Combined treatment of advanced malignant melanoma with coumarin and cimetidine

Summary Immunostimulant therapy with coumarin and cimetidine was evaluated in 17 patients with advanced malignant melanoma. Induction therapy with coumarin 100 mg daily was given for 8 weeks, whereupon cimetidine 1000 mg daily was added. No patients had been previously treated with cytotoxic drugs, and all patients had a good performance status. In 16 patients progressive disease was observed, and only 1 patient experienced no change in condition, lasting 30 weeks. We conclude that treatment with this schedule of coumarin and cimetidine is without effect in advanced malignant melanoma.     

Adjuvant interferon treatment of melanoma

Interferon is a pleiotropic antitumor biological agent that elicits its effect in a dose-dependent manner. Interferon has been tested in high, medium, and low doses; controlled studies, however, indicated that only high-dose therapy markedly prolonged the survival rate. Due to its high toxicity, the high-dose treatment modality has not been widely accepted. At present, neither the optimal dose, nor the duration of interferon adjuvant therapy are established. Furthermore, parameters that could predict responders to treatment are not yet identified. Before careful evaluation of the large-scale, controlled, multi-centric studies, the authors recommend strategy that combines intermediate and high-dose therapy for adjuvant treatment of patients with melanoma.     

Does vinblastine add to the potency of alpha interferon in the treatment of renal cell carcinoma?

The combination of alpha interferon and vinblastine has been reported to yield a response rate of 30-40% in previously untreated patients with metastatic renal cell carcinoma. This combination was given to nine patients with advanced metastatic renal carcinoma after they failed or relapsed on alpha-interferon alone, to attempt to evaluate the role of vinblastine in this combination. Neither complete nor partial response was observed. Two patients had disease stabilization for two and seven months. Our preliminary results suggest that vinblastine did not add to the efficacy of interferon in this group of patients.     

Confirmation studies of Soviet research on immunological effects of microwaves: Russian immunology results

This paper presents the results of a replication study performed to investigate earlier Soviet studies conducted between 1974 and 1991 that showed immunological and reproductive effects of long‐term low‐level exposure of rats to radiofrequency (RF) electromagnetic fields. The early studies were used, in part, for developing exposure standards for the USSR population and thus it was necessary to confirm the Russian findings. In the present study, the conditions of RF exposure were made as similar as possible to those in the earlier experiments: Wistar rats were exposed in the far field to 2450 MHz continuous wave RF fields with an incident power density in the cages of 5 W/m² for 7 h/day, 5 days/week for a total of 30 days, resulting in a whole‐body SAR of 0.16 W/kg. Effects of the exposure on immunological parameters in the brain and liver of rats were evaluated using the complement fixation test (CFT), as in the original studies, and an additional test, the more modern ELISA test. Our results, using CFT and ELISA, partly confirmed the findings of the early studies and indicated possible effects from non‐thermal RF exposure on autoimmune processes. The RF exposure resulted in minor increases in formation of antibodies in brain tissue extract and the exposure did not appear to be pathological. In addition, a study was conducted to replicate a previous Soviet study on effects from the injection of blood serum from RF‐exposed rats on pregnancy and foetal and offspring development of rats, using a similar animal model and protocol. Our results showed the same general trends as the earlier study, suggesting possible adverse effects of the blood serum from exposed rats on pregnancy and foetal development of intact rats, however, application of these results in developing exposure standards is limited. Bioelectromagnetics 31:589–602, 2010. © 2010 Wiley‐Liss, Inc.     

Systemic administration of human leukocyte interferon to melanoma patients. III. Increased helper:suppressor cell ratios in melanoma patients during interferon treatment

Malignant melanoma patients treated with human leukocyte interferon (IFN-alpha) displayed increased natural killer (NK) cytotoxicity to K562 targets within the first 2 weeks of therapy. This study explored the possibility of T-cell regulation of this NK response, as evidenced by a variation in T-cell subpopulations. T-cell subset levels were studied in 9 patients who received daily doses of IFN-alpha over a period of 42 days. Five monoclonal antibodies to T-cell surface markers were used: Leu 1 (pan-T), Leu 2a (T suppressor/cytotoxic), Leu 3a (T helper/inducer), HNK-1 (Leu 7, a marker for NK cells), and B73.1 (an antibody against the Fc receptor on NK/K cells). Percentages of these markers were measured on days 0, 3, 7, and 21 of treatment. Percentages of Leu 1-positive cells and Fc-receptor-positive cells remained relatively constant throughout treatment in all patients. A trend toward a decrease in suppressor cells and an increase in helper cells peaking on day 7 and returning to earlier values by day 21 was found in 5 patients. The increase in NK cytotoxicity was not reflected consistently in proportions of HNK-1-positive cells or Fc receptor-bearing cells within the first week of therapy. The most significant finding was an increase in the helper:suppressor cell ratio peaking on day 7 and returning to pretreatment values by day 21. This increase was seen in every patient studied. The average pretreatment Leu 3a:Leu 2a ratio was 0.67 increasing to an average value of 1.47 on day 7 (p less than 0.005). Leu 3a:Leu 2a ratios returned to pretreatment values, in parallel to NK activity, despite continuation of interferon therapy.     

Studies on the effects of vinblastine and colchicine on Trypanosoma gambiense

Vinblastine and colchicine induce the anucleate form of Trypanosoma gambiense. Light microscopic studies indicated that the anucleate form was not always produced as a result of inhibition of nuclear duplication, but was formed as a result of delay or inhibition of separation of the two nuclei after completion of nuclear division. Studies showed that vinblastine and colchicine caused disorder in arrangement of axonemal microtubules of the extracellular flagella and increased formation of both protofilaments and the axoneme composed of protofilaments in trypanosomes. Moreover, treatment with colchicine resulted in disintegration of previously existing pellicular microtubules and formation of cytoplasmic projections that appeared as protrusions from a small part of the surface membrane.     

Short- and long-term effects of vinblastine on the rat adrenal medulla

Summary The effects of a single high dose (10mg/kg) of vinblastine (vb) sulfate (Velbe, Lilly) on the ultrastructure, catecholamine (CA) content and activity of CA-synthesizing enzymes of the rat adrenal medulla were studied for up to 120h after intravenous injection of the drug.By 1 h, microtubules were virtually absent from chromaffin cells and preganglionic cholinergic axons, and typical paracrystals had appeared inside the nerve fibers. By 16h microtubules were completely reconstituted and paracrystals had disappeared. From 16h onwards, there was an increasing depletion of storage granules from adrenaline (A) — producing cells, which coincided with biochemical determinations showing a reduction of adrenal A to about 40 % of control levels by 48 h, with noradrenaline (NA) remaining in the range of controls. Both A- and NA-storing cells showed an extensive proliferation of the rough endoplasmic reticulum (ER). Vb caused a marked increase in tyrosine hydroxylase (TH; +113%) and dopamine -hydroxylase (DBH; +82%) activities after 48 h. Splanchnicotomy completely abolished the vb-mediated increase in TH and DBH activities. A smaller increase (+ 47 %) in enzyme activity was observed with phenylethanolamine N-methyltransferase (PNMT). Vb (10^–5M) had no apparent effect on granule content and the amount of rough ER in chromaffin cells, which were cultured for 48 h.The results demonstrate that a single high dose of vb has relatively little short-term effects on the rat adrenal medulla, but causes drastic long-term changes in CA-content and enzyme activities that are mediated by the preganglionic nerves. These changes could be interpreted as an effort to compensate for a loss of CA-stores in peripheral adrenergic nerves (cf. Cheney et al., 1973). The differential long-term effect of vb on adrenal NA and A might be due to the lower induction of PNMT as compared to TH and DBH activities and/or to a preferential release of A versus NA, which may occur at high frequencies of stimulation of the splanchnic nerves.Supported by grants from the Deutsche ForschungsgemeinschaftDedicated to Professor G. Petry in honor of his 65th birthday     

Catharanthine C16 substituent effects on the biomimetic coupling with vindoline: preparation and evaluation of a key series of vinblastine analogues

The examination of the catharanthine C16 substituent effects on the Fe(III)-promoted biomimetic coupling reaction with vindoline is detailed, confirming the importance of the presence of a C16 electron-withdrawing substituent, and establishing an unanticipated unique role (>10-fold) that the C16 methyl ester plays in the expression of the natural product properties. Thus, replacement of the vinblastine C16' methyl ester with an ethyl ester (10-fold), a cyano group (100-fold), an aldehyde (100-fold), a hydroxymethyl group (1000-fold) or a primary carboxamide (>1000-fold) led to surprisingly large reductions in cytotoxic activity.     

Contrasting effects of maytansine and vinblastine on the alkylation of tubulin sulfhydryls

The ansa macrolide maytansine is a competitive inhibitor of vinblastine for binding to tubulin. Both drugs are potent inhibitors of microtubule assembly in vitro but maytansine, unlike vinblastine, is unable to induce tubulin aggregation or to stabilize colchicine binding. In this study, the effects of maytansine and vinblastine on the accessibility of tubulin's sulfhydryl groups were compared. It was found that 10 μm vinblastine inhibited the reaction of bovine brain tubulin with [¹⁴C]iodoacetamide by 45%. In contrast, maytansine, even up to 100 μm, had no effect on the reaction. However, when the two drugs were tested in combination, maytansine was a potent inhibitor of vinblastine's effect, consistent with the two drugs competing for the same or overlapping sites, but suggesting that the nature of the binding was different. In contrast, maytansine did not affect the suppression of alkylation induced by colchicine and podophylotoxin, consistent with these drugs binding to different sites. Maytansine and vinblastine were each able to increase the formation of $\text{β}{}^1$ by the bifunctional reagent, N,N′-ethylenebis-(iodoacetamide); $\text{β}{}^1$ is the designation for an electrophoretically faster migrating form of β-tubulin which apparently contains an intrachain crosslink. Thus, in at least the portion of the tubulin molecule involved in $\text{β}{}^1$ formation, the two drugs have similar effects. Since maytansine does not appear to suppress any competing alkylation reactions, it is possible that the enhancement of $\text{β}{}^1$ formation represents a genuine conformational effect. Since the sulfhydryl groups of tubulin may be involved in regulating microtubule assembly, it is likely that maytansine and vinblastine differ in the manner in which they inhibit microtubule assembly.     

Thymostimulin: an immunohistochemical and immunological evaluation

The immunohistochemical and immunological properties of a rabbit serum raised against the calf thymic hormonal factor "Thymostimulin" were studied on mammalian and human thymuses, discussing the problem of species-specificity. The serum was also injected in chick embryos to study the possible interrelationship between avian thymus and Bursa of Fabricius.     

Diversity in immune-cell interactions: states and functions of the immunological synapse

The contact-dependent exchange of signals between epithelial and neuronal cells results from close membrane-membrane appositions, which are stabilized for years by polarized adhesion, cytoskeletal assemblies and extracellular scaffold proteins. By contrast, owing to a lack of scaffold proteins, interactions between immune cells such as T lymphocytes and antigen-presenting cells (APCs) comprise a spectrum of structurally diverse and short-lived interaction modes that last from minutes to hours. Signals exchanged between T cells and APCs are generated in a specific contact region, termed the "immunological synapse", that coordinates cytoskeletal dynamics with the T-cell receptor (TCR), the engagement of accessory receptors and membrane-proximal signaling. Recent data shed light on the different physical and molecular interaction modes that occur between T cells and APCs, including their dynamics and transition stages, and their consequences for signaling, activation and T-cell effector function.