[en] In order to facilitate the study of oxidative stress in lung tissue, rat lung slices with impaired antioxidant defenses were prepared and used. Incubation of lung slices with the antineoplastic agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) (100 μM) in an amino acid-rich medium for 45 min produced a near-maximal (approximately 85%), irreversible inhibition of glutathione reductase, accompanied by only a modest (approximately 15%) decrease in pulmonary nonprotein sulfhydryls (NPSH) and no alteration in intracellular ATP, NADP⁺, and NADPH levels. The amounts of NADP(H), ATP, and NPSH were stable over a 4-hr incubation period following the removal from BCNU. The viability of the system was further evaluated by measuring the rate of evolution of ¹⁴CO₂ from D-[¹⁴C(U)]-glucose. The rates of evolution were almost identical in the compromised system when compared with control slices over a 4-hr time period. By using slices with compromised oxidative defenses, preliminary results have been obtained with paraquat, nitrofurantoin, and 2,3-dimethoxy-1,4-naphthoquinone

[en] Bacteria able to mineralize 100-200 ppm of pentachlorophenol (PCP) were isolated by selective enrichment from PCP-contaminated soil from 3 geographic areas in Minnesota. Sampling areas were separated from each other by up to 185 miles; history and level of contamination with a variety of compounds varied between sites. Pure cultures of bacteria were selected for further characterization based on growth properties, site of isolation, and return of radiolabeled PCP as ¹⁴CO₂ in initial serum bottle experiments. Although differing somewhat in their response to various biochemical and biophysical tests, all strains were Gram-negative, oxidase-, catalase-, and phosphatase-positive, not motile, grow as yellow colonies on solid medium, limited in their use of single carbon sources,and ranged in mol% G + C of DNA between 58.8-63,8%. All strains were assigned to the genus Flavobacterium

[en] The rapid development of powerful UV-laser sources allows the investigation of macroscopic and microscopic details of elementary chemical reactions important in combustion processes. Experimental results on the effect of selective translational and vibrational excitation of reactants in elementary combustion reactions using laser photolysis and time-resolved atomic line resonance absorption, laser-induced fluorescence and CARS spectroscopy are compared with the results of theoretical studies on ab initio potential energy surfaces and thermal rate parameters. Thermal elimination of hydrogen chloride from 1,2-dichloroethane and 1,1,1-chlorodifluoroethane is a main industrial route to some important monomer compounds. Inducing thic radical chain reactions by UV-exciplex laser radiation offers the advantage that a monomolecular process with low activation energy becomes the rate determining step. This allows lower process temperatures with decreasing energy expense and avoiding the high temperature formation of by products

[en] The possible role in vivo of osseous structures in binding radioactive iron injected as a low-molecular-weight complex was studied in mice, using combined autoradiography and histomorphometry on sections of undecalcified, plastic-embedded femur epiphyses/metaphyses. A single intraperitoneal injection of 10 microCi ⁵⁹Fe (1.2 micrograms Fe) per animal as citrate within 3 hours led to a preferential accumulation of this metal in the osteoid mineralized tissue interphase (osteoid seams) of bone. Within the next 2 days the labeling intensity in this localization diminished markedly to approximate levels of the bone marrow and calcified bone. The bulk of the injected radioiron was utilized according to known erythrokinetics. Findings suggest a direct entry of free, ie, not transferrin-bound, iron into osteoid seams and its consecutive rapid removal from this site

[en] A study of the sampling efficiency for polynuclear aromatic hydrocarbons (PAH) in air of two adsorbents, XAD-2 resin and polyurethane foam (PUF), was performed under summer and winter ambient conditions. Two aspects were investigated: (1) collection efficiency for ambient PAH vapor and (2) retention efficiency for native and perdeuteriated PAH spiked onto the adsorbents before sampling. The XAD-2 resin had a higher collection efficiency for naphthalene than did PUF. Some spiked PAH that were volatile or reactive were also recovered more efficiently with XAD-2 resin than with PUF. Lower sampling temperatures improved the recoveries of volatile PAH with PUF, but the recoveries of reactive PAH, such as cyclopenta[cd]pyrene, were not improved at lower temperatures for either adsorbent. The stability of PAH collected on quartz-fiber prefilters and XAD-2 or PUF backup traps as a function of the storage time was also investigated. Storage at room temperature in the dark for 30 days did not have an adverse effect on ambient PAH collected with XAD-2 resin or on perdeuteriated PAH spiked onto the adsorbent prior to sampling. However, a decreasing concentration trend with storage time for naphthalene, anthracene, and [²H₁²]benzo[a]pyrene collected or spiked on PUF was found. 19 references, 4 figures, 1 table

[en] Uteroferrin, an acid phosphatase with a spin-coupled and redox-active binuclear iron center, is paramagnetic in its pink, enzymatically active, mixed-valence (S = 1/2) state. Phosphate, a product and inhibitor of the enzymatic activity of uteroferrin, converts the pink, EPR-active form of the protein to a purple, EPR-silent species. In contrast, molybdate, a tetrahedral oxyanion analog of phosphate, transforms the EPR spectrum of uteroferrin from a rhombic to an axial form. With both electron spin echo envelope modulation (ESEEM) and electron nuclear double resonance (ENDOR) spectroscopies, we observe a hyperfine interaction of [95Mo]molybdate with the S = 1/2, Fe(II)-Fe(III) center of the protein. A pair of 95Mo resonances centered at the 95Mo Larmor frequency at the applied magnetic field and separated by a hyperfine coupling constant of 1.2 MHz is evident. Therefore, a single monomeric species of molybdate is close to, and likely a ligand of, the binuclear cluster. 1H ENDOR studies on uteroferrin reveal at least six sets of lines mirrored about the 1H Larmor frequency. Two pairs of these lines become reduced in intensity when the protein is exchanged against D2O. Moreover, ESEEM and 2H ENDOR spectra display resonances at the 2H Larmor frequency. Therefore, the metal-binding region of the protein is accessible to solvent. Additional deuterium lines observable by ESEEM spectroscopy provide evidence for a population of strongly coupled, readily exchangeable protons associated with the binuclear center. The measured hyperfine coupling constants for these deuterons are orientation-dependent with splittings of nearly 4 MHz at g3 = 1.59 and less than 1 MHz at g1 = 1.94. In the presence of molybdate, ESEEM spectra of D2O-exchanged samples reveal a resonance at the 2H Larmor frequency, with no evidence of spectral components due to strongly coupled deuterons

[en] This book consists of 39 chapters. Some of the titles are: Bacillus subtilis repair test, Induced reversion using human adenovirus, The fluctuation test in bacteria, Chemical mutagenesis with diploid human fibroblasts, The specific locus test in the mouse, The bone marrow micronucleus test, and Sperm morphology in testing in mice

[en] A cadmium-saturation technique for quantifying metallothionein in mammalian tissues was evaluated for use in fish tissue. Metallothionein characteristically binds 7 gram-atoms of a metal such as cadmium per mole of protein so saturating MT with respect to one metal and then quantifying that metal would thus result in the indirect quantification of MT. The authors administered 3 mg ¹⁰⁹cadmium/kg body weight by intraperitoneal injection over a 5-day period to adult brook trout Salvelinus fontinalis to induce MT in liver and kidney tissues. Homogenates were centrifuged and the supernatant was used to quantitate cadmium in three fractions: 100,000 g supernatant, cadmium-saturated MT, and unsaturated MT. The cadmium-saturated MT method involved the following steps: saturation of MT in an aliquot of 100,000 g supernatant with excess cadmium; removal of excess cadmium by addition of 2% hemoglobin; denaturation of hemoglobin by heating at 100⁰C followed by rapid cooling on ice; centrifugation at 10,000 g; digestion of an aliquot of supernatant in concentrated nitric acid for 16 hours at 70⁰C, and quantification of cadmium by atomic absorption and graphite furnace techniques or radiometric measurement with a scintillation counter. The cadmium saturation technique was modified in two ways so the amount of cadmium bound to unsaturated MT could be measured; first, the binding sites on MT were not saturated with excess cadmium, and second, the concentration of hemoglobin added to remove free cadmium and aid in coagulating low-molecular-weight proteins was 1% instead of 2%. The method gave precise measurements of MT concentrations when aliquots of liver homogenate which were analyzed separately were quantified by atomic absorption or radiometric measurements. Two to four times more cadmium and MT concentrated in the liver of treated fish than in the kidney

[en] Xanthates are mostly of technical significance as samplers of metal sulfides in mining flotation. Alkali-metal-xanthates are stable, crystalline substances. As Xanthates are hydrolyzed by stomach acid, poisoning is mainly caused by the hydrolysis products alcohol and carbon disulfide. Xanthates, however, are known to be strong fish poisons. Recently xanthates are being discussed as helpful agents in environmental protection because of their ability to remove harmful heavy metals from contaminated waters. The present work was undertaken, to provide more information on the fate and effects on aquatic organisms of these environmental chemicals

[en] There were 1,724 lung cancer cases registered at the Yunnan Tin Corporation in the period 1954-1986, of which 90% had a history of working underground. Previous exposure to radon, and radon daughters and arsenic is considered to be responsible for the high incidence of lung cancer in these miners. Arsenic may come from inhalation of arsenic-containing ore dust or other environmental arsenic pollution. It appears that radon exposure accounts to a greater extent than arsenic for the increase of lung cancer in these miners. Pathological study was made of 100 surgically resected lung cancer specimens. In this way the distribution and composition of dust retention was determined in relation to peripheral lung cancer