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Biomedical subjects

B Gardner

Publications and source records attributed to B Gardner.

At least 37 records · Page 2Linked to original sources
PubMed1996

Eat your cereal.

Explore the source record for details and available documents.

Humans↗
PubMed1996

A clinical magnetic resonance imaging study of the traumatised spinal cord more than 20 years following injury.

One hundred and fifty three patients who had sustained a spinal cord injury more than 20 years previously were assessed neurologically and by MRI scanning of their spinal cords. The spinal cord pathologies shown were, in order of prevalence, extended atrophy, malacia, syrinx, cyst, disruption and tethering. There was no relationship between the prevalence of any type of pathology and the degree of spinal canal compromise or angulation of the spine adjacent to the level of injury. Neurological changes after initial neurological stabilisation were seen only in patients with extended atrophy, malacia or a syrinx, not in those with only a cyst or cord disruption. Tethering is always associated with other lesion(s). Longer syrinxes were more likely to have associated neurological changes than shorter ones. The most common neurological change was pain.

Adult↗
PubMed1996

Pharmacological analysis of dopamine stimulation of [35S]-GTP gamma S binding via human D2short and D2long dopamine receptors expressed in recombinant cells.

1. The activation of G-proteins by agonist-occupied D2 or D3 dopamine receptors in membranes from recombinant cells expressing the cloned receptors has been analysed by a [35S]-guanosine 5'-[gamma-thio] triphosphate ([35S]-GTP gamma S) binding assay. 2. The rate of [35S]-GTP gamma S binding was increased by dopamine in a dose-dependent manner in membranes from CHO cells stably expressing either the D2short or D2long dopamine receptor. 3. The dopamine-induced stimulation of [35S]-GTP gamma S binding could be inhibited by a range of antagonists. Affinities for antagonists derived from the inhibition of the dopamine stimulation of [35S]-GTP gamma S binding correlated very well with affinities derived from radioligand binding studies. 4. When the maximum [35S]-GTP gamma S binding responses stimulated by dopamine acting at different receptor subtypes were compared, there was a tendency for the stimulation via the D2short receptor to be greater than via the D2long receptor and for the stimulation via the D3 dopamine receptor to be less than for either D2 receptor. These differences in maximal response were also seen when the inhibitory effects of dopamine on adenylyl cyclase via the three receptor subtypes were compared. 5. The stimulation of [35S]-GTP gamma S binding by dopamine in membranes from recombinant cells therefore provides an excellent system for studying the molecular nature of agonism and the receptor/G-protein interactions for these receptors.

Adenylyl Cyclases↗
PubMed1995

Interaction of protein 4.1 with the red cell membrane: effects of phosphorylation by protein kinase C.

Phosphorylation with endogenous protein kinase C causes the membrane skeletal protein, band 4.1, to lose its capacity to attach to one of two classes of high-affinity binding sites on the red cell membrane. These sites are the ones eliminated by proteolysis in situ of glycophorin C; the surviving type of site is located in a C-terminal peptide of the glycophorin C, retained on the membrane after proteolysis, which is also the site of attachment of p55. A synthetic peptide, comprising the 28 C-terminal residues of glycophorin C, also binds protein 4.1. Phosphorylation of the intact cells, stimulated by phorbol ester, approximately halves the retention of glycophorin C in the membrane cytoskeletons prepared from these cells and reduces the affinity of extracellular glycophorin C epitopes for their antibody.

Cytoskeletal Proteins↗
PubMed1995

Monoclonal antibodies recognizing epitopes on the extracellular face and intracellular N-terminus of the human erythrocyte anion transporter (band 3) and their application to the analysis of South East Asian ovalocytes.

This report describes the production and characterization of 13 rodent monoclonal antibodies to the human erythrocyte anion transport protein AE1 (syn. band 3). Eleven antibodies (4 murine and 7 rat) recognize epitopes dependent on the integrity of the third extracellular loop of the protein. Two antibodies (1 murine and 1 rat) recognize epitopes on the N-terminal cytoplasmic domain. Quantitative binding studies using radioiodinated IgG and Fab fragments of antibodies to extracellular epitopes on AE1 ranged from 77,000 to 313,000 (IgG) and from 241,000 to 772,000 (Fab) molecules bound at saturation. The results indicate that the epitopes recognized by different antibodies vary in their accessibility and suggest that there is heterogeneity in the organization of individual AE1 molecules in the red blood cell membrane. Quantitative binding studies on South East Asian ovalocytes using several antibodies to AE1 and an anti-Wrb show a marked reduction in the number of antibody molecules bound at saturation. These results are consistent with the existence of highly cooperative interactions between transmembrane domains of AE1 in normal erythrocytes and the disruption of these interactions in the variant AE1 found in South East Asian ovalocytes.

Animals↗
PubMed1995

The three-dimensional solution structure of a constrained peptidomimetic in water and in chloroform. Observation of solvent induced hydrophobic cluster.

A large number of protein-protein interactions involved turn or loop regions. The excised linear peptides from these regions reveal complex conformational averaging. To circumvent this motional averaging and to stabilize the beta-turn conformation, extensive effort has been devoted to the design of constrained peptidomimetics. Here, we report the three-dimensional solution structure of a 12-membered cyclic peptidomimetic. The structures were calculated from NMR studies performed in chloroform and in water at 263 and 278K, respectively. This 12-membered cyclic scaffolding is part of a program to design and to construct conformationally stable beta-turn peptidomimetics. The impact of the surrounding environment on the conformation of this constrained peptidomimetic is discussed. The general structural features of the cyclic mimetic are retained in both environments; however, the formation of a hydrophobic patch in the aqueous solvent is evident.

Amino Acid Sequence↗
PubMed1995

Intrathecal baclofen--a multicentre clinical comparison of the Medtronics Programmable, Cordis Secor and Constant Infusion Infusaid drug delivery systems.

A retrospective review was carried out of 34 consecutive traumatic spinal cord damaged patients who have had the Medtronics Programmable, Cordis Secor or Constant Infusion Infusaid intrathecal baclofen drug delivery systems inserted between July 1987 and 1992. The results indicate that whilst this treatment has many benefits there is a significant risk of complications, some potentially fatal. It should only be provided by a skilled and experienced team. The Medtronics Programmable pump is an excellent pump. It is of particular benefit where the therapeutic window is small or fine-tuning required. The Constant Infusion Infusaid is adequate if less precise control and continuous infusion is sufficient. It is of particular benefit in financially disadvantaged countries. The Cordis Secor device is helpful when unpredictable intermittent relief of spasticity is required but is otherwise limited by its complication rate.

Adolescent↗
PubMed1995

Relative microbial resistance of gastric, ileal and cecal bladder augmentation in the rat.

PURPOSE: Bladder resistance to bacterial infection after gastrocystoplasty, ileocystoplasty and cecocystoplasty was investigated in the rat. MATERIALS AND METHODS: Bladders were infected with Escherichia coli 6 to 13 months after augmentation and urine culture was obtained weekly for 3 months. RESULTS: No differences were observed in the number of infected animals within each group or electrolyte data among groups. The number of animals infected after surgery but before E. coli challenge was lowest in the gastrocystoplasty group. Bladder stones formed only in ileocystoplasty and cecocystoplasty groups. No group had a change in urinary pH. CONCLUSIONS: Gastrocystoplasty may be associated with a lower incidence of spontaneous infection and stone formation. An aggressive infection protocol may have masked differences in susceptibility to infection. Since urinary pH was unchanged after gastrocystoplasty, use of the rat may not be appropriate for augmentation studies.

Animals↗
PubMed1994

Quantitation of the number of molecules of glycophorins C and D on normal red blood cells using radioiodinated Fab fragments of monoclonal antibodies.

Two rat monoclonal antibodies (BRAC 1 and BRAC 11) have been produced. BRAC 1 recognizes an epitope common to the human erythrocyte membrane glycoproteins glycophorin C (GPC) and glycophorin D (GPD). BRAC 11 is specific for GPC. Fab fragments of these antibodies and BRIC 10, a murine monoclonal anti-GPC, were radioiodinated and used in quantitative binding assays to measure the number of GPC and GPD molecules on normal erythrocytes. Fab fragments of BRAC 11 and BRIC 10 gave values of 143,000 molecules GPC per red blood cell (RBC). Fab fragments of BRAC 1 gave 225,000 molecules of GPC and GPD per RBC. These results indicate that GPC and GPD together are sufficiently abundant to provide membrane attachment sites for all of the protein 4.1 in normal RBCs.

Animals↗
PubMed1994

A novel form of congenital dyserythropoietic anemia associated with deficiency of erythroid CD44 and a unique blood group phenotype [In(a-b-), Co(a-b-)].

We have used a panel of well-characterized monoclonal antibodies (MoAbs) to examine the blood cells of a patient with a novel form of congenital dyserythropoietic anemia (CDA) characterized by intra-erythroblastic and intra-erythrocytic membranous inclusions. Twelve antibodies defining three nonoverlapping epitope groups on the extracellular domain of CD44 all failed to react with the red blood cells (RBCs) of the patient. A rabbit antibody to the cytoplasmic domain of CD44 from normal RBCs failed to react with the patient's RBC ghosts. In contrast, the patient's lymphocytes, granulocytes, and monocytes showed apparently normal CD44 expression. Bone marrow preparations stained with CD44 antibodies and visualized with 125I antimouse Ig (F(ab')2) followed by autoradiography showed positive staining of lymphocytes and myeloid cells but not of most orthotolidine-positive erythroblasts. The patient's RBCs also gave weaker than normal reactions with MoAbs of anti-LWab specificity while MoAbs to glycophorins A, B, and C, Rh polypeptides, CD47, CD55, CD58, CD59, acetylcholinesterase, and Lutheran and Kell glycoproteins all gave normal reactions. Agglutination tests with human blood grouping sera demonstrated that the RBCs of the patient have the unique phenotype In(a-b-), Co(a-b-) and that they also lack the high incidence RBC antigen AnWj. The phenotype In(a-b-) would be expected because these antigens are known to be expressed on CD44. There is also some evidence associating the AnWj antigen with CD44. However, the CO blood group locus is on chromosome 7p whereas that for CD44 is on chromosome 11p. Quantitative binding assays using 125I-labeled Fab fragments of CD44 antibodies did not show any evidence for reduced levels of CD44 on RBCs from the parents of the patient or from her unaffected sister. The parents and sister had the common Colton blood group phenotype [Co(a+b-)]. Neither deficiency of CD44 nor absence of Colton antigens are general features of CDA because erythrocytes from patients with CDA I, CDA II, CDA III, and two other unclassified CDAs had normal expression of CD44 and normal Colton blood group phenotypes. Further analysis of the defect(s) present in the patient's erythroid cells may provide useful information regarding membrane assembly and the regulation of differentiation in normal erythroid cells.

Anemia, Dyserythropoietic, Congenital↗