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Biomedical subjects

B Gardner

Publications and source records attributed to B Gardner.

At least 19 recordsLinked to original sources

T cell-derived IL-10 promotes lung cancer growth by suppressing both T cell and APC function.

We have found previously that human lung cancers potently induce T lymphocyte IL-10 production in vitro. To assess the impact of enhanced T cell-derived IL-10 on antitumor immunity in vivo, we utilized transgenic mice expressing IL-10 under the control of the IL-2 promoter. We have shown previously that Lewis lung carcinoma cells (3LL) have more aggressive growth potential in IL-10 transgenic mice compared with control littermates. In this study, we show that transfer of T cells from IL-10 transgenic mice to control littermates transferred the IL-10 immunosuppressive effect and led to enhanced 3LL tumor growth. In addition to changes in T cell-mediated immunity, professional APC from IL-10 transgenic mice were found to have significantly suppressed capacity to induce MHC alloreactivity, CTL responses, and IL-12 production. Tumor Ag-pulsed dendritic cells from IL-10 transgenic mice also failed to generate antitumor reactivity. These results suggest that increased levels of T cell-derived IL-10 severely impair antitumor immunity in vivo, due to defects in both T cell and APC function.

Adoptive Transfer

Agonist action at D2(long) dopamine receptors: ligand binding and functional assays.

1. The activities of a range of agonists at D2(long) dopamine receptors expressed in CHO cells have been determined in ligand binding and in a functional assay, the stimulation of [35S]-GTPgammaS binding. 2. For several agonists (apomorphine, dopamine, pergolide, quinpirole, NPA, ropinirole, talipexole) binding in the absence of added guanine nucleotides was best described in terms of interaction at higher and lower affinity states, whereas for other agonists (bromocriptine, DHEC, lisuride, 3-PPP) a one binding site model was a good description of the data. In the presence of GTP (100 microM) all agonist binding data were best described by a one site model. 3. All of the agonists tested increased [35S]-GTPgammaS binding above the basal level and the maximal effects and potencies of the agonists in this test were different. There was no clear relation between the ability of an agonist to stabilize the formation of the ternary complex of agonist/receptor/G-protein and the maximal activity of the agonist or the amplification factor (ratio of dissociation constant for binding to receptor to EC50 in functional assay). 4. A comparison was made between the profiles of the D2(short) and D2(long) receptor isoforms in these assays.

Animals

Cervical and breast cancer screening in wheelchair dependent females.

The aim of this study was to compare the attendance rates for cervical and breast cancer screening in wheelchair dependent spinal cord injured (SCI) women with those in the general female population in England. The study was conducted as a postal questionnaire survey with an effective response rate of 79%. The attendance rates of the eligible SCI groups were 84% for cervical screening and 72% for mammography, both figures being well within the national average attendance rates in the general female population. Difficulties with cervical screening were reported in 58% and with mammography in 43% of the cases, including restricted access to clinics, examining rooms and examining couches and positioning during the procedure. These were also the main reasons given for non attendance. The article points out ways to enable even more wheelchair dependent women to benefit from the preventative screening programmes.

Adult

Surveillance in the management of the cancer patient with special reference to breast and colon cancer.

Senior surgeons of the Society of Surgical Oncology were surveyed concerning their followup practices for patients with colon and breast cancer and compared them with the recommendations in the current literature. Intensive followup is not indicated for patients with breast cancer patients and all surgeons agree by using physical examination and mammograms predominantly. Colon cancer followup was variable and the literature indicates a small survival advantage for intensive followup.

Biomarkers, Tumor

Factors associated with acute and chronic pain following traumatic spinal cord injuries.

Previous studies have estimated that between 25% and 45% of people with spinal cord injury report severe levels of chronic pain. Few studies have examined this longitudinally. This study examines the primary pain sites, intensity and variability of perceived pain in 76 patients, 6 weeks post injury and 45 patients from the same cohort, 8 year post discharge. Demographic information reveals a close similarity with the database (40,000) from Stover and Fine's cohort (1986). Data was assessed using visual analogue scales, measures were also taken of functional independence (FIM), emotional status and coping. At 6 weeks post injury, most pain is sited in the thoracic spine area, and in the upper and lower limbs. At 1 year post discharge, most pain is reported to be in the thoracic spine area, the lumbar region and the chest. Twenty-three per cent of the 6 week group reported that the intensity of their pain was severe, whilst at 1 year, 41% of the sample complained of severe pain. Factors associated with the pain at both time points were explored using correlational analyses. The emotional, functional and psychological factors that predict pain severity were explored using multiple regression analysis. Twenty-four per cent of those reporting moderate to severe pain at 6 weeks post injury were still reporting pain at 1 year post discharge. This study examines the relative contribution of psychological factors in reported pain.

Activities of Daily Living

Eat your cereal.

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Humans

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

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

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

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

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

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