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Biomedical subjects

M F Smith

Publications and source records attributed to M F Smith.

At least 127 records · Page 7Linked to original sources
PubMed1995

Treatment of postfiltration bleb leaks with autologous blood.

BACKGROUND: Managing filtration surgery bleb leaks can be difficult as well as frustrating. Treatment options traditionally have included aqueous suppressants, patching, and bleb compression devices. Previously, if conservative management failed, surgical revision was considered. METHODS: Six patients with thin avascular blebs and discrete leaking holes (2 had had full-thickness procedures, 4 had had trabeculectomy with mitomycin C) underwent subconjunctival injection of approximately 1 ml of whole autologous blood. Injections were made just lateral and just medial to the domed cystic elevation of the blebs. RESULTS: Five of six eyes were leak-free by the second day after the procedure. No complications occurred. After 4 to 12 months of follow-up, four eyes are currently leak-free. In these eyes, intraocular pressure is between 8 and 12 mmHg. CONCLUSION: Subconjunctival peribleb injection of autologous blood may be a safe and helpful adjunct in treating selected postfiltration surgery bleb leaks.

Aged↗
PubMed1995

Expression of follicle-stimulating hormone and luteinizing hormone receptor messenger ribonucleic acids in bovine follicles during the first follicular wave.

The objective of the present study was to characterize expression of mRNAs encoding FSH and LH receptors during follicular development and at different stages of the first follicular wave in cattle. Following estrus, groups of heifers (3-5 per group) were ovariectomized on the day of initiation of the first follicular wave (as determined by ultrasonography; Day 0), or on Days 2, 4, 6, 8, or 10 after initiation of the first wave. FSH and LH receptor mRNAs were detected within follicles > or = 4 mm and in some smaller follicles by in situ hybridization and were quantified by image analysis. FSH receptor mRNA was expressed in granulosa cells of all growing follicles, starting in some follicles with only one layer of granulosa cells. Irrespective of day of the follicular wave, the level of expression of FSH receptor mRNA in granulosa cells of healthy antral follicles ranging from 0.5 to 14 mm in diameter did not vary significantly with follicular size (r = 0.02, p > 0.10). Expression of LH receptor mRNA was first observed in theca interna cells of follicles shortly after antral formation. Irrespective of day of the follicular wave, the levels of LH receptor mRNA in theca interna cells of healthy antral follicles ranging from 0.5 to 14 mm increased with follicular size (r = 0.39, p < 0.01). In granulosa cells, LH receptor mRNA was expressed only in healthy follicles > 9 mm in diameter and was first observed in the dominant follicles collected on Day 4. Expression of mRNA for LH receptor, but not for FSH receptor, changed (p < 0.01) with the stage of the first follicular wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Expression of messenger ribonucleic acid encoding tissue inhibitor of metalloproteinases-2 within ovine follicles and corpora lutea.

Metalloproteinase inhibitors, such as tissue inhibitors of metalloproteinases 1 and 2 (TIMP-1 and -2), play a key role in the regulation of metalloproteinases that modify extracellular matrix composition. Although expression of TIMP-1 within ovarian tissues has been well characterized, little information is available regarding expression of TIMP-2. The objective of the present studies was to characterize the ontogeny and localization of TIMP-2 messenger RNA (mRNA) within ovine preovulatory follicles and luteal tissue. Total cellular RNA was isolated from preovulatory follicles collected before (presurge; n = 3), or 12-14 h after (post surge; n = 4) an LHRH-induced gonadotropin surge, and from luteal tissue collected on days 3, 7, 10, 13, and 16 post estrus (n = 5, 5, 4, 5, and 5, respectively). TIMP-2 mRNA was expressed by both presurge and postsurge follicles, and expression did not increase after the gonadotropin surge (P = 0.44). In situ hybridization localized TIMP-2 mRNA primarily to the thecal layer of post-surge follicles (n = 3). TIMP-2 mRNA was also localized in a heterogeneous distribution within corpora lutea collected on days 3 and 10 post estrus (n = 3 each). Concentrations of TIMP-2 mRNA (picograms per microgram tissue DNA) were greater in corpora lutea collected during the early luteal phase (days 3 and 7) than the late luteal phase (day 16; P < 0.05). TIMP-2 mRNA was detected in purified populations of both small (n = 4) and large (n = 3) luteal cells, and mRNA concentrations (picograms per microgram DNA) were greater in the large luteal cells (P < or = 0.0002). In addition, immunoreactive TIMP-2 (approximately 21,000 M(r)) was detected by Western blot analysis of ovine luteal cell secreted proteins. We conclude that 1) TIMP-2 mRNA is expressed by the thecal layer of ovine preovulatory follicles and expression is not increased by the preovulatory gonadotropin surge; 2) expression of TIMP-2 mRNA is maximal during the early luteal phase; and 3) expression of TIMP-2 mRNA is greatest in large luteal cells.

Animals↗
PubMed1995

Expression of messenger ribonucleic acid encoding cytochrome P450 side-chain cleavage, cytochrome p450 17 alpha-hydroxylase, and cytochrome P450 aromatase in bovine follicles during the first follicular wave.

The objective of the present study was to investigate changes in the expression of messenger RNAs (mRNAs) encoding cytochrome P450 side-chain cleavage (P450scc), cytochrome P450 17 alpha-hydroxylase (P450c17), and cytochrome P450 aromatase (P450arom) at different stages of the first follicular wave of the bovine estrous cycle. Groups of heifers (three to five per group) were ovariectomized on the day of initiation of the first follicular wave (as determined by ultrasonography, day 0) or on days 2, 4, 6, 8, and 10 after initiation of the first follicular wave following estrus. Expression of mRNAs encoding P450scc, P450c17, and P450arom was detected by in situ hybridization and quantified by image analysis. P450scc mRNA was localized to theca interna cells of large preantral follicles and also to granulosa cells of follicles 4 mm or greater in diameter. mRNA for P450c17 was localized exclusively to theca interna cells, whereas P450arom mRNA was localized to granulosa cells of follicles 4 mm or greater in diameter. There were changes in mRNA levels for all three enzymes in thecal and/or granulosa cells at different times of the first follicular wave. Before identification of the dominant follicle (i.e. on days 0 and 2), there was no change in expression of P450scc and P450c17 mRNAs, whereas expression of P450arom mRNA was higher on day 2 than on day 0. Maximal mRNA levels for all three enzymes were observed on day 4. By day 6, P450scc and P450c17 mRNA levels were reduced compared to those on day 4, whereas P450arom mRNA levels remained elevated. On day 8, mRNA levels for all three enzymes were reduced. After initiation of the second follicular wave (day 10), dominant follicles from the first wave were at an advanced stage of atresia. P450scc and P450arom mRNAs were undetectable in granulosa cells, and very low levels of P450scc and P450c17 mRNAs were observed in theca interna cells. Before identification of the dominant follicle, mRNA levels for all three enzymes were similar within a cohort of follicles. Therefore, expression of these enzymes may not be associated with the mechanism of selection of the dominant follicle during a follicular wave.

Animals↗
PubMed1994

Binding of IL-1 alpha, IL-1 beta, and IL-1 receptor antagonist by soluble IL-1 receptors and levels of soluble IL-1 receptors in synovial fluids.

These studies have examined the binding of the three IL-1 ligands, IL-1 alpha, IL-1 beta, and IL-1 receptor antagonist (IL-1 ra), to soluble forms of types I and II IL-1Rs (sIL-1RI and sIL-1RII). This interaction was measured in direct binding experiments, in which the ligands bound to immobilized sIL-1R, and in inhibition experiments, in which sIL-1R in solution inhibited the binding of IL-1 ligands to immobilized sIL-1R. In addition, the effects of sIL-1R on the detection of IL-1 ligands by ELISA were examined. Finally, levels of sIL-1R in synovial fluid samples were determined, and their effects on measurement of IL-1 in these samples were estimated. IL-1 beta bound more avidly to sIL-1RII than IL-1 alpha or IL-1ra, primarily because of a slow dissociation rate. In contrast, IL-1 ra bound more avidly than IL-1 alpha or IL-1 beta to sIL-1RI, again because of a slow dissociation rate. sIL-1RII and sIL-1RI inhibited the detection of IL-1 beta and IL-1ra, respectively, by ELISA. Low levels of sIL-1RI (approximately 1.0-2.5 ng/ml) were present in all synovial fluids, irrespective of the degree of inflammation, and were correlated inversely with the levels of measured IL-1ra. In contrast, higher levels of sIL-1RII (approximately 10-20 ng/ml) were found in inflammatory synovial fluids and were not correlated with IL-1ra levels. IL-1 beta could not be detected in any synovial fluid. These results suggest that some IL-1 beta and IL-1ra may be bound in vivo to sIL-1RII and sIL-1RI, respectively, leading to underestimations of cytokine concentrations in body fluids when measured by ELISA.

Animals↗
PubMed1994

LPS-induced expression of the human IL-1 receptor antagonist gene is controlled by multiple interacting promoter elements.

Expression of the IL-1 receptor antagonist (IL-1ra) can be induced by treatment of monocytes and macrophages with LPS. We have previously demonstrated that the most proximal 294 bp of the human IL-1ra promoter are sufficient for full basal activity and LPS responsiveness. In the present study, we demonstrate the presence of one inhibitory and three positive-acting LPS response elements (LRE) within this proximal 294-bp IL-1ra promoter fragment. By both 5'-deletional analysis and heterologous promoter studies, an element between -294 and -250 was found to mask the LPS response. By 5'-deletional analysis and heterologous promoter experiments, two positive-acting LRE were identified between -250 and -200 (LRE3) and -200 and -148 (LRE2) which exhibited cooperativity in that neither element alone was active. Furthermore, LRE2 also cooperated with a more proximal site between -148 and -31 (LRE1), which also was not active alone. LRE1 was identified as an NF-kappa B-binding site. Site-directed mutagenesis of this site, located between -93 and -84, resulted in a > 50% decrease in the LPS responsiveness of the 294-bp promoter. By electrophoretic mobility shift assays, with or without specific antisera to members of the rel/NF-kappa B family, the complex binding to LRE1 was shown to contain primarily NF-kappa B1/p50 and lesser amounts of RelA/p65. These results indicate that the net activation of the human IL-1ra promoter in response to LPS involves the functional interaction of at least four cis-acting DNA elements within the proximal 294 bp.

Base Sequence↗
PubMed1994

Prenatal diagnosis of glutathione synthase deficiency.

Prenatal diagnosis for glutathione synthase (EC 6.3.2.3) deficiency in two pregnancies of an at-risk couple was performed on amniotic fluid taken at 16 weeks' gestation. 5-Oxoproline (pyroglutamic acid) levels were 970 and 790 mumol/l compared with the normal mean value of 29 mumol/l (range 13-51 mumol/l). The pregnancies were terminated and the diagnosis in one case was subsequently confirmed by assay of glutathione synthase in cultured fetal fibroblasts. In the other, post-mortem tissue samples failed to grow.

Adult↗
PubMed1994

Peripheral blood neutrophil production of interleukin-1 receptor antagonist and interleukin-1 beta.

The objective of this study was to characterize interleukin-1 receptor antagonist (IL-1ra) and interleukin-1 beta (IL-1 beta) production by human peripheral blood neutrophils (polymorphonuclear leukocytes; PMN). Unstimulated PMN contained IL-1ra protein in the absence of IL-1ra mRNA; IL-1 beta mRNA and protein were undetectable. Lipopolysaccharide (LPS), granulocyte/macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha), individually, transiently increased IL-1ra steady-state mRNA levels in PMN, with associated increases in IL-1ra protein synthesis. LPS, GM-CSF, and TNF-alpha generated similar increases in IL-1 beta mRNA, yet only LPS resulted in detectable synthesis of IL-1 beta protein. IL-4 enhanced LPS-induced IL-1ra production by PMN and inhibited LPS-induced IL-1 beta production. by PMN and inhibited LPS-induced IL-1 beta production. IL-1ra protein present within stimulated PMN supernatants existed in the 22- to 25-kD glycosylated form. Polymerase chain reaction amplification determined that only sIL-1ra mRNA was present within stimulated PMN; icIL-1ra mRNA was undetectable. These results indicate that freshly isolated PMN possess a small amount of IL-1ra protein and that these cells can respond to stimuli with a low level of sIL-1ra transcription and translation. PMN may be a major source of IL-1ra in inflammatory exudates where these cells predominate.

Base Sequence↗
PubMed1994

Generalized dual-energy-window scatter compensation in spatially varying media for SPECT.

The detection of scattered photons in the photopeak energy window hinders accurate activity estimation in single-photon-emission computed tomography (SPECT). To compensate for photons scattered in spatially varying media, a framework for generalized dual-energy-window scatter subtraction has been developed. Generalized scatter subtraction factors are introduced, and these factors are decomposed into terms dependent on the uniform (average) and spatially varying components of the source activity distribution. The variation of these factors with projection pixel location and gamma camera position is analysed for a simulated myocardial perfusion study with a 99Tc(m) source radionuclide and a non-uniform thorax model. Monte Carlo methods are used to model photon transport and detection. The application of pixel-dependent scatter subtraction factors for scatter compensation is evaluated in an image reconstruction experiment for this simulated myocardial perfusion study. Generalized matrix inverses with noise-dependent regularization are used for image reconstruction. For this simulation, use of a pixel-dependent scatter subtraction factor and a constant scatter subtraction factor are effective for scatter compensation. Activity estimates within the left ventricular myocardium for these two methods are practically the same as those obtained from image reconstructions where the detection of Compton-scattered photons is included in the system matrix.

Heart Ventricles↗
PubMed1994

Molecular cloning of an ovine ovarian tissue inhibitor of metalloproteinases: ontogeny of messenger ribonucleic acid expression and in situ localization within preovulatory follicles and luteal tissue.

Secretion of a tissue inhibitor of metalloproteinases (TIMP-1) is initiated by ovine preovulatory follicles after the gonadotropin surge. In addition, TIMP-1 is a major secretory product of ovine corpora lutea. We have isolated an approximately full-length cDNA clone for TIMP-1 from an ovine luteal cDNA library. The 887-basepair cDNA obtained was 95%, 86%, and 77% identical to the reported nucleotide sequences of bovine, human, and mouse TIMP-1 cDNAs, respectively. Total cellular RNA was isolated from preovulatory follicles collected before (presurge; n = 5) or 12-14 h after (postsurge; n = 4) a LHRH-induced gonadotropin surge (36 h after prostaglandin F2 alpha-induced luteolysis); from luteal tissue collected on days 3, 7, 10, 13, and 16 postestrus (n = 5, 5, 4, 5, and 5, respectively); and from purified populations of small (n = 4) and large (n = 3) luteal cells. Concentrations of TIMP-1 mRNA (picograms per micrograms tissue DNA) were increased in preovulatory follicles after exposure to a gonadotropin surge (P < or = 0.01). TIMP-1 mRNA was localized primarily to the granulosa layer of postsurge follicles by in situ hybridization. Concentrations of TIMP-1 mRNA in luteal tissue did not differ throughout the luteal phase (P = 0.07). However, TIMP-1 mRNA was localized predominantly to specific cells located in the connective tissue surrounding and within day 3 corpora lutea. In situ hybridization of day 10 corpora lutea localized TIMP-1 mRNA predominantly to specific cells that were randomly dispersed throughout the luteal tissue. TIMP-1 mRNA was expressed by purified populations of both small and large luteal cells collected from day 10 corpora lutea. Concentrations of TIMP-1 mRNA (picograms per micrograms DNA) were greater in the large luteal cell populations (P < or = 0.0001). We conclude that 1) expression of TIMP-1 mRNA by the granulosa layer of ovine preovulatory follicles increased after the gonadotropin surge, whereas TIMP-1 mRNA concentrations during the luteal phase remained constant; 2) during the luteal phase, TIMP-1 mRNA was localized to specific cells surrounding (day 3) or located within (day 10) the corpus luteum; and 3) expression of TIMP-1 mRNA was greatest in large luteal cells.

Amino Acid Sequence↗
PubMed1994

Pattern of protein production by bovine corpora lutea during luteolysis and characterization of expression of two major secretory products of regressing corpora lutea.

Although the decrease of progesterone in serum and in luteal tissue during luteal regression is well characterized, relatively little is known about changes in proteins produced by the corpus luteum during this time. The first objective was to examine changes in patterns of protein secretion that might be associated with functional and structural luteal regression. The second objective was to characterize the expression of two major secretory products of regressing corpora lutea. Thirty normally cyclic heifers were randomly assigned at day 15-16 of the oestrous cycle (oestrus = day 0) to be ovariectomized at 0 h (no PGF2 alpha; n = 5) or at 4, 8, 12, 24 or 48 h after PGF2 alpha-induced luteal regression (n = 5 per time point). Total cellular RNA was isolated from tissue frozen at the time of ovariectomy. Thin slices (< 1 mm) of tissue were placed in methionine-deficient minimum essential media with [35S]methionine and placed in a humidified CO2 incubator at 38 degrees C. Media and tissues were collected 6 h later. Changes in profiles of secreted proteins were analysed by one-dimensional SDS-PAGE. A number of proteins (relative molecular mass ranging from 14,300 to 200,000) were produced by luteal tissue at each time point (0-48 h). The major secretory proteins had relative molecular masses of approximately 21,500, 28,200, 43,700 and 46,000. Secretion of the relative molecular mass 46,000 protein(s) increased (P < 0.05) between 4 and 24 h after PGF2 alpha injection compared with the 0 h group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Production of tissue inhibitor of metalloproteinases-1 by porcine follicular and luteal cells.

The objectives of the first experiment were to characterize the pattern of protein secretion by 1) porcine follicles before and after the preovulatory gonadotropin surge and 2) corpora lutea on d 4 and 11 after estrus (d 0 = estrus). Gilts were ovariectomized 1) on d 20 after estrus and before the preovulatory gonadotropin surge (pre-estrus group; n = 3), 2) 18 to 36 h after the onset of estrus and after the preovulatory gonadotropin surge (estrus group; n = 3), 3) on d 4 after estrus (n = 3), and 4) on d 11 after estrus (n = 4). Changes in pattern of protein secretion were determined by densitometric scanning of fluorographs. In the pre-estrus group, the major proteins secreted by follicular shells (FS) and granulosa cells (GC) had relative molecular masses (M(r)) of approximately 40,000, 46,000, and 55,000. In the estrus group (FS and GC), secretion of a M(r) 40,000 protein was decreased (P < .05) and secretion of a M(r) 30,000 protein was increased (P < .05) relative to the pre-estrus group. A predominant M(r) 30,000 protein was also secreted by corpora lutea on d 4 and 11. The objective of Exp. 2 was to determine whether synthesis of the M(r) 30,000 protein could be increased during the follicular phase by treatment with hCG, suggesting a role for the preovulatory gonadotropin surge in altering the pattern of protein secretion. Gilts were injected (i.m.) with saline (n = 3) or 500 IU of hCG (n = 3) on d 18 of the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Mechanisms associated with corpus luteum development.

The transition of a preovulatory follicle into a corpus luteum is a complex process involving mechanisms similar to wound healing and tumor formation. The objective of this review is to focus on mechanisms associated with corpus luteum development with specific attention to the follicular lineage of luteal cells, mechanisms associated with luteinization, and neovascular changes during luteal development. Corpora lutea are a continuation of follicular maturation and form from granulosal and theca interna cells. There is morphological and immunological evidence in ruminant species for the differentiation of granulosal and theca interna cells into large and small steroidogenic luteal cells, respectively. Different morphological, physiological, and biochemical characteristics of large and small luteal cells may reflect different follicular lineages with separate embryological origins. Following the preovulatory gonadotropin surge, follicular cells begin morphological, endocrinological, and biochemical changes associated with luteinization. Luteinization involves the transition of a preovulatory follicle into a highly vascular corpus luteum capable of secreting large quantities of progesterone. In addition, various cell types undergo hyperplasia, hypertrophy, and(or) migration during corpus luteum formation. An essential component of corpus luteum development is the recruitment of a blood supply. The development of a new microcirculatory bed involves breakdown of the follicular basement membrane, endothelial cell migration, endothelial cell proliferation, and development of capillary lumina. This process is regulated by the interaction of angiogenic and antiangiogenic substances. Further clarification of the preceding mechanisms may result in the development of improved methodologies for controlling the time of ovulation and(or) increasing pregnancy rates.

Animals↗
PubMed1994

Glaucoma after penetrating keratoplasty.

Glaucoma after penetrating keratoplasty remains a management problem. The incidence is significant because of the status of those eyes undergoing PKP. Many have had multiple previous surgeries, and aqueous outflow may be compromised before the PKP. The surgery itself causes additional damage to the angle, often inducing peripheral anterior synechiae formation, with further impediment to aqueous outflow. Control of postkeratoplasty glaucoma is complicated by the need to preserve graft clarity for visual function. Medical treatment with aqueous suppressants is the first line of care. Since the introduction of apraclonidine 0.5%, and with topical carbonic anhydrase inhibitors soon to be introduced, perhaps medical management will become easier. When medical management fails, if the angle is open and viable, argon laser trabeculoplasty may be an option. If further intervention is indicated, the authors recommend a drainage seton (double-plate Molteno, or Baerveldt tube) in those eyes with good visual potential. For those eyes with poor visual potential (or those patients who cannot undergo surgery), we recommend contact Nd: YAG CPC.

Glaucoma↗
PubMed1994

Restaurant noise, hearing loss, and hearing aids.

Our multidisciplinary team obtained noise data in 27 San Francisco Bay Area restaurants. These data included typical minimum, peak, and average sound pressure levels; digital tape recordings; subjective noise ratings; and on-site unaided and aided speech discrimination tests. We report the details and implications of these noise measurements and provide basic information on selecting hearing aids and suggestions for coping with restaurant noise.

Hearing Aids↗