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Biomedical subjects

J Mertin

Publications and source records attributed to J Mertin.

At least 55 records · Page 3Linked to original sources

Importance of the spleen for the immuno-inhibitory aciton of linoleic acid in mice.

Certain immuno-inhibitory effects of a polyunsaturated fatty acid, linoleic acid (C18:2), no longer occur after splenectomy of young adult CBA mice. This observation suggest that the spleen is a major intermediary in the action of C18:2 on the lymphoreticular system. Pathways of this action remain to be elucidated. Possibilities include C18:2-stimulated suppressor cell generation in the spleen, or excess biosynthesis of immuno-inhibitory prostaglandins by splenic macrophages.

Animals↗

Micromethods for induction and assay of mouse mixed lymphocyte reactions and cytotoxicity.

A new method in which induction of mixed lymphocyte responses and cytotoxicity can be performed under identical conditions is described. This enables the investigation of the relationship between MLR and cytotoxicity. A micro method for the 51Cr release assay for cytotoxicity is described using both mitogen-induced blasts and tumors as target cells. Under the conditions used data obtained is suitable for linear regression analysis, enabling quantitative comparisons to be made.

Animals↗

Hyperphenylalaninaemia and experimental allergic encephalomyelitis.

Previous suggestions to the effect that a reduced proportion of long chain and unsaturated fatty acids in the CNS as induced by experimental hyperphenylalaninaemia in young rats may alter the biochemical reactivity and stability of the myelin have been examined using experimental allergic encephalomyelitis (EAE). Lewis rats treated chronically with phenylalanine during development showed a higher susceptibility to EAE and a more severe course of the disease than their medium-treated litter mates. The possible implications of this observation for EAE as an experimental model of multiple sclerosis (MS) is discussed briefly in the light of the decreased levels of unsaturated fatty acids found in the CNS of MS patients.

Animals↗

Influence of polyunsaturated fatty acids on survival of skin allografts and tumor incidence in mice.

Subcutaneous or oral administration of the polyunsaturated fatty acid linoleic acid prolongs survival of skin allografts in mice. Mice fed on a diet deficient in polyunsaturated fatty acids show a relative immunopotentiation, as indicated by accelerated skin allograft rejection and decreased incidence and rate of development of methylcholanthrene-induced tumors. These observations support the hypothesis that polyunsaturated fatty acids take part in immunoregulatory mechanisms.

Animals↗

The mechanism of immunoinhibition by arachidonic and linoleic acid: effects on the lymphoid and reticulo-endothelial systems.

Subcutaneous injection with certain polyunsaturated fatty acids (PUFA), in particular linoleic acid (C18:2), has recently been shown to prolong the survival of skin allografts in mice and to reduce both primary and secondary cytotoxic responses by isolated spleen cells. In this study we have examined changes in the lymphoid and reticulo-endothelial systems of both grafted and ungrafted mice treated according to the schedules shown to prolong allograft survival. Many of the changes in the lymphoid and reticulo-endothelial systems which can be produced by allografting could also be produced in ungrafted animals by PUFA treatment. These changes included: increased 125IudR uptake by spleen, lymph nodes, and bone marrow, increased spleen and lymph node weight, increased proportion of red pulp and granulocyte precursors in the spleen, and reticulo-endothelial activation as shown by an increased rate of carbon clearance. The combined effects of allografting and C18:2 on peripheral lymph node weight were greater than the effect of either treatment alone, but fell short of the sum of both treatments. Allografting increased 125IudR uptake/unit organ weight, not only in the peripheral lymph nodes, but also in bone marrow, thymus and spleen. When allografted animals were C18:2 treated, this increase was considerably reduced, uptake being little different from that in C18:2 treated ungrafted controls. The number of theta-positive cells in the spleen was markedly increased by a tumor allograft, but such an increase could not be seen in allografted animals when treated with C18:2. Whilst prolonged C18:2 treatment led to destructive changes in the spleen, immunoinhibition could still be demonstrated after shorter treatments with C18:2 when no gross histological evidence for tissue destruction was apparent. Partial reversibility of inhibition of cytotoxic activity of isolated spleen cells could be domonstrated when treatment was discontinued.

Animals↗

Pilot study with antilymphocyte globulin in the treatment of multiple sclerosis.

Twenty patients with multiple sclerosis, in whom treatment with azathioprine and steroids had not altered the progression of the disease, were given additional treatment with either antilymphocyte globulin (ALG) (seven patients), thoracic duct drainage (TDD) (five patients) or a combination of both (eight patients). Four of the seven patients treated with the addition of ALG showed remarkable improvement which has lasted little improvement. In the eight patients receiving both had severe allergic reactions to ALG which prevented adequate dosage. TDD alone was performed in patients sensitive to ALG. These five patients showed little improvement. In the eight patients receiving both ALG and TDD there was marked improvement in four patients which has again lasted several years. The main side effect of ALG therapy is allergic reactions. Major infections or tumour formation did not occur in any patients.

Antilymphocyte Serum↗

Specific inhibitory action of polyunsaturated fatty acids on lymphocyte transformation induced by PHA and PPD.

Both saturated (SFA) and unsaturated fatty acids (UFS) inhibited PHA- and PPD-induced lymphocyte transformation. The degree of inhibition varied with the nature of the fatty acid (FA) and further comparison with their effect on unstimulated lymphocyte cultures suggests a specific action of polyunsaturated fatty acid (PUFA) on the lymphocyte PHA- and -PPD interaction. These findings are briefly discussed in the light of similar observations with PUFA-derived prostaglandins.

Arachidonic Acids↗

Non-specificity of laboratory test for diagnosis of multiple sclerosis.

It has been claimed that the inhibiting effect of linoleic acid on the macrophage electrophoretic mobility test provides a specific laboratory method for the diagnosis of multiple sclerosis (M.S.) and may also enable susceptible relatives of M.S. patients to be identified. Three trials of the method under double-blind conditions have failed to confirm that the test is diagnostically useful.

Animals↗