Immunological response in the mouse melanoma model after local hyperthermia.

Our study was aimed to characterize the phenotype and functional endpoints of local microwave hyperthermia (LHT, 42 degrees C) on tumor infiltrating and spleen leukocytes. The effectiveness of LHT applied into the tumor of B16F10 melanoma-bearing C57/BL6 mice was compared with anesthetized and non-treated animals. Subpopulations of leukocytes were analyzed using the flow cytometry, and the cytotoxic activity of splenocytes against syngeneic B16F10 melanoma and NK-sensitive YAC-1 tumor cell lines was evaluated in (51)Cr-release assay. Similarly, the in vitro modification of the heat treatment was performed using healthy and melanoma-bearing splenocytes. We found a 40 % increase of activated monocytes (CD11b+CD69+) infiltration into the tumor microenvironment. In the spleen of experimental animals, the numbers of cytotoxic T lymphocytes (CTLs-CD3+CD8+) and NK cell (CD49b+NK1.1+) raised by 22 % and 14 %, respectively, while the NK1.1+ monocytes decreases by 37 %. This was accompanied by an enhancement of cytotoxic effector function against B16F10 and YAC-1 targets in both in vivo and in vitro conditions. These results demonstrate that LHT induces better killing of syngeneic melanoma targets. Furthermore, LHT evokes the homing of activated monocytes into the tumor microenvironment and increases the counts of NK cells and CTL in the spleen.

Effect of agroclavine on NK activity in vivo under normal and stress conditions in rats.

Agroclavine is a natural, clavine type of ergot alkaloid with D1 dopamine and a-adrenoceptor agonistic properties. We showed previously that in vitro agroclavine enhances natural killer (NK) cell activity, increases interleukin-2 and interferon-gamma production and prolongs the survival time of tumor-bearing mice. The aim of this study was 1) to test the effect of agroclavine on NK activity in vivo, and 2) to assess the potential toxicity of high doses of agroclavine on cardiac and liver functions using creatine kinase MB (CKMB) and alanine aminotransferase (ALT) as biochemical markers in normal and stressed animals. The effect of stress was studied because we examined promising anticancer properties of agroclavine and malignant diseases are supposed to be a potent stressful event for patients. In our experiments 3-month-old male rats of the Wistar-Kyoto strain were used. Agroclavine was injected intraperitoneally (0.5 mg/kg or 0.05 mg/kg) 30 min before stress (four hours' restraint and immersion in 23 degrees C water). The animals were killed 30 min after stress, blood was collected and the spleen was removed. Non-stressed animals treated with agroclavine were killed 5 h after the drug administration. The results confirmed our previous in vitro results and showed that also in vivo agroclavine increases NK cell activity under non-stress conditions. Agroclavine only slightly increased CKMB and had no influence on ALT in non-stressed animals. These promising results are limited by the fact that agroclavine (0.5 mg/kg) diminished NK cell activity and significantly increased ALT and CKMB under stress conditions.

Anticipation of acute stress in isoprenaline-sensitive and - resistant rats: strain and gender differences.

The effect of stress anticipation was studied in two inbred Wistar rat strains with high and low sensitivity to isoprenaline. The animals were exposed to tail-flick and 4-hr water immersion restraint stress on two consecutive days. On the first day stress was applied to one group and the next day to the anticipation group. The changes in adrenal, heart and spleen weights, tail-flick latency, incidence of gastric ulcers, and the antioxidant defense system in the sensorimotor cortex were compared with two non-stressed control groups. Anticipatory stress decreased adrenal weights. The content of thiobarbituric acid reactive substances (TBARS) was increased both in acute and anticipatory stress; superoxide dismutase, glutathione peroxidase, and antioxidative capacity were increased in anticipatory stress only. Stress anticipation decreased the pain threshold in the isoprenaline-sensitive and increased in the isoprenaline-resistant rats and led to more frequent gastric ulcers in the isoprenaline-resistant group. Significant sex differences were observed both in adrenal weights and TBARS content. The relative adrenal weights were negatively correlated with the TBARS content. We suggest that the outcome of anticipatory stress may depend upon the relation between the hormonal and antioxidant functions of the adrenals and that anticipation-induced activation of antioxidant enzymes may ameliorate the acute stress response. Anticipation itself was found to be a stronger stressor than physical acute stress.

The influence of repeated prestressors on single stress response in rats.

The effect of various stressors of different intensity applied in random order before the final single immersion restraint stress was tested in two inbred rat strains, isoprenaline-sensitive and isoprenaline-resistant. The isoprenaline-sensitive strain revealed higher incidence of heart lesions after this single acute stress and low incidence of gastric lesions. The isoprenaline-resistant strain had the opposite characteristics. These differences were constantly reproducible when this strong stressor was used. After prestress by different stressors (tail-flick, ether anaesthesia, Porsolt swimming stress) at different time schedules, the incidence of gastric ulcer lesions, the weight of organs (heart, adrenals, spleen) changed substantially in isoprenaline-sensitive rats only. The most important result was reversal of the extent of gastric lesions. The isoprenaline-sensitive strain revealed more lesions than the isoprenaline-resistant one. The repeated different prestressors mainly changed the reactivity of animals, isoprenaline-sensitive rats becoming more similar to isoprenaline-resistant rats. These findings urged us to interpret carefully the results obtained in stress research with different and multiple stressors both in animals and humans.

[Cross-sectional study of choice of drug therapy in the acute phase of treatment in acute myocardial infarct--part 1]. / Prurezová studie volby farmakoterapie v akutní fázi lécby akutního infarktu myokardu--1. cást.

INTRODUCTION: Treatment of acute myocardial infarction is undergoing changes. In the treatment of acute myocardial infarction in particular the following proved useful: thrombolysis, administration of anti-aggregating drugs, beta-blockers and inhibitors of angiotensin converting enzyme. An decisive part is played by the interval between the onset of symptoms and the beginning of hospital treatment. OBJECTIVE: To describe treatment of patients hospitalized at intensive care units for acute myocardial infarctions. Investigate differences between faculty and other hospitals. METHOD: The authors investigated by means of questionaires in a prospective study during the first three months in 1996 all patients who were hospitalized on account of acute myocardial infarction. The investigation was implemented in seven intensive care units of faculty hospitals and in nine intensive care units of hospitals and information on diagnosis, pharmacotherapy and results of therapy were assembled. During the first 24 hours of treatment more detailed information was procured. RESULTS: Antiaggregants were used in 88%, nitrates in 77.8%, thrombolytics, beta-blockers and and ACE inhibitors in ca 30% patients. Percutaneous transluminal coronary angioplasty was used in ca 7% patients. CONCLUSIONS: The authors describe treatment of the acute stage of myocardial infarction. In faculty hospitals in 1996 thrombolysis, percutaneous transluminal coronary angioplasty, beta-blockers and nitrates by the i.v. route were used more frequently.

The effect of drugs on the mortality of mice inoculated with Friend leukaemia virus or toxoplasma gondii.

Infection and tumors provoke substantial changes accompanied with the disbalance of many neuroendocrine factors which in their summarizing effects influence the life span of animals. Our previous results showed enhanced mortality after one injection of morphine in association with Friend leukaemia virus infection. The aim of this study was to examine the effects of some other opioids (pethidine and pentazocine) and an acetylcholine esterase inhibitor neostigmine on the survival of animals under two conditions: (1) Friend leukaemia virus infection which mostly depressed immune functions, and (2) Toxoplasma gondii infection which in general enhanced the immune status. In contrast to our previous observation with morphine, the mortality induced by single doses of pethidine (150 mg/kg) or pentazocine (50-75 mg/kg) was unchanged during the Friend leukaemia virus infection. A single injection of neostigmine (0.42 or 0.56 mg/kg) was significantly more lethal in DBA-2 mice infected with Friend leukaemia virus. Neostigmine in doses of 0.33 and 0.4 mg/kg caused death in 46 % and 57 %, respectively, of animals infected with Toxoplasma gondii which was significantly higher in comparison with only 8 % and 12.5 % in control groups. Pethidine (150 mg/kg) killed 70 % of Toxoplasma gondii infected animals and even 90 % of non-infected mice. Thus, the Friend leukaemia virus and Toxoplasma gondii infections increased toxicity only of some drugs which may, at least partly, be associated with altered immune status during infection and involvement of the cholinergic system.

Neuroimmunomodulation of natural killer (NK) cells by ergot alkaloid derivatives.

Ergot alkaloids (EAs), products of Claviceps spp., are widely used in various fields of clinical medicine (neurology, psychiatry, endocrinology). In the present work we studied the neuroimmunomodulative effect of EAs on activation of NK cells and their signalling pathways. Furthermore, the killing capability of rat NK cells in vitro was examined in the presence of glycosidic derivatives of elymoclavine, agroclavine, and liposome-encapsulated EAs. The engagement of appropriate NK cell membrane receptors by EAs cause an indirect enhancement of adenylyl cyclase system through inhibition of G-protein al,2-subunit (up to 50 % of control values). All of the tested EAs enhanced the rat NK cell-mediated cytotoxic activity in vitro, particularly against target cells of astrocyte origin (C-6 glioma). The present results argue for a possible EA immunomodulatory role of cell-mediated immunity in tumour regression processes.

Exposure to stress alters the effects of dynorphins in the hot plate test.

The analgesic effects of intracerebroventricularly (i.c.v.) administered dynorphin A(1-13) and its analog dynorphin A(1-10)amide using the hot plate test were studied in mice. Both dynorphins applied i.c.v. by the freehand method had an analgesic effect but no effect was seen when applied i.c.v. through an implanted cannula. Moreover, freehand i.c.v. injection of saline increased the time of immobility in the forced swimming test and glycaemia levels compared with intact mice. In contrast to the freehand injection, saline administration through an implanted cannula did not influence the immobility of animals in forced swimming test when compared with the intact controls. These results suggest that 1) the freehand method is very stressful procedure of administration which could influence the effects of dynorphins in the hot plate test and 2) dynorphins exert an analgesic effect in the hot plate test only when combined with a stressor (freehand i.c.v. injection).

Behavioral characteristics of two rat strains differing in sensitivity to the cardiotoxic effect of isoprenaline.

Behavioral pattern was studied in two inbred strains of rats which have different responses to stress. These strains were originally developed from a randomly bred Wistar rat colony, according to high or low myocardial cells sensitivity to cardiotoxic effect of isoprenaline. One strain is very sensitive to isoprenaline cardiotoxicity (IS = isoprenaline sensitive) the other strain is more resistant (IR = isoprenaline resistant). In the IR strain the immobilization immersion stress causes high incidence of gastric ulcers, while the IS strain is prone to heart pathology. In this communication we report the differences in behavior of these two rat lines in three tests: open field, intruder's test and Porsolt's forced swimming test. The IS animals were passive and anxious in open field test, submissive in intruders test and they showed more floating time in Porsolt's forced swimming test. The IR rats were active, aggressive and dominant.

Influence of dynorphin A (1-13) and dynorphin A (1-10) amide on stress-induced analgesia.

Dynorphin A (1-13) and its analog dynorphin A (1-10) amide were applied intracerebroventricularly in male ICR mice. Both dynorphins did not reveal any analgesic activity in tail-flick test under normal (non-stressed) conditions. However, in combination with stress (forced swimming or whole body vibration) both dynorphins prolonged tail-flick latencies when compared with stressed saline controls. Naloxone inhibited the effect of dynorphins in forced swimming test. Neither dynorphin A (1-13) nor dynorphin A (1-10) amide increased tail-flick latencies when combined with weak immobilization stress. Our results suggest that the analgesic effects of dynorphins are potentiated by strong stressors.

[Differences in the behavior of organic lesions, immunologic and metabolic parameters in 2 inbred strains of rats]. / Rozdíly chování orgánových lézí, imunologických a metabolických parametru u dvou inbredních kmenu potkanu.

Two inbred rat strains were obtained by selective breeding and inbreeding: IR (isoprenaline resistant) and IS (isoprenaline sensitive). In addition to known differences between the two strains (1) other differences were found. As compared to IS strain, IR rats were more aggressive and showed more comfort behaviour in open field test. IR rats developed larger stress-induced gastric lesions but smaller heart lesions. They had larger spleen and thymus and more severe arthritis after Freund adjuvans administration. The two strains might be useful in studying the effects of drugs on various pathological processes. Their hybrids are being used to study interrelations between different genetic factors.

Immune status and survival of opiate- and cocaine-treated mice infected with Friend virus.

In as much as the immunomodulatory effects of opiates and cocaine are known to modify spontaneous host defenses against infection, we investigated the effects of morphine, pentazocine and cocaine on the time course of Friend virus infection in mice. Repeated i.p. injections with increasing doses of morphine hydrochloride (10-100 mg/kg for 10 days before infection, a dose regimen which induced tolerance to the acute antinociceptive effects of the drug, followed by 30 mg/kg for 14 days postinfection) did not increase the mortality due to Friend virus infection. This regimen did not significantly affect the immune response of infected mice assessed in terms of delayed hypersensitivity (ear thickness) and the hemagglutination assay. In contrast, a single challenge with a large dose of morphine (up to 300 mg/kg), which is not lethal in noninfected mice, increased mortality markedly (up to 100%) in infected mice when administered at day 14 or 21 postinfection. Repeated i.p. injections with pentazocine (50 mg/kg b.i.d. for 5 days before infection, followed by 30 mg/kg for 14 days postinfection) had no influence on mortality or immune responses in infected mice; similar results were obtained with a single high-dose injection (up to 100 mg/kg). Lastly, repeated i.p. injections of cocaine, using the same experimental procedure as that for pentazocine, decreased immune responsiveness and slightly increased mortality, whereas a single injection was devoid of lethal effect. These findings suggest that chronic opioid treatment does not lower host resistance to viral infection but that the latter could increase the toxicity of a single high dose of morphine.(ABSTRACT TRUNCATED AT 250 WORDS)