Search PubMed⌕ Search

Biomedical subjects

J L Burton

Publications and source records attributed to J L Burton.

At least 19 recordsLinked to original sources
PubMed2007

Depressed DHEA and increased sickness response behaviors in lame dairy cows with inflammatory foot lesions.

Lameness is a multifactorial condition influenced by the environment, genetics, management and nutrition. Detection of lameness is subjective and currently limited to visual locomotion observations which lack reliability and sensitivity. The objective of this study was to search for potential biomarkers of inflammatory foot lesions that underlie most cases of lameness in dairy cows, with a focus on the sickness response and relevant endocrine, immune and behavioral changes. Serum and peripheral blood mononuclear cells (PBMC) were collected from eight sound and eight lame high-producing Holstein cows. Immune cell activation was investigated in PBMCs using a candidate gene approach in which the expression of pro-opiomelanocortin, interleukin-1beta, l-selectin, matrix metalloproteinase-9 and glucocorticoid receptor-alpha was measured via quantitative real time-RT-PCR. Endocrine changes were investigated by monitoring serum concentrations of cortisol and dehydroepiandrosterone (DHEA). Additionally, systematic behavioral observations were carried out to characterize a behavioral profile associated with a sickness response typical of this condition. Lame cows showed significantly lower eating (P=0.01) and ruminating (P=0.01) behaviors and higher incidence of self-grooming (P=0.04) compared to sound cows. Lame cows also showed a 23% decrease in serum DHEA (P=0.01) and 65% higher cortisol:DHEA ratio (P=0.06) compared to sound cows. However, no significant differences were found in candidate gene expression between lame and sound cows. In association with sickness behaviors, serum DHEA concentration and cortisol:DHEA ratio are promising objective indicators of inflammatory foot lesions in dairy cattle and may be useful as diagnostic targets for animals in need of treatment.

Animals↗
PubMed2006

Analysis of the bovine neutrophil transcriptome during glucocorticoid treatment.

The objective of this study was to characterize a large portion of the bovine neutrophil transcriptome following treatment with the anti-inflammatory glucocorticoid dexamethasone (Dex). Total RNA was isolated from blood neutrophils of healthy cattle (5 castrated male Holsteins) immediately following cell purification (0 h) or after ex vivo aging for 4 h with or without added Dex. Additional neutrophils were cotreated with a glucocorticoid receptor (GR) antagonist (RU486) and Dex for 4 h. RNA was amplified, dye labeled (Cy3 or Cy5), and hybridized to a series of National Bovine Functional Genomics Consortium (NBFGC) microarrays. LOWESS data normalization followed by mixture model analyses showed that 11.15% of the spotted NBFGC cDNAs (2,036/18,263) were expressed in 4-h (untreated) neutrophils. Subsequent two-step mixed-model analysis detected (P < or = 0.05) 1,109 differentially expressed genes, of which contrast analysis indicated those that were independently responsive to aging (1,064), Dex (502), RU486 + Dex (141), or RU486 (357). In silico analysis revealed that 416 of the differentially expressed genes are unknown, 59 did not cluster well based on known function, and 634 clustered into 20 ontological categories. Independent validation of differential expression was done for 14 of the putatively Dex-responsive genes across these categories. Results showed that Dex induced rapid translocation of GR into the neutrophil nucleus and signaled dramatic alterations in expression of genes that delay apoptosis, enhance bactericidal activity, and promote tissue remodeling without inflammation or fibrosis. Thus these findings revealed hitherto unappreciated plasticity of blood neutrophils and potentially novel anti-inflammatory/wound-healing actions of glucocorticoids.

Animals↗
PubMed2006

Bee pollen product supplementation to horses in training seems to improve feed intake: A pilot study.

The objective of this study was to determine the efficacy of supplementation of Dynamic Trio 50/50, a bee pollen-based product, to improve physical fitness, blood leukocyte profiles, and nutritional variables in exercised horses. Ten Arabian horses underwent a standardised exercise test (SET), then were pair-matched by sex and fitness and randomly assigned to BP (receiving 118 g of Dynamic Trio 50/50 daily) or CO (receiving 73 g of a placebo) for a period of 42 days. A total collection was conducted from days 18 to 21 on six geldings to determine nutrient retention and neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility. Horses were exercise conditioned and completed another SET on day 42. V160 and V200 were calculated from SET heart rates (HR). Lactate, glucose, haematocrit (HT) and haemoglobin (HB) concentrations were determined from SET blood samples. Total leukocyte count, and circulating numbers of various leukocytes and IgG, IgM and IgA concentrations were determined in rest and recovery blood samples from both SETs. Geldings on BP (n = 3) ate more feed than CO. BP had less phosphorus excretion, and tended to retain more nitrogen. BP tended to digest more NDF and ADF while having lower NDF digestibility and tending to have lower ADF digestibility. No treatment differences existed for V160 and V200, HR, lactate, HT and HB. There was a trend for lymphocyte counts to be lower in BP than CO on day 42. Dynamic Trio 50/50 supplementation may have a positive effect on performance by helping horses in training meet their potentially increased nutrient demands by increasing feed intake and thus nutrient retention.

Animal Nutritional Physiological Phenomena↗
PubMed2006

Short communication: A potential antiapoptotic phenotype in neutrophils of cows milked once daily in early lactation.

The objectives of this experiment were to compare the circulating concentrations of cortisol and determine whether these correlated with the expression profiles of a set of candidate apoptosis genes in neutrophils of Holstein-Friesian cows milked once vs. 3 times daily for 28 d postpartum. Cows on the once-daily milking regimen had significantly higher plasma cortisol concentrations on d 3, 14, and 28 postpartum than did those milked 3 times daily. On d 3 postpartum, when differences in cortisol and neutrophil counts were highest between the groups, mean mRNA abundance of nuclear factor kappaB p65 subunit, IkappaBalpha, X-linked inhibitor of apoptosis; and heat shock protein 70 were higher in neutrophils of the cows milked once daily than in cows milked 3 times daily. However, no correlations were detected among plasma cortisol concentration, neutrophil count, or neutrophil gene expression in this study. Results suggest that the modest neutrophilia associated with once daily milking of cows immediately postpartum may be related to modifications in the cells' apoptotic program by factors other than cortisol.

Animals↗
PubMed2005

Genetic basis and risk factors for infectious and noninfectious diseases in US Holsteins. I. Estimation of genetic parameters for single diseases and general health.

Health data collected from 1996 to 1999 from 177 herds in Minnesota and Wisconsin were analyzed to establish genetic basis for infectious and noninfectious diseases. Three types of health traits were targeted. First, available infectious conditions were used to identify animals that are superior in their general immunity (including innate immunity) for infectious diseases. Generalized immunity may be thought of as a combination of immune responses to a variety of immune system challenges. Second, single infectious and noninfectious diseases were analyzed separately. Third, infectious reproductive diseases as one category of related conditions, and cystic ovary disease as one category of 3 related noninfectious ovary disorders were studied. Data were analyzed using a threshold model that included herd, calving year, season of calving, and parity as cross-classified fixed factors; and sire and cow within sires as random effects. Days at risk and days in milk at the beginning of a record were included by fitting the days as continuous covariates in the model. A heritability value of 0.202 +/- 0.083 was estimated for generalized immunity. Heritability values of 0.141 and 0.161 were estimated for uterine infection and mastitis, respectively. Heritability of single noninfectious disorders ranged from 0.087 to 0.349. The amount of additive genetic variance recovered in the underlying scale of noninfectious disorders tended to zero when combining multiple conditions. The study supports combining infectious diseases into categories of interest but we do not recommend the same approach for noninfectious disorders.

Abomasum↗
PubMed2004

Videos have a role in postgraduate necropsy education.

AIMS: This is the first study to investigate the usefulness of structured, scripted videos as an adjunct to the mortuary based training of histopathology trainees in necropsy techniques. METHODS: Four structured and scripted videos describing aspects of necropsy health and safety, evisceration, general dissection techniques, specialist dissection techniques, and reconstruction were shown to histopathology trainees attending the 2001 University of Sheffield short course on the autopsy. Delegates who agreed to participate in the study were asked to complete a short questionnaire seeking Likert-type and free text responses concerning the usefulness of the videos in postgraduate necropsy training. Free text responses were analysed using a themed content analysis. RESULTS: All 38 delegates who viewed the videos agreed to participate in the study. Of these, 35 found the videos enjoyable and 34 found them interesting. Thirty one felt the videos enhanced their learning experience. Advantages of the videos included the ability to learn about specialist techniques rarely encountered in the mortuary, the ability to teach large numbers of students at once, allowing students to learn at their own pace, and as a tool for revision. Repetition between the videos, a lack of interactivity, and a lack of sufficient detail on general necropsy techniques were felt by participants to be the principal disadvantages of this teaching tool. CONCLUSIONS: Videos are an acceptable teaching tool for students. They have a valuable role to play as an adjunct to dissection in teaching junior histopathology trainees about specialist necropsy dissection techniques.

Autopsy↗
PubMed2004

Short communication: amino acid transporters in porcine mammary gland during lactation.

The objective of this study was to determine whether mRNA transcripts for the amino acid (AA) transporter proteins CAT-1, CAT-2B, B(0,+), and ASCT1 are present in porcine mammary tissue (MT). Transcript abundance on d 7 and 17 of lactation was determined by Northern blot analysis, and absolute quantification was performed by real-time polymerase chain reaction. Porcine MT expresses CAT-1, CAT-2B, B(0,+), and ASCT1 during lactation. Preliminary findings indicate that B(0,+) mRNA abundance tended to decrease on d 17 compared with that on d 7.

Amino Acid Transport System y+↗
PubMed2004

Hyperimmunization of steers with J5 Escherichia coli bacterin: effects on isotype-specific serum antibody responses and cross reactivity with heterogeneous gram-negative bacteria.

Isotype-specific antibody responses and cross reactivity were profiled following hyperimmunization of steers with J5 Escherichia coli bacterin. The vaccine was administered at time 0, 30 d later, and every 2 wk for 10 subsequent immunizations. Blood was collected preimmunization and multiple times following each immunization. Isotype-specific anti-J5 Escherichia coli antibody response profiles in diluted sera harvested from each sample were assayed by ELISA and recorded as optical density. Selected sera were assayed for anti-J5 Escherichia coli antibody titers and used to determine cross reactivity against a variety of gram-negative bacteria. Immunization number and day postimmunization influenced response profiles for anti-J5 E. coli IgM, IgG(1)and IgG(2) antibodies. Two immunizations increased mean serum IgM and the IgG(1)antibody profiles above preimmunization levels, but 5 immunizations were required to detect significant IgG(2) antibody responses that were above preimmunization levels. Isotype-specific cross reactivity of the serum antibodies with a variety of heterologous gram-negative bacteria was also increased by hyperimmunization. However, no cross reactivity was observed for Staphylococcus aureus, purified lipopolysaccharide, or lipid A. Our results indicate that multiple booster doses of J5 E. coli bacterin may be required to elicit high levels of cross-reactive serum IgG(2) antibodies.

Animals↗
PubMed2004

Genetic variation in bovine mononuclear leukocyte responses to dexamethasone.

The objective of this study was to determine whether bovine mononuclear leukocytes exhibit genetic variability prior to and after a glucocorticoid hormone challenge in vivo. Test animals included 60 pedigreed Holstein bulls treated on 3 consecutive days with dexamethasone and 5 untreated control bulls. Eight indicator traits of leukocyte responsiveness to dexamethasone included the percentages of circulating B cells, T cells (CD4, CD8, and workshop cluster 1 molecule expressed by bovine gammadelta T cell), major histocompatibility complex (MHC) I and II expressing cells, and mean expressions of surface MHC I and MHC II on circulating cells. Blood for this work was collected from each test bull 10 times before, during, and after dexamethasone administration, with corresponding samples taken for control bulls. Random regression models with treatment-specific serial correlation were applied to the leukocyte data sets to estimate genetic and nongenetic sources of variation in baseline and recovery aspects of the traits. All traits responded predictably to glucocorticoid challenge. Genetic variation was observed in baseline measurements of all traits, with heritability estimates ranging from 0.21 +/- 0.03 to 0.60 +/- 0.06. Genetic variation in linear recovery from nadir values following dexamethasone administration was significant only for percentage CD4, percentage CD8, and for surface expression of MHC II. The genetic covariance between basal and linear recovery was positive and significant for percentage CD4, percentage CD8, and MHC II expression. The bovine lymphocyte antigen DRB3.2 locus accounted for significant proportions of total variation in percentage MHC II cells and MHC I expression. These results suggest that genetic variability exists for important basal and glucocorticoid-modified phenotypes of bovine mononuclear leukocytes, implying that immunocompetence traits impacted by this stress hormone may be enhanced by genetic selection.

Animals↗
PubMed2004

Multivariate head injury threshold measures for various sized children seated behind vehicle seats in rear impacts.

Government recommendations to place children into the rear areas of motor vehicles to avoid airbag induced injuries have been complicated by the fact that most adult occupied front seats will collapse into the rear area during rear-impacts, and thus pose another potentially serious injury hazard to rear-seated children. Many variables affect whether or not a front seat occupant will collapse into the rear child, and whether that interaction could be injurious to the child. For instance, the severity of rear impact, coupled with front and rear occupant sizes (mass and stature), and the level of front seat strength, all interrelate to influence whether or not a rear seated child is likely to be impacted and possibly injured. The most common types of child injuries in these instances are head and chest injuries. In this study, a "high-low" experimental method was employed with a multi-level "factorial analysis" technique to study "multivariate" biomechanics of child head injury potential determined from rear-seated 3 and 6 year-old child surrogates in different types of vehicle bodies mounted to a sled system. The sled-buck systems were towed rearward into crushable barriers that matched the crash pulses of the vehicle types being tested. Various sizes of adult surrogates (i.e. 50 kg up to 110 kg), seated in both the "typical" low strength "single recliner" collapsing type front seat (i.e. 3.2 kN) and a much stronger "belt-integrated" seat design (i.e. up to 14.5 kN), were tested in the two different "sled body-buck" set-ups at various impact levels (i.e. 22.5 to 50 kph). One set-up used a popular minivan vehicle body with "built-in booster" seats for the 3 year-old. The other used a 4-door family sedan vehicle body with the 6 year-old in a standard rear bench seat. The parameters of the tests enabled the experimental data to be combined into polynomial "head injury" functions of the independent variables so the "likelihood" of rear child head-injury potential could be "mapped" over ranges of the key parameters. Accident cases were compared with predictions to verify the methodology.

Accidents, Traffic↗
PubMed2003

Refining the diagnosis of hydatidiform mole: image ploidy analysis and p57KIP2 immunohistochemistry.

AIM: To determine whether image analysis of ploidy status and immunohistochemical analysis of p57KIP2 (a paternally imprinted, maternally expressed gene) can be used to refine the diagnosis of molar pregnancy. METHODS AND RESULTS: The original histological diagnosis in 40 randomly selected cases of hydatidiform mole was reviewed and confirmed in 38 cases (22 complete moles, 16 partial moles). These cases were anonymized and submitted for further analysis. Tissue from each case was submitted for flow cytometric assessment of DNA ploidy using a FACSort flow cytometer and for automated image cytometric assessment using a novel digital imaging system. Tissue sections from each case were immunostained with a monoclonal mouse antibody to p57KIP2. Correlations between the histopathological diagnosis, image cytometry, flow cytometry and p57KIP2 immunohistochemistry were determined using kappa statistics. The concordance between histological diagnosis and p57KIP2 was very good (kappa = 0.89). Twenty of the 22 (90.9%) complete moles showed no immunoreactivity for p57KIP2. The remaining two cases showed nuclear immunoreactivity in villous cytotrophoblast. In one of these, the pattern of staining resembled that of a partial mole. In the other, the staining pattern supported the diagnosis of a twin molar/non-molar pregnancy. All 16 partial moles were p57KIP2 immunoreactive. On flow cytometry, all 22 complete moles were diploid and 12/16 partial moles were triploid (the remaining four cases originally diagnosed as partial moles were found to be diploid). On image cytometry, one case originally diagnosed as complete mole was found to contain a triploid population. Thus, by using a combination of image cytometry and p57KIP2 status we were able to refine the diagnosis of molar pregnancy in five (13%) of the cases studied. CONCLUSIONS: Automated image cytometry is a readily performed investigation which is comparable to, but more sensitive than, flow cytometry. Complementary use of ploidy analysis and p57KIP2 status can now help to distinguish a diploid hydropic miscarriage (p57KIP2-positive), diploid complete mole (p57KIP2-negative) and triploid partial mole (p57KIP2-positive).

Adult↗
PubMed2003

Medical educators' personal attitudes towards the necropsy.

AIMS: To explore the personal attitudes of medical educators to the necropsy. METHODS: A "theoretical sample" of individuals, with widely disparate views, was selected from University of Sheffield Medical School affiliated staff. These individuals underwent semi-structured interviews (in private) to elucidate their personal attitudes towards the necropsy (in relation to the possibility of their own necropsy or that of a close relative). RESULTS: Nine themes pertaining to personal attitudes towards the necropsy were identified. In general medical educators had a positive attitude towards the necropsy. CONCLUSIONS: This study suggests that medical educators still believe that the necropsy is of value in medical education, despite dramatic curricular revisions in the UK, declining necropsy rates, and adverse media attention to the necropsy.

Attitude of Health Personnel↗
PubMed2003

Health and safety at necropsy.

The postmortem room is a source of potential hazards and risks, not only to the pathologist and anatomical pathology technician, but also to visitors to the mortuary and those handling the body after necropsy. Postmortem staff have a legal responsibility to make themselves aware of, and to minimise, these dangers. This review focuses specifically on those hazards and risks associated with the necropsy of infected patients, with foreign objects present in the body, and with bodies that have been contaminated by chemicals or radioactive sources.

Autopsy↗
PubMed2003

Necropsy practice after the "organ retention scandal": requests, performance, and tissue retention.

AIMS: After the so called "organ retention scandal" in the UK this study set out to assess the impact on death certification and hospital (consent) necropsies, including the postmortem retention of tissues and organs. METHODS: Data were prospectively gathered over a one year period for all deaths occurring at the Royal Hallamshire Hospital, Sheffield, UK to determine the frequencies with which death certificates were completed and necropsies were requested. The seniority of the clinician undertaking these duties was recorded. Pathologists were asked to record the extent of every necropsy during the study period. The type and planned uses of tissues retained were recorded. RESULTS: Death certificates were issued for 88.5% of the 966 deaths for which clinicians completed proformas. Of these, 88.9% were issued by preregistration and senior house officers. Consent was sought for a necropsy in 6.2% of cases (usually by non-consultant staff) and was granted in 43.4% of these. The overall, medicolegal, and hospital necropsy rates were 13.4%, 9.9%, and 3.5%, respectively. Tissues were retained from 55.4% of necropsies for diagnostic purposes, although sampling does not appear to be systematic. CONCLUSIONS: Death certification and seeking consent for a necropsy are frequently delegated to junior clinical staff. This may explain the low standard of death certification reported by others and the low necropsy rate. The decline in the necropsy rate and the low rate of sampling for histological examination highlight the decline of the hospital necropsy and the lack of a systematic approach to tissue sampling.

Autopsy↗
PubMed2002

Survival tactics of M. paratuberculosis in bovine macrophage cells.

Mycobacterium paratuberculosis (M. paratuberculosis) is a facultative intracellular bacterium with the ability to survive and proliferate inside the vesicles of macrophage cells. How M. paratuberculosis and other mycobacteria survive in this hostile environment is not well understood. Present research findings can be divided into three possibilities: (1) mycobacteria may interfere with host protein expression and trafficking to stop vesicle maturation, (2) mycobacteria may express proteins that interfere with macrophage activation in a more direct manner, or (3) mycobacteria may enter macrophages in such a way as to avoid the normal process of activation via Toll-like receptors and other, as yet unknown mechanisms. Research thus far has predominately centered on possible macrophage/mycobacteria protein interactions. To more completely define how mycobacteria interfere with the process of phagosome maturation our group has recently taken a functional genomics approach, allowing the macrophage to "tell" us what host genes may be affected by phagocytosis of mycobacteria. We used DDRT-PCR to examine differences in macrophage cell gene expression during phagocytosis of E. coli and M. paratuberculosis. Macrophage cells not exposed to any phagocytosis target and in the process of phagocytosing latex beads were used as negative and positive controls, respectively. To date, we have identified 380 DDRT-PCR amplicons corresponding to transcripts whose expression profiles appear to be altered during the general process of phagocytosis. Dot-blot and Northern blot hybridizations with a subset of these amplicons were performed to confirm results observed with DDRT-PCR. Our preliminary results indicate that macrophage gene expression profiles change dramatically following phagocytosis and that gene expression profiles following phagocytosis of M. paratuberculosis are different than those following phagocytosis of E. coli or latex beads.

Animals↗
PubMed2002

Offline telepathology diagnosis of colorectal polyps: a study of interobserver agreement and comparison with glass slide diagnoses.

BACKGROUND/AIMS: Technological advances have produced telepathology systems with high quality colour images and reasonable transmission times. Most applications of telepathology have centred on the remote diagnosis of frozen sections or remote real time expert opinions. This study investigates the reproducibility and accuracy of offline telepathology as a primary diagnostic medium for routine histopathology specimens. METHODS: One hundred colorectal polyps (50 hyperplastic, 50 adenomatous) were presented in a randomised order to five histopathologists as offline images on a telepathology workstation. Six images of each case were used: the slide label, a low power scan of all material on the slide, and four higher magnification views. The times taken to prepare the images, and to make the diagnoses, were recorded. Interobserver agreement was measured with kappa statistics and compared with the glass slide diagnoses. RESULTS: The kappa statistics for the interobserver agreement on the telepathology images lay in the range of 0.90-1.00, which is interpreted as excellent agreement, and were significantly higher than those for the glass slide diagnoses (range, 0.84-0.98; p = 0.001). The median time taken to capture the images for a case was 210 seconds. The median time taken to make a diagnosis from the telepathology images was five seconds, which was significantly shorter than for the glass slide diagnoses (median, 13 seconds; p < 0.0005). CONCLUSIONS: Offline telepathology has the potential to be a primary diagnostic medium for routine histopathology with a high degree of reproducibility and short diagnosis times. Further studies are required to validate offline telepathology for different types of specimens and different operators of the image capture system.

Adenoma↗
PubMed2002

The effect of phytoestrogens on the female genital tract.

Environmental oestrogens have been implicated in the pathogenesis of hormonally treated cancers (such as breast and prostate cancer), male infertility, and abnormalities of the male and female reproductive tracts. They may be derived from plants (phytoestrogens), pharmaceuticals, or other synthetic compounds not originally intended to have oestrogenic activity (including soy based infant formulas). This review will discuss the evidence from both animal studies and humans for an effect of these ubiquitous compounds on the development of the human female genital tract, in addition to prolonging the menstrual cycle, alleviating symptoms of the menopause, and protecting against the development of endometrial carcinoma.

Endometrial Neoplasms↗