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Biomedical subjects

K M Byrne

Publications and source records attributed to K M Byrne.

At least 19 recordsLinked to original sources
PubMed2006

Outcome of clinical pregnancies after ovulation induction using metformin.

The objective of this study was to review the first 50 clinical pregnancies of women with polycystic ovarian syndrome (PCOS) who had ovulation induced either with metformin alone, or in combination with clomifene. The study was confined to women with PCOS attending our infertility service. A register of clinical pregnancies was maintained of women who conceived after metformin therapy. The metformin was continued throughout the first trimester. The outcome of pregnancy was determined by individual chart review. Of the 50 women, 21 conceived with a combination of clomifene and metformin, and 29 with metformin alone. Seven women had a first trimester loss and 43 had a live birth. There were no perinatal deaths, no neonatal seizures and no congenital malformations. There were also no multiple pregnancies. The overall caesarean rate was 37%, and none of the babies had an Apgar score less than 7, at 5 min. This study found no evidence of any adverse clinical effects when metformin is continued in the first trimester of women with PCOS following ovulation induction. There was also no evidence of an increase in the rate of miscarriage or multiple pregnancy.

Adult↗
PubMed2002

Isolation and characterization of canine satellite cells.

Satellite cells were isolated from biopsies of the biceps femoris of adult dogs. Virtually all cells expressed muscle-specific proteins. Proliferation of satellite cells increased as the concentration of fetal calf serum (FCS) was increased from 1 to 10% of the basal medium. The addition of mitogenic growth factors resulted in greater proliferation than that of cells cultured in basal medium alone. Maximum proliferation was obtained when fibroblast growth factor-basic (FGF2) was added to the medium, but differences existed between sources or types. Proliferation did not plateau when the concentration of recombinant human FGF2 was 75 ng/ml but reached maximum levels when 50 ng/ml of bovine FGF2 or 10 ng/ml of growth hormone or insulin-like growth factor-1 were added to the medium. Proliferation of satellite cells decreased when more than 5 ng/ml of transforming growth factor-alpha was included in the medium. Exposure of canine satellite cells to chemically defined media induced greater fusion of total nuclei (ODM-34%; 4F, ITT-CF, and SFG-23%) than exposure to other treatments, such as basal medium plus 2 mg/ml of 1-beta-d-arabinofuranosylcytosine, 5% chick embryo extract, 1% horse serum (average 9% fused nuclei), or 1% FCS (2% fused nuclei). Actin, myosin, desmin, neural cell adhesion molecule, MyoD1, and myogenin were expressed by canine satellite cells, but expression of major histocompatibility complex class II antigen was not detected. Reverse transcriptase-polymerase chain reaction detected expression of messenger ribonucleic acid for interleukin-6 (IL-6), IL-15, and leukemia inhibitory factor by canine satellite cells. Collectively, these data suggest that isolated canine satellite cells display properties of other types of myogenic cells and may be useful for further study of the regulation of postnatal myogenesis.

Animals↗
PubMed2001

Patterns of expression of muscle-specific markers of differentiation in satellite cell cultures: determination by enzyme-linked immunoculture assay and confocal immunofluorescent assay.

Equine satellite cell clone SE-11 and ovine satellite cell clone I(1)were evaluated for expression of myosin heavy chain, myogenin, desmin, and muscle-specific actin over a 240 h period in culture. An enzyme-linked immunoculture assay (ELICA) was capable of detecting these proteins at all time points evaluated. A linear relationship was demonstrated between the natural logarithm of the absorbance values (corrected for cell number) from the ELICA and percent fusion in both SE-11 and I(1)cultures. The r(2)values for SE-11 cultures were: desmin 0.82, muscle actin 0.81, myogenin 0.78, and myosin 0.70. The r(2)values for I(1)cultures were: desmin 0.77, muscle actin 0.72, myogenin 0.70, and myosin 0.61. Our confocal results support the idea that differences exist between species in the differentiation dynamics of satellite cells. Further, these data suggest that the ELICA may be applied to previously conducted experiments, enabling additional data to be obtained with relation to muscle protein expression.

Actins↗
PubMed2001

Bovine mammary immune response to an experimental intramammary infection with a Staphylococcus aureus strain containing a gene for staphylococcal enterotoxin C1.

Staphylococcal enterotoxin C (SEC), a superantigen, is the most frequently expressed enterotoxin by bovine strains of Staphylococcus aureus causing mastitis. To examine the possible impact of SEC on the immune response of the bovine mammary gland, we monitored changes in lymphocyte subpopulations in mammary glands of four lactating cows after intramammary instillation of S. aureus strain Rn4220 transformed with a plasmid containing a gene coding for SEC1. Four other lactating cows received the same strain transformed with the plasmid without the SEC1 gene (positive control), and four cows were untreated (negative control). Mammary quarter milk samples for somatic cell count (SCC) analysis and determination of N-acetyl-beta-D-glucosimindase (NAGase) activity levels were collected daily for 21 d postinstillation. Flow cytometry utilizing three-color analysis was used to phenotype lymphocyte subpopulations isolated from milk samples collected on d 0, 4, 7, 11, 14, 18, and 21 postinstillation from all the cows. Milk from mammary gland halves (positive control and experimental) or all mammary quarters (negative control) was collected for flow cytometric analysis. Increased NAGase activity, SCC, and isolated S. aureus demonstrated that infection was established in mammary quarters intrammarily instilled with bacteria. There were no significant differences (P > 0.05) in the proportions of BoCD4 helper T lymphocytes or BoCD8 cytotoxic T lymphocytes between the two infected treatment groups. There was a significant day x treatment difference of the proportion of a gammadelta T cell subpopulation that did not express BoCD2, but did express the ACT2 activation molecule and a significant treatment difference of a gammadelta T cell subpopulation that expressed BoCD2, but not the ACT2 activation molecule (P < 0.05). Results do not support the hypothesis that the presence of the gene for SEC1 alters the mammary BoCD4 or BoCD8 T lymphocyte response to infection.

Acetylglucosaminidase↗
PubMed2000

Dietary lutein stimulates immune response in the canine.

The possible immuno-modulatory action of dietary lutein in dogs is not known. Female Beagle dogs (17-18-month old; 11.4+/-0.4kg body weight) were supplemented daily with 0, 5, 10 or 20mg lutein for 12 weeks. Delayed-type hypersensitivity (DTH) response to saline, phytohemagglutinin (PHA) and a polyvalent vaccine was assessed on Weeks 0, 6 and 12. Blood was sampled on Weeks 0, 2, 4, 8 and 12 to assess (1) lymphocyte proliferative response to PHA, concanavalin A (Con A), and pokeweed mitogen (PWM), (2) changes in peripheral blood mononuclear cell (PBMC) populations, (3) interleukin-2 (IL-2) production and (4) IgG and IgM production. After the completion of 12-week study, we continued to collect the blood weekly up to 17 weeks to evaluate the changes in immunoglobulin production upon first and second antigenic challenges on Weeks 13 and 15. Plasma lutein+zeaxanthin was undetectable in unsupplemented dogs but concentrations increased (P<0.05) rapidly on Week 2 in lutein-supplemented dogs. Thereafter, concentrations generally continued to increase in dose-dependent manner, albeit at a much slower rate. Dogs fed lutein had heightened DTH response to PHA and vaccine by Week 6. Dietary lutein increased (P<0.05) lymphocyte proliferative response to all three mitogens and increased the percentages of cells expressing CD5, CD4, CD8 and major histocompatibility complex class II (MHC II) molecules. The production of IgG increased (P<0.05) in lutein-fed dogs after the second antigenic challenge. Lutein did not influence the expression of CD21 lymphocyte marker, plasma IgM or IL-2 production. Therefore, dietary lutein stimulated both cell-mediated and humoral immune responses in the domestic canine.

Adjuvants, Immunologic↗
PubMed2000

Modulation of humoral and cell-mediated immune responses by dietary lutein in cats.

The immuno-modulatory role of dietary lutein in domestic cats is unknown. Female Tabby cats (10-month old; n=56) were supplemented daily for 12 weeks with 0, 1, 5 or 10mg lutein. Blood was collected on Weeks 0, 2, 4, 8 and 12 to assess the following: (1) mitogen-induced peripheral blood mononuclear cells (PBMCs) proliferation, (2) changes in PBMC subpopulations, (3) interleukin-2 (IL-2) production and (4) plasma immunoglobulin (Ig)G production. In addition, delayed-type hypersensitivity (DTH) response to concanavalin A (Con A) or a polyvalent vaccine was performed on Weeks 0, 6 and 12. Dietary lutein increased plasma lutein concentrations in a dose-dependent manner (p<0.001) and concentrations had not reached steady state after 12 weeks of feeding in cats given 5 or 10mg lutein. Concentrations of plasma retinol and alpha-tocopherol were not influenced by diet. The DTH response to vaccine but not to Con A increased (p<0.05) in a dose-dependent manner on Week 6. Compared to control, cats fed lutein also showed enhanced Con A- and pokeweed mitogen-stimulated PBMCs proliferation. Dietary lutein also increased the percentages of CD4+ and CD21+ lymphocytes on Week 12 but had no significant effect on pan T, CD8 and MHC class II markers. Plasma IgG was higher (p<0.05) in cats fed 10mg lutein on Weeks 8 and 12. These results support the immuno-modulatory action of lutein in domestic cats.

Animals↗
PubMed2000

A standardized gating technique for the generation of flow cytometry data for normal canine and normal feline blood lymphocytes.

Flow cytometry is becoming a commonly used technique to characterize a variety of cells. It provides a powerful application to rapidly determine the relative percentages of T-lymphocyte subsets and B-lymphocytes. The effectiveness of its application, however, is dependent on standardization, especially in a clinical setting. Application of flow cytometry to veterinary diagnostics has been limited by the unavailability of reagents and by the unstandardized characterization of normal values using antibodies not commercially available, but typically provided through the generosity of other researchers. This paper presents a standardized gating protocol, and average values and ranges observed for normal canine and feline blood lymphocytes using commercially available antibodies to cell surface markers for CD5, CD3, CD4, CD8, MHC II, and B lymphocytes. The averages for these markers on gated lymphocytes were as follows: Canine CD5 83.3%, Canine CD4 45.0%, Canine CD8 28.8%, Canine MHC II 98.0%, Canine B Cell 12.9%, Canine CD4/CD8 ratio 1.87, Feline T lymphocytes 77.3%, Feline CD4 44.5%, Feline CD8 25.7%, Feline B Cell 24.1%, Feline CD4/CD8 Ratio 1.75. Normal values were also established for a mixed breed group of dogs, and old versus young dogs. This information will provide researchers and clinicians with a standardized protocol for gating, which establishes a basis for comparison between techniques, and a measure of phenotypic percentages for flow cytometry in normal dogs and cats based on this standardization and commercially available antibodies.

Age Factors↗
PubMed2000

Isolation of bovine mammary lymphocytes for fluorescent activated flow cytometry.

A detailed methodology is described for the isolation of T lymphocytes from bovine mammary gland secretions for flow cytometry. Mammary gland secretions are collected and centrifuged to separate the leukocytes from the mammary supernatant. The leukocytes are purified using a density gradient and diluted for fluorescent staining. Using tri-color fluorescent staining, the T lymphocytes are identified by monoclonal antibodies and stained with secondary antibodies. Flow cytometry is used to quantify the cellular subpopulations of the T lymphocytes. Proportional and statistical analysis of the flow cytometric data is conducted with computer software, CELLQuest and SAS.

Animals↗
PubMed2000

Traditional and emerging methods for analyzing cell activity in cell culture.

The selection of appropriate techniques to assay for markers of cell activity is important for obtaining optimal results in cell culture-based research. This paper is intended as a guide to many of the assays currently available and new techniques that have been recently introduced in the literature. This paper addresses both manual assay techniques, including the use of hemocytometers, phase contrast microscopy, cell staining, and the immunofluorescent antibody assay (IFA), and automated assays for cell activity, including stained optical density, proliferating cell nuclear antigen, creatine kinase assay, DNA quantification, electronic cell counting, flow cytometry, magnetic cell sorting, image analysis, chemiluminescence, radioisotope labeling, precursor incorporation, in-situ hybridization/ligand binding, and enzyme-linked immuno-culture assay (ELICA). Advantages/disadvantages and applicability of these assays to different areas of cell culture research are discussed, and guidelines for selecting an appropriate assay are suggested.

Cell Count↗
PubMed2000

Standardized flow cytometry gating in veterinary medicine.

Gating in flow cytometry is used to select subpopulations of cells for analysis. The technique is critical for subsequent analysis in order to select the population, free of debris and unrelated cells. Accurately quantifying subpopulations in clinical cases is necessary for correct diagnosis. Human lymphocytes are selected by backgating on populations of CD45+high CD14- cells. These reagents are not available widely across species. In veterinary medicine, markers to identify lymphocytes are usually limited to T-lymphocyte, CD4, CD8, and B-lymphocyte surface antigens. A standardized gating technique using a T-lymphocyte antibody is described and is applicable across species where limited phenotype markers are available.

Animals↗
PubMed2000

Calcium oxalate stones in feline littermates.

Two feline littermates were diagnosed with calcium oxalate uroliths. Both had been maintained on a commercially available dry diet with reduced magnesium and urine acidifying properties. One female littermate was diagnosed by visualising the stones by radiographs while the second littermate, also female, became blocked when one of the uroliths lodged in the urethra. Two other, unrelated cats in the household, of similar age and raised under the same conditions, did not develop calcium oxalate uroliths.

Animal Feed↗
PubMed2000

Dietary beta-carotene stimulates cell-mediated and humoral immune response in dogs.

The role of beta-carotene on immune response in domestic dogs is not known. Female Beagle dogs were fed 0, 2, 20 or 50 mg beta-carotene/d; blood was sampled at wk 0, 1, 2, 4 and 8 for analysis of the following: lymphoproliferation, leukocyte subpopulations and concentrations of interleukin-2 (IL-2), immunoglobulin (Ig)G and IgM. Delayed-type hypersensitivity (DTH) response was assessed at wk 0, 3 and 7. beta-Carotene supplementation increased plasma beta-carotene concentrations in a dose-dependent manner. Compared with unsupplemented dogs, those fed 20 or 50 mg of beta-carotene had higher CD4+ cell numbers and CD4:CD8 ratio. However, there was no treatment difference in CD8+, CD21+ and major histocompatability complex (MHC) class II+ cells. Plasma IgG, but not IgM concentration was higher in dogs fed beta-carotene throughout the study period. The DTH response to phytohemagglutinin (PHA) and vaccine was heightened in beta-carotene-supplemented dogs. beta-Carotene feeding did not influence mitogen-induced lymphocyte proliferation or IL-2 production. Immune response was impaired in dogs classified as low beta-carotene absorbers compared with similar dogs fed the same amount of beta-carotene. Therefore, dietary beta-carotene heightened cell-mediated and humoral immune responses in dogs.

Animals↗
PubMed2000

In vitro model of equine muscle regeneration.

Equine satellite cells are responsible for muscle healing and regeneration in the mature horse. We describe the in vitro cell culture conditions required for clonal populations of equine satellite cells to undergo both proliferation and differentiation. Our hypothesis is that these in vitro conditions model regeneration of muscle and can be used to evaluate potential therapeutics. In this study, 2 areas of satellite cell response were tested: proliferation of clones induced by growth factors, and fusion induced by culture conditions. Equine satellite cell clones showed differences in their response to growth factors as well as accumulation of cellular protein concentrations. Equine satellite cells proliferate in response to both human and bovine FGF. IGF-1, a powerful mitogen of other satellite cell culture systems, was not as effective for inducing equine satellite cell proliferation. Protein concentrations were also measured in satellite cell cultures. Clones differed in cellular protein produced depending on growth conditions. Conditions inducing differentiation into myotubes was also determined for a 96 well assay and can be used to study the final stage of functioning muscle production. This in vitro model is the first step in identifying potential therapeutics to speed wound healing and promote muscle regeneration in horses.

Animals↗
PubMed1999

Temperature dependent characteristics of a recombinant infectious hematopoietic necrosis virus glycoprotein produced in insect cells.

A recombinant infectious hematopoietic necrosis virus (IHNV) glycoprotein (G protein) was produced in insect cells using a baculovirus vector (Autographa californica nuclear polyhedrosis virus). Characteristics of this protein were evaluated in relation to native viral G protein. A full-length (1.6 kb) cDNA copy of the glycoprotein gene of IHNV was inserted into the baculovirus vector under control of the polyhedrin promoter. High levels of G protein (approximately 0.5 microgram/1 x 10(5) cells) were produced in Spodoptera frugiperda (Sf9) cells following recombinant baculovirus infection. Analysis of cell lysates by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot revealed a recombinant IHNV G of slightly higher mobility on the gel than the viral G protein. Differences in mobility were abrogated by endoglycosidase treatment. When the recombinant G protein was produced in insect cells at 20 degrees C (RecGlow), immunostaining and cell fusion activity demonstrated surface localization of the protein. In contrast, when recombinant protein was produced at 27 degrees C (RecGhigh), G protein was sequestered within the cell, suggesting that at the 2 different temperatures processing differences may exist. Eleven monoclonal antibodies (MAbs) were tested by immunoblotting for reactivity to the recombinant G protein. All 11 MAbs reacted to the reduced proteins. Four MAbs recognized both RecGhigh and RecGlow under non-reducing conditions; however, 1 neutralizing MAb (92A) recognized RecGlow but failed to react to RecGhigh under non-reducing conditions. This suggests that differences exist between RecGlow and RecGhigh which may have implications in the development of a properly folded recombinant G protein with the ability to elicit protective immunity in fish.

Animals↗
PubMed1999

Immunogenicity of a recombinant infectious hematopoietic necrosis virus glycoprotein produced in insect cells.

A recombinant infectious hematopoietic necrosis virus (IHNV) glycoprotein (G protein), produced in Spodoptera frugiperda (Sf9) cells following infection with a baculovirus vector containing the full-length (1.6 kb) glycoprotein gene, provided very limited protection in rainbow trout Oncorhynchus mykiss challenged with IHNV. Fish were injected intraperitoneally (i.p.) with Sf9 cells grown at 20 degrees C (RecGlow) or 27 degrees C (RecGhigh) expressing the glycoprotein gene. Various antigen (Ag) preparations were administered to adult rainbow trout or rainbow trout fry. Sera collected from adult fish were evaluated for IHNV neutralization activity by a complement-dependent neutralization assay. Anti-IHNV neutralizing activity was observed in sera, but the percent of fish responding was significantly lower (p < 0.05) in comparison to fish immunized with a low virulence strain of IHNV (LV-IHNV). A small number of fish immunized with RecGlow or RecGhigh possessed IHNV G protein specific antibodies (Abs) in their serum. Cumulative mortality (CM) of rainbow trout fry (mean weight, 1 g) vaccinated by i.p. injection of freeze/thawed Sf9 cells producing RecGlow was 18% in initial trials following IHNV challenge. This level of protection was significant (p < 0.05) but was not long lasting, and neutralizing Abs were not detected in pooled serum samples. When trout fry (mean weight, 0.6 g) were vaccinated with supernatant collected from sonicated Sf9 cells, Sf9 cells producing RecGlow, or Sf9 cells producing RecGhigh, CM averaged 46%. Protection was enhanced over negative controls, but not the positive controls (2% CM), suggesting that in the first trial soluble cellular proteins may have provided some level of non-specific protection, regardless of recombinant protein expression. Although some immunity was elicited in fish, and RecGlow provided short-term protection from IHNV, Ab-mediated protection could not be demonstrated. The results suggest that recombinant G proteins produced in insect cells lack the immunogenicity associated with vaccination of fish with an attenuated strain of IHNV.

Animals↗