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Biomedical subjects

P Robertson

Publications and source records attributed to P Robertson.

At least 73 records · Page 4Linked to original sources
PubMed1989

Effects of methyl ethyl ketone pretreatment on hepatic mixed-function oxidase activity and on in vivo metabolism of n-hexane.

1. Male Fischer-344 rats were given methyl ethyl ketone (MEK; 1.87 ml/kg), a potentiator of the neurotoxicity of n-hexane, by gavage for 4 days prior to a single inhalation exposure to n-hexane (1000 ppm). 2. Samples of blood, liver, testis and sciatic nerve were obtained and analysed for n-hexane, MEK and their metabolites by g.l.c.-mass spectrometry. 3. Pretreatment with MEK increased the concentrations of 2,5-hexanedione (2,5-HD; the proximal neurotoxin) in blood, sciatic nerve and testis relative to concentrations in the tissues in sham-treated controls. 4. Concentrations of 2,5-dimethylfuran, a metabolite of 2,5-HD, were increased in all four tissues tested. 5. After 1-7 days treatment with MEK, the activity of 7-ethoxycoumarin O-deethylase was increased (up to 500%), but benzphetamine N-demethylase activity was virtually unaffected. 6. Hence, the potentiating effects of MEK on the neurotoxicity of n-hexane appear to arise, at least in part, from the activating effects of MEK on selected microsomal enzymes responsible for n-hexane activation.

Animals↗
PubMed1989

School and the in-center pediatric hemodialysis patient.

Life "on the machine" can significantly disrupt the social and academic school experience of preadolescent and adolescent renal failure patients because of their frequent absences. When hemodialysis patients were offered treatments after school and on Saturday mornings, patients, families, and staff reported significant improvement in the patients' social integration and academic performance.

Adaptation, Psychological↗
PubMed1988

Antibodies to HIV are produced within the central nervous system of all subjects with all categories of HIV infection.

Anti-HIV antibodies were found in the cerebrospinal fluid of all 41 subjects tested whose serum contained these antibodies. To ensure that locally produced antibody was being detected, a sensitive assay was used to demonstrate the integrity of the blood-brain barrier. Antibodies to ubiquitous adenovirus group antigens were sought, simultaneously, in CSF and serum. A lack of adenovirus antibodies in CSF of subjects seropositive for adenovirus was required before CSF anti-HIV antibodies could be considered to be produced within the central nervous system. Of the 41 subjects tested eight were asymptomatic, eight were clinically well but had persistent lymphadenopathy, 14 were immunodeficient and had constitutional symptoms (AIDS-related complex or ARC) and 11 had AIDS. Oligoclonal banding was detected in the CSF of 16 subjects and a pleocytosis was present in 24. Neither finding clustered with a particular stage of infection. It appears that HIV infection of T lymphocytes and the central nervous system occurs simultaneously, early in the course of the infection. All HIV infected subjects are at risk of developing primary neurological as well as immunological sequelae. Currently poorly understood resistance factors must protect both lymphocytes and nervous system tissue from damage by the HIV virus, as to date, the majority of infected subjects have not become immunodeficient or developed neurological disease.

AIDS-Related Complex↗
PubMed1984

Immunosuppression by human skin cancers.

Biopsy samples from normal skin (12 samples) and skin lesions diagnosed as either basal cell (17 cases) or squamous cell carcinoma (5 cases) were frozen, disrupted and extracted with aqueous buffer. The sterilised extract was added to an in vitro system of cultured bovine lymphocytes. The response of the lymphocytes to PHA was measured by tritiated thymidine uptake. Extracts of both basal cell and squamous cell cancers inhibited normal PHA stimulation of lymphocyte mitogenesis. Blastogenesis was reduced by more than 50% by all of the cancer extracts tested. In contrast, similar extracts from normal skin showed less than 40% inhibition.

Animals↗
PubMed1980

A simple radioactive binding assay for the detection of rheumatoid factor in serum.

A simple radioactive binding assay for the detection of rheumatoid factor (RF-RBA) is described. Test sera are complement inactivated by incubation in 0.13 M ethylene diaminetetraacetic acid (EDTA) at 37 degrees C and then incubated with 125I-labelled heat-aggregated IgG. Rheumatoid factor bound, labelled IgG is separated from free by precipitation with 2.5% (w/v) polyethylene glycol 6000. Sera from 78 patients and 24 controls were tested in the RF-RBA assay and the results compared with those obtained by the rheumatoid latex test and the rheumaton test. 37 sera were positive and 59 sera were negative for rheumatoid factor by the 3 methods used. A positive correlation (r = 0.56, P less than 0.01) was observed between the rheumaton titre and the RF-RIA result.

Humans↗
PubMed1980

The pre-schooler.

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Accident Prevention↗
PubMed1978

Calcium and magnesium binding to gamma-carboxyglutamic acid-containing peptides via metal ion nuclear magnetic resonance.

The determination of binding constants of metal ions to biomolecules is approachable via many techniques. Metal ion NMR spectroscopy is an alternative to more traditional techniques and is complementary to them, particularly in investigations of the interactions of metal ions with relatively small peptides containing multiple ionizing groups. The method requires relatively small amounts of material, is fairly fast, and is carried out at equilibrium. Our study has been of calcium and magnesium ion binding to gamma-carboxyglutamic acid (Gla)-containing peptides. Dissociation constants of approximately 0.6 mM for the binding of either metal ion to Z-D-Gla-D-Gla-OMe have been obtained. The procedure for determination of these constants via metal ion NMR is discussed.

Calcium↗