Antiproliferative and antitumor activity of the 2-cyanoaziridine compound imexon on tumor cell lines and fresh tumor cells in vitro.

BACKGROUND: Imexon, a 2-cyanoaziridine, is therapeutic and reverses lymphadenopathy and splenomegaly in the LP-BM5 murine retrovirus-induced immunodeficiency disease (murine AIDS). It can restore chemotherapy-induced immunosuppression. Imexon reduced the incidence of lymphoma in severe combined immune deficient mice inoculated with human lymphocytes. PURPOSE: To determine its antitumor activity, we screened imexon against fresh human tumor cells and tumor cell lines. To determine the time-concentration relationships of its cytotoxicity, we studied the effects of imexon on macromolecular synthesis and on the cell cycle. METHODS: Imexon was incubated at 1-200 micrograms/mL with various tumor cell lines, mitogen-stimulated peripheral blood lymphocytes, and fresh tumor cells. Cell survival, macromolecular synthesis, and cell cycle progression were studied. RESULTS: The concentration of imexon that caused 50% inhibition of growth was under 10 micrograms/mL for lymphocytes stimulated with mitogens. It was about 3-10 micrograms/mL for B-cell lymphomas and both multi-drug-resistant and -sensitive myeloma cell lines. Imexon inhibited four of seven fresh lymphoma and 11 of 16 fresh myeloma biopsy specimens to less than 40% of the control. A 1-hour exposure of lymphoma cells to 50-100 microgram/mL followed by removal of drug by washing the cells and continuing culture resulted in greater than 95% inhibition during the next 48-72 hours. Imexon selectively inhibited protein synthesis during the first 24-48 hours of exposure of lymphoma and myeloma cells. Cells exposed to inhibitory concentrations of imexon were blocked in cell cycle progression. CONCLUSION: Imexon may be a potentially useful agent in the treatment of malignant disease, particularly lymphoid malignancies, and should be explored further.

Effect of immunotherapy with Corynebacterium parvum and methanol extraction residue of BCG administered intravenously on host defense function in cancer patients.

The effects of active nonspecific immunotherapy were studied in 42 patients receiving daily iv Corynebacterium parvum at 2 mg/m2 in 14-day courses and in 14 patients receiving iv methanol extraction residue of BCG (MER) at 0.5 mg/m2 weekly. The host defense evaluations included measurement of the number of adherent macrophage precursors per milliliter of blood (monocyte adherence), serum lysozyme, and antibody-dependent cell-mediated cytotoxicity (ADCC) of peripheral blood mononuclear cells to chicken red blood cells (CRBC) or human red blood cells (HRBC). During a single course of C. parvum, monocyte adherence did not rise significantly, whereas ADCC of peripheral blood mononuclear cells to CRBC and HRBC rose significantly (15.7-49.9% and 34.8-53.5% lysis of target cells, respectively). However, after a mean of 4.5 months on therapy, monocyte adherence increased an average of 7.5-fold. During weekly MER therapy, monocyte adherence, serum lysozyme, and ADCC of peripheral blood mononuclear cells to CRBC rose significantly within 4-7 days after the first dose (3.8-8.7 adherent cells/ml blood x 10(4), 7.6-10.8 microgram, and 34.4-41.4% target cell lysis, respectively). The host defense parameter, which was subnormal in the cancer patients (monocyte adherence), was boosted into the normal range in all the deficient patients by iv MER. The host defense parameters, which were normal or slightly elevated in the patients before therapy (serum lysozyme and ADCC of peripheral blood mononuclear cells to CRBC and HRBC), were hyperactivated above the upper limit of the normal range in 71.4, 71.4, and 50% of the patients, respectively, by iv MER. These methods can quantitatively reflect activation of monocytes and killer cells by C. parvum and MER and may be useful for evaluation and quantitation of both active nonspecific and immunorestorative immunotherapy in general.

Increased labeling of human melanoma cells in vitro using combinations of monoclonal antibodies recognizing separate cell surface antigenic determinants.

A panel of mouse anti-melanoma monoclonal antibodies (MoAb) were analyzed for reactivity with human melanoma cells singly and in combination. Five MoAb, ZME-018, 96.5, P94, 4.2, and 5.1, reactive with individual cell surface melanoma-associated antigens were tested with seven melanoma cell lines and seven fresh tumor biopsies. Cells were incubated with the MoAb, indirectly stained with fluorescein-conjugated goat anti-mouse immunoglobulin, and analyzed by flow cytometry. Percentage of labeled cells and relative fluorescence intensity (FI) with individual MoAb varied with different cell lines and biopsy samples. The most reactive MoAb, ZME-018, 96.5, and P94, labeled 29-93% of the cells from cell lines with relative FI of 2-59 units, thereby demonstrating phenotypic diversity of these cells. Similar results were obtained with cells derived from tumor biopsies, where 1-73% of cells were labeled and relative FI ranged from 0-27. These variations were reduced by using a "cocktail" of MoAb which recognized different melanoma-associated antigens. In cell lines both the percentage of labeled cells (range, 82-95%) and relative FI (range, 36-115) increased substantially (P less than 0.025 and P less than 0.005, respectively) when a "cocktail" prepared from all five MoAb rather than individual MoAb was used. A cocktail of MoAb increased the percentage of labeled tumor biopsy cells (range, 53-78; P less than 0.01) and relative FI (range, 11-69; P less than 0.025). The mean FI obtained by incubating cells with a cocktail of suboptimal concentrations of three MoAb (ZME-018, 96.5, P94) was 48 +/- 12 (SD), which was significantly increased compared to the mean FI seen with suboptimal concentrations of MoAb alone (ZME-018, 7 +/- 10; 96.5, 8 +/- 7; P94, 2 +/- 2; P less than 0.005). These findings were confirmed by radioimmunoassay using a combination of two MoAb, ZME-018 and 96.5. The data suggest that cocktails of MoAb were more effective than single MoAb alone for melanoma tumor cell labeling in vitro and might be more effective for tumor imaging and therapy.

Control of a hand grasp neuroprosthesis using an electroencephalogram-triggered switch: demonstration of improvements in performance using wavepacket analysis.

Volitionally modulated electroencephalographic (EEG) waves were monitored for the purpose of controlling a hand neuroprosthesis in people with tetraplegia. The region of the EEG signal spectrum monitored was the occipital alpha wave (8-13 Hz), and volitional modulation was achieved with the opening and closing of the eyes. In a set of 13 trials evaluated, a subject with tetraplegia successfully completed ten trials undertaking stimulated grasp and release using the EEG-triggered switch. EEG signal data recorded during the 13 trials were also post-processed off-line using wavepacket analysis. Following this signal processing, the speed and reliability of the EEG-triggered switch, when operated by the subject with tetraplegia, was significantly improved (p < 0.002). Such improvements provide system performance that is likely to be acceptable to a neuroprosthesis user during activities of daily life.

Selective motor neuropathy of the median nerve caused by a ganglion in the carpal tunnel.

Carpal tunnel syndrome is the commonest peripheral compressive neuropathy. Typically, sensory symptoms predominate at presentation with motor dysfunction seen in more chronic cases. Isolated motor compression is rare. We present a case of selective median nerve motor neuropathy caused by a carpal tunnel ganglion.

Outcome of axillary nerve injuries treated with nerve grafts.

This study evaluates the outcome of axillary nerve injuries treated with nerve grafting. Thirty-six patients were retrospectively reviewed after a mean of 53 months (minimum 12 months). The mean interval from injury to surgery was 6.5 months. Recovery of deltoid function was assessed by the power of both abduction and retropulsion, the deltoid bulk and extension lag. The deltoid bulk was almost symmetrical in nine of 34 cases, good in 22 and wasted in three. Grade M4 or M5* was achieved in 30 of 35 for abduction and in 32 of 35 for retropulsion. There was an extension lag in four patients. Deltoid bulk continued to improve with a longer follow-up following surgery. Nerve grafting to the axillary nerve is a reliable method of regaining deltoid function when the lesion is distal to its origin from the posterior cord.

The surgical treatment of brachial plexus injuries.

BACKGROUND: Brachial plexus injuries cause a devastating loss of function in the arm. The aim of this study was to review the results of surgical treatment of patients with brachial plexus injuries. METHODS: Forty-seven patients were reviewed. Five patients did not undergo surgery. Forty-two patients had exploration and 38 had primary surgery with neurolysis, nerve graft or neurotization or a combination. Four patients had other reconstructive surgery primarily. Secondary reconstructive surgery consisted of joint fusions and tendon transfers to enhance or replace the primary surgery. RESULTS: Nerve grafting achieved 62% Medical Research Council (MRC) grade M3 or better. Intercostal neurotization (ICN) of the musculocutaneous nerve (MCN) for elbow flexion achieved M3 or better in 69% of patients. CONCLUSIONS: Primary nerve reconstruction, combined with joint fusions and tendon transfers, provides a worthwhile return of function to many patients. We advise early exploration (i.e. within 2 weeks when possible) for patients with complete C5-T1 lesions or C5,6,7 lesions in conjunction with high energy injuries. In order to obtain optimal results patients with brachial plexus injuries should be referred to appropriate units as early as possible.

Detection of fatigue in the isometric electrical activation of paralyzed hand muscles of persons with tetraplegia.

Paralyzed muscle fatigue is the eventual depression of force due to either prolonged or repetitive electrical stimulation of motor units. The robustness and safety of future functional electrical stimulation (FES) systems will rely on their ability to detect the onset of muscle fatigue. The relative degree of muscle activation can be estimated by monitoring the M-wave. The aim of this study was to test a proposed method of quantitative fatigue assessment that detects muscle force output and its corresponding M-wave measured concurrently. The detection of force and M-wave concurrently allows any reduction in muscle force output to be attributed to either changes in the fatigue state of the stimulated muscle or changes in the degree of stimulus activation of that muscle. The fatigue assessment scheme can thereby accommodate the corresponding changes in muscle force caused by an alteration in the stimulation intensity during fatigue. The Extensor Digitorum Communis (EDC), Extensor Pollicis Longus (EPL), and Flexor Pollicis Longus (FPL) muscles of two C5/C6 tetraplegic men were studied. Stimulation recruitment tests over the pulsewidth range from 0 to 200 micros, were performed at intervals during 20 min of maximal stimulation (200 micro/s). Muscle force correlated to the M-wave parameter, second phase area, with mean correlation coefficients of greater than 0.82, when the muscle was in either a nonfatigued or fatiguing state. After the initial force, likely to be primarily due to the fast glycolytic (FG) motor units, had declined the M-wave demonstrated only minor changes throughout the fatigue of muscle force during 20 min of constant maximal stimulation. The second phase area and root-mean-square (rms) of the M-wave [see Fig. 2(a) reflected muscle activation during modulated stimulation and also remained relatively constant during the fatigue-related force decline when the muscle was stimulated at a constant intensity. This detection of M-wave parameters satisfies the defined requirement for a myoelectric parameter that indicates electrical activation, but is relatively invariant to muscular fatigue. Index Terms-Electrical stimulation, electromyography (EMG), functional electrical stimulation (FES), muscle fatigue, spinal cord injury, tetraplegia.

The use of bilateral stimulated hand grasp in the bimanual activities of persons with tetraplegia.

Grasp and release has been provided to both upper extremities of subjects with tetraplegia using percutaneous and fully implanted stimulation. This is to determine quantitatively the performance of these subjects in three bimanual tests using two handed stimulation. Their performance here is compared with two separate cases: the same tests using single handed stimulation assisted by a nonstimulated hand and using two unstimulated hands. It was found that bilateral stimulation significantly improved the efficacy of performing the bimanual tests assessed over that using unilateral stimulation assisted by the nonstimulated hand (in two of three tests) or no stimulation three of three tests). These results show quantitative evidence of the benefits of providing bilateral stimulation for the completion of bimanual tasks for persons with tetraplegia who are appropriate candidates for stimulated grasp. These benefits were observed especially in cases where the ability of the subject in completing the task using unilateral stimulation was not strong.

Quantitative evaluation of two methods of control of bilateral stimulated hand grasps in persons with tetraplegia.

Electrical stimulation has been applied to the paralyzed muscles of both hands of two persons with tetraplegia using percutaneous and implantable electrodes. Two separate methods of user control were being investigated. The first monitored the myoelectric signals from the user's own sternocleidomastoid muscles and the second monitored wrist joint angle. These signals were used as commands to modify the stimulated grasps. The hands were instrumented to detect the degree of hand closure and grip force and the users matched these to specific target parameters using the controller during tracking tasks. Performance in these tracking tasks was measured quantitatively. Wrist control was found to be less sensitive to the direction of hand opening/closing required than the myoelectric control. The user's performance with the myoelectric control demonstrated sensitivity to the target size and the speed of hand movement in response to the command control. The wrist controller required less training than the myoelectric controller for users to become proficient in its use. Based on these results, the wrist controller and the myoelectric controller both provide successful control of bilateral hand grasp and release. Of the two controllers, the wrist controller is likely to provide the greater ease of use, although it is only available to the population of users with active wrist extension.

Relationship of exposure to human T lymphotropic virus and T helper cells in homosexual men.

The detection of serum antibodies (Ab) against HTLV-III in individuals with AIDS and related symptoms (ARC) has unambiguously defined the association of the virus infection to AIDS. This study was done to determine the extent of exposure to HTLV-III in homosexual men by measuring (Ab) and relating it to the stage of disease and T cell subsets. We found Ab in 89.5% of the 492 men with the median titers by stage of disease being 1600 for symptom-free, 6400 for ARC or Kaposi's sarcoma, and 4800 for opportunistic infection (OI), respectively. There was no correlation between Ab titers and either absolute or relative T helper cells (T4+), even though these cells decreased with disease severity. More specifically, however, symptom free patients had a normal distribution of the helpers of suppression (T4+/Leu8+), whereas, in symptomatic men, there was a significant decrease suggesting that the target cell for the virus is a subpopulation of the T helper cell.

Cytostatic and cytotoxic activity of lymphokine-activated killer cell supernatants.

Incubation of peripheral blood mononuclear cells with interleukin-2 (IL-2) results in the release of a factor which is cytostatic and cytotoxic both to tumor cell lines (A375M, A375P, C480, MCF-7, Hey) and fresh tumor cells (in the human tumor cloning assay), including breast cancer, colon cancer, melanoma, myeloma and ovarian cancer. The factor cannot be detected in a 4-h chromium-release assay, but is best demonstrated after tumor cells have been to it for exposed 3 days. The factor is not cytotoxic to normal peripheral blood leukocytes or normal fibroblasts, and is not toxic to certain targets sensitive to lymphokine-activated killer (LAK) cells, such as K562 and Daudi cells. The factor is diffusible, non-dialyzable, relatively stable to heat and acid and does not contain appreciable amounts of targets resistant to interferon-alpha and beta, tumor necrosis factor beta and interleukin-1. The data suggest that there are several mechanisms of LAK cell activity against tumor cells including one which requires direct interaction of LAK and tumor cells and one which is mediated by LAK cell supernatant. The former is detected by 4-h chromium release while the latter is not.