Novel in vivo electrophysiological assay for the effects of cocaine and putative "cocaine antagonists" on dopamine transporter activity of substantia nigra and ventral tegmental area dopamine neurons.

The aim of these studies was to establish a rapid in vivo assay for evaluating potential "cocaine antagonists," i.e., drugs postulated to block cocaine binding to the dopamine transporter (DAT) without corresponding blockade of dopamine reuptake. The assay is based on the ability of dopamine, and drugs that elevate synaptic dopamine levels, to inhibit the extracellular single unit activities of midbrain dopamine neurons in chloral hydrate-anesthetized rats. As expected, cocaine itself (0.06-16 mg/kg, i.v.) caused a dose-dependent inhibition of firing of both substantia nigra and ventral tegmental area (VTA) dopamine neurons, but had a significantly higher potency on VTA than nigral dopamine cells (ED(50)'s 1.2 and 8.8 mg/kg, respectively). VTA cells were also inhibited to a greater extent (to 4.7 +/- 4.5% vs. 41.3 +/- 6.3% of baseline rates at 16 mg/kg, respectively). We next evaluated GBR12909, a piperazine analog promoted as a "cocaine antagonist" because of its ability to bind with high affinity to the DAT, while only modestly elevating extracellular dopamine levels. The agonist- and antagonist-like properties of GBR12909 were evaluated on only VTA dopamine cells since these neurons were more fully inhibited by cocaine and have been implicated in its rewarding effects. Given alone, GBR12909 exhibited modest "cocaine-like" activity insofar as it partially inhibited VTA dopamine neurons (to 59.0 +/- 4.6% of baseline at 8 mg/kg). However, consistent with an antagonist profile, pretreatment with a low (0.5 mg/kg) dose of GBR12909, which depressed firing only slightly, resulted in a >2-fold rightward shift in the dose-response curve to cocaine (ED(50) 2.6 mg/kg). We conclude that electrophysiological testing of putative "anti-cocaine" drugs for their abilities to inhibit the firing of VTA dopamine neurons, and to block their inhibitory responses to cocaine, may provide a rapid in vivo screen for compounds expected to behave as functional cocaine antagonists in the dopamine reward system.

Combined stimulation with the T helper cell type 2 cytokines interleukin (IL)-4 and IL-10 induces mouse mast cell apoptosis.

Mast cells are found in connective and mucosal tissues throughout the body. Their activation via immunoglobulin E (IgE)-antigen interactions is promoted by T helper cell type 2 (Th2) cytokines and leads to the sequelae of allergic disease. We now report a mechanism by which Th2 cytokines can regulate mast cell survival. Specifically, we find that interleukin (IL)-4 and IL-10 induce apoptosis in IL-3-dependent bone marrow-derived mast cells and peritoneal mast cells. This process required 6 d of costimulation with IL-3, IL-4, and IL-10, and expression of signal transducer and activator of transcription 6 (Stat6). Apoptosis was coupled with decreased expression of bcl-x(L) and bcl-2. While this process occurred independent of the Fas pathway, culture in IL-3+IL-4+IL-10 greatly sensitized mast cells to Fas-mediated death. Additionally, we found that IgE cross-linkage or stimulation with stem cell factor enhanced the apoptotic abilities of IL-4 and IL-10. Finally, IL-3-independent mastocytomas and mast cell lines were resistant to apoptosis induced by IL-3+IL-4+IL-10. These data offer evidence of Th2 cytokine-mediated homeostasis whereby these cytokines both elicit and limit allergic responses. Dysregulation of this pathway may play a role in allergic disease and mast cell tumor survival.

Radioimmunotherapy of relapsed B-cell lymphoma with yttrium 90 anti-idiotype monoclonal antibodies.

Tumor-specific anti-idiotype (anti-Id) monoclonal antibodies (MoAbs) to B-cell lymphomas have been administered to patients, resulting in significant clinical responses. However, clinical responses have been limited by the emergence of Id-negative lymphoma. To overcome the problem of tumor heterogeneity, we conducted a pilot evaluation of the safety and effectiveness of yttrium 90 (90Y)-labeled anti-Id and shared Id (sId) MoAbs in non-Hodgkin's B-cell lymphoma. Nine patients with relapsed B-cell lymphoma in whom tumor was successfully targeted with 111In-labeled anti-Id MoAb were treated with 90Y-labeled anti-Id MoAb. A total of 19 courses (one to four per patient) were administered using 1,000 to 2,320 mg unlabeled clearing MoAb and 10 to 54 mCi 90Y MoAb per patient. Two of nine patients had a complete response, one a partial response, three stable disease, and three disease progression. Time to progression varied from 1 to 12 months. Toxicities were predominately hematologic, and only one patient developed infection and required transfusion. At progression, three of five assessable patients had Id-positive lymphoma and two had Id-negative lymphoma. Human antimouse antibodies (HAMA) did not develop in the patients after treatment. 90Y anti-Id MoAbs demonstrated excellent in vivo stability, produced significantly tumor regression in three of nine patients, exhibited acceptable toxicities, and elicited no HAMA formation. Further investigation of repetitive, low-dose 90Y anti-Id and MoAb therapy is warranted; however, the advantages of a pan B MoAb may prove the latter to be the agent of choice for the radio immunotherapy of B-cell lymphoma.

Expression of shared idiotypes in chronic lymphocytic leukemia and small lymphocytic lymphoma.

The expression of shared idiotypes (Slds) has been studied on malignant CD5+B cells from patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) using a panel of 37 murine monoclonal antibodies previously demonstrated to be reactive with Slds derived from follicular B-cell lymphomas. Thirteen anti-Slds identified tumor cells from 31 of 105 (30%) CLL patients and 4 of 6 SLL patients. In comparison, the same panel of anti-Slds is reactive with 33% of follicular and diffuse B-cell lymphomas. Ten of these anti-Slds reacted with CLL cases at similar frequencies to that of the B-cell lymphomas. Two anti-Slds, which are known to react with autoantibodies, were significantly more prevalent in CLL than in B-cell lymphomas. These data confirm the presence of Slds in CLL and provide further evidence of an association between CLL and autoimmunity. The identification of a panel of antibodies reactive with a significant number of CLL and SLL patients will facilitate the application of anti-idiotype antibody therapy in these diseases.

Murine monoclonal antibody therapy in two patients with chronic lymphocytic leukemia.

We infused the murine monoclonal antibody T101 into two patients with advanced refractory chronic lymphocytic leukemia (CLL) after confirming its reactivity with their CLL cells. One patient received doses of 1, 3, and 12 mg; the second patient received 10 mg. Antibody was delivered over 10--15 min. The major observations were: (1) T101 murine monoclonal antibody did bind to cells with T65 surface antigen and saturated these cells in vivo; (2) cells that bound T101 disappeared from the circulation by 2 hr after treatment, as evidenced by a marked drop in lymphocyte counts; (3) T101 serotherapy resulted in some intravascular cell injury associated with sequestration and probably destruction in the liver and lung; (4) free serum T101 was demonstrable, but disappeared by 2--4 hr after infusion; (5) rapid infusion of T101 did not induce significant modulation of T65; (6) rapid infusion of greater than 10 mg of T101 was associated with significant systemic reactions. Monoclonal antibodies may someday have an application in leukemia therapy, but additional experimental trials are clearly indicated.

Relationships between MMPI and CPI types for male heroin abusers.

The similarity between typological systems based on the MMPI and CPI was investigated in a sample of male heroin users. The typologies had fairly high classification rates (85 and 75%, respectively) and evidenced relationships that seem consistent with psychological theory. Methods of using the two inventories and the respective typological systems in tandem were suggested, and the possibility of predicting the configural patterns of one inventory from those of the other was explored.

Personality patterns of drug abusers as shown by MMPI profiles.

MMPI and 16 PF patterns of a group of drug abusers who were participating in a voluntary VA Drug Abuse Program were investigated. The MMPI profiles of 91 male veterans who ranged in age from 18-45 years were classified according to two-point code types. A comparison was made of the most frequently occurring code types among drug abusers, medical patients, and psychiatric patients. The two modal profile types among drug abusers were the 4-9/9-4 and the 2-4/4-2, which accounted for 32% of the sample. An additional comparison between the two modal types and responses to the 16 PF was made. Results indicate a closer resemblance to psychiatric patients than to medical patients, and the variety of high point code types is discussed. The similarity between the present sample of modal code types with research on drug abusers undertaken 20 years previously also is discussed.

Locus of control as predictive of goal-directed behavior.

EEO Upward Mobility Program participants were compared with three different control groups along I-E locus of control dimensions. With this instrument and these Ss, no significant differences were found when participation in the program was used as an indicator of goal-directed behavior.

An empirical typology of heroin abusers.

The MMPI profiles of 59 participants in a VA Drug Abuse Program were analyzed. A total of eight types were defined by factor analysis. Three of the groups accounted for 60% of the Ss. The three groups had profiles that involved elevations on scales 2, 4, 8, and 9.