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Biomedical subjects

E Rawlings

Publications and source records attributed to E Rawlings.

17 recordsLinked to original sources
PubMed2003

A comparison of total intravenous with balanced anaesthesia for middle ear surgery: effects on postoperative nausea and vomiting, pain, and conditions of surgery.

We compared postoperative nausea and vomiting (PONV), pain and conditions for surgery in patients scheduled for middle ear surgery. In a double-blind study, 100 patients were randomly allocated to receive either balanced anaesthesia (group A) using fentanyl, propofol and isoflurane, or total intravenous anaesthesia (group B) using propofol and remifentanil infusions. Pain scores, nausea/vomiting scores, conditions for surgery and analgesic requirements were recorded for 18 h post operatively. In the recovery ward, patients in group B suffered significantly less PONV (p = 0.026) with a reduced requirement for anti-emetic medication (p = 0.023); however, this difference was not maintained on the ward. The overall incidence of PONV was 34% and 17% in groups A and B, respectively. Initial pain scores were higher in group B in the recovery ward (p = 0.003) and patients required more morphine administration (p = 0.002); however, pain scores were similar on the ward. Conditions for surgery were found to be better in group B.

Adult↗
PubMed2002

Detection of streptomycin and dihydrostreptomycin residues in milk, honey and meat samples using an optical biosensor.

Immuno-biosensor inhibition assays for the detection of streptomycin and dihydrostreptomycin residues in whole cows' milk, honey, pig kidney and pig muscle are reported. The antibody showed high cross-reactivity with dihydrostreptomycin in various foodstuffs (buffer 103%, milk 96%, honey 84%, kidney extract 129% and muscle extract 98%). There was no significant cross-reaction with other aminoglycosides or commonly used antibiotics. A streptomycin derivative was used to prepare a stable, reusable sensor chip surface. The assay allowed the direct analysis of bovine whole milk (fat content approximately 3.5%). Honey samples required dilution with buffer, while kidney and muscle samples from pigs were homogenized in an aqueous extraction buffer and clarified by centrifugation. The limit of detection for each assay was determined from known streptomycin-free samples (n = 20; mean - (3 x standard deviation)) and the results were as follows: milk 30 microg kg(-1), honey 15 microg kg(-1), kidney 50 microg kg(-1) and muscle 70 microg kg(-1). Repeatability (or relative standard deviation) between runs were calculated (n = 3) at the respective Community maximum residue limits (MRL) and 0.5 x MRL with the exception of honey since no European MRL exists at present. Results were determined as 4.3% (200 microg kg(-1)) and 2.8% (100 microg kg(-1)) in milk, 13.3% (40 microg kg(-1)) and 9.5% (20 microg kg(-1)) in honey, 7.1% (1000 microg kg(-1)) and 7.6% (500 microg kg(-1)) in kidney and 7.1% (500 microg kg(-1)) and 11% (250 microg kg(-1)) in muscle.

Animals↗
PubMed2002

Improved clean-up for the determination of lasalocid in 'difficult' food matrices.

Methodology has been developed for the determination of lasalocid in analytically 'difficult' matrices such as processed and spiced foods. The procedure was based on an existing silica-based solid-phase extraction (SPE) clean-up to which was added a novel NH2 SPE step before HPLC with fluorescence detection. Use of the additional step enabled the determination of lasalocid in matrices such as baby food, meat pies ('pasties'), etc. Analysis of these matrices was not possible using the standard clean-up on its own. Chromatography showed a massive reduction in the amount of co-extractives and interferences. Validation data were obtained down to the 10-40 mg kg(-1) level for a range of products. Recoveries ranged from 74% at 10 microg kg(-1) for pork sausages to 96% at 40 microg kg(-1) for meat pies.

Animals↗
PubMed2001

Somatically mutated regions of immunoglobulin on human B-cell lymphomas code for peptides that bind to autologous major histocompatibility complex class I, providing a potential target for cytotoxic T cells.

Lymphoma-derived immunoglobulin idiotype (Id) is a well-characterized, tumor-specific antigen on B-cell malignancies. Immunotherapy using lymphoma immunoglobulin can lead to clinical responses mostly associated with anti-Id antibody. We cloned the Id from B-cell lymphomas, sequenced them, and used bioinformatics to select autologous MHC class I binding peptides from somatically mutated regions of the lymphoma Id. Peptides from patients who were HLA-A1, HLA-A2, HLA-A3, or HLA-A11 positive were analyzed in the T2 stabilization assay and a competitive peptide-binding assay. By both methods, approximately half of the peptides analyzed, regardless of HLA type, bound with intermediate or high affinity. Peptide binding affinity was similar to viral peptide sequences known to provide targets for cytotoxic T cells. Further investigation of lymphocyte responses to stimulation by autologous Id peptides versus Id peptides from other patients revealed that three of five patients in complete remission or with low volume, stable disease responded to self-peptides by IFN-gamma secretion greater than that seen with non-self peptides, whereas none of five patients with progressive disease responded to their own lymphoma Id. We have shown that mutated regions of lymphoma Id contain MHC class I binding peptides that are potential targets for cytotoxic T cells. Immunotherapy using the tumor-specific mutated regions from lymphoma Id avoids the need to break innate tolerance toward the germ-line protein sequences present on normal and malignant B cells.

Amino Acid Sequence↗
PubMed1996

Pharmacokinetics and immunodynamics of chimeric IL-2 receptor monoclonal antibody SDZ CHI 621 in renal allograft recipients.

SDZ CHI 621 is a murine-human chimeric monoclonal antibody (mAb) to the interleukin-2 (IL-2) receptor (CD25) intended for prophylactic immunosuppression against acute rejection in the first several weeks following kidney transplantation. A multicentre, prospective, dose-finding study was conducted in 37 primary, mismatched cadaver kidney transplant patients to assess its tolerability, pharmacokinetics and immunodynamics. Successive cohorts of patients were stratified to receive total doses of 20, 30, 40 or 60 mg (n = 4, 4, 14, 15, respectively) administered as 15- or 20-mg intravenous infusions with the first dose given preoperatively and subsequent doses within the first 10 days posttransplant. Daily mAb serum concentrations were analysed by a radioimmunoassay method and the percentage of peripheral T-lymphocytes expressing CD25 from serial blood samples was determined by FACScan. Intravenous administrations were well tolerated. mAb concentration profiles exhibited a biphasic decline with an initial t1/2 of 14.4 +/- 14.2 h, terminal t1/2 of 13.4 +/- 6.0 days, distribution volume (Vss) of 6.9 +/- 3.31 and clearance of 17.4 +/- 7.8 ml/h. The concentration-effect (mAb-CD25) relationship indicated that mAb concentrations exceeding a threshold of about 0.7 microgram/ml corresponded to complete suppression of CD25 (< or = 3% CD25+ T-cells). The threshold mAb concentration was exceeded at all dose levels, whereas the duration above the threshold (and thus of CD25 suppression) rose with increasing dose: 20 mg, 20 +/- 7 days; 30 mg, 32 +/- 6 days; 40 mg, 37 +/- 10 days; and 60 mg, 53 +/- 17 days. As mAb concentrations declined below the threshold following the last dose, CD25 expression returned to baseline (18-44% CD25+ T-cells) within a few days.

Adolescent↗
PubMed1996

Activation antigen expression on human T cells. I. Analysis by two-colour flow cytometry of umbilical cord blood, adult blood and lymphoid tissue.

Activation antigens (actags) were detected on T cells at low levels of intensity by carefully defining negative cells with a panel of control antibodies. The mean percentage of blood T cells from healthy volunteers that expressed actags were 22% (CD25), 54% (CD26), 38% (CD38), 12% (CD54), 6% (CD69) and 21% (HLA-DR). The variability of actag expression detected by this sensitive method was determined on healthy volunteers by repeated estimation over a year. The percentage of T cells expressing CD25 and CD26 varied no more than repeated estimation of the CD4 T cell subset, whereas other actags showed greater variability. The antigen density of these actags on T cells was determined in relation to CD4 antigen density, and for most actags ranged from 10% to 75% of the level of CD4 antigen density except for CD7 and HLA-DR, which could exceed that of CD4. Different degrees of actag expression characterized T cells from different blood and lymphoid tissues. CD26, CD38 and CD45RA were universally expressed in cord blood at higher antigen density than adult blood. This immature pattern was consistent with recent thymic emigration. CD25, CD45RO, CD54 and HLA-DR progressively increased from cord blood through adult blood to lymphoid tissues, consistent with antigen-driven activation, whereas CD26 and CD45RA decreased. CD69, a very early activation antigen, abruptly increased in lymphoid tissue, exceeding CD25 by two-to-three-fold and suggesting a pre-activation state that may not involve commitment to antigen-driven proliferation. CD7 and CD38 expression was higher in cord blood and lymphoid tissue than in adult blood, indicating both an antigen-independent and -dependent up-regulation.

Adult↗
PubMed1995

Prolonged action of a chimeric interleukin-2 receptor (CD25) monoclonal antibody used in cadaveric renal transplantation.

A high affinity chimeric CD25 mAb (chRFT5: SDZ CHI 621) blocking interleukin-2 binding to the interleukin-2 receptor alpha-chain was evaluated in a phase I/II study in human renal cadaveric transplantation. The chRFT5 was well tolerated with no immediate adverse effects during 6 spaced infusions (from before transplantation to day 24) in 24 patients escalating from 2.5- to 25-mg dosages. The chRFT5 had a long terminal half-life with a mean of 13.1 days. There was good correlation between the detection of chRFT5 in the serum by radioimmunoassay, the coating and suppression of CD25 on T cells, and antibody activity in patient serum samples. The chRFT5 activity persisted in vivo for up to 120 days. No antibody response to the chRFT5 was detected in any of the patients, even though two patients who required treatment with antithymocyte globulin or OKT3 developed xenogeneic antiglobulin responses while chRFT5 was still present in vivo. There was a 33% incidence of rejection and the first rejection episode always occurred during chRFT5 therapy. Patients who did not reject during therapy did not reject during the first year following transplantation. Equal numbers of patients received dual and triple immunosuppressive therapy together with chRFT5. Posttransplant lymphoproliferative disorder developed in 2 patients, both on triple therapy, at 9 months after transplantation. The disorder did not develop in any patient receiving dual therapy, and no further cases have been observed to a minimum of 2 years' follow-up. No other viral, fungal, or bacterial infectious complications were prevalent in patients treated with chRFT5.

Adult↗
PubMed1988

Pre-implantation diagnosis of HPRT-deficient male and carrier female mouse embryos by trophectoderm biopsy.

In an animal model for Lesch-Nyhan syndrome, the affected male embryos, as well as the carrier female embryos, have been successfully identified by biochemical microassay of a sample of trophectoderm cells taken from the mouse embryos at the blastocyst stage. The embryos were removed from the uterus, diagnosed and returned to the uterus within 2 days without the need for cryopreservation. The diagnosis was confirmed at 14 days gestation by analysis of the hypoxanthine phosphoribosyl transferase (HPRT) status of the fetuses. Live young were obtained from biopsied embryos after transfer.

Animals↗
PubMed1986

Separate ontogeny of two macrophage-like accessory cell populations in the human fetus.

Human macrophage-like accessory cells were analyzed as they emerge in the absence of extrinsic antigens during fetal development. Monoclonal antibodies to monocytes/macrophages were used in combination with antibodies to HLA class II molecules. In the yolk sac and mesenchyme sampled at wk 4 to 6 of fertilization age, cells with dendritic morphology formed two populations distinguishable by phenotypic criteria: type i (majority) carried both macrophage-associated (RFD7+) and monocyte-associated markers (UCHM1+) but no detectable HLA-DR antigen, and type ii (minority) constitutively expressed class II (HLA-DR and -DP) but no RFD7 and UCHM1. The emergence of this heterogeneity preceded the formation of both thymus and bone marrow. During additional development, type i and type ii cells seeded to different microenvironments and underwent some additional phenotypic changes. Cells of type i, the RFD7+ population with high lysosomal (acid phosphatase) activity, were seen in the thymic cortex, marginal zone of lymph nodes, splenic red pulp, and in the midst of erythropoietic activity within the bone marrow. These cells were UCHM1- and class II-. Cells of type ii formed the population of HLA-DR+, RFD7- interdigitating cells, early inhabitants of T cell areas in the developing thymic medulla, lymph nodes, spleen, and tonsil. The Type ii cells that had already settled in their nichès expressed not only HLA-DR and -DP but also HLA-DQ, and another class II antigen identified by the antibody RFD1, which shows the restricted tissue distribution of HLA-DQ, but is governed by genes that are outside of and telomeric to the HLA-DQ region (or HLA-DR). Finally, subpopulations of macrophages (RFD7+, acid phosphatase-positive) in the fetal gastrointestinal and hepatic systems were HLA-DR+; the latter appear to include precursors of Kupffer cells in the developing liver.

Acid Phosphatase↗
PubMed1985

An immunoradiometric assay for human factor VIII/von Willebrand factor (VIII:vWF) using a monoclonal antibody that defines a functional epitope.

A murine monoclonal antibody has been produced (RFF-VIII:R/2) that binds specifically to human factor VIII-related antigen (VIII:RAg) in plasma and in vascular endothelial cells but has no reactivity with factor VIII procoagulant antigen (VIII:cAg). This antibody is a potent inhibitor of von Willebrand factor activity (VIII:vWF) in that it can totally neutralize ristocetin-induced aggregation of platelet rich plasma and inhibit platelet adhesion at high flow rates. RFF-VIII:R/2 can be used in a one-stage, fluid phase immunoradiometric assay that can detect VIII:RAg at concentrations of 0.001 u/ml. This method has been used to analyse plasma from patients with von Willebrand's disease (vWD). Results obtained in these patients showed a high degree of correlation between the monoclonally-defined epitope and VIII:vWF levels measured by ristocetin-induced aggregation of washed platelets. This correlation was maintained in those patients with the 'variant' types of vWD who exhibit highly disparate VIII:vWF and VIII:RAg levels when the latter is determined using polyclonal antisera. It appears that this monoclonal antibody recognizes a site on the VIII:RAg molecule which is associated with its interaction with the platelet membrane. Immunoradiometric assays using RFF-VIII:R/2 offer a simplified, reproducible means of detecting functionally-active VIII:RAg as an alternative or supplement to techniques involving platelet interactions.

Animals↗
PubMed1983

Monoclonal antibodies to human procoagulant factor VIII.

VIII:C was purified from intermediate-purity concentrate by adsorption on polyelectrolyte E5 and affinity chromatography on Sepharose/anti-VIIIR:Ag. The highly purified VIII:C preparation (sp. act. 1598 U/mg) was used to immunize Balb-C mice. Spleen cells from a mouse with a serum antibody titer of 963 U/ml were fused with P3 NSI mouse myeloma cells. Hybrid clones were screened by a coagulation inhibition assay and by a four-layer antibody adsorption procedure. Nine monoclonal antibodies specific to VIII:C were produced. Five of these antibodies have been cloned and grown in mouse ascitic fluid. Antibody titers from ascitic fluid ranged from 35 to 82,000 BU/ml. The antibodies, when radiolabeled, form a high-molecular-weight complex with antigens present in normal plasma and factor VIII concentrate, but not when incubated with CRM-negative hemophilic plasma. A two-site assay using a combination of monoclonal antibodies is able to detect VIII:CAg in normal plasma and in factor VIII concentrate. Sensitive two-site immunoradiometric assays using monoclonal antibodies as the solid phase have been set up.

Animals↗
PubMed1982

Preparation of factor IX deficient human plasma by immunoaffinity chromatography using a monoclonal antibody.

A murine hybridoma clone is described that grows continuously in culture and produces a monoclonal antibody we have called Royal Free Monoclonal Antibody to factor IX No. 1 (RFF-IX/1). This has high affinity for a coagulation site on factor IX. RFF-IX/1 immobilised on sepharose can be used to deplete factor IX from normal human plasma. This immunoaffinity depleted plasma is indistinguishable from severe Christmas disease plasma and can be used as the substrate in a one stage coagulation assay for factor IX. The affinity column has high capacity and can be regenerated so that large scale production from normal plasma of factor IX deficient plasma as a diagnostic reagent is now feasible.

Animals↗
PubMed1979

The effect of intragastric feeding with amino acids on liver regeneration after partial hepatectomy in the rat.

The incorporation of 14C-thymidine into DNA was measured at 4-hr intervals from 16 to 32 hr after partial hepatectomy in groups of rats. Rats forcefed solutions of amino acids or branched-chain amino acids showed a significant reduction in the DNA specific activity 24 hr after partial hepatectomy when compared to rats forced fed an equal volume of water. Intragastric feeding with ketoanalogues of the branched-chain amino acids did not alter thymidine incorporation into DNA significantly. The finding that intragastric feeding depresses DNA synthesis after partial hepatectomy contrasts with our studies indicating increased synthesis of albumin in partially hepatectorized animals receiving similar feeding and indicates different control mechanisms for DNA and albumin synthesis.

Amino Acids↗