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Biomedical subjects

R Barton

Publications and source records attributed to R Barton.

At least 55 records · Page 3Linked to original sources
PubMed1990

Recurrent medulloblastoma: frequency of tumor enhancement on Gd-DTPA MR imaging.

Thirty-two children with medulloblastoma were evaluated postoperatively with conventional and gadolinium-enhanced MR imaging. Eleven patients had abnormal cranial MR studies; nine of these had recurrent tumor. In six patients recurrent tumor enhanced with Gd, while in the other three patients recurrent tumor did not enhance. The remaining two patients had areas of abnormal Gd enhancement that were caused by radiation-induced breakdown of the blood-brain barrier rather than by recurrent tumor. This study shows that not all recurrent medulloblastoma enhances and that the absence of Gd enhancement does not necessarily indicate the absence of recurrent tumor.

Adolescent↗
PubMed1989

A cell adhesion molecule, ICAM-1, is the major surface receptor for rhinoviruses.

Rhinoviruses, which cause common colds, possess over 100 serotypes, 90% of which (the major group) share a single receptor. Lymphocyte function associated molecule 1 (LFA-1) mediates leukocyte adhesion to a wide variety of cell types by binding to intercellular adhesion molecule 1 (ICAM-1). We demonstrate identity between the receptor for the major group of rhinoviruses and ICAM-1. A major group rhinovirus binds specifically to purified ICAM-1 and to ICAM-1 expressed on transfected COS cells, and binding is blocked by three ICAM-1 monoclonal antibodies (MAb) that block ICAM-1-LFA-1 interaction, but not by an ICAM-1 MAb that does not block ICAM-1-LFA-1 interaction. This suggests that the ICAM-1 contact site(s) for LFA-1 and rhinoviruses is proximal or identical. In addition, ICAM-1 MAb block the cytopathic effect in HeLa cells mediated by representative major but not minor group rhinoviruses. ICAM-1 is induced by soluble mediators of inflammation, suggesting that the host immune response to rhinovirus may facilitate spread to uninfected cells.

Antibodies, Monoclonal↗
PubMed1989

Pharmacological comparison of active and passive experimental allergic encephalomyelitis in the rat.

Models of actively induced and passively transferred experimental allergic encephalomyelitis (EAE) have been compared in the rat. The time of disease onset, severity of clinical symptoms and percent incidence were compared and assessed for their suitability for evaluation of immunosuppressive agents. The passive EAE model had an earlier disease onset (6 +/- 0.1 days) and 100% of the cell recipients (n = 45) developed severe clinical symptoms, including paralysis of the tail and hind limbs. In contrast, the active EAE model had a mean disease onset day of 13 +/- 0.1 and only 53% of the induced rats (n = 85) developed EAE clinical symptoms which were variable. The average symptom score in both models was inhibited by dexamethasone (1 mg/kg/day p.o.; day 0 to 3), methotrexate (3 mg/kg i.p. single dose; day 1) and cyclosporin A (30 mg/kg/day p.o.; day 0 to 7). The above study indicates that the passive EAE model is more advantageous for pharmacologic evaluation of immunosuppressive agents.

Animals↗
PubMed1989

Alcohol promotion on television.

A study in the United Kingdom has shown that the advertising of alcohol on television targets young people particularly. There is a strong case for banning alcohol advertisements from this medium.

Adolescent↗
PubMed1988

Un-health promotion: results of a survey of alcohol promotion on television.

To estimate how widely and to whom alcoholic drinks are promoted 1258 television advertisements were studied over a 10 week period that included the Christmas and New Year holidays in 1986-7. A total of 156 advertisements (12%) promoted alcohol, and this percentage increased significantly over the holiday period to 17%. These advertisements were longer than those advertising other products, and just over half (56%) occupied the first position in commercial breaks. During sports programmes and between the hours of 1800 and 1900 there was an increase in the number of advertisements for alcohol, but there was no difference before and after 2100. It was found that the extent and influence of the promotion of alcohol were great and that such advertising is seen by many children and adolescents.

Advertising↗
PubMed1988

Variation in cytoplasmic microtubule organization and spindle length between the two forms of the dimorphic fungus Candida albicans.

Candida albicans is a dimorphic fungus capable of growing as a budding yeast and as a filamentous hypha. We have used the technique of immunofluorescence to study the changes in the microtubule cytoskeleton during the cell cycle in both growth forms. This approach has revealed the presence of an extensive system of microtubules, including cytoplasmic microtubules and a rod-like intranuclear spindle. We have provided a complete description of the arrangement of cytoplasmic and spindle microtubules at each phase of the yeast cell cycle. A novel and characteristic feature of the yeast phase of Candida is the presence of an array of short microtubules at the neck of the doublet cell. This neck-associated array (NAA), is apparently organized independently of the main microtubule-organizing centre, the spindle pole bodies, at late anaphase. Analysis of microtubule patterns in the hyphal state reveals that the general arrangements of microtubules are similar to those seen in the yeast phase. These patterns suggest a role for the cytoplasmic microtubules in the nuclear migration that occurs during hyphal growth. A major finding is that the mitotic spindle in hyphae is considerably longer (12-20 microns) than the spindle in yeast cells (7-8 microns). This may reflect the role of the hyphal mitotic spindle not only in nuclear division but also in the positioning of the daughter nuclei at the centres of hyphal compartments.

Candida albicans↗
PubMed1988

How financial barriers can frustrate good arthritis care.

Current insurance practices discriminate against the arthritis patient who does not require acute-level care. Such practices inadequately deal with the financial barriers to the procurement of the health care services that are effective in relieving pain and increasing mobility and quality of life. The result often is frustration for both the patient and the physician.

Aged↗
PubMed1985

Reversal of gamma-radiation-induced leukemogenesis in mice by immunomodulation with thiabendazole and dinitrofluorobenzene.

The effect of thiabendazole (TBZ) and dinitrofluorobenzene (DNFB) on radiation-induced leukemogenesis was investigated in the C57BL/6 mouse model. Administration of TBZ-DNFB during, post, or during and post irradiation successfully blocked leukemogenesis, as indicated by the absence of leukemia blast cells in thymus and peripheral blood, as well as prevented thymic lymphoma. TBZ-DNFB treatment prevented the development of leukemia when studies were terminated both after 7 months of last irradiation (disease fully developed) and after 5 months of last irradiation (disease in the process of development). This TBZ-DNFB treatment also resulted in a significant increase in survival.

Animals↗
PubMed1985

ImmunoConcentration--a new format for solid-phase immunoassays.

A new format for solid-phase immunoassays has been developed in which a monoclonal antibody-coated membrane, incorporated into a cylindrical, disposable device, regulates sample and reagent delivery. We illustrate the method with a two-site, immunoenzymometric assay that can detect human choriogonadotropin at less than 50 int. units/L (4 micrograms/L) in urine and less than 25 int. units/L (2 micrograms/L) in serum and takes less than 5 min to perform. The solid-phase antibody is located in a circular area in the center of the membrane so that in the presence of the hormone, after addition of substrate, a blue enzyme product is generated in this circular area. The high ratio of surface area to volume within the microporous matrix of the membrane assures short diffusion distances and therefore rapid binding of liquid-phase reagents to the solid phase. Pseudo-first-order reaction kinetics describe the binding of antigen to immobilized antibody and the binding of enzyme-labeled antibody to immobilized antigen. The speed and simplicity of this format may facilitate testing for many analytes, both soluble and particulate, as well as serological testing.

Alkaline Phosphatase↗
PubMed1981

Isolation of three separate anaphylatoxins from complement-activated human serum.

Recent methodologies used in preparing anaphylatoxins from complement-activated serum are described. Activation of the alternative pathway generates C3a and C5a; however, activation of the classical pathway is required to generate the anaphylatoxin from C4. This article describes an activation scheme that simultaneously generates all three of the anaphylatoxins (e.g., C3a, C4a and C5a) in human serum and outlines a procedure for isolating each as homogeneous products. Purification of intact anaphylatoxins directly from complement-activated serum takes place only if an exopeptidase in serum, known as carboxypeptidase N (SCPN), is properly inhibited. A new series of mercapto derivatives of arginine analogs are introduced as potent and effective inhibitors of SCPN. These inhibitors permit normal complement activation but prevent degradation of the released activation fragments C3a, C4a or C5a. The SCPN inhibitor previously used was 6-aminohexanoic acid (EACA), but it required a 1 M concentration for effective inhibition, the substituted mercapto-guanido compounds prove to be effective in the mM range.

Aminocaproic Acid↗
PubMed1981

A randomized comparison of radiotherapy with a radiotherapy--chemotherapy combination in stage IV carcinoma of the head and neck.

Between 1975 and 1978, 23 patients with Stage IV, unresectable, squamous cell carcinoma of the head and neck were randomized to receive radiotherapy (RT, 11 patients), or radiotherapy-chemotherapy (RT & CT, 12 patients). The response rate for the 12 RT & CT patients was four complete remissions (CR) and four partial remissions (PR); the 11 RT patients had one CR and three PR. The presence of a responses (CR or PR) significantly enhanced the median survival (14 vs. 5 months; P = 0.005). The duration of objectives remission was longer among the RT & CT patients when compared with RT patients (6 vs. 2.3 months, P = 0.18). The median survival of the RT & CT group was 12 months compared with 5.6 months for the RT group (P = 0.13). One RT & CT patient remains alive with disease at 44 months, one RT patient remains alive without disease at 30 months. The present chemotherapy regimen did not modify the pattern of failure and only marginally increased patient survival. It did, however, increase the response rate. The authors plan to reactivate the trial with modification in the induction chemotherapy and the addition of postradiation maintenance CT consisting of sequential bleomycin and cis-platinum.

Aged↗
PubMed1980

Advanced carcinoma of the tonsil. Treatment results.

A series of 205 patients with advanced carcinoma of the tonsil treated with irradiation is reported. The overall 3-year survival for stage, I, II and III patients was 63 per cent and the 5-year survival 35 per cent. The 5-year survival for stage IV patients was 9 per cent. The volume of the tumor and the extent of lymph node metastases were important prognostic factors for survival. The strongest factor influencing survival was the initial performance status independent o state (p less than 0.001).

Adult↗