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M F Smith

Publications and source records attributed to M F Smith.

At least 91 records · Page 5Linked to original sources
PubMed1997

Intracellular IL-1 receptor antagonist promoter: cell type-specific and inducible regulatory regions.

The objective of these studies was to examine the molecular mechanisms involved in transcriptional regulation of the gene for the intracellular structural variant of the IL-1 receptor antagonist (icIL-1Ra) molecule. By reverse transcription-PCR analysis, constitutive expression of endogenous icIL-1Ra mRNA was observed in the epithelial cell lines A431 and HT-29, but not in the macrophage cell lines RAW 264.7 and U937, or in the lymphocyte cell lines Raji and Jurkat. However, icIL-1Ra mRNA expression was observed in response to stimulation with LPS in RAW 264.7 cells and to PMA and LPS in U937 cells. To examine the mechanisms of transcriptional regulation, 4.5 kb of the 5' flanking sequence was isolated from the human icIL-1Ra gene, sequenced, cloned into a luciferase expression vector (pIC4525.Luc), and examined in transfection studies. The pIC4525.Luc construct exhibited a pattern of expression in epithelial and macrophage cell lines similar to that of the endogenous icIL-1Ra gene. To obtain a generalized map of cell type-specific and inducible cis-acting DNA elements, nested 5' deletional mutants of the icIL-1Ra promoter were constructed. Results from transfection studies with these icIL-1Ra promoter/luciferase fusion constructs indicated that constitutive expression in epithelial cells was under the control of three positively acting regions located between bases -4525 to -1438, -288 to -156, and -156 to -49. In contrast, basal expression of pIC4525.Luc in transfected but unstimulated RAW 264.7 cells was under the control of a weak inhibitory region located between bases -4525 to -1438 and a strong positive element between -156 and -49. LPS induction of icIL-1Ra transcription in RAW 264.7 cells was regulated by strong positively acting DNA regions between bases -1438 to -909 and -156 to -49. In summary, the proximal region of the icIL-1Ra promoter, between bases -156 to -49, contains positive cis-acting elements that are needed for expression in both epithelial and monocyte cell lines. However, our results indicate that the ability of this proximal promoter region to control expression is strongly influenced, both positively and negatively, by other upstream cis-acting elements in a cell type-specific manner.

Amino Acid Sequence↗
PubMed1997

Phylogenetic evidence of mitochondrial DNA introgression among pocket gophers in New Mexico (family Geomyidae).

Mitochondrial DNA (mtDNA) variation in the cytochrome b gene was determined for two divergent taxa of pocket gophers, Thomomys bottae actuosus and T. b. ruidosae. These two taxa hybridize in a narrow contact zone, but introgression of nuclear markers such as allozymes or chromosomes does not extend much beyond the hybrid zone (Patton et al. 1979). We found that despite their distinctness, the two subspecies shared very similar mtDNA haplotypes. By a comparison of phylogenetic histories derived from nuclear markers (allozymes) and from mtDNA haplotypes sampled in different populations of T. bottae from New Mexico, we show that apparent similarity is due to an introgression of T. b. ruidosae mtDNA into T. b. actuosus nuclear background. Evidence of introgression is not limited to the present-day contact zone between these two taxa, but extends at least 75 km away from it. The actuosus haplotype coexists along with the ruidosae mtDNA in the Gallinas Mts., which are inhabited by otherwise pure T. b. actuosus, while further north only typical actuosus haplotypes were detected. Of several potential mechanisms which could lead to such a geographical pattern of variation, we argue that a combination of range shifts due to climatic fluctuations, and genetic drift are most likely. Horizontal gene transfers due to hybridization are historical events which seem rather common among pocket gophers. Although they can be identified with careful phylogenetic study using independent data sets, the potential for misinterpreting a gene tree as an organismal tree is great in this and other groups of animals.

Animals↗
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

Changes in messenger ribonucleic acid encoding luteinizing hormone receptor, cytochrome P450-side chain cleavage, and aromatase are associated with recruitment and selection of bovine ovarian follicles.

The objective of this study was to investigate changes in expression of mRNAs encoding FSH receptor (FSHr), LH receptor (LHr), cytochrome P450 side-chain cleavage (P450(scc)), cytochrome P450 17alpha-hydroxylase (P450(c17)), and cytochrome P450 aromatase (P450(arom)) during recruitment and selection of bovine ovarian follicles. Dairy heifers (4-5 per group) were ovariectomized at 12, 24, 36, 48, 60, 72, 84, or 96 h after initiation of the first follicular wave following estrus as determined by ultrasonography (Time 0 = initiation of follicular wave; mean +/- SEM = 42.0 +/- 2.6 h after estrus). Expression of mRNAs encoding FSHr, LHr, P450(scc), P450(c17), and P450(arom) was detected by in situ hybridization and quantified by image analysis. Antral follicles were classified as healthy or atretic. Healthy follicles expressed higher (p < 0.01) amounts of mRNAs for gonadotropin receptors and steroidogenic enzymes than did atretic follicles, and expression of LHr, FSHr, P450(scc), P450(c17), and P450(arom) increased (p < 0.01) with follicular size and stage of the follicular wave. Expression of mRNAs for P450(scc), P450(arom), and LHr was time- and size-dependent during recruitment and selection. During recruitment, expression of mRNAs for P450(scc) and P450(arom) was first detected in granulosa cells of 16 of 21 of the follicles 4-6 mm in diameter at 12 h. At 24 and 36 h, almost all follicles 6-9 mm in diameter, but not those 4-5 mm in diameter, expressed both P450(scc) and P450(arom) mRNA in the granulosa cells. At 48 h and thereafter, P450(scc) and P450(arom) mRNA were expressed predominantly in one healthy large follicle per cow with a few exceptions. Expression of LHr mRNA was first detected in granulosa cells at 36 h and was always found in granulosa cells of one follicle > or = 8 mm per cow with exception of one cow at 36 h (no expression) and another two cows, one each at 36 and at 84 h (expression in 2 follicles). In addition, LHr mRNA expression in the granulosa cell layer was limited to follicles that also expressed mRNAs for P450(scc) and P450(arom) in the granulosa cells. In summary, follicular recruitment in cattle was associated with expression of P450(scc) and P450(arom) mRNA within granulosa cells, and the process of follicular selection was associated with initiation of LHr mRNA expression in granulosa cells.

Animals↗
PubMed1997

Expression of messenger ribonucleic acid (mRNA) encoding 3beta-hydroxysteroid dehydrogenase delta4,delta5 isomerase (3beta-HSD) during recruitment and selection of bovine ovarian follicles: identification of dominant follicles by expression of 3beta-HSD mRNA within the granulosa cell layer.

The objective of the present study was to examine changes in expression of mRNA encoding 3beta-hydroxysteroid dehydrogenase delta4,delta5 isomerase (3beta-HSD) during recruitment and selection of bovine ovarian follicles. Dairy heifers (4-5/time period) were ovariectomized at 12, 24, 36, 48, 60, 72, 84, or 96 h after initiation of the first follicular wave (Time 0) following estrus. Expression of 3beta-HSD mRNA was localized by in situ hybridization and quantified by image analysis. Expression of 3beta-HSD mRNA was first detected in theca interna cells of preantral follicles with a well-developed theca layer and in granulosa cells of follicles > or = 8 mm in diameter. Regardless of stage of follicular wave, expression of 3beta-HSD mRNA in granulosa cells of follicles > or = 8 mm was correlated with follicular size (r = 0.665; p < 0.01). The 36-h time period appeared to be a transition period for selection since dominant follicles were detected by size and expression of 3beta-HSD mRNA in some cows but not in others. By 48 h after wave initiation, dominant follicles could be identified by both size and expression of 3beta-HSD mRNA. Expression of mRNA for 3beta-HSD in theca cells was higher (p < 0.05) at 24 h than at 12 h and remained elevated thereafter through 96 h. In contrast to theca cells, expression of mRNA for 3beta-HSD was undetectable within granulosa cells at 12 and 24 h. At 36 h, 3beta-HSD mRNA was expressed in granulosa cells of healthy follicles > or = 8 mm, and expression was higher (p < 0.05) at 48 h compared with 36 h. Expression of 3beta-HSD mRNA levels increased further in granulosa cells (p < 0.05) at 84 and 96 h compared to 48 h. Upon detection of mRNA for 3beta-HSD in granulosa cells, high levels of expression were always found in one (dominant) follicle/cow with the exception of two cows at 36 and 84 h that expressed 3beta-HSD mRNA in two large healthy follicles. Expression of 3beta-HSD mRNA was also detectable in granulosa cells of a few large atretic follicles in which remnant granulosa cells appeared to be luteinized. Healthy follicles expressed higher (p < 0.05) levels of 3beta-HSD mRNA in both theca and granulosa cells than did atretic follicles. Expression of 3beta-HSD mRNA in theca cells was higher (p < 0.01) in dominant follicles than in other subordinate healthy follicles. These results indicate that only selected dominant follicles express 3beta-HSD mRNA within granulosa cells, and expression increased in both thecal and granulosa cells during the follicular wave. Therefore, expression of 3beta-HSD mRNA within granulosa cells may be associated with the mechanism of selection of the dominant follicle during a follicular wave and may be required for maximum steroid production during follicular dominance.

Animals↗
PubMed1997

Expression of tissue inhibitor of metalloproteinase-1 protein and messenger ribonucleic acid by the oviduct of cyclic, early-pregnant, and ovariectomized steroid-treated gilts.

It has been suggested that tissue inhibitor of metalloproteinases (TIMP)-1 has a role in reproductive tissues, regulating tissue remodeling or enhancing embryonic development. Oviductal TIMP-1 mRNA levels and protein expression were examined in gilts during the estrous cycle and early pregnancy and in steroid-treated ovariectomized (OVX) gilts by explant culture, two-dimensional SDS-PAGE and fluorography, dot-blot hybridization, immunoblot analysis, RIA, and immunocytochemical studies. TIMP-1 mRNA levels in the oviduct during the estrous cycle were greater (p < 0.02) on Days 2, 15, and 18 than on other days examined, and analysis of oviductal functional segments indicated an effect of day (p < 0.003), an effect of segment (p < 0.007), and a day x segment effect (p < 0.03). The level of TIMP-1 mRNA was greater (p < 0.003) in the isthmus (I) on Day 2 than in the ampulla (A) or infundibulum (INF) or on other days examined (0 and 12). In steroid-treated OVX gilts, an effect of treatment with estradiol valerate (EV) + progesterone (P4) was shown with increased (p < 0.003) TIMP-1 mRNA levels. De novo synthesis of TIMP-1 protein was found throughout the estrous cycle and early pregnancy in all functional segments, but protein expression was greater in the I and greatest on Day 2. In steroid-treated OVX gilts, TIMP-1 protein synthesis was greatest in the I regardless of treatment, but with increased intensity after EV+P4 treatment. TIMP-1 protein was found in oviductal flushings during the estrous cycle and early pregnancy, and in steroid-treated OVX gilts regardless of day, status, or treatment. Differences in TIMP-1 concentrations in oviductal fluid were found by day (p < 0.001), with breed differences detected between the Meishan and standard Western breeds. TIMP-1 protein was immunolocalized primarily to luminal epithelium of the INF, A, and I on all days of the estrous cycle and early pregnancy and to some cells in the stroma and blood vessel walls. Staining intensity correlated with TIMP-1 protein levels in oviductal flushings. The role of TIMP-1 in the oviduct remains to be established.

Animals↗
PubMed1997

Breast tumour imaging using incomplete circular orbit pinhole SPET: a phantom study.

Improvements in 99Tcm-sestamibi breast lesion visualization using single photon emission tomography (SPET) may help define the clinical role of this technique alongside X-ray mammography in the diagnosis and management of breast cancer. Pinhole SPET offers the advantages of high resolution and sensitivity when compared to conventional parallel-beam collimation for sources located near the pinhole aperture. In this work, the potential of incomplete (180 degrees) circular orbit (ICO) SPET with pinhole collimation is investigated as a means to visualize small (6.4 and 9.6 mm diameter) spherical simulated tumours, at clinical count densities and tumour-to-background ratios, in a breast phantom. ICO pinhole SPET is compared to complete circular orbit (CCO) pinhole SPET for reference, and planar breast imaging (scintimammography) using parallel-beam and pinhole collimators. A prototype box-shaped pinhole collimator with a 4 mm diameter circular aperture was used to acquire projections of an 890 ml breast phantom both in isolation and mounted on a cylinder filled with a mixture of 99Tcm-pertechnetate and water. A heart phantom containing 99Tcm activity in the myocardium was placed in the cylinder. Simulated tumours containing 99Tcm were placed in the breast phantom and scanned at clinically relevant count densities and scan times with tumour-to-normal tissue concentration ratios of 5.0:1 (9.6 mm sphere) and 7.7:1 (6.4 mm sphere). Phantom data were reconstructed using pinhole filtered backprojection (FBP) and maximum likelihood-expectation maximization (ML-EM). The tumours were not visualized with scintimammography, in which lesion contrast and signal-to-noise were estimated from region of interest analysis to be < 2% and 0.01, respectively. Average (over lesion size and scan time) contrast and signal-to-noise in the ICO (CCO) SPET images were 33% and 1.72 (34% and 1.3), respectively. These values indicate that ICO pinhole SPET has the potential to improve visualization of small (< 10 mm) breast tumours when compared with scintimammography, which may be beneficial for the early classification of cancers of the breast.

Breast Neoplasms↗
PubMed1997

The relation between fetal abdominal circumference and birthweight: findings in 3512 pregnancies.

OBJECTIVES: To establish the relation between fetal abdominal circumference and birthweight in a large population of fetuses; to identify whether the error in estimating birthweight by abdominal circumference varied with the magnitude of abdominal circumference; and to establish whether adding femur length to abdominal circumference caused a clinically important reduction of error in predicting birthweight. DESIGN: A retrospective study. SETTING: The ultrasound department of a teaching maternity hospital offering a tertiary referral service. SAMPLE: From 3512 nondiabetic women with a normally formed singleton fetus, an abdominal circumference measurement of the infant was made within seven days of delivery; of these, 1213 had a femur length measurement performed at the same time. RESULTS: There was a linear relation between abdominal circumference and birthweight. There was a strong inverse correlation between the proportional error in predicting birthweight from the abdominal circumference and the magnitude of the abdominal circumference. Both the Campbell and Wilkin equation (abdominal circumference alone) and the Hadlock equation (abdominal circumference and femur length) were associated with systematic errors, especially with larger birthweight infants. The median absolute errors for the two equations were not significantly different overall (6.98% and 6.86% respectively), although the Hadlock equation was significantly more accurate in predicting birthweight in infants weighing greater than 4500 g. However, no threshold value of abdominal circumference or of estimated fetal weight using the Hadlock equation had a positive predictive value in estimating infants of > 4500 g of greater than 35%. CONCLUSIONS: Prediction of birthweight should be by abdominal circumference alone. Table 1 presents robust estimates of the error of predicting birthweight using fetal abdominal circumference.

Abdomen↗
PubMed1997

The effect of gamma ray penetration on angle-dependent sensitivity for pinhole collimation in nuclear medicine.

The sensitivity of a pinhole collimator for gamma ray imaging in nuclear medicine is dependent on the angle of incidence of the gamma rays. The effect of penetration near the pinhole aperture on angle-dependent sensitivity was investigated using experimental measurements and numerical modeling. Projection data measurements were acquired with Tc-99m and I-131 point sources using tungsten pinhole inserts with 1.0 to 4.0 mm diameter apertures. Curves of the form sinx theta, where theta is the angle of the incident ray with the surface of the detector crystal, were fit to sensitivity measurements from the projection data. Experimentally measured x values were between 3.3 and 4.1 for Tc-99m and between 5.1 and 7.2 for I-131. Penetration near the pinhole aperture was modeled using (1) an expression for effective pinhole diameter that is a generalization of Anger's formula for normally incident photons and (2) a photon transport simulation code. Experimentally measured sensitivity exponents x from new and previously reported experimental observations were modeled within 15% by the numerical simulations. For modeling using the generalized expression for effective diameter the average error was 1.4% and the standard deviation was 7.7%. For the photon transport simulation code the average error was 1.5% and the standard deviation also was 7.7%. The effect of pinhole aperture design parameters on angle-dependent sensitivity for high resolution pinhole apertures was modeled using a photon transport simulation code. The sensitivity exponents x were greater for 364 keV photons than for 140 keV photons and were greater for small aperture diameters, small acceptance angles, and large aperture channel heights. These results provide theoretical justification for incorporating sinx theta sensitivity corrections, with x greater than the value of 3 for an impenetrable pinhole, in filtered back projection and iterative reconstruction algorithms for single photon emission computed tomography (SPECT) pinhole imaging. Simulated I-131 SPECT studies for uniformly active cylinders showed that activity concentrations were underestimated toward the outside of the cylinders when a sin3 theta rather than the correct sinx theta sensitivity correction was applied in image reconstruction.

Biophysical Phenomena↗
PubMed1997

Lipopolysaccharide and Raf-1 kinase regulate secretory interleukin-1 receptor antagonist gene expression by mutually antagonistic mechanisms.

Lipopolysaccharide (LPS) treatment of monocytic cells has been shown to activate the Raf-1/mitogen-activated protein kinase (MAPK) signaling pathway and to increase secretory interleukin-1 receptor antagonist (sIL-1Ra) gene expression. The significance of the activation of the Raf-1/MAPK signaling pathway to LPS regulation of sIL-1Ra gene expression, however, has not been determined. This study addresses the role of the Raf-1/MAPK signaling pathway in regulation of sIL-1Ra gene expression by LPS. Cotransfection of the murine macrophage cell line RAW 264.7 with a 294-bp sIL-1Ra promoter/luciferase construct (pRA-294-luc) and a constitutively active Raf-1 kinase expression vector (pRSV-Raf-BXB) resulted in induction of sIL-1Ra promoter activity, indicating that Raf-1, like LPS, can regulate sIL-1Ra promoter activity. An in vitro MAPK analysis indicated that both LPS treatment and pRSV-Raf-BXB transfection of RAW 264.7 cells increases p42 MAPK activity. An in vitro Raf-1 kinase assay, however, failed to detect LPS-induced Raf-1 kinase activity in RAW 264.7 cells, suggesting that in RAW 264.7 cells, Raf-1 kinase is not an activating component of the LPS signaling pathway regulating MAPK activity or sIL-1Ra promoter activity. This observation was supported by results from transfection studies which demonstrated that expression of a dominant-inhibitory Raf-1 mutant in RAW 264.7 cells does not inhibit LPS-induced MAPK activity or sIL-1Ra promoter activity, indicating that LPS-induced sIL-1Ra promoter activation occurs independent of the Raf-1/MAPK signaling pathway. In additional studies, cotransfection of RAW 264.7 cells with pRA-294-luc and increasing amounts of pRSV-Raf-BXB caused a dose-dependent inhibition of LPS-induced sIL-1Ra promoter activity, indicating that the role of the Raf-1 pathway in the regulation of sIL-1Ra promoter activity by LPS is as an antagonizer. Interestingly, LPS treatment of RAW 264.7 cells, cotransfected with pRA-294-luc and pRSV-Raf-BXB, also inhibited pRSV-Raf-BXB-induced sIL-1Ra promoter activity, suggesting that inductions of sIL-1Ra promoter activity by LPS and Raf-1 actually occur by mutually antagonistic mechanisms. In support of this conclusion, sIL-1Ra promoter mapping studies indicated that LPS and Raf-1 responses localized to different regions of the sIL-1Ra promoter. Further studies demonstrated that mutual antagonism between the LPS and Raf-1 kinase pathways is not promoter specific, as the same phenomenon is observed in assays using a c-fos enhancer/thymidine kinase promoter/luciferase construct (pc-fos-TK81-luc). Additionally, mutual antagonism with regard to sIL-1Ra promoter activity also was observed between the LPS and MEK kinase pathways, indicating that mutual antagonism can occur in more than one MAPK activation pathway.

Animals↗
PubMed1997

Impact of health care reform on the business and practice of ophthalmology.

This study examines the attitudes and opinions of 122 Texas ophthalmologists facing the health care reform movement. It illustrates the commercial practice of ophthalmology today, how practitioners would like it to be, and what they see as the future trends. The study also explores the options and future plans of ophthalmologists for maintaining practice revenues.

Analysis of Variance↗
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↗
PubMed1997

Concentration of tissue inhibitor of metalloproteinases (TIMP)-1 in ovine follicular fluid and serum.

Tissue inhibitor of metalloproteinases (TIMP)-1 mRNA and protein localize within granulosal cells of post-gonadotropin-surge follicles and luteal tissue in ewes. Our objectives were to test the hypotheses that 1) follicular fluid concentration of TIMP-1 increases following a gonadotropin surge induced by LHRH agonist (Exp. 1) and 2) luteal status affects peripheral serum concentration of TIMP-1 (Exp. 2 and 3). In Exp. 1, the concentration of TIMP-1 within antral fluid from post-surge follicles (28.7 +/- 6.65 microg/mL) was greater (P < .02) than from pre-surge follicles (2.37 +/- 2.47 microg/mL). In Exp. 2, serum concentration of TIMP-1 did not differ among d 0 to 6 (1.27 +/- .55 microg/mL) of the estrous cycle or among periods of luteal maintenance (1.29 +/- .06 microg/mL), spontaneous luteal regression (1.19 +/- .09 microg/mL), or luteal development (1.22 +/- .08 microg/mL). However, serum concentration of TIMP-1 was greater ( P < .001) during the period of luteal maintenance (1.14 +/- .04 microg/mL) than during PGF2alpha-induced luteolysis (d 26; .85 +/- .06 microg/mL) and induced luteal absence (d 27 to 33; .95 +/- .05 microg/mL). In Exp. 3, ewes (n = 14) were bled daily from d 1 to 19 (d 0 = estrus) and at 12-min intervals for 6 h on d 3, 10, and 17. Although concentration of TIMP-1 varied considerably within and among ewes, mean concentration of TIMP-1 per ewe per day increased ( P < .05) from d 3 to 17. These data indicate that follicular fluid concentration of TIMP-1 increases following a gonadotropin surge, but the contribution of ovarian derived TIMP-1 to peripheral serum concentration is negligible.

Animals↗
PubMed1997

Follicular function in lactating dairy cows treated with sustained-release bovine somatotropin.

The objective of this study was to determine the long-term, short-term, and residual effects of bovine somatotropin (bST) on ovarian function. Twenty-six Holstein cows were assigned to one of four groups and given either bST (500 mg) or saline for seven injection cycles (14 d between injections). Groups were 1) seven injection cycles of saline (control), 2) seven injection cycles of bST, 3) three injection cycles of bST followed by four injection cycles of saline, and 4) three injection cycles of saline followed by four injection cycles of bST. Beginning in the middle of the fourth injection cycle, an estrous cycle was synchronized for study. Serum concentrations of bST and insulin-like growth factor I were lowest during saline injections and increased after bST injections. Growth of the first wave dominant follicle was similar; however, start of the second follicular wave was approximately 48 h earlier in those cows treated with bST (groups 2, 3, and 4). Cows treated with somatotropin had a similar pattern of follicular growth, but tended to have more class 1 (3 to 5 mm) follicles and had more class 2 (6 to 9 mm) follicles than did the control cows. Peak concentrations of serum FSH were lower and occurred earlier for the cows treated with bST. There were no differences in the long-term or short-term effects of bST on ovarian function. Furthermore, cows that were switched from bST to saline (group 3) showed a residual effect of bST for up to 3 wk.

Animals↗
PubMed1997

Results of intraoperative 5-fluorouracil or lower dose mitomycin-C administration on initial trabeculectomy surgery.

PURPOSE: This study was conducted to review outcomes in eyes following primary trabeculectomy supplemented intraoperatively with 5-fluorouracil (5-FU) or lower dose mitomycin-C (MMC). PATIENTS AND METHODS: We retrospectively reviewed the medical records of 73 eyes of 63 patients with progressive, far advanced open angle glaucoma who had undergone initial trabeculectomy with intraoperative application of 5-FU, 50 mg/mL for 5 min (N = 37), or MMC, 200 micrograms/mL for 3-5 min (N = 36), and with at least 12 months follow-up. RESULTS: Mean preoperative intraocular pressures (IOPs) in the MMC and 5-FU groups were 24.3 +/- 7.6 and 24.6 +/- 9.3 mm Hg, respectively. Postoperatively, IOPs were similar at 6-month interval follow-up examinations in the MMC and 5-FU groups. At an average follow-up of 20.9 months, mean final visit postoperative IOPs were 10.2 +/- 3.6 (p < 0.001) and 9.7 +/- 3.4 mm Hg (p < 0.001) in the MMC and 5-FU groups, respectively, requiring an average of 0.25 and 0.22 antiglaucoma medications per eye, respectively. Interval follow-up complications were similar between groups and included four bleb leaks in the MMC group, and three bleb leaks in the 5-FU group. Visual acuity remained stable in 71 of 73 eyes. CONCLUSIONS: Both antifibrosis agents provide good intermediate term IOP control and may be appropriate for use in those eyes requiring final "target" IOPs in the low teens or single digits.

Adult↗
PubMed1997

Treatment of bleb leaks with transforming growth factor-beta in the rabbit model.

PURPOSE: The mechanism through which peribleb injection of autologous blood results in resolution of bleb leak in the rabbit model remains unclear. This study evaluates the clinical and histologic effects of peribleb injection of transforming growth factor-beta (TGF-beta) after leak induction in mitomycin-C-treated blebs. METHOD: Posterior lip sclerectomies treated with mitomycin-C were created in New Zealand White rabbits. On postoperative day 7, a standardized stab incision was performed on all blebs, and the eyes were randomized to receive a peribleb injection of either TGF-beta or of a balanced salt solution. RESULTS: Injection of TGF-beta was associated with the resolution of bleb leak and maintenance of a functioning bleb in 50% (4 of 8) of treated eyes. The remaining TGF-beta-treated eyes and control eyes demonstrated continued bleb leaks or bleb failures with intraocular pressure returning to preoperative levels. Histologic examination revealed increased peribleb cellularity and denser collagen deposition in the TGF-beta-treated eyes compared with that observed in control eyes. CONCLUSIONS: Peribleb TGF-beta injections may contribute to healing bleb leaks, but the injections do not appear in this model to be as useful as whole-blood injections.

Animals↗