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Biomedical subjects

C Green

Publications and source records attributed to C Green.

At least 217 records · Page 12Linked to original sources
PubMed1989

A study of the photodegradation of leukotriene B4 by ultraviolet irradiation (UVB, UVA).

In view of the presence of the polymorphonuclear leukocyte (PMN) chemoattractant Leukotriene B4 (LTB4) in the surface scale of the psoriatic lesion and the known therapeutic effect of phototherapy in psoriasis, the photostability of LTB4 was investigated. LTB4 was irradiated with dosages of UVB (290-320 nm) ranging from 100-1500 mJ cm-2 and with dosages of UVA (320-400 nm) ranging from 5-40 J cm-2. Topical application of UVB irradiated LTB4 to the forearm skin of normal volunteers showed a marked reduction in cutaneous erythema, paralleled histologically by reduced transepidermal PMN migration when compared with sites of application of unirradiated and UVA irradiated LTB4. High performance liquid chromatography (HPLC) demonstrated a dose-dependent photodegradation of LTB4 by UVB irradiation. UVA irradiation produced no such effect. The wavelengths responsible lie within the absorption spectrum of LTB4. In vitro chemotaxis studies, using an under agarose technique, showed a statistically significant reduction in the migration of PMN from both psoriatic and non-psoriatic subjects to the UVB irradiated LTB4 compared with the unirradiated LTB4, whilst UVA irradiated LTB4 produced a normal PMN chemotactic response.

Chemotaxis, Leukocyte↗
PubMed1989

Stability of murine monoclonal anti-A, anti-B and anti-A,B ABO grouping reagents and a multi-centre evaluation of their performance in routine use.

We have previously reported the production of 3 murine monoclonal reagents for ABO typing (designated ES-9, ES-4 and ES-15). This study presents results of tests of stability of these 3 reagents, together with a fourth murine monoclonal antibody (LM103/107). In addition, data are also presented from a multi-centre evaluation of the performance of the murine monoclonal reagents in routine ABO typing of both donors and patients using a wide variety of techniques, both manual and automated. The potency and stability of the 4 monoclonal antibody based reagents is compared with a broad selection of monoclonal and polyclonal ABO typing reagents. The reagents used for comparison were produced by European and United States manufacturers in both the public and private sector and are widely used in routine ABO typing. The Scottish monoclonal reagents have been used successfully to ABO type over 500,000 blood samples in 7 centres within the UK, with no discrepant results.

ABO Blood-Group System↗
PubMed1989

A private red cell antigen, Jones, causing haemolytic disease of the newborn.

Two previously unpublished low-incidence antigens, Jones and Hol., are identical. The antigen is a dominant, autosomally inherited character that segregates independently from the loci for the ABO, MNS, Duffy and Yt blood group systems and is different from previously published infrequent antigens. The antigen is apparently unaffected by enzyme treatment and is well developed on red cells of neonates. The antibody reacts best by indirect antiglobulin testing, is IgG and has caused haemolytic disease of the newborn. This private blood group antigen, named Jones, has been assigned the ISBT number 700047.

Adult↗
PubMed1989

The ABO, Lewis and related blood group antigens; a review of structure and biosynthesis.

Numerous studies have shown that the antigenic determinants of the ABO blood group system are closely related in biochemical terms to the antigenic determinants of the Hh, P, Lewis and Ii blood group systems. The blood group antigens of each of these systems are formed by the addition of specific sugars to an oligosaccharide precursor chain which may be bound through sphingosine to fatty acids (glycolipid) or through serine or threonine to a peptide chain (glycoproteins). The direct gene products of each of these blood group systems are the glycosyltransferase enzymes which catalyse the addition of the specific sugar thus conferring the specified blood group activity to the glycolipid or glycoprotein molecule. The antigenic determinants of the ABO and Lewis systems in addition to red cells also exist in the body secretions in soluble form when the relevant genes are expressed in the phenotype. The antigens expressed on both the red cells and in the secretions are determined by the interaction of Hh, Sese, ABO and Lele genes.

ABO Blood-Group System↗
PubMed1989

Measurement by HPLC of desferrioxamine-available iron in rabbit kidneys to assess the effect of ischaemia on the distribution of iron within the total pool.

A method for the determination of desferrioxamine-available iron in tissue fractions is described which involves incubation with desferrioxamine, extraction of desferrioxamine and its iron-bound form, ferrioxamine, and quantitation of these two forms of the drug by reversed-phase hplc analysis. Chelatable iron levels in the 1-10 microMolar region could be accurately and reproducibly measured using this technique. The desferrioxamine-available iron levels in both the cortex and medulla of rabbit kidneys were significantly elevated (up to 2-fold) after the organs had been subjected to 2 hours warm ischaemia or 24 hours cold storage at 0 degrees C in hypertonic citrate solution. There was no change in the total iron content of the tissues under these circumstances and thus a redistribution of intracellular iron to more available pools had presumably taken place as a result of ischaemia. This redistribution of iron may be an important factor in the initiation of peroxidative damage to cell membranes upon reperfusion of the organ with oxygen.

Animals↗
PubMed1989

Polyethylene glycol in the production of blood grouping reagents: some further advantages.

The use of various water-soluble non-ionic polymers, including polyethylene glycol (PEG) 8000, has been described in the preparation of diagnostic blood grouping reagents. The major advantages of using PEG in this way are ease of preparation and the ability to concentrate antibodies. We describe here two previously unreported advantages of using PEG: (i) substantial reductions in the volume of red cells required for adsorption of isoagglutinins; and (ii) the ability to store PEG precipitates in a 'dry' form substantially reduces storage requirements.

Blood Grouping and Crossmatching↗
PubMed1988

311 nm UVB phototherapy--an effective treatment for psoriasis.

Fifty two psoriatic patients were treated with a new experimental fluorescent lamp (Philips TL-01) emitting a narrow band at 311 +/- 2 nm (UVB) which had the advantage of a reduction in burning and carcinogenic wavelengths when compared with conventional broad band UVB therapy. Results of the '311' treated group when compared with broad band UVB therapy revealed a similar percentage of patients achieving a satisfactory response with fewer burning episodes and an increase in duration of remission.

Humans↗
PubMed1988

Inheritance and linkage data for an unusual combination of genes (at the LKE, PI and C6 loci) in a single large sibship.

Analysis of the groups of a large sibship showed that the locus for the blood group LKE is not closely linked to the loci for MNS, Rh, HLA, Pi, Gm and C6 and is genetically independent of the loci for P1, K, Xg, Au, secretor, and C3. The locus for the Auberger (Au) blood group was shown to be genetically independent of the locus for the blood group Kell and of the loci for C3, C6, Gc, HLA, Pi and Gm groups.

Blood Group Antigens↗
PubMed1988

Inhibition of progesterone secretion from granulosa cells by estradiol and androgens in the domestic hen.

We previously reported no difference in progesterone (P4) secretion from the granulosa layer of the largest follicle (F1) of the domestic hen regardless of the maturity of the F1 follicle. However, coincubation of the granulosa and thecal layers resulted in inhibition of P4 secretion from the less mature F1, but not from the more mature F1. The goal of this study was to determine if estradiol (E2) and androgens secreted by the thecal layer suppress P4 production by the granulosa cells. We removed the granulosa layer from less mature F1 follicles and dispersed granulosa cells (1 x 10(5)) were incubated (3 h) in triplicate with one of these treatments: control, E2, testosterone (T), androstenedione (A), and dihydrotestosterone (DHT; at concentrations of 1 x 10(-7), 1 x 10(-6), and 1 x 10(-5) M), LH (100 ng) as well as LH plus E2, T, A, and DHT at the same concentrations. P4 secretion was measured in the medium and cells, and the experiment was replicated seven times. We found a dose-related suppression of basal and LH-stimulated P4 production by all steroids. In a second experiment (n = 3-5), we tested the specificity of the androgens in suppressing P4 production by granulosa cells by using the aromatase inhibitor 7-(4'-amino)phenylthio-4-androstene-3,17-dione. This compound did not reduce the effectiveness of T in suppressing P4 production. Finally in Exp 3 (n = 4-7), E2 and T were tested individually and in combination at concentrations of 1 X 10(-8)-1 X 10(-5) M. We found a possible synergistic effect, in that the combination of E2 plus T suppressed P4 to a greater degree than either steroid alone. Our results indicate that 1) E2 and androgens suppress basal and LH-stimulated P4 production by granulosa cells in a dose-related manner; 2) androgen suppression of P4 production is not mediated by aromatization to estrogen; and 3) the suppressive effects of E2 and androgens may be synergistic. We conclude that E2 and androgens secreted by the thecal layer may regulate P4 production by the granulosa layer.

Androgens↗
PubMed1988

Endothelial-smooth muscle interactions in vitro: effects of high pH, flowing medium and extracellular matrix.

The interactions of cultured bovine aortic and human umbilical or saphenous vein endothelium with cultured fibroblasts or smooth muscle cells were studied using light microscopy, scanning electron microscopy, and a radioisotope adhesion assay. (1) Resuspended fibroblasts or smooth muscle cells readily 'overgrew' confluent endothelial monolayers under static culture conditions, but not when cultures were exposed to a continuously stirred medium. (2) Exposure of cultured endothelial or smooth muscle cells to a moderately alkaline environment alters the disposition of pericellular concanavalin. A positive extracellular material. This does not affect the initial adhesion of endothelial or smooth muscle cells, but does affect cell spreading. (3) Endothelial adhesion to cultured smooth muscle cells involves both adhesion and spreading. Recently subcultured or rapidly proliferating smooth muscle cells support initial adhesion, but not spreading. Spreading appears to require the establishment of a suitable extracellular matrix, and this is inhibited both by a flowing medium and by an alkaline extracellular environment.

Animals↗
PubMed1987

The identification of specific Rhesus-polypeptide-blood-group-ABH-active-glycoprotein complexes in the human red-cell membrane.

1. RhD,c and E immune complexes isolated from 3H- and 125I-surface-radiolabelled and unlabelled intact human red cells were analysed by SDS/polyacrylamide-gel electrophoresis. 2. Apparent Mr values of 31,900 for RhD polypeptide and 33,100 for Rhc,E polypeptide were obtained under both reducing and non-reducing conditions. Glycosylation of RhD,c and E polypeptides was not detected. 3. RhD,c and E immune complexes also contain a glycoprotein component. RhD glycoprotein (apparent Mr 45,000-100,000) is distinct from Rhc,E glycoprotein(s) (apparent Mr 35,000-65,000). Rh (Rhesus) glycoprotein carbohydrate moieties are susceptible to endo-beta-galactosidase digestion and carry blood-group-ABH determinants. This suggests the presence of polylactosaminoglycan-type structures. 4. Rh glycoproteins are not present in Rh immune complexes as a result of non-specific adsorption of membrane glycoproteins during the membrane-solubilization phase of immune-complex isolation because RhD immune complexes isolated from a 1:1 (v/v) mixture of Acde/cde and OcDE/cDE red cells do not contain blood-group-A-active glycoprotein. 5. Blood-group-A immune complexes isolated from group-A red cells of the appropriate Rh phenotypes contain the 31,900- and 33,100-apparent-Mr Rh polypeptides. 6. It was concluded from the above evidence that non-covalent Rh-glycoprotein-Rh-polypeptide complexes exist in the native red-cell membrane. 7. The 31,900- and 33,100-apparent-Mr Rh polypeptides are absent from blood-group-A immune complexes isolated from regulator type Rhnull cells (donor A.L.), but are replaced by a 33,800-apparent-Mr Rhnull-specific polypeptide (Rhnull polypeptide). It is suggested that Rhnull polypeptide is an aberrant product of the Rh gene complex.

Antigen-Antibody Complex↗
PubMed1987

Cholesterol transfer from rat, human and sheep erythrocytes.

1. The spontaneous transfer of cholesterol out of sheep, rat and human erythrocyte membranes was measured. 2. The rates of cholesterol transfer did not correlate with the very different levels of sphingomyelin in the membranes. 3. Cholesterol transferred at similar rates out of vesicles made of lipids extracted from the three types of erythrocyte. 4. The results are discussed in relation to the proposal that cholesterol and sphingomyelin are closely associated in cell surface membranes.

Animals↗