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Biomedical subjects

A Buckley

Publications and source records attributed to A Buckley.

49 records · Page 3Linked to original sources
PubMed1986

A prospective comparison of selective and universal electronic fetal monitoring in 34,995 pregnancies.

We investigated the effects of using intrapartum electronic fetal monitoring in all pregnancies, as compared with using it only in cases in which the fetus is judged to be at high risk. Predominant risk factors included oxytocin stimulation of labor, dysfunctional labor, abnormal fetal heart rate, or meconium-stained amniotic fluid. This prospective alternate-month clinical trial took place over a 36-month period during which 34,995 women gave birth. In alternate months, either 7 (for "selective monitoring") or 19 (for "universal monitoring") fetal monitors were made available in the labor and delivery unit. During the "selective" months, 6420 of 17,409 women (37 percent) were electronically monitored, as compared with 13,956 of 17,586 women (79 percent) during the "universal months." Universal monitoring was associated with a small but significant increase in the incidence of delivery by cesarean section because of fetal distress, but perinatal outcomes as assessed by intrapartum stillbirths, low Apgar scores, a need for assisted ventilation of the newborn, admission to the intensive care nursery, or neonatal seizures were not significantly different. We conclude that not all pregnancies, and particularly not those considered at low risk of perinatal complications, need continuous electronic fetal monitoring during labor.

Adult↗
PubMed1986

Neutralizing (54K) and non-neutralizing (54K and 48K) monoclonal antibodies against structural and non-structural yellow fever virus proteins confer immunity in mice.

The capacity of monoclonal antibodies to protect mice passively against yellow fever (YF) virus infection was investigated. Both neutralizing (54K-specific) and non-neutralizing (54K- and 48K-specific) antibodies protected mice against challenge with the RMP substrain of YF virus. Average survival times of mice inoculated intracerebrally with a standard lethal dose of YF virus differed according to the strain used: thus mice inoculated with the most neurovirulent viruses, FNV and Asibi, survived for 6 X 50 and 7 X 65 days respectively, and those with RMP virus survived for 15 X 75 days. The capacity of antibodies to protect mice passively against virus challenge was directly related to virus neurovirulence. Possible mechanisms and the significance of protection by antibodies against non-structural proteins that do not mediate neutralization, are discussed.

Animals↗
PubMed1985

Use of the biotin-streptavidin interaction to improve flavivirus detection by immunofluorescence and ELISA tests.

The specificity and sensitivity of immunofluorescence microscopy and ELISA tests were compared both with and without the use of biotinylated anti-species antibody and streptavidin, conjugated with either fluorescein isothiocyanate or horse radish peroxidase. In the biotin-streptavidin system monoclonal and polyclonal antibodies against yellow fever virus had titres between ten- and fifty-fold higher and background readings, particularly in ELISA tests, were noticeably reduced. Plaque variants of yellow fever virus, selected for their apparent loss of antigenic determinants against some monoclonal antibodies in conventional fluorescence tests, were found to possess the antigenic determinants when tested with the more sensitive system.

Animals↗
PubMed1985

Sustained release of epidermal growth factor accelerates wound repair.

Epidermal growth factor (EGF) is a potent mitogen in vitro, but its biological role is less clear. The vulnerary effects of EGF were evaluated in a model of wound repair, the polyvinyl alcohol sponge implanted subcutaneously in rats. EGF was purified to homogeneity by reverse-phase HPLC and quantified by receptor binding assay and amino acid analysis. Preliminary data showed moderate promotion of granulation tissue formation by daily injections of 10 micrograms of EGF. To test the hypothesis that long-term exposure to EGF is required for complete cellular response, the factor was incorporated into pellets releasing 10 or 20 micrograms of biologically active EGF per day, and the pellets were embedded within the sponges. Slow release of EGF caused a dramatic increase in the extent and organization of the granulation tissue at day 7, a doubling in the DNA content, and 33% increases in protein content and wet weight, as compared with placebo controls. Although collagen content was also increased by almost 50%, the relative rate of collagen synthesis remained the same, suggesting that the morphological and biochemical increase in collagen resulted from increased numbers of fibroblasts rather than a specific stimulation of collagen synthesis. These results indicate that the local sustained presence of EGF accelerates the process of wound repair, specifically neovascularization, organization by fibroblasts, and accumulation of collagen.

Animals↗
PubMed1985

Accelerated wound repair, cell proliferation, and collagen accumulation are produced by a cartilage-derived growth factor.

Cartilage-derived growth factor (CDGF), a cationic polypeptide of approximately 18,000 mol wt, was prepared from bovine articular cartilage; other sources were bovine and human scapular and costal cartilage. Previous studies have shown that CDGF stimulates the proliferation of cultured mouse fibroblasts as well as chondrocytes and endothelial cells from various sources. In this study, CDGF was shown to stimulate dose-dependently the accumulation of DNA and collagen by rat embryo fibroblasts and a population of fibroblasts derived from granulation tissue. CDGF also stimulated the proliferation of cultured bovine capillary endothelial cells dose-dependently. To evaluate the effects of CDGF in vivo, we implanted polyvinyl alcohol sponges subcutaneously in rats. 6 d postimplantation, sponges were injected with 300 micrograms of partially purified CDGF, a dose which takes into account the cell numbers in the sponges as compared with cell cultures. CDGF rapidly disappeared from the sponges and only approximately 10% of the initial dose was present at 4 h. Despite its transient presence, CDGF caused a relative increase in sponge DNA content of 2.6-fold at 48 h and 2.4-fold at 72 h. We repeated the sponge experiment by using 500-ng injections of CDGF purified to near homogeneity by heparin-Sepharose chromatography. Purified CDGF caused significant increases in sponge collagen, protein, and DNA content at 48 and 72 h after a single injection. The effects of CDGF were abolished by heat and unaffected by reduction of disulfide linkages. Morphologically, CDGF did not evoke an inflammatory response, and its effect on proliferating endothelial cells and fibroblasts was, therefore, probably direct. However, increases in DNA content of sponges could not be fully accounted for by increased DNA synthesis, which suggests that recruitment may be an important component of the in vivo response. Taken together, the effects of CDGF on cultured cells and granulation tissue suggest that the sustained presence of CDGF in vivo may greatly enhance its effects upon wound repair.

Animals↗
PubMed1985

Neutralization of yellow fever virus studied using monoclonal and polyclonal antibodies.

Monoclonal and polyclonal antibodies with known specificity for either the 54K envelope glycoprotein or the 48K non-structural glycoprotein of yellow fever (YF) virus-infected cells were studied in plaque reduction neutralization tests. Viruses employed in the tests comprised wild-type and vaccine strains of YF and a selection of other flaviviruses. Of 17 monoclonal antibodies examined, six of the 54K-specific antibodies neutralized at least one YF preparation. Both vaccine and wild-type YF viruses varied in their susceptibility to neutralization and there were also differences between individual 17D vaccine strains. The monoclonal antibodies produced a range of titres with the different viruses, the most potent, 864, leaving no non-neutralizable fraction. Addition of anti-globulin, complement or other antibodies did not affect the results. YF-neutralize antibodies which bound to other flaviviruses did not necessarily neutralize them; hence, neutralization could be defined as either homotypic, heterotypic or both homotypic and heterotypic. A polyclonal antiserum and a broadly reacting monoclonal antibody produced almost identical neutralization results in tests with wild-type YF viruses. In contrast, the polyclonal antiserum produced higher titres with vaccine strains of YF. In mouse passive protection experiments on the other hand, the monoclonal antibody did not differentiate between these viruses.

Animals↗
PubMed1985

Examination of the immunological relationships between flaviviruses using yellow fever virus monoclonal antibodies.

Monoclonal antibodies prepared against vaccine strains of yellow fever (YF) virus were initially characterized by fluorescence microscopy of Vero cells infected with YF virus strain 17D. When similarly tested against representatives of all flavivirus subgroups, the antibodies produced a wide spectrum of reactions ranging from the monospecific to the broadly cross-reactive; at least five antigenic domains in the YF virus envelope glycoprotein were identified. Monoclonal antibodies differentiated between YF virus vaccine strains (17D, 17DD, FNV), wild-type viruses and plaque variants selected from a 17D pool. One isolate from a patient with YF was antigenically similar to the Brazilian vaccine strain 17DD. Several of the antibodies reacting with the YF viral envelope glycoprotein in biological tests identified the 54K envelope glycoprotein; 45K and 26K polypeptides in YF 17D virus-infected cells were also identified by radioimmunoprecipitation and polyacrylamide gel electrophoresis. Neither of these polypeptides was found in uninfected cells. They may represent short-lived precursors of the 54K protein, post-translational cleavage or breakdown products. Other antibodies reacted with a 48K polypeptide in virus-infected cell lysates. This may be the non-structural NV3 protein described for YF virus. Its appearance on the surface of unfixed infected cells, but not on released virions, was demonstrated by fluorescence microscopy.

Animals↗
PubMed1985

Presence of epidermal-derived thymocyte activating factor/interleukin 1 in normal human stratum corneum.

Keratinocytes produce a molecule, epidermal-derived thymocyte activating factor (ETAF), which is biologically and physiochemically similar to the polypeptide hormone interleukin 1 (IL-1). Because the stratum corneum (SC) is composed of terminally differentiated keratinocytes, we questioned whether ETAF/IL-1 could be isolated from this tissue. The extraction of normal human SC with a physiologic saline solution yielded a large amount of ETAF/IL-1 activity, as measured by the in vitro thymocyte co-stimulator assay. SC-derived ETAF/IL-1 (scETAF/IL-1) eluted from a sizing column with an approximate molecular weight of 15,000, and demonstrated three isoelectric point forms after separation on a chromatofocusing column. By these physiochemical characteristics, scETAF/IL-1 was found to be similar, if not identical to human keratinocyte- and macrophage-derived ETAF/IL-1. Further, a number of biologic effects known to occur in vivo after the administration of ETAF/IL-1, such as fever, neutrophilia, and an increase in plasma levels of acute-phase proteins, were all induced by the injection of scETAF/IL-1 into endotoxin-nonresponsive mice. scETAF/IL-1 was also found to stimulate collagenase production by human fibroblasts in vitro. In summary, our studies have established that normal human SC contains a large quantity of scETAF/IL-1. Whether scETAF/IL-1 integrates into the earliest afferents phases of local inflammatory responses, or merely represents a means of disposal of excessively produced hormone is currently unresolved.

Amyloid↗
PubMed1983

Immunofluorescence studies on the antigenic interrelationships of the Hughes virus serogroup (genus Nairovirus) and identification of a new strain.

Titrations of hyperimmune antisera by indirect immunofluorescence using each virus of the Hughes serogroup (Hughes, Zirqa, Punta Salinas, Soldado and Farallon) demonstrated their individual antigenic identities. Furthermore, an antigenically related virus, designated Puffin Island (PI) virus, was shown both by indirect immunofluorescence and by neutralization in XTC cells to be distinguishable from the other viruses. These viruses readily established persistent infections in Vero cells after producing only moderate cytopathic effects. Treatment of persistently infected cultures with either fluorodeoxyuridine or bromodeoxyuridine made no significant difference to the percentage of immunofluorescent cells. Attempts to demonstrate haemagglutination by Zirqa virus were unsuccessful.

Antigens, Viral↗
PubMed1983

Monoclonal immunoglobulin M antibody to Japanese encephalitis virus that can react with a nuclear antigen in mammalian cells.

An immunoglobulin M (IgM) class monoclonal antibody raised against Japanese encephalitis virus reacted with an epitope on the nonstructural virus protein P74 (NV4 in the old nomenclature) of several flaviviruses and also with an antigen present in the nuclei of a variety of mammalian cell types. This antigen had a characteristic granular distribution by immunofluorescence and may correspond to a polypeptide of molecular weight 56,000 seen in nitrocellulose transfers of sodium dodecyl sulfate-polyacrylamide gels. Cross-reactivity with nuclear antigen was also occasionally observed in the IgM antibody fraction of mice early after infection with Japanese encephalitis virus and also in acute sera from some clinical cases of encephalitis containing IgM antibody to Japanese encephalitis virus.

Animals↗
PubMedDate not supplied

The role of ERCP in children and adolescents.

The diagnostic and therapeutic role of ERCP in 42 patients ranging from 1 to 19 years of age is discussed. ERCP provided useful additional information in 15 patients with biliary tract disease, 15 patients with pancreatic disease, and 9 patients with abdominal pain. The appropriate duct was cannulated in 95% of cases. Mild pancreatitis occurred in two patients after ERCP. Endoscopic papillotomy was successful in five patients. ERCP plays an important part in the investigation of unexplained biliary tract and pancreatic disease. It rarely demonstrates abnormal pathology in patients with otherwise unexplained abdominal pain.

Abdominal Pain↗