records attributed to R M Roberts.

At least 55 records · Page 3Linked to original sources
PubMed1998

Loss of the signature six carboxyl amino acid tail from ovine interferon-tau does not affect biological activity.

Interferon-tau (IFN-tau) is a type I IFN that is secreted from conceptuses of Bovidae (sheep, cattle, and related ruminant ungulates) for a few days during early pregnancy. It acts to prolong the life span of the corpus luteum. All secreted forms of IFN-tau, like the related IFN-omega, are 172 amino acids in length and differ from IFN-alpha and -beta by the presence of six additional amino acids at their carboxyl termini. The aim of this study was to determine whether this carboxyl tail was important for biological activity of IFN-tau, particularly for its antiluteolytic function in ewes. Full-length ovine IFN-tau (p3) and a mutated form truncated by six amino acids at its carboxyl terminal (p3Trn6, 166 amino acids) were produced in Escherichia coli. Both proteins had similar antiviral activities (2.12 +/- 0.92 x 10(8) IU/mg for p3; 1.96 +/- 0.58 x 10(8) IU/mg for p3Trn6) when tested on Madin-Darby bovine kidney (MDBK) cells. Antiproliferative activity, as measured on human Daudi cells by determining the protein concentration required to inhibit growth by 50%, was slightly higher (p < 0.05) for p3Trn6 (7.36 +/- 0.46 pM) than for p3 (13.99 +/- 0.85 pM). Most importantly, p3 and p3Trn6 were equally capable of prolonging the life span of the corpus luteum of nonpregnant ewes when the proteins were administered at doses of either 60 or 300 microg/day into the uterine lumen through indwelling uterine cannulae from Day 10 to Day 18 postestrus. Therefore, the carboxyl-terminal amino acid extension for IFN-tau does not appear to serve a functional role in the action of these proteins.

Animals↗
PubMed1998

Pepsin-related molecules secreted by trophoblast.

The pregnancy-associated glycoproteins (PAGs) were first described as placental antigens of cattle that were also present in the blood serum of the mother after implantation. Molecular cloning studies have shown that they are members of the aspartic proteinase gene family and closely related to the pepsinogens. An enzymatic role seems unlikely, as at least some of them have mutations likely to render them enzymatically inactive. Nevertheless, these molecules have retained the substrate-binding cleft of the pepsins and are expressed abundantly in trophectoderm, particularly in the invasive binucleate cell component. There may be as many as 100 PAG genes in cattle and sheep, many of which are transcribed. PAGs are also products of the placenta of the pig, a species whose progenitors diverged from the ruminants at least 55 million years ago. There is even evidence for PAG-like molecules outside the Artiodactyla. Although their function remains elusive, it seems unlikely that these placentally expressed molecules are simply oddities in view of their long-term evolutionary survival and conspicuous presence at the fetal-maternal interface.

Animals↗
PubMed1997

The diversity and evolutionary relationships of the pregnancy-associated glycoproteins, an aspartic proteinase subfamily consisting of many trophoblast-expressed genes.

The pregnancy-associated glycoproteins (PAGs) are structurally related to the pepsins, thought to be restricted to the hooved (ungulate) mammals and characterized by being expressed specifically in the outer epithelial cell layer (chorion/trophectoderm) of the placenta. At least some PAGs are catalytically inactive as proteinases, although each appears to possess a cleft capable of binding peptides. By cloning expressed genes from ovine and bovine placental cDNA libraries, by Southern genomic blotting, by screening genomic libraries, and by using PCR to amplify portions of PAG genes from genomic DNA, we estimate that cattle, sheep, and most probably all ruminant Artiodactyla possess many, possibly 100 or more, PAG genes, many of which are placentally expressed. The PAGs are highly diverse in sequence, with regions of hypervariability confined largely to surface-exposed loops. Nonsynonymous (replacement) mutations in the regions of the genes coding for these hypervariable loop segments have accumulated at a higher rate than synonymous (silent) mutations. Construction of distance phylograms, based on comparisons of PAG and related aspartic proteinase amino acid sequences, suggests that much diversification of the PAG genes occurred after the divergence of the Artiodactyla and Perissodactyla, but that at least one gene is represented outside the hooved species. The results also suggest that positive selection of duplicated genes has acted to provide considerable functional diversity among the PAGs, whose presence at the interface between the placenta and endometrium and in the maternal circulation indicates involvement in fetal-maternal interactions.

Amino Acid Sequence↗
PubMed1997

Expression of a plasmin/trypsin Kunitz inhibitor by pig trophoblast.

Under the influence of progesterone, the porcine uterus synthesizes plasmin/trypsin inhibitor (PTI), a low molecular weight protein (M(r) approximately 14,000) belonging to the Kunitz family of proteinase inhibitors. Here it is demonstrated that mRNA for the same protein is produced by the developing trophoblast during early pregnancy and by the placenta throughout gestation. The transcript for PTI was represented in approximately 0.1% of total phage plaques of a day 13-17 porcine conceptus cDNA library. It shared 99% nucleotide sequence identity with the cDNA isolated from the uterine library and encoded a 112-amino-acid protein identical to the uterine-produced PTI, which has a well-defined Kunitz domain comprised of 64 residues at its amino terminus. Northern analysis and in situ hybridization studies confirmed that expression of PTI by the conceptus begins as early as day 10 of pregnancy and is continued in placental tissues until at least day 90 of gestation. Expression was trophoblast specific at day 20 of gestation, as in situ hybridization detected no mRNA in the embryo. The pattern of PTI expression during pregnancy is consistent with a role either in controlling trophoblast invasiveness or in inhibiting proteinases with trypsin-like specificity released by immune or inflammatory cells.

Amino Acid Sequence↗
PubMed1997

Ancient DNA from Polynesian rats: extraction, amplification and sequence from single small bones.

The human colonisation of Polynesia was a major event in world prehistory. It represents one of the last human population migrations, and one which required crossing major water barriers. Though the subject of Pacific population origins has been approached by scholars from numerous fields for nearly a century, recent years have seen the problem addressed by human geneticists. Since the initial report describing the recovery of DNA from skeletal remains, ancient DNA studies have also focused on the Pacific region. In this paper we present the results of ancient DNA analyses of Rattus exulans, an animal that was transported by ancestral Polynesians through the Pacific to the far reaches of the Polynesian triangle. Analysis of DNA of R. exulans skeletal remains has many advantages over studies of ancient human remains, yet the one drawback has been the recovery of ancient DNA from single bones of these very small rodents. We have successfully modified standard extraction protocols for ancient DNA and have consistently extracted, amplified and sequenced mitochondrial DNA (mtDNA) from less than 0.1 g of R. exulans bone and tooth samples recovered from archaeological sites throughout the Pacific, ranging from 400 to 2000 years old.

Animals↗
PubMed1997

The antiproliferative and antiviral activities of IFN-tau variants in human cells.

The IFN-tau are type I IFN expressed by the early trophoblast of cattle and sheep but have activity on human cells and have been predicted to have potential therapeutic value. We have compared a series of mutant bovine and ovine IFN-tau with regard to their ability to inhibit the proliferation of Daudi cells and to evoke an antiviral (AV) response in WISH cells. Whereas Daudi cell growth was inhibited by Bo-IFN-tau1 in the 1 nM range, WISH cells were much less responsive, requiring exposure to 150 nM for protection against vesicular stomatitis virus. Replacement of lysines at positions 34, 107, 121, and 132 in Bo-IFN-tau, which are in regions predicted to interact with the type I receptor, led to modest but significant alterations in antiproliferative (AP) and AV activities. Replacement of the lysine residues at 160 and 164 had marked effects on biopotency, with K160 being particularly important. The different IFN-tau were able to activate the transcription factors ISGF3 and AAF (GAF) in Daudi cells at concentrations that correlated reasonably well with their AP potencies. Stat activation occurred in WISH cells in response to approximately 2 nM Bo-IFN-tau1, but ISGF3 formation could not be demonstrated even at the 100-fold higher IFN-tau concentrations that gave viral protection. Pretreatment of WISH cells with Hu-IFN-gamma allowed ISGF3 formation to be observed in response to subsequent treatment with Bo-IFN-tau1 or type I human IFN but did not increase the AV responsiveness of the cells. No evidence was found that IFN-tau elicit uniquely different responses on human cells than type I Hu-IFN, except they are much less potent. The data emphasize the importance of a region near the carboxyl terminus for the functional activity of type I IFN, and that although ISFG3 formation may be necessary, its mere presence is not sufficient to provide an antiviral response.

Amino Acid Sequence↗
PubMed1997

Adenovirus-mediated gene transfer by perivitelline microinjection of mouse, rat, and cow embryos.

To determine the fate of an episomally expressed transgene, mouse, rat, and cow zygotes were injected into the perivitelline space with approximately 100 pl of buffer containing the replication-defective human adenovirus, AdCMVLacZ/sub360. Viral concentrations ranged from 2.5 to 2.5 x 10(5) plaque-forming units (pfu)/100 pl. As viral titer increased, fewer embryos were able to develop to blastocysts. In the mouse, the percentage of blastocysts formed ranged from 82% in controls to 16% after injection at the highest titer. In the rat and cow, a similar decrease in blastocyst formation was noted (62% to 6% and 26% to 4%, respectively). Reporter gene (galactosidase, LacZ) activity could be detected in mouse embryos after injection at a concentration of only 25 pfu/100 pl, whereas a tenfold higher titer was required in the other two species to observe the blue LacZ reaction product. When examined after 5 (mouse), 6 (rat), or 9 (cow) days of in vitro culture, the proportion of LacZ-positive embryos ranged from 15% to 96%, 6% to 76%, and 18% to 58% in mouse, rat, and cow embryos, respectively, depending upon viral concentration. However, a large percentage of positive embryos proved to be expression mosaics, the degree of which was likewise dependent on titer. While none of the embryos showed LacZ activity at 30 h after injection, 70% of mouse, 8% of rat, and 20% of cow embryos expressed the reporter gene at 42 h. Delaying the timing of injection revealed that the efficiency with which mouse and rat embryos could be infected decreased with increasing degree of differentiation. Only 35% and 18% of mouse embryos expressed the reporter gene after injection at the morula or blastocyst stage, respectively. A similar drop in efficiency was noted in rat embryos when injections took place at the 8-cell, morula, or blastocyst stage, with 70%, 33%, and 9% of embryos, respectively, subsequently showing LacZ activity. Likewise, advanced development resulted in a decrease in the efficiency of viral-mediated gene transfer in cow embryos, with 100%, 78%, and 68% of embryos being positive after injection at the 8-cell, morula, or blastocyst stage, respectively. These results demonstrate that a human adenovirus can be used to express a reporter gene transiently in nonhuman embryos.

Adenoviridae↗
PubMed1997

Effect of variants of interferon-tau with mutations near the carboxyl terminus on luteal life span in sheep.

Mutant forms of recombinant ovine interferon-tau (oIFN-tau) have been previously prepared by site-directed mutagenesis of an ovine gene with the purpose of establishing relationships between structure and function of the molecule. These mutant forms have altered antiviral and antiproliferative activities, and receptor-binding affinities, and their ability to extend estrous cycle length after being injected i.m. into nonpregnant ewes has been established. In experiment 1, i.m. injection of either PBS (vehicle) alone or with 0.1 mg (n = 4), 0.5 mg (n = 4), or 2.0 mg (n = 3) of recombinant olFN-tau (S4, identified below) was performed twice daily on Days 11-18 postestrus (Day 0 = estrus). Luteal life span was extended (p < 0.05) by 4.8 days after injection of 0.5 mg or 2.0 mg oIFN-tau; injection of 0.1 mg had no effect (p > 0.05) on luteal life span relative to the group that received vehicle alone. In subsequent experiments, the dosage of oIFN-tau was 1.0 mg per injection twice daily. The objective of experiment 2 was to determine the effect of mutated forms of oIFN-tau on luteal life span in sheep. Fifty-seven ewes received twice-daily injections (i.m.) from Day 10 to Day 20 postestrus of PBS (vehicle) either alone (n = 9), with 0.3 mg/injection of bacterial contaminating proteins (BP; n = 10), or with 1 mg/injection of one of the following forms of recombinant oIFN-tau: 1) a fully active, 172-amino acid (aa) oIFN-tau (S4, n = 10); 2) a form lacking 11 aa at the carboxyl terminus and with an I143-->T mutation (S1), which had very low antiviral and antiproliferative activities and receptor-binding affinities (n = 9); 3) a truncated form identical to S1 but with I143 restored (TRN11), which had low antiviral and antiproliferative activities but only slightly reduced receptor-binding affinities (n = 10); and 4) a form similar to wild type S4 (S4-K) with low antiviral and antiproliferative activities but only slightly reduced receptor-binding affinities (n = 9). Luteal life span was slightly longer (p < 0.05) in the TRN11 and S4-K groups (19.6 and 20.6 days, respectively) than in the PBS, BP, and S1 groups (16.2, 16.8, and 17.5 days, respectively). In the S4 group, mean luteal life span was 33.6 +/- 5.9 days (range 15.5-64 days). A third experiment entailing twice-daily injections of either 0.3 mg BP (n = 6), 1 mg TRN11 (n = 5), 1 mg S4-K (n = 5), or 1 mg S4 (n = 5) was conducted in which the pyrogenic effect of the oIFN-tau was also examined. Luteal life span was longer (p < 0.05) in the S4-K and S4 groups (18.9 and 28 days, respectively) than in the BP and TRN11 groups (16.6 and 17.6 days, respectively). Intramuscular injection of all forms of IFN-tau caused hyperthermia in ewes initially, but ewes appeared to become refractory to treatment after several days. In summary, extension of luteal life span was more closely associated with biological activity as assessed in vitro than with receptor binding affinities.

Animals↗
PubMed1997

Multiple pregnancy-associated glycoproteins are secreted by day 100 ovine placental tissue.

Pregnancy-associated glycoprotein (PAG)-1 (PAG1) and pregnancy-specific protein B are either identical or closely related antigens released by trophoblast binucleate cells of placentas of cattle. Sheep and other ruminants produce similar products. There is evidence, however, that these antigens, which are related structurally to the pepsinogens and other aspartic proteinases, are not single gene products but members of an extensive family. Here, the sequential use of ammonium sulfate precipitation and Sepharose blue, anion-exchange, and cation-exchange chromatographies, as well as isoelectric elution from a Mono P column, has allowed several PAG1-related molecules to be purified from the medium after culture of explants from Day 100 sheep placentas. Each of these PAGs cross-reacted to a varying extent with a panel of three different anti-PAG1 antisera. Four of them, all of which were major secretory products of the placenta, were subjected to amino-terminal microsequencing. Although each was related to ovine (ov) PAG1, none was identical. Reverse transcription-polymerase chain reaction was then used to amplify PAG1-related cDNA from Day 100 placental RNA. Seven novel full-length cDNA, all distinct from ovPAG1, were identified from 25 cDNA selected for sequencing. Only two of these (ovPAG3 and ovPAG7) encoded polypeptides identical in sequence at their inferred amino termini to one of the PAGs (ovPAG65) purified from explant cultures. Even so, they were only 84% identical in overall sequence. The remaining five cDNA were unique. In situ hybridization analysis revealed that expression of ovPAG3 and ovPAG7, like that of ovPAG1, is confined to trophoblast binucleate cells. The data confirm that at Day 100 of pregnancy the ovine placenta produces many different PAGs, which differ considerably in sequence and immunological cross-reactivity.

Amino Acid Sequence↗
PubMed1997

Molecular cloning of ovine and bovine type I interferon receptor subunits from uteri, and endometrial expression of messenger ribonucleic acid for ovine receptors during the estrous cycle and pregnancy.

Interferon-tau (IFN-tau), a type I IFN structurally related to IFN-alpha, is regarded as the major antiluteolytic factor secreted by the conceptus of ruminant ungulate species before definitive trophoblast attachment and implantation. It mediates its effects by acting on the uterine endometrium, where it blunts the normal pulsatile production of PGF2alpha, presumably as a result of its binding to type I IFN receptors. In this study, we describe the complementary DNAs for the two known subunits, IFNAR1 and IFNAR2, of this receptor isolated from bovine and ovine endometrial complementary DNA libraries by homology cloning. Although there is extensive inferred amino acid sequence similarity between bovine and ovine IFNAR1 (92% identity) and between bovine and ovine IFNAR2 (88% identity), they have diverged extensively from the human receptor subunits (approximately 67% and approximately 58% identity, respectively). Despite these differences in primary structure, the respective subunits from all three species are organized similarly in their extracellular and cytoplasmic regions, and the bovine and ovine subunits have each retained a number of polypeptide motifs implicated in signal transduction. These uterine receptors also appear not to be splice variants. The cloned ovine IFNAR1 subunit, for example, possesses the expected four extracellular SD100 domains of full-length bovine and huIFNAR1, and only the homologs of the so-called long form (huIFNAR2c) of human IFNAR2 have so far been identified. RT-PCR procedures indicate that the messenger RNA for both subunits are found, not only in endometrium, but in all other tissues examined except those ofpreimplantation conceptuses, which presumably cannot respond to the IFN-tau they produce. Quantitative RNase protection assays of ovine endometrial RNA show that the expression of neither subunit changes greatly during the estrous cycle or pregnancy. These data suggest that the type I IFN receptor, which is expressed by the endometrium and binds IFN-tau, is probably not a structurally unusual form.

Amino Acid Sequence↗
PubMed1997

Silencing of the gene for the alpha-subunit of human chorionic gonadotropin by the embryonic transcription factor Oct-3/4.

CG is required for maintenance of the corpus luteum during pregnancy in higher primates. As CG is a heterodimeric molecule, some form of coordinated control must be maintained over the transcription of its two subunit genes. We recently found that expression of human CG beta-subunit (hCGbeta) in JAr human choriocarcinoma cells was almost completely silenced by the embryonic transcription factor Oct-3/4, which bound to a unique ACAATAATCA octameric sequence in the hCGbeta gene promoter. Here we report that Oct-3/4 is also a potent inhibitor of hCG alpha-subunit (hCGalpha) expression in JAr cells. Oct-3/4 reduced human GH reporter expression from the -170 hCGalpha promoter in either the presence or absence of cAMP by about 70% in transient cotransfection assays, but had no effect on expression from either the -148 hCGalpha or the -99 hCGalpha promoter. Unexpectedly, no Oct-3/ 4-binding site was identified within the -170 to -148 region of the hCGalpha promoter, although one was found around position -115 by both methylation interference footprinting and electrophoretic mobility shift assays. Site-directed mutagenesis of this binding site destroyed the affinity of the promoter for Oct-3/4, but did not affect repression of the promoter. Therefore, inhibition of hCGalpha gene transcription by Oct-3/4 appears not to involve direct binding of this factor to the site responsible for silencing. When stably transfected into JAr cells, Oct-3/4 reduced the amounts of both endogenous hCGalpha mRNA and protein by 70-80%. Oct-3/4 is therefore capable of silencing both hCGalpha and hCGbeta gene expression. We suggest that as the trophoblast begins to form, reduction of Oct-3/4 expression permits the coordinated onset of transcription from the hCGalpha and hCGbeta genes.

Base Sequence↗
PubMed1997

Control of extracellular matrix remodelling within ovarian tissues: localization and regulation of gene expression of plasminogen activator inhibitor type-1 within the ovine corpus luteum.

Extensive extracellular matrix remodelling occurs within the lifespan of the corpus luteum, particularly during corpus luteum formation and regression. A major mechanism for the regulation of extracellular matrix remodelling is via local production of specific proteinase inhibitors, such as the serine proteinase inhibitor plasminogen activator inhibitor type-1 (PAI-1). The objective of the present study was to characterize the localization, ontogeny and regulation of PAI-1 expression within ovine corpora lutea. Urokinase binding activity was detected within medium conditioned by ovine luteal cells. Production of PAI-1 by ovine luteal cells was confirmed by immunoprecipitating it from labelled proteins in culture medium. mRNA encoding PAI-1 was present within developing (day 3), mature (day 10) and regressing (30 h after prostaglandin F2 alpha injection on day 10 after the onset of oestrus) corpora lutea as demonstrated by in situ hybridization. The ontogeny of PAI-1 mRNA expression was characterized within corpora lutea collected on days 3, 7, 10, 13 and 16 after the onset of oestrus (n = 4, 4, 4, 3 and 4, respectively). Expression of PAI-1 mRNA did not differ during the luteal phase (P = 0.06), although a trend for an increase in the amount of PAI-1 mRNA was observed on day 16. Expression of PAI-1 mRNA was also examined during luteal regression in corpora lutea collected 0, 6, 12, 24 and 36 h after injection of prostaglandin F2 alpha on day 10 after the onset of oestrus (n = 4 at each time). Relative PAI-1 mRNA concentrations changed significantly during luteolysis induced by prostaglandin F2 alpha (P = 0.0002). Administration of prostaglandin F2 alpha resulted in a transient sevenfold increase in PAI-1 mRNA 6 h after injection (P = 0.0001) but by 12 h the amounts had returned to values similar to those detected on day 10. We conclude that PAI-1 is a major secretory product of ovine luteal cells and that a transient increase in PAI-1 mRNA occurs during luteolysis induced by prostaglandin F2 alpha. PAI-1 probably plays a key local role in the control of extracellular proteolysis during the luteal phase.

Animals↗
PubMed1996

Silencing of the gene for the beta subunit of human chorionic gonadotropin by the embryonic transcription factor Oct-3/4.

The transcription factor Oct-3/4 may be important in maintaining embryonic cells in an undifferentiated state. It is probably down-regulated at about the time that human chorionic gonadotropin (hCG) is first expressed in embryonic trophectoderm. Here we report that Oct-3/4 strongly inhibits the hCGbeta subunit (hCGbeta) promoter in JAr choriocarcinoma cells. Oct-3/4 reduced chloramphenicol acetyltransferase (CAT) reporter expression from the -305hCGbeta promoter by about 90% in transient co-transfection assays, but had no effect on expression from the -249hCGbeta promoter. The -305/-249 hCGbeta fragment specifically bound synthetic Oct-3/4 protein as measured in electrophoretic mobility shift assays, and the Oct-3/4-binding site was localized around -270 by methylation interference footprinting. Site-directed mutagenesis of this binding site abolished Oct-3/4 repression. When stably transfected into JAr cells, Oct-3/4 reduced the amounts of both endogenous hCGbeta messenger RNA and hCG protein to less than 10% of controls. We suggest that silencing of Oct-3/4 in trophectoderm is a prerequisite for hCG up-regulation in early human embryos at the time of maternal recognition of pregnancy.

Base Sequence↗
PubMed1996

A type I ovine interferon with limited similarity to IFN-alpha, IFN-omega and IFN-tau: gene structure, biological properties and unusual species specificity.

A gene encoding a 195 amino-acid (a.a.) polypeptide with a putative 23 a.a. signal sequence that had about 60% a.a. sequence identity to ovine interferon-omega (OvIFN-omega) and 55% or less identity to BoIFN-tau, OvIFN-tau and all known IFN-alpha and -beta has been identified from an ovine genomic DNA library. Surprisingly, it shared almost complete identity to genes for rabbit IFN-omega within its coding sequence and proximal promoter region, although the two were different in their 3'-ends. This IFN (tentatively termed ovine IFN-omega variant, OvIFN-omegav), purified in recombinant form from E. coli, had normal antiviral activity when tested on sheep fetal tongue and brain cells and rabbit kidney cells, but very low activity towards bovine, goat and human cells. It competed with 125I-labeled BoIFN-tau for binding to IFN receptors on ovine cells. Expression of OvIFN-omegav was not detected by reverse transcription-PCR either in ovine peripheral blood leukocytes infected with Sendai virus, or in any other tissues examined. OvIFN-omegav may represent a previously unrecognized, non-virally inducible type I subtype distinct from IFN-alpha, -beta, -omega and -tau. The presence of a conserved gene in rabbit and sheep could reflect a recent interspecies transfer.

Amino Acid Sequence↗
PubMed1996

Results of peripheral endovascular procedures in the operating room.

PURPOSE: This study presents the results of closed (percutaneous) and open endovascular procedures performed exclusively by vascular surgeons in the operating room and compares them with results from combined series from the literature, including primarily closed procedures in radiology or cardiology facilities. METHODS: Retrospective review of 607 consecutive peripheral arterial and venous angioplasties, stents, thrombolytic cases, and inferior vena caval filters in 446 patients was analyzed for immediate success rate, complication rate, and 1-year life table patency rate. RESULTS: The incidence of initial technical success was: aorta, 89%; iliac artery, 91%; superficial femoral artery, 90%; popliteal artery, 91%; tibial arteries, 79%; arm arteries and veins, 86%; renal arteries, 100%; IVC filters, 98%; and iliofemoral veins, 100%. The 1-year primary patency rates, including technical failures, were 70.3% in 113 femoropopliteal procedures and 83.7% in 194 iliac arteries. Advantages to the use of the operating room included: (1) simultaneous angioplasty during a bypass operation for abnormalities proximal or distal to the graft, (2) correction of lesions first discovered during thrombectomy, and (3) optimum patient monitoring and sedation in the operating room. CONCLUSIONS: Endovascular procedures performed by vascular surgeons in the operating room lead to results comparable with procedures performed in nonsurgical interventional suites, and the use of the operating room has advantages.

Adult↗
PubMed1996

Interferon-tau and pregnancy.

A type I interferon known as IFN-tau is expressed massively by the outer epithelium (trophectoderm) of the preimplantation trophoblast of ruminant ungulate species, such as cattle and sheep, for a few days during early pregnancy. They signal to the mother that she is pregnant and indirectly prevent regression of the corpus luteum so that progesterone production is maintained and normal ovarian cyclicity avoided. Despite their clear roles as reproductive hormones, the IFN-tau have the typical antiviral, antiproliferative, and immunomodulatory activities of other type I IFN. They are most closely related to the 172 amino acid IFN-omega. Unlike other type I IFN, they are not virally inducible and appear to be produced constitutively as the trophectoderm first forms during the development of the blastocyst. The discovery of the IFN-tau illustrates the diverse activities of interferons and their likely involvement in the normal embryonic development of mammals. The diversity of mechanisms different groups of mammals use to prolong the functional life span of the corpus luteum in early pregnancy is probably the consequence of genetic conflict between the genes of the mother and her offspring, which has led to remarkably high rates of change in placental structure and trophoblast signaling mechanisms.

Animals↗
PubMed1996

The interferon-tau genes of the giraffe, a nonbovid species.

Genes for interferon-tau (IFNT) have been cloned from several Bovidae, and the IFNT lineage has been predicted to have arisen from the IFNW, as the divergence of the Ruminantia from other artiodactyls. Southern genomic blotting with probes specific for IFNT identified a gene in the giraffe, a nonbovid member of the Ruminantia. Here this gene has been cloned, sequenced, and expressed. It encodes a 172-amino acid mature protein with antiviral activity on bovine cells. Giraffe IFN-tau lacks the normally conserved Cys99 but has a pair of other cysteines (Cys64 and Cys86) that could provide a disulfide bridge. The giraffe IFNT gene possesses the highly conserved promoter region that distinguishes IFNT from IFNW. It seems likely that IFNT emerged before the divergence of the Giraffidae and Bovidae, which occurred some 24 million years ago.

Amino Acid Sequence↗