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Biomedical subjects

L Mackenzie

Publications and source records attributed to L Mackenzie.

28 records · Page 2Linked to original sources
PubMed1987

A cross-reactive idiotype on anti-DNA and lymphocytotoxic antibodies.

The possibility that shared idiotypes may be present on antibodies of different specificities was explored using sera from 13 patients with systemic lupus erythematosus. Eleven sera had anti-DNA and seven carried the 16/6 idiotype (ID). Two of the sera with 16/6 ID also had lymphocytotoxic antibodies, the activity of which was blocked by antibody to the 16/6 ID. Our studies reveal that 16/6 ID is present on two antibodies with different binding specificities.

Antibodies, Antinuclear↗
PubMed1986

[Expression of T-lymphocyte antigens by serum B lymphocytes in rheumatoid polyarthritis].

Molecules recognised by the monoclonal antibodies Leu 1 - OKT 1 - Mid 5 (CD5 molecules) were originally shown on human T cells and are equivalent to Lyt-1 molecules in the mouse. These surface molecules are detectable on some human B cells, but are weakly expressed. We have therefore tested the effects of the tumour-promoter, phorbol myristic acetate (PMA) on expression of these molecules on B cells. Sheep red blood cell rosette-depleted lymphoid organ or blood cells from 8 controls and 10 rheumatoid arthritis (RA) patients were examined fresh and cultured with PMA for 48 hours and the cells stained with Leu 1 or Mid 5 by indirect immunofluorescence. Cells were analysed by UV microscopy or flow cytometry. More RA blood B cells were positive for Leu 1 than normals before culture. Following incubation with PMA, the percentage of positive cells increased in all cell populations (1-49% in RA patients and 5-26% in controls). There was no difference in the expression of Leu 1 on Kappa--or lambda--positive cells before and after culture in PMA. Leu 1 positive cells were under-represented in Epstein-Barr virus-driven cell lines.

Adult↗
PubMed1985

Salsolinol and dopamine in rat medial basal hypothalamus after chronic ethanol exposure.

Endogenous levels of salsolinol and dopamine were measured by a gas chromatography/mass spectrometry (GC/MS) - selected ion monitoring technique using deuterated internal standards in Long Evans rats chronically exposed to ethanol for ten months. Chronic ethanol exposure produced significant increases of dopamine and salsolinol concentrations in the medial basal hypothalamus but not striatum. The data suggest that the occurrence of salsolinol in rat brain tissue is a consequence of an in vivo Pictet-Spengler cyclization.

Alcoholism↗
PubMed1985

Potentiation of photodynamic therapy with haematoporphyrin derivatives by glucocorticoids.

The effect of glucocorticoids on tumour destruction by photodynamic therapy (PDT) with haematoporphyrin derivative (HPD) and light has been examined in a transplantable mouse tumour model. Administration of glucocorticoid after irradiation enhanced the effect of PDT on both Lewis lung carcinoma and B16 melanoma. Administration of methylprednisolone acetate in depot form concurrently with HPD inhibited the response to PDT while soluble hydrocortisone sodium succinate had no effect. Correctly timed administration of glucocorticoid may have a place in treatment of human tumours by PDT with HPD. Glucocorticoid did not reduce the temporary photosensitivity of the skin induced by HPD.

Animals↗
PubMed1984

Resistance of schedule-induced behaviours to hippocampal lesions.

It has been reported that electrolytic lesions of the hippocampus accelerate the onset of schedule-induced drinking (SID) and also lead to significant increases in adrenal weights [2]. In the present experiment three groups of Long Evans rats received electrolytic or 6-Hydroxydopamine or sham lesions of the hippocampus and one group received electrolytic cortical lesions. Half of each group were tested 1 hr/day for 10 days under scheduled food delivery and the other half received food in a single presentation. It was found that both electrolytic hippocampal and cortical lesions reduced the level of SID compared with sham and 6-Hydroxydopamine lesions which did not differ from each other. However, there is support for the suggestion that hippocampal catecholamine neurones are involved in corticosterone regulation as shown by a significant increase in plasma corticosterone levels in non-scheduled, 6-Hydroxydopamine lesioned rats.

Animals↗
PubMed1983

Isolation of cell cycle-dependent gamma ray-sensitive Chinese hamster ovary cell.

A technique for the isolation of gamma ray-sensitive Chinese hamster ovary (CHO) cell mutants is described, which uses nylon cloth replica plating and photography with dark-field illumination to directly monitor colonies for growth after gamma irradiation. Two gamma ray-sensitive mutants were isolated using this method. One of these cells (XR-1) had a two-slope survival curve: an initial steep slope and then a flattening of the curve at about 10% survival. Subsequently, it was found that this cell is sensitive to gamma irradiation in G1, early S, and late G2 phases of the cell cycle, whereas in the resistant phase (late S phase) its survival approaches that of the parental cells. The D37 in the sensitive G1 period is approximately 30 rads, compared with 300 rads of the parental cell. This mutant cell is also sensitive to killing by the DNA breaking agent, bleomycin, but is relatively insensitive to UV light and ethyl methane sulfonate, suggesting that the defect is specific for agents that produce DNA strand breakage.

Animals↗
PubMed1981

Elusive allowances.

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Attitude to Health↗