Albert August Luderer

Glass-Ceramic-Mediated, Magnetic-Field-Induced Localized Hyperthermia: Response of a Murine Mammary Carcinoma

Hyperthermia has been found to be a useful modality for cancer therapy. In this report, a biocompatible, ferrimagnetic glass-ceramic capable of inducing localized hyperthermia by hysteresis heating upon exposure to an alternating magnetic field is presented. When the glass-ceramic was placed in the region of a subcutaneously transplanted, weakly antigenic breast carcinoma and subjected to the magnetic field, sufficient temperature rise was obtained to cause significant (approximately 50%) tumor regrowth delay and a 12% permanent control. The data demonstrate that glass-ceramic-mediated hysteresis heating may be a useful therapeutic approach in the treatment of cancer which offers the advantage of producing a highly localized and predictable tumor volume hyperthermia.

Hysteresis heating for the treatment of tumours

A method is described whereby, utilising a biocompatible magnetic glass-ceramic material, effective hysteresis heating in living tissue was accomplished. Initial experiments on mice showed that a significant heating effect can be obtained in the ceramic-impregnated regions. An analysis is also given for the projected safe operating field-frequency regime of the hysteresis therapy.

Evanescent Wave Immunosensors for Clinical Diagnostics

With the recent trend in clinical diagnostics toward cost containment and decentralization, medical personnel and deliverers of health care have looked to new technological advances for simpler, more rapid testing systems. Nowhere is this need more pronounced than in the field of quantitative immunoassay.

Rapid, quantitative human lymphocyte separation and purification in a closed system.

Abstract A thixotropic, silicone based gel (specific gravity 1.0674) has been developed which permits the rapid isolation of human blood lymphocytes. Gel is incorporated within an evacuated blood draw tube containing crystalline EDTA. Lymphocyte separations are performed within the unopened tube. Quantitative yields of lymphocytes from whole blood are obtained with mononuclear cells comprising 93 percent of the recovered cells. In vitro T and B cell mitogenic responses of recovered lymphocytes are normal thus proving the efficacy of this approach to clinical lymphocyte isolations.

The T Cell Antigen Receptor

Initiation of the immune response following antigenic challenge begins with the specific interaction of epitopes on the antigen- and plasma membrane-associated receptors found on the cell surface of lymphocytes. Certainly the interaction of antigen with both regulatory and effector thymus-derived lymphocytes (T cells) is a critical event in this process. According to clonal selection theories (Burnett, 1969), antigen initially interacts with a relatively small number of T cells that exhibit antigen receptors of the appropriate specificity.

Preparation and characterization of an 125I-labeled sendai virus ligand

Abstract In an attempt to prepare a radioviral ligand that was effective both as an antigen in binding to antibody and as a ligand that effectively binds to receptor-bearing cells, inactivated Sendai virus was adsorbed to immobilized fetuin at 4°C and recovered by temperature elevation at 37°C. The eluted virus was iodinated using the chloramine-T procedure and free iodine and labeled virus were separated on a Sepharose 4B column. Radiolabeted virus contained 1000 to 5000 cpm per hemagglutination unit and over 90% of the counts were sedimented following high-speed centrifugation. Radioviral ligand was 80% reactive with immobilized Sendai virus antibody, 70% reactive with sheep red blood cells,and 1% reactive with receptor-negative horse red blood cells. Pretreatment of the cells with neuraminidase completely inhibited the virus binding reaction. The reaction with receptor-bearing cells was competitively inhibited by unlabeled Sendai virus, but not by murine leukemia virus or T-2 coliphage. Radioviral ligand binding to human lymphoblastic cell line CCL-119 was a saturable reaction, a result that demonstrates the absence of virus-virus aggregates. The preparation of an effective cell-reactive radioviral ligand was dependent on the initial purification from immobilized receptor-containing proteins.

Detection and molecular specificity of murine thymocyte receptors for GAT in responder and non-responder mice utilizing a microradioreceptor assay

Abstract A microassay for the detection of murine thymocyte antigen receptors reactive to GAT ∗ has been developed. Immunochemical specificity was demonstrated under competitive binding conditions utilizing labeled antigen. Only GAT could competitively displace 125 I GAT from the thymocyte receptor. Erythrocytes did not bind 125 I GAT whereas myeloma MPC-11 or acute lymphoblastic leukemia CCRF-CEM cell lines bound ≅ 3.5-fold less GAT than thymocytes. The magnitude of thymocyte ligand binding was approximately 4-fold greater at 37°C than at 4°C. Biased displacement studies under conditions which favored phagocytosis indicated that 70% of the cell-associated counts were surface (plasma membrane) bound, making it unlikely that phagocytosis was the source of ligand uptake. Similarly, thymocyte suspensions adsorbed to petri dishes for 45 min at 37°C or assayed in the presence of NaN 3 showed no dimunition in B 0 binding. A rabbit anti-mouse T cell monospecific serum was capable of blocking 125 I GAT binding whereas normal serum was without effect. The specifie binding of GAT to thymocytes occurred through a trypsin-sensitive thymocyte membrane component. In further studies, the equilibrium displacement of 125 I GAT from the T cell GAT receptor by copolymers GA or GT demonstrated that the thymocyte receptor(s) for GAT in unimmunized responder and non-responder mice react with GAT through apparently identical antigenic determinants within the GAT terpolymer. These specificity data corroborate in-vivo functional data and suggest that the T cell antigen receptor for GAT does not regulate the GAT immune response by itself.