Acute exposure to power-frequency magnetic fields has no effect on the acquisition of a spatial learning task by adult male mice

A series of four experiments was performed to determine whether acute exposure to a range of 50 Hz magnetic fields had any effect on a learning task in adult male CD1 mice. A radial-arm maze placed within the bore of an electromagnet was used to assess spatial discrimination learning for food reward. Subjects were reduced to 85% of their free-feeding weight and were placed in the maze for up to 15 minutes each day for 10 days. Performance of the task was measured by using maximum likelihood techniques to calculate the probability that an animal would not reenter any given arm of the maze. Experimental subjects were exposed to a vertical, 50 Hz sinusoidal magnetic field at 5 μT, 50 μT, 0.5 mT, or 5.0 mT (rms). Control subjects were exposed only to a background time-varying field of less than 50 nT and the ambient static field of about 40 μT. The variation in the applied magnetic field was less than 5% except at the ends of the arms, where it approached 10%. It was found that all eight groups of subjects (n = 10 in all cases) showed similar increases in performance with testing, and the acquisition curve for each group of experimental subjects was not significantly different from that of their control group (P > 0.05 in all cases). It was concluded that exposure had no effect on learning at any flux density. This result is contrary to the findings of a number of preliminary studies, although other studies have reported that magnetic fields do not affect spatial learning in adult male rodents. It is possible that differences between experimental conditions might explain some of this apparent discrepancy. © 1996 Wiley-Liss, Inc.     

Prenatal exposure to a 50 Hz magnetic field has no effect on spatial learning in adult mice

Male CD1 mice were exposed in utero to a 50 Hz sinusoidal magnetic field at 5 mT (rms) for the period of gestation and were raised subsequently without applied fields. At 82-84 days of age, they began a radial-arm-maze experiment that was designed to test for deficits in spatial learning in memory. Mice exposed in utero and sham-exposed mice exhibited no statistically significant differences in performances. © 1996 Wiley-Liss, Inc.     

Energy conservation through recycling of used oil

This study concentrates on the investigation of energy and environmental benefits for used oil pertaining to its reuse through: (i) recovering the heating value of used oils in a combustion process and (ii) re-refining of used oil to produce fresh lube oil products. Tests were made with the used oil samples by ICP technique and the results were compared with standard requirements. We have found that the problems could successfully be solved through used oil management practices including collection centers, transporters, and processors by providing encouragement and financial support towards the re-refining industry. The novelty and value of our work lies in the conclusion that reformulation of motor oil results in lower levels of hazardous elements in used oils.     

Immunization with a plant-produced colorectal cancer antigen

Cancer vaccination has become an important focus of oncology in recent years. Active immunization with tumor-associated antigens such as colorectal cancer antigen GA733-2 is thought to potentially overcome the reoccurrence of metastasis. As recombinant protein production in bioreactors is costly and subject to growing safety concerns, we tested plants as an alternative for the expression of a potential colorectal cancer vaccine. Comparing colorectal cancer antigen GA733-2 produced in tobacco plants with the same antigen produced in insect cell culture, we found a similar humoral immune response to injection of either of the two antigen preparations into mice. Some minor differences were observed in the cellular response that might be due to impurities. Our studies compare for the first time, immunization with the same antigen expressed in either plants or insect cell culture. This will provide important data for use of plants as production systems of therapeutics.     

Comparative LCA of industrial objects

Goal, Scope and Background  This paper is the second part of the publication which is devoted to comparative LCA analysis of the industrial pumps. The previous paper deals with the methodological aspects concerning quality assessment and forms an independent work. This paper uses practically only the methodological suggestions made there. The main aim of the presented study is to make a comparison between the industrial pumps which are based on two different technologies. The Life Cycle Assessment method is used to check whether the differences of the manufacturing processes influence the level of the potential environmental impact during the whole life cycle of the analysed products. Methods  The Life Cycle Assessment is carried out using the Ecoindicator99 method. Additionally, an extensive quality analysis of the LCA study is made (Part I). To make the process of an identification of the data easier and faster, they are assigned to a special data documentation form. To ensure the credibility of the LCA results different methods of interpretation are used. Results and Discussion  The LCA analysis shows clear superiority of the pumps manufactured using modern technology. It seems that this superiority results not only from the differences in the emissions, but also from different characteristics of effectiveness in the usage stage. Thanks to the uncertainty analysis, each LCA result is provided with the range of uncertainty. Conclusions  The LCA results are supported by different techniques of interpretation: the sensitivity-, the contribution-, the comparative-, the discernability- and the uncertainty analysis. There is strong evidence of the superiority of the pumps based on the modern technology. Recommendations and Outlook  The main source of the environmental impact in the case of pumps is the usage stage and the consumption of energy. That is why it should be the main area to improve. The LCA results show that actions taken in the usage stage and energy consumption can lead to a considerable reduction of the environmental impacts.     

Design and synthesis of de novo cytotoxic alkaloids through mimicking taxoid skeleton

Based on a common pharmacophore model and the hypothesis that the baccatin core of taxoids is a scaffold securing the proper orientation of the side chains, a bicyclic alkaloid scaffold was designed as a baccatin surrogate. Using this scaffold, two novel macrocyclic and open-chain 'taxoid-mimicking' compounds were synthesized. Two of these 'taxoid-mimics', 2 and 3, were found to possess cytotoxicity with micromolar level IC50 values against human breast cancer cell lines.     

Effects of cellulose, carboxymethylcellulose and inulin fed to rats as single supplements or in combinations on their caecal parameters

We compared the effect of diets containing different nondigestible carbohydrates: cellulose (C), inulin (IN) and carboxymethylcellulose (CMC) as single supplements or in dietary combination on caecal physiology of rats. Sixty male Wistar rats (Rattus norvegicus) were divided into five groups and for 4 weeks were fed a casein diet with the compared carbohydrates (4% of diet) or a combination of IN+C or IN+CMC (both 4+4%). Diet intake and FCR index remained unaffected by the treatments, whereas IN improved the body weight gain of rats compared to CMC. Compared to C group, all diets containing IN and CMC decreased the caecal pH as well as enlarged the caecum, thus increasing the weights of contents and tissue, especially upon CMC treatment. Rats given carboxymethylcellulose (CMC and IN+CMC groups) had watery caecal digesta, and some of them suffered from diarrhoea. In the case of CMC, the caecal enlargement was due to tissue hypertrophy and digesta accumulation mostly in response to an increased bulk of contents. Unlike C+IN, the dietary combination of CMC- and inulin-enhanced fermentation in the caecum of rats, however the proportion of acetate, propionate and butyrate was less beneficial. Compared to CMC, inulin gave a higher concentration of SCFA, especially of butyrate and propionate. The action of inulin in the caecum of rats could be pronounced by dietary treatment combined with CMC.     

Design, synthesis and biological activity of novel C2-C3' N-Linked macrocyclic taxoids

A series of novel macrocyclic taxoids was designed and synthesized by connecting the C-2 and C-3' N positions of the taxoid framework with various tethers. Cytotoxicity of these macrocyclic taxoids was evaluated against a human breast cancer cell line LCC6-WT, and a couple of the taxoids exhibited 0.09-0.3 microM IC(50) values.     

Accelerated degradation of adenine nucleotide in erythrocytes of patients with chronic renal failure

Recently, we have shown that erythrocytes obtained from patients with chronic renal failure (CRF) exhibited an increased rate of ATP formation from adenine as a substrate. Thus, we concluded that this process was in part responsible for the increase of adenine nucleotide concentration in uremic erythrocytes. There cannot be excluded however, that a decreased rate of adenylate degradation is an additional mechanism responsible for the elevated ATP concentration. To test this hypothesis, in this paper we compared the rate of adenine nucleotide breakdown in the erythrocytes obtained from patients with CRF and from healthy subjects.Using HPLC technique, we evaluated: (1) hypoxanthine production by uremic RBC incubated in incubation medium: (a) pH 7.4 containing 1.2 mM phosphate (which mimics physiological conditions) and (b) pH 7.1 containing 2.4 mM phosphate (which mimics uremic conditions); (2) adenine nucleotide degradation (IMP, inosine, adenosine, hypoxanthine production) by uremic RBC incubated in the presence of iodoacetate (glycolysis inhibitor) and EHNA (adenosine deaminase inhibitor). The erythrocytes of healthy volunteers served as control.The obtained results indicate that adenine nucleotide catabolism measured as a hypoxanthine formation was much faster in erythrocytes of patients with CRF than in the cells of healthy subjects. This phenomenon was observed both in the erythrocytes incubated at pH 7.4 in the medium containing 1.2 mM inorganic phosphate and in the medium which mimics hyperphosphatemia (2.4 mM) and metabolic acidosis (pH 7.1). The experiments with EHNA indicated that adenine nucleotide degradation proceeded via AMP-IMP-Inosine-Hypoxanthine pathway in erythrocytes of both patients with CRF and healthy subjects. Iodoacetate caused a several fold stimulation of adenylate breakdown. Under these conditions: (a) the rate of AMP catabolites (IMP + inosine + adenosine + hypoxanthine) formation was substantially higher in the erythrocytes from patients with CRF; (b) in erythrocytes of healthy subjects degradation of AMP proceeded via IMP and via adenosine essentially at the same rate; (c) in erythrocytes of patients with CRF the rate of AMP degradation via IMP was about 2 fold greater than via adenosine.The results presented in this paper suggest that adenine nucleotide degradation is markedly accelerated in erythrocytes of patients with CRF.     

Glycosyltransferases in plant and animal tissues effects of fixation and lead on enzyme activity.

As the initial step toward the cytochemical localization of glycosyl-transferases in situ, biochemical determinations of these enzyme activities from onion root tips and L1210 cells were performed before and after fixation as well as in the presence of lead ions. Glycosyltransferase activity from roots fixed in buffered formaldehyde or glutaraldehyde before homogenization decreased as the concentration of the fixative or fixation time was increased. Formaldehyde fixation was less inhibitory than glutaraldehyde; 35% of the glycosyltransferase activity was retained after 30 min fixation in 2% formaldehyde while 25% of the enzyme activity remained after a similar fixation in glutaraldehyde. Substantially higher levels of L1210 cell glycosyltransferase activity were retained after a 30 min 2% formaldehyde fixation (60% sialyltransferase; 82% galactosyltransferase), but inhibition by glutaraldehyde was similar to that observed for onion root galactosyltransferase. Glycosyltransferase from formaldehyde-fixed roots was inhbited 35% by lead nitrate, but sialytransferase from formaldehyde-fixed L1210 cells was unaffected by lead ions. These findings are encouraging for further studies aimed at the development of cytochemical technique to localize glycosyltransferase in plant and animal tissues.