Antioxidant properties of estrogens

The author expounded present state of knowledge concerning antioxidant properties of estrogens. Estradiol, apart from its main hormonal effect, probably displays two mechanisms of antioxidant action. One of them results from hydroxyphenolic structure of their molecule. Estradiol may donate hydrogen atoms from its phenolic hydroxyl group to lipid peroxyradicals what results in the termination of the chain reactions of cell membrane phospholipides, which are the key reactions in cell damage. Estradiol also inhibits oxidative modification of LDL lipoprotein which plays the main role in atherogenesis. The other mechanism of antioxidative action of estradiol is probably associated with its stimulatory effect on natural cellular antioxidant enzymes. Data on this subject are scarce and controversial. The mechanisms of antioxidant action of estrogens require further investigation.     

Inverse relationship between total testosterone and anti-oxidized low density lipoprotein antibody levels in ageing males

Accumulating evidence indicates the involvement of sex hormones in atherogenesis. Endogenous testosterone is inversely related to the majority of risk factors for atherosclerosis and is known to be a potent immunomodulator. Recently, autoantibodies to oxidized LDL (anti-oxLDL Ab) were shown to predict carotid and coronary atherosclerosis. The aim of this study was to investigate the relationship between these antibodies and testosterone level in ageing males. The study group comprised 65 males over 50 years old (42 with coronary artery disease). Serum anti-oxLDL Ab titer was measured by enzyme-linked immunoassay and total serum testosterone by radioimmunoassay. A significant inverse correlation was found between serum anti-oxLDL Ab titer and testosterone concentration (r=-0.346, P=0.0047). Alteration in serum anti-oxLDL Ab titres showed no correlation to classical cardiovascular risk factors, e.g. body mass index, waist/hip ratio, smoking, total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol. In multiple regression analysis only testosterone level was independently associated with anti-oxLDL Ab. These data suggest a that fall of testosterone concentration in ageing men can influence either oxidative modification of LDL or the immune response to these lipoproteins which may be important in the pathogenesis of atherosclerosis.     

Anxiolytic-like effects of preferential dopamine D3 receptor agonists in an animal model

The aim of the present study was to examine a potential anxiolytic-like action of (+)-7-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (7-OH-DPAT), a preferential dopamine D(3) receptor agonist, and (N-[4-[4-(2-methoxyphenyl)-1-piperazinyl]butyl]-2-naphthylcarboxamide (BP 897), partial dopamine D(3) receptor agonist. Diazepam was used as a reference compound. The anxiolytic-like effect of those drugs was tested in the conflict drinking test (Vogel test) in male Wistar rats. The obtained results showed that 7-OH-DPAT and BP 897 (like diazepam) induced anxiolytic-like effects in the conflict drinking test. 7-OH-DPAT (0.05 and 0.1 mg/kg), BP 897 (0.5 mg/kg) and diazepam (5 and 10 mg/kg), tested at the effective doses in an animal model, did not affect motor coordination but produced significant reduction in exploratory activity in the open field test. These data suggest that preferential dopamine D(3) agonists may play a role in the therapy of anxiety, however, further studies are necessary to elucidate the mechanism of these actions.     

Release of volatile organic compounds from textile floor coverings in higher temperatures

The effect of temperatures 23 degrees C, 29 degrees C, and 50 degrees C on emission of 4-phenylcyclohexene (4-PC), styrene, total volatile organic compounds (VOCs) and formaldehyde from textile floor coverings with textile backing and styrene/butadiene latex precoat was examined. Tested coverings didn't show emission of styrene and formaldehyde. At 23 degrees C and 29 degrees C two tested coverings showed emission of 4-PC on low level. The higher emission was observed from all coverings at 50 degrees C. VOCs emission from coverings increased with increasing of temperature, especially at 50 degrees C. In conclusion some of new textile floor coverings can cause contamination of indoor air after application of sub-floor heating. Contamination, however, will decrease with time.     

Stereotactic methods in interdisciplinary diagnosis and treatment of posterior fossa tumours

For over 2 years, we have had access to latest generation apparatus and software for planning and stereotactic treatment as well as for x-rays treatment. Until now, we have carried out over 100 procedures. These included 52 stereotactic biopsies of neoplasms, some of them located within the structures of the posterior fossa. In this report, we have discussed the possibilities and effectiveness of diagnosis and treatment of tumours located in different structures, including posterior cave. In the study, we used stereotactic methods. We have described biopsies of the following tumours: cerebellar hemisphere tumour (diagnosed as "metastatic atypic planoepitheliale carcinoma" in a patient with coexisting orbit lymphoma), a bifocal lesion (located in cerebellar hemisphere and cerebellar peduncle, diagnosed as pilocytic astrocytoma of WHO malignancy grade II/III), and lesion (located in the pons, diagnosed as pilocytic astrocytoma WHO grade II).     

Pentoxifylline inhibits leukocyte infiltration and splenocyte cytotoxicity against murine colon adenocarcinoma

Pentoxifylline (PTX), a methylxanthine derivative, is commonly used in patients suffering from peripheral vascular diseases. Besides its well-known hemorheological properties PTX has been found to decrease the secretion of some inflammatory cytokines such as TNF, IL-12 and IFN-gamma. PTX also suppresses lymphocyte cytotoxicity, affecting mainly the perforin-dependent pathway. We investigated the influence of PTX on the splenocyte cytotoxicity and leukocyte infiltration in a murine colon adenocarcinoma model. We observed that PTX decreased the cytotoxic activity of isolated splenocytes against C-26 cells and reduced the inflammatory cell infiltration in the peritumoral tissue. Thus, our results strongly suggest the necessity of further studies concerning the safety of PTX use, especially in elderly patients or patients with already diagnosed cancer.     

Nociceptin inhibits acquisition of amphetamine-induced place preference and sensitization to stereotypy in rats

Nociceptin (also called orphanin FQ), a 17-amino-acid peptide, is the natural ligand of the nociceptin opioid peptide (NOP) receptor. This peptide shows similarities, in its structure, to opioid peptides, mainly to dynorphin A. However, unlike opioid peptides, it does not produce a conditioned place preference or aversion but inhibits rewarding effect of drugs of abuse. The present study was designed to examine the ability of nociceptin to block the acquisition of amphetamine-induced place preference, and the development of amphetamine-induced sensitization to stereotypy in rats. Our experiments indicated that repeated administration of nociceptin at increasing doses during conditioning significantly attenuated the reinforcing effect of amphetamine in conditioned place preference paradigm. Nociceptin did not change the acute effect of amphetamine-induced stereotypy but prevented the development of sensitization to stereotypy measured on the challenge day. Our results suggest the involvement of nociceptin in long-lasting neuronal adaptation after repeated amphetamine treatment.