PubMed Health⌕ Search

Biomedical subjects

A E Eggers

Publications and source records attributed to A E Eggers.

At least 19 recordsLinked to original sources

A chronic dysfunctional stress response can cause stroke by stimulating platelet activation, migraine, and hypertension.

A hypothesis is presented on the mechanism of acute intracranial occlusion. The hypothesis is that a chronic dysfunctional response to stress can include migraine, hypertension and systemic platelet activation (a hypercoagulable state). Stress is defined as the perception of excessive threats or demands. Migraine, hypertension, and platelet activation constitute a physiological triad that exists as a distinct entity and can undergo sudden provoked or unprovoked worsening, causing acute stroke. The hypertension and headache may not be apparent in every stroke, much as headache is absent in acephalgic migraine. In support of this idea, a literature review is undertaken which leads to the conclusion that the labile rise in blood pressure and headache often seen with acute stroke are unlikely to be caused by the stroke. Systemic platelet activation has been documented in both migraine and stroke and is the missing piece of the puzzle. Migraine (or non-specific headache) and hypertension are markers of co-existing platelet activation, the hypercoagulable state which causes stroke. Migraine, and, putatively, hypertension and platelet activation, are driven by overactive pacemaker cells in the dorsal raphe nucleus of the midbrain, the nucleus which mediates one arm of the physiologic response to stress. A therapeutic prediction is made that drugs such as ethosuximide, which block the low voltage-activated T-type calcium channel, which is one of the ion channels implicated in the generation of pacemaker currents in the dorsal raphe nucleus, would be useful in stroke prevention.

Chronic Disease↗

Neurological theory of hypertension.

Review of the older literature on the relationship between migraine and hypertension, written in the era before either condition could be treated, discloses a high rate of co-morbidity. A neurological theory of essential hypertension is proposed in which the two diseases are brought together into one entity. It is hypothesized that abnormally functioning serotonergic pacemaker cells in the dorsal raphe nucleus, as part of a chronic stress response, inappropriately activate and inhibit parts of the central and autonomic nervous systems, so as to cause the two conditions. This theory builds on a previously published neural theory of migraine.

Brain↗

New neural theory of migraine.

Insufficient attention has been given to reports in the literature describing patients with symptomatic migraine who, in addition to, or instead of, the well-recognized zones of hypofusion, have zones of hyperperfusion, which can be interpreted as hypermetabolism due to neuronal activation. A new neural theory of migraine is proposed in which it is hypothesized that migraine is an electrical disease of the brain in which abnormally-functioning serotonergic pacemaker cells in the raphe nuclei inappropriately activate and inhibit wide areas of the brain. Excessive neuronal activation could cause migraine stroke by excitotoxicity and could explain the association of migraine with epilepsy. The serotonergic nuclei are positioned to mediate stress-induced migraine.

Brain↗

Induction of anti-idiotypic antibodies to a myeloma protein linked covalently to muramyl dipeptide.

BALB/c mice immunized with the MOPC-315 myeloma protein linked covalently to the adjuvant muramyl dipeptide developed antibodies against the MOPC protein. The anti-idiotypic nature of the antibodies was demonstrated by the ability of N epsilon-2,4-dinitrophenyl-l-lysine, a known MOPC-315 ligand, to block antibody binding. Immunized mice developed protection against in vivo challenge with MOPC-315 tumor cells. No anti-tumor cell-mediated cytotoxicity could be demonstrated in immunized and challenged mice.

Acetylmuramyl-Alanyl-Isoglutamine↗

Idiotypic control of the immune response.

Anti-idiotypic antibodies are antibodies against the antigenic determinants (idiotypes) of an antibody's antigen-binding region. Anti-idiotypes can bind near (Ab2 gamma) or away (Ab2 alpha) from the antigen-combining site or can carry the internal image of the antigen (Ab2 beta). Idiotypes and anti-idiotypes have been described in T- and B-cell systems. They have been used in basic research to purify and characterize receptors and ligands against receptors, to treat tumors, to make vaccines and to diagnose and suppress the immune response. In experimental myasthenia gravis anti-idiotypes protect animals against the disease, block idiotype binding and share idiotypic specificities.

Animals↗

Treatment of experimental myasthenia with autologous idiotypes linked to muramyl dipeptide.

In order to develop a new treatment of experimental autoimmune myasthenia gravis (EAMG), rabbits were injected with purified acetylcholine receptor (AChR) from Torpedo californica. Polyclonal affinity-purified anti-AChR antibodies (idiotypes, Ids) were coupled covalently to muramyl dipeptide and injected back into the same (i.e. autologous) rabbits from which the Ids were obtained. Treated animals developed anti-Ids that bound to the F(ab')2 fragments of the Ids as demonstrated by ELISA and that also blocked binding of Ids to AChR in a radioimmunoassay. Treated animals showed a protective effect compared to control animals when challenged with a second injection of AChR. Anti-AChR titres in surviving animals achieved a steady-state equilibrium. No apparent toxicity from the treatment was noted.

Acetylmuramyl-Alanyl-Isoglutamine↗

Use of adult fibroblasts coupled to muramyl dipeptide to induce antitumor immunity.

Murine splenocytes immunized in vitro against syngeneic adult kidney fibroblasts coupled sequentially with a glycylglycylcystamide spacer, and the p-nitrophenyl ester of muramyl dipeptide developed direct cell-mediated cytotoxicity to the immunizing cells which cross-reacted against syngeneic fibrosarcoma cells. These results extended previous observations showing the reverse pattern of cross-reactivity. Derivatized kidney fibroblasts also gave protection in an in vivo protection-challenge experiment performed with the tumor cells. A hypothesis is presented relating this kind of autoimmunity to tumor immunity.

Acetylmuramyl-Alanyl-Isoglutamine↗

In vivo immunization against autologous glioblastoma-associated antigens.

A glioblastoma patient was immunized in vivo with a mixture of autologous and homologous glioblastoma cells coupled to adjuvant peptide and cord-factor analog. Immune activity of peripheral blood lymphocytes was measured in a short-term 51chromium-release assay against autologous tumor target cells. The patient developed direct cell-mediated cytotoxicity against tumor-associated antigens, which appeared to be T-cell mediated.

Adjuvants, Immunologic↗

In vitro immunization against autologous glioblastoma cells coupled to adjuvant peptide.

A glioblastoma patient was immunized in vitro against autologous tumor cells. Tumor cell immunogens coupled to adjuvant peptide induced direct cell-mediated cytotoxicity, which was measured with a short-term 51chromium release assay. Plain tumor cells were non-antigenic. Cytotoxicity was largely eliminated by erythrocyte-sedimentation of effectors. These results suggest the feasibility of immunizing glioblastoma patients against autologous tumor-associated antigens.

Acetylmuramyl-Alanyl-Isoglutamine↗

T cell nature of adjuvant peptide--induced antitumor cell-mediated cytotoxicity.

The direct cell-mediated antitumor cytotoxicity induced by coupling a murine methylcholanthrene-induced sarcoma with N-acetylmuramyl-L-alanyl-D-isoglutamine (adjuvant peptide) was eliminated by treatment of effector cells with anti-Thy 1.2 or anti-Lyt 2.2 monoclonal antibody and complement. Cytotoxicity was not H-2 restricted.

Acetylmuramyl-Alanyl-Isoglutamine↗

Use of covalently bound cord factor analog to increase tumor immunogenicity.

Mice were immunized in vitro and in vivo against the tumor-associated antigens of a methylcholanthrene-induced tumor, using immunogen cells coupled to a cord factor analog (trehalosedihemisuccinatemonohexadecylamide). Immune activity was measured with a short-term 51Cr-release assay. The cord factor analog potentiated immunity induced by adjuvant peptide.

Acetylmuramyl-Alanyl-Isoglutamine↗

Direct cell-mediated cytotoxicity in experimental allergic encephalomyelitis.

Splenocytes from guinea pigs with experimental allergic encephalomyelitis were assayed in a short-term 51Cr release assay for cytolytic activity against target cells coated with myelin basic protein. The basic protein was attached to target cells via a concanavalin A bridge which had been complexed to the basic protein with glutaraldehyde. Cytolytic activity was detected in symptomatic animals and the activity could be boosted by culture in vitro with additional basic protein. Histone was used as a control antigen.

Animals↗

Chemical enhancement of tumor immunogenicity.

C57BL/6 spleen cells immunized in vitro against syngeneic methylcholanthrene-induced sarcoma cells(MC-1 cells) modified with various chemical reagents show cytotoxic activity against unmodified MC-1 cells in a short-term 51Cr release assay, whereas unmodified MC-1 cells are nonimmunogenic. The effector cells cross-react widely with many other fibroblastic and epithelioid tumors, even those that are not H-2 matched, as well as with some nonneoplastic cells. Priming mice in vivo with a hapten leads to enhanced anti-tumor cytotoxicity developed by spleen cells from these mice immunized in vitro against tumor cells modified with the same hapten. Cytotoxic activity is largely, but not completely, removed by treatment with anti-theta serum and C. The existence of suppressor cells that can inhibit an anti-tumor response is demonstrasted in in vitro immunizations of mixtures of spleen cells from normal mice and mice primed with mitomyhcin-treated tumor cells, the latter suppressing the former.

Animals↗

Tumor-specific immunogenicity induced by chemical modification.

C57BL/6J spleen cells were immunized in vitro against cells from a syngeneic 3-methylcholanthrene-induced sarcoma, either modified with diazotized sulfanilic acid or left unmodified. The spleen cells were harvested after 5 days and run in a short-term 51Cr-release assay against unmodified tumor cells as targets. The spleen cells sensitized against the modified but not the unmodified tumor cells were cytotoxic for the unmodified tumor cell targets but not for two other syngeneic tumor cell lines or syngeneic spleen cells, thus indicating the production of tumor-specific cytotoxicity.

Animals↗

Immune response to an allogeneic progressively growing solid tumor.

A C57BL/6 (B6) methylcholanthrene-induced solid tumor grows progressively in BALB/c mice. The BALB/c mice fail to develop in their spleens cytotoxic lymphocytes directed against the histocompatibility (H-) antigens of the tumor. A B6 skin graft is rejected normally by mice with the progressively growing B6 tumor and skin graft rejection has no influence on the growth of the tumor. Tissue culture-carried tumor cells work satisfactorily as target cells in a 51Cr release assay with effector lymphocytes immunized against B6 H-antigens, but the tumor cells will not work as an immunogen for H-antigens for an in vitro immunization. "Fresh" tumor cells removed from their in vivo environment and separated on a discontinuous bovine serum albumin gradient also work as target cells. The conclusion is drawn that the host cytotoxic lymphocyte response against the tumor, as defined by a short-term 51Cr release assay, suffers from both sensitization and effector stage defects that probably do not involve serum factors or suppressor cells.

Animals↗

Suppressor cells in tumor-bearing mice capable of nonspecific blocking of in vitro immunization against transplant antigens.

Spleen cells from mice with progressively-growing methyl-cholanthrene-induced tumors, when immunized in vitro against transplant alloantigens, developed less cytotoxic activity against these antigens as measured by a short-term chromium-release assay than did spleen cells from normal mice. The hyporesponsiveness of spleen cells from the tumor-bearing mice seemed to be due to the presence of suppressor cells which could be removed by nylon-column passage but not by anti-theta treatment and which, in mixture experiments, could inhibit the response of normal spleen cells. The suppression appeared to occur at the sensitization stage and not at the effector stage of the in vitro tests. No evidence was found for mediation of the suppression by soluble factors. These observations emphasize the growing importance of suppressive mechanisms in tumor immune systems.

Absorption↗