ALBERT

Notes: Summary Background: Metallothionein (MT)# synthesis can be stimulated in many organs not only by various metals such as cadmium, zinc, and copper, but also by many nonmetalic compounds or experimental conditions such as oxidative stress. The latter lead to the hypothesis that MT is induced in response to free radicals formed in tissues and lipid peroxidation. Aims of the study: Whether the relationship between lipid peroxidation amd MT synthesis is a common phenomenon also valid for lipid peroxidation induced by dietary factors such as chronic vitamin E inadequacy and autoxidation products of polyenoic fatty acids derived from thermally oxidized oil was investigated in the presence study. Methods: The relationship between the induction of metallothionein isoforms I and II (MT-I and MT-II) in response to diet-induced lipid peroxidation using a rat model system in which lipid peroxidation was examined in vivo by chronic vitamin E inadequacy or by administration of lipid peroxidation products from a thermally treated polyenoicrich oil with either basal (dietary zinc concentration: 48 mg/kd; experiment 1) or Zn-stimulated MT levels (dietary zinc concentration: 305 mg/kd; experiment 2) was studied. In both experiments, growing male rats were fed diet containing either a fresh or a thermally treated soybean oil with deficient of sufficient amounts of vitamin E (14 and 11 vs. 648 and 560 mg α-tocopherol equivalents per kg diet) over 40 days according to a bifactorial experimental design. Plasma and liver concentrations of tocopherols and hepatic levels of thiobarbituric acid-reacitve substances (TBARS) were measured by high performance liquid chromatography. MT isoform concentrations in rat liver were isolated and quantified by ion-exchange high performance liquid chromatography and atomic absorption spectrometry. Results: Irrespective of the zinc supply, rats receiving inadequate amounts of vitamin E with the diet had markedly lower plasma and liver concentrations of α-tocopherol and total tocopherols than vitamin E-sufficient rats. ANOVA also revealed an interaction between the diet factors vitamin E and oil on tocopherols in plasma and liver of rats from both experiments. In experiment 1, where rats received normal amounts of dietary zinc, ingestion of the thermally treated oil impaired the tocopherol status compared to the treatment with the fresh oil, although this effect was only obvious in the vitamin E-deficient groups. In experiment 2, where rats received excessive amounts of zinc, the thermally treated oil did not contribute to a reduction of the tocopherol status in plasma and liver. In both experiments a significant increase in TBARS level, indicative of lipid peroxidation, was observed in the liver at chronic vitamin E inadequacy, but no effect of the oil was observed. Here, we show that the dietary treatment had some effects on the synthesis of liver metallothionein isoforms. In groups, receiving normal amounts of zinc, there was a significant interaction between the dietary treatments on the levels of MT-I and MT-II in liver. Chronic vitamin E inadequacy which was accompanied by diminisched tocopherol levels in liver induced the synthesis of MT-I and MT-II. When vitamin E inadequacy was combined with the ingestion of a thermally treated polyenoic acid-rich oil hepatic levels of MT-I and MT-II remained low. In experiment 2, where rats were fed the high zinc diet, vitamin E inadequacy caused an increase of hepatic MT-I level just as in experiment 1, although this MT stimulating effect was irrespective of the oil. For MT-II there was a 43% increase in the vitamin E-deficient group fed the fresh oil compared to all the other groups, although this effect was not statistically significant. The liver MT isoform response to stress was similar in rats with basal MT levels and Zn-induced liver MT levels. The failing effect of the thermally treated oil on MT levels which were stimulated by vitamin E deficiency in experiment 2 was possibly due to the low oxidation grade of the thermally treated oil. Conclusion: The present results are strongly indicative of an apparent induction of MT isoform synthesis in response to an impaired antioxidant defence system in the lipid regions of liver cells induced by vitamin E inadequacy. In contrast, thermally treated polyenoic-rich oils with a certain oxidation grade seem to restrain the induction of MT isoform synthesis under the present experimental conditions.

Notes: Abstract The thermal decomposition of pyrrolidinedithiocarbamate and piperidinedithiocarbamate complexes of CoII, NiII, CuII and HgII have been studied by thermogravimetry and differential scanning calorimetry. The decomposition intermediates and final products were identified by their X-ray diffraction patterns. The i.r. spectra are discussed in terms of the thermal decomposition pathways.

Notes: Abstract. The magnetic and electric hyperfine interaction frequencies of 197m Hg, 191Pt, 183Os, and 183Re in Co(hcp) were determined for parallel and perpendicular orientations of the magnetization relative to the c axis. Single-crystal samples were used, and the techniques of nuclear magnetic resonance on oriented nuclei and modulated adiabatic fast passage on oriented nuclei were applied. In addition, the nuclear spin-lattice relaxation constants in Co(hcp) were determined for 188Ir, 183Os, and 183Re. The descriptions of the magnetization behaviour and the anisotropy of the hyperfine interaction were tested in detail for 191Pt. The available data on the hyperfine interaction of the 5d elements in Co(hcp) are compiled. The use of these data to obtain information on the electronic structure of these systems, and in particular on the orbital part of the magnetism, is discussed.

Notes: Abstract. The spatial dependence of K α emission generated from laser-produced hot electrons is investigated experimentally and theoretically. In addition, the conversion efficiency of K α production as a function of laser intensity is measured and compared with modeling results. We use the terawatt Ti:sapphire laser at MPQ and vary the peak intensity from 1015 to 1018 W/cm2 with a pulse duration of 200 fs. A solid Cu target is placed at various positions in the laser focus, which allows one to vary the intensity but keep the total energy on the target constant. When the target is near best focus, the FWHM of the K α emission, measured using a knife-edge, is considerably larger than the FWHM of the laser intensity. In measuring the efficiency of K α production using the fundamental wavelength of the laser, a clear maximum of K α emission is observed at a position away from best focus, where the peak intensity is down by more than an order of magnitude from the value at best focus. When the second harmonic of the laser is used, the K α emission is peaked near best focus. The K α emission from layer targets is used to obtain an estimate of the temperature of the hot electrons. Modeling of K α production, using a Monte Carlo electron/photon transport code, shows the relationship between incident electron energy and the emitted K α emission. Efficient K α generation from the low-intensity wings of the laser pulse contributes to the large spot size of the K α emission. The lower electron temperatures that are expected for the second harmonic explain the differences in the location of maximum K α emission for the two wavelengths. We discuss the use of K α emission in photoionizing inner-shell electrons with the goal of achieving X-ray lasing at short wavelengths.

Notes: Abstract.  A tungsten-rhodium coating on the integrated platform of a transversely heated graphite atomiser (THGA) was used as a permanent chemical modifier for the determination of Cd in sediment slurries by electrothermal atomic absorption spectrometry. Slurries were ultrasonicated during 20 s before being delivered to the previously W-Rh treated platform. The permanent W-Rh modifier remains stable by approximately 250 measurements when 20 μl of slurries containing up to 1.0% m/v are delivered into the atomiser. In addition, the permanent modifier increases the tube lifetime up to 720 analytical firings. Also, when the W-Rh permanent modifier was employed, there was less variation of the slope of the analytical curves during the total atomiser lifetime, resulting in a decreased need of re-calibration during routine analysis, increasing the sample throughput. The atomiser lifetime was limited to the THGA wall durability, because the W-Rh treated platform was intact after more than 720 analytical firings. Detection limits based on integrated absorbance for 1.0% m/v slurries were 1.5 ng g−1 Cd for 250 μg W +200 μg Rh permanent modifier and 11.5 ng−1 Cd for 5 μg Pd +3 μg Mg(NO3)2. Results for the determination of cadmium in sediment slurries using the W-Rh permanent modifier were in agreement with those obtained with dissolved sample solutions by using Pd + Mg(NO3)2, since no statistical differences were found by the paired t-test at the 99% level.

Notes: Abstract The uptake and metabolism of 3H-benzylaminopurine(3H-BAP) were studied in explanted stem pith andleaves of tobacco and in the hypocotyls and cotyledonsof cucumber. The explants were kept for 2, 5, 8 and 20h on MS medium with 0.8 mg.l−1 2,4-D,0.5 mg.l−1 BAP and 13.2 mg.l−1 aspartic acid(induction medium) with or without 3H-BAP and14C-sucrose. The highest uptake of 3H-BAPwas observed in tobacco leaves and cucumbercotyledons. The major metabolite in both species was3H-benzylaminopurine riboside (3H-BAPR). Thehighest level was found in explanted cucumbercotyledons after 20 h in culture, the lowest inexplanted tobacco stem pith. Intensive 7-glucosylationof 3H-BAP was observed in explanted tobaccoleaves after 20 h in culture, where the levels of7-glucoside of 3H-BAP and of free 3H-BAPwere equal. To study the morphogenic effect of growth regulators(BAP and 2,4-D), the explants were subcultured aftershort-term induction (20 h) to MS medium without anygrowth regulators. In most cases, incubation of 20 hon induction medium was sufficient to induce therespective morphogenesis. Cucumber hypocotyl andtobacco stem pith explants formed a callus on theirbasal end. Root formation was observed on explantedcucumber cotyledons and shoot formation on tobaccoleaves. Long-term culture (3 weeks) of tobacco leaveson induction medium led to the formation of callus andglobules. The microscopic analysis of globulesindicated the presence of meristematic and tracheidalcells.