Schiff base adducts of hemoglobin. Modifications that inhibit erythrocyte sickling

Normal and sickle erythrocytes were exposed in vitro to millimolar concentrations of 31 different carbonyl compounds. Schiff base (imine) linkages were formed with amino groups of intracellular hemoglobin. Adducts were isolated by gel electrofocusing and could be dissociated by dialysis. Aromatic aldehydes proved more reactive than aliphatic aldehydes, and ketones were unreactive. The influence of various ring substituents on the reactivity of aromatic aldehydes was found to conform closely to traditional concepts regarding electronic and steric effects. Several of the aromatic aldehydes were shown to markedly increase the oxygen affinity of hemoglobins A and S. In particular, 2,4-dihydroxybenzaldehyde and o-vanillin, at concentrations of 5 mM, produced 2- to 3-fold reductions in the P50 (partial pressure of oxygen at half-saturation) of sickle hemoglobin in whole blood. Since low degrees of oxygen saturation promote erythrocyte sickling, compounds of this type significantly inhibit sickling at reduced partial pressures of oxygen.     

Syntheses of novel 3-amino-2(1H)-thioxo-4(3H)-quinazolinones and evaluation of their immunotropic activity. Part III

The synthesis of two series of derivatives containing the quinazolinone-4 moiety is described. 3-Amino-2(1H)-thioxo-4(3H)-quinazolinone (1) was subjected to reactions with halogenoketones and halogenoaldehydes, leading to the production of the corresponding ketones, aldehydes, Schiff bases, and 6-oxo-1,4,5-thiadiazin[2,3-b]quinazoline derivatives. Subsequently, 1 was condensed with selected alpha, beta-unsaturated carbonyl compounds, aldehydes, ketones, acid chlorides, and esters. The compounds were tested for their potential activity in a model of humoral and cellular immune response. The tests showed that the compounds exhibited differential immunotropic activities. Of particular interest is compound 19, exhibiting a strong stimulatory activity with regard to cellular immune response and compound 16 exerting a strong inhibitory action in both types of the immune response.     

Heterogeneity of Rapid Sand Filters and Its Effect on Contaminant Transport and Nitrification Performance

Laboratory and full-scale experiments were conducted to investigate the development and effect of heterogeneity caused by filter media nonuniformity, biofilm, particles, precipitates, and gas bubbles in rapid sand filters used for drinking-water treatment. Salt tracer experiments were conducted in laboratory columns and in a waterworks, where a new tracer method for rapid sand filters was developed. Pore-water velocities and dispersivities were estimated by fitting an analytical solution to the measured breakthrough curves. Results of the column experiments showed an increase in average longitudinal dispersivity of more than 33% in the 116?h after the start of filtration with a constant pore-water velocity and a zero-order nitrification rate of 9??mg?N/L/h. The full-scale experiments showed that the rapid sand filter was heterogeneous with pore-water velocities ranging from 2.2 to 3.3??m/h for the same inlet flow. A first-order nitrification reaction with spatially variable pore-water velocity could be interpreted as a zero-order reaction with a constant pore-water velocity. A model demonstrated that filter heterogeneity could result in higher filter outlet ammonium concentrations.     

Multiple GPI-anchored receptors control GDNF-dependent and independent activation of the c-Ret receptor tyrosine kinase

The application of a newly developed thermal desorption method for the analysis of workplace air to the analysis of polar compounds is reported. The method was validated for both pumped and diffusive sampling of test gases containing polar volatile organic compounds (esters, alcohols, ketones or aldehydes) on adsorption tubes and subsequent analysis of these tubes. Carbosieve SIII, Carboxen 569, Carbopack B and Tenax TA were used as solid adsorbents. Analysis was performed by thermal desorption of the analytes from the adsorbent tubes followed by gas chromatography-flame ionisation detection (GC-FID). It could be demonstrated that thermal desorption-GC-FID is feasible also for the analysis of polar compounds and that problems arising from the high concentration levels of some analytes in workplace air could be solved.     

Carbonyl reductase activity exhibited by pig testicular 20 beta-hydroxysteroid dehydrogenase

The carbonyl reductase activity exhibited by pig testicular 20 beta-hydroxysteroid dehydrogenase (20 beta-HSD) was examined using a recombinant enzyme. Kinetic parameters were obtained for 48 carbonyl group-containing substrates, including aromatic aldehydes, aromatic ketones, cycloketones, quinones, aliphatic aldehydes and aliphatic ketones. 20 beta-HSD showed a high affinity towards quinones, such as 9,10-phenanthrenequinone, alpha-naphthoquinone and menadione (Km values of 4, 2 and 5 microM, respectively), and the substrate utilization efficiency (Vmax/Km) of the enzyme against these quinones was very high. Cyclohexanone and 2-methylcyclohexanone were also reduced with a high Vmax/Km value, but not cyclopentanone or 2-methylcyclopentanone. Various aromatic aldehydes and ketones including benzaldehyde- and acetophenone-derivatives were reduced by 20 beta-HSD. Especially, 4-nitrobenzaldehyde and 4-nitroacetophenone were reduced with high Vmax/Km values in the related compounds. The enzyme also reduced the pyridine-derivatives, 2-, 3-, and 4-benzoylpyridine, with the Vmax/Km value for 2-benzoylpyridine being the highest. 20 beta-HSD reduced aliphatic aldehydes and aliphatic ketones, but was more effective on the former. The correlation between the structure of carbonyl compounds and their substrate Vmax/Km is discussed.     

Chondrosarcoma of the nasal septum

120 pieces of silk suture (1# & 4#) were sterilized with formaldehyde at different time period. Group II and III each had 20 pieces and was disinfected with ethylene oxide or high pressure respectively. The tension of each silk suture was measured with tensomether. The result showed that there was no significant difference compared with the control groups (P > 0.05). This suggests that silk suture maintains the same tension in the experiments after repeated sterilization with formaldehyde, with ethylene oxide, or with highpressure sterilization once.     

Larox Pressure Filters in Filtration and Washing of Non-Ferrous Minerals Concentrates and Metallurgical Slurries

Automatic pressure filter with horizontally positioned filtration chambers and one endless filter cloth was first introduced in the late 1960s. Actual product development and process adaptation was done during the 1970s. During the next decade this type of dewatering equipment established a firm position in a wide range of applications in mining, metallurgical, and chemical industries worldwide. More than 320 of these first generation LAROX PF filters are in operation in many types of dewatering applications. The maximum unit size has been 35 m². In many cases, particularly in mining applications, the size of one unit has not been enough. For large production capacities in mining and mineral processing LAROX introduced in 1992 the big PF filter with maximum filtering area up to 144 m², the second generation PF filter. The big 144 has 24 filter plates (filter chambers) and all mechanical operations are performed hydraulicaly. The normal size PF filters (below 38 m²) are also available with hydraulic operation devices. The second generation PF and big PF filters considerably increase the application range of this type of dewatering equipment.

There are many processes in the mining, mineral and metallurgical industries, where improved efficiency in the solid/liquid separation would help achieve significant savings in energy consumption, affluent treatment costs, capital cost by simplifying the process, operation costs and especially labor costs. In most cases the efficiency can be improved by replacing the existing solid/liquid separation process with pressure filtration.     

Effect of Moisture on the Adsorption of Volatile Organic Compounds by Zeolite 13×

The adsorption of volatile methanol, acetone, and benzene onto zeolite 13× was studied in the presence of water vapor. Breakthrough curves for these volatile organic compounds (VOCs) were measured by using a gas-phase Fourier transformation infrared (FT-IR) spectrometer instead of a gas chromatograph (GC) because a gas-phase FT-IR spectrometer provides a more rapid response to the change of gas concentration than that of GC. To observe the influences of humidity (i.e., water vapor) on the performance of zeolite 13× during the VOC adsorption, the adsorption experiments were carried out at three different initial concentrations and two humidity conditions for each VOC. The results showed a significant influence of increased humidity on the breakthrough time, the shapes of breakthrough curves, and the uptake of VOCs. For the case of the benzene and water vapor coadsorption system, the presence of the moisture caused a greater decrease in the VOC uptake as well as the breakthrough time than for the other VOC–water coadsorption systems. A modified Freundlich-type isotherm was introduced in this study to describe the decrease in the uptake of VOCs in the presence of the moisture. This modified empirical equation provided a good fit to experimental results, with an average error of 8%.     

Indoor emissions from conversion varnishes

Conversion varnishes are two-component, acid-catalyzed varnishes that are commonly used to finish cabinets. They are valued for their water and stain resistance, as well as their appearance. They have been found, however, to contribute to indoor emissions of organic compounds. For this project, three commercially available conversion varnish systems were selected. A U.S. Environmental Protection Agency (EPA) Method 24 analysis was performed to determine total volatile content, and a sodium sulfite titration method was used to determine uncombined (free) formaldehyde content of the varnish components. The resin component was also analyzed by gas chromatography/mass spectroscopy (GC/MS) (EPA Method 311 with an MS detector) to identify individual organic compounds. Dynamic small chamber tests were then performed to identify and quantify emissions following application to coupons of typical kitchen cabinet wood substrates, during both curing and aging. Because conversion varnishes cure by chemical reaction, the compounds emitted during curing and aging are not necessarily the same as those in the formulation. Results of small chamber tests showed that the amount of formaldehyde emitted from these coatings was 2.3-8.1 times the amount of free formaldehyde applied in the coatings. A long-term test showed a formaldehyde emission rate of 0.17 mg/m2/hr after 115 days.     

Comparison of extraction methods and detection systems in the gas chromatographic analysis of volatile carbonyl compounds

High-resolution gas chromatography (HRGC) with electron-capture detection (ECD), nitrogen-phosphorus detection (NPD), flame ionization detection (FID) or with mass spectrometry-selected ion monitoring (MS-SIM) was used in the analysis of volatile carbonyl compounds. Eighteen carbonyl compounds that are typically produced during lipid peroxidation were derivatized quantitatively with pentafluorophenylhydrazine (PFPH) at room temperature, to afford their corresponding water-insoluble hydrazones. These derivatives were extracted into non-polar phases by means of either liquid-liquid extraction (LLE) (hexane) or solid-phase extraction (SPE) on 3 ml C18 octadecyl-bonded phase cartridges. Detection limits of 10(-14) and 10(-12) mol/ml per aldehyde were achieved with the ECD and MS-SIM systems, respectively. The effects of extraction conditions on sensitivity and recovery were determined by performing parallel HRGC-ECD and HRGC-MS-SIM analyses of pentafluorophenylhydrazones of the eighteen compounds under study. Recoveries of 51.4-78.9 +/- 1.2-4.5 and 80.9-98.3 +/- 1.0-3.5% were obtained with LLE and SPE, respectively. The method was applied to the analysis of the volatile carbonyl compounds in various heated vegetable oils (corn, palm or sunflower) and to the analysis of volatile aldehydes in human urine.     

Are aldehydes in heat-sterilized peritoneal dialysis fluids toxic in vitro?

OBJECTIVE: Chemical analysis of several brands of peritoneal dialysis fluids (PD fluids) has revealed the presence of 2-furaldehyde, 5-HMF (5-hydroxymethylfuraldehyde), acetaldehyde, formaldehyde, glyoxal, and methylglyoxal. The aim of this study was to investigate if the in vitro side effects caused by glucose degradation products, mainly formed during heat sterilization, are due to any of these recently identified aldehydes. DESIGN: Cell growth media or sterile filtered PD fluids were spiked with different concentrations of thealdehydes. MEASUREMENTS: In vitro side effects were determined as the inhibition of cell growth of cultured mouse fibroblasts or stimulated superoxide radical release from human peritoneal cells. RESULTS: Our results demonstrate that the occurrences of 2-furaldehyde, 5-HMF, acetaldehyde, formaldehyde, glyoxal, or methylglyoxal in heat-sterilized PD fluids are probably not the direct cause of in vitro side effects. In order to induce the same magnitude of cell growth inhibition as the heat-sterilized PD fluids, the concentrations of 2-furaldehyde, glyoxal, and 5-HMF had to be 50 to 350 times higher than those quantified in the PD fluids. The concentrations of acetaldehyde, formaldehyde, and methylglyoxal observed in the heat-sterilized PD fluids were closer to the cytotoxic concentrations although still 3 to 7 times lower. CONCLUSION: Since none of these aldehydes caused in vitro toxicity at the tested concentrations, the toxicity found in PD fluids is likely to be due to another glucose degradation product, not yet identified. However, it is possible that these aldehydes may still have adverse effects for patients on peritoneal dialysis.     

Column Test Studies of Ochre Biofilm Formation in Geotextile Filters

This paper presents a study of ochre formation in geotextile filters. Ochre is a substance found sticking to solid surfaces of drainage systems that may cause clogging. The accumulation of such materials in a drainage system may have undesirable implications, such as a decrease in drainage flow capacity and an increase in soil pore pressure; instability of soil masses and retaining systems; and alteration of the direction of flow and development of pipes. Ochre formation is the result of microbial activities on iron compounds naturally found in seepage water. Even though geotextiles have been widely used in drainage systems, very few studies have considered ochre formation in the tests. Laboratory column filter tests were conducted to simulate the ochre formation process under similar conditions to those in geotechnical works and to assess the long-term performance of a geotextile. Ochre is most likely to be formed at an aerated/nonaerated interface in the filter. In order to obtain this condition, the underneath face of the filters was opened to the atmosphere. Three different types of geotextile—nonwoven polyester, nonwoven polypropylene, and woven polypropylene—were used in the tests. Control tests were also conducted with a sand filter to provide a basis for comparison. Hydraulic conductivity changes and iron retention within the permeameters were monitored throughout the tests. Ochre was formed under the presence of iron ions and iron bacteria. During the test period, the filters were not clogged to such an extent as to induce a global reduction in the permeability of the drainage system. Nevertheless, at the end of the tests a considerable amount of ochre was found in all filters and there was a significant variation in the permeability of the geotextile filters when tested in isolation. These studies may contribute to discovering whether ochre can be considered as a biofilm, evaluating the clogging potential and defining mitigating measures.     

Indoor air quality impacts of ventilation ducts: ozone removal and emissions of volatile organic compounds

The concentrations of contaminants in the supply air of mechanically ventilated buildings may be altered by pollutant emissions from and interactions with duct materials. We measured the emission rate of volatile organic compounds (VOCs) and aldehydes from materials typically found in ventilation ducts. The emission rate of VOCs per exposed surface area of materials was found to be low for some duct liners, but high for duct sealing caulk and a neoprene gasket. For a typical duct, the contribution to VOC concentrations is predicted to be only a few percent of common indoor levels. We exposed selected materials to approximately 100-ppb ozone and measured VOC emissions. Exposure to ozone increased the emission rates of aldehydes from a duct liner, duct sealing caulk, and neoprene gasket. The emission of aldehydes from these materials could increase indoor air concentrations by amounts that are as much as 20% of odor thresholds. We also measured the rate of ozone uptake on duct liners and galvanized sheet metal to predict how much ozone might be removed by a typical duct in ventilation systems. For exposure to a constant ozone mol fraction of 37 ppb, a lined duct would initially remove approximately 9% of the ozone, but over a period of 10 days of ozone removal efficiency would diminish to less than 4%. In an unlined duct, in which only galvanized sheet metal is exposed to the air-stream, the removal efficiency would be much lower, approximately 0.02%. Therefore, ducts in ventilation systems are unlikely to be a major sink for ozone.     

Chlorophyll a fluorescence: a tool for the investigation of toxic effects in the photosynthetic apparatus

The effects of environmental pollutants, such as triazines, urea herbicides, phenols, nitro aromatic compounds, aldehydes, hydrogen sulfide, volatile halogenated aliphatic and aromatic compounds, and alkylbenzenes, the photosynthesis of green algae were investigated by using detailed analysis of chlorophyll a fluorescence. Application of quenching analysis by means of a pulse amplitude-modulated fluorometer allows the discrimination of different modes of action. Blocks of the electron-transport chain, the action of uncouplers, and fluorescence quenching by nitroaormatic compounds could be distinguished. Hydrogen sulfide and short-chain aldehydes seem to react in the same way, probably by reaction with components of the electron-transport chain. Nonreactive volatile compounds affect chlorophyll fluorescence in a strictly hydrophobicity-dependent manner. The quenching analysis suggests an inhibition of utilization of proton-motive force for ATP synthesis. Detailed analysis of fluorescence patterns may be of great help for identification of toxic pollutants and their sources.     

Concentrations of selected contaminants in cabin air of airbus aircrafts

The concentrations of selected air quality parameters in aircraft cabins were investigated including particle numbers in cabin air compared to fresh air and recirculation air, the microbiological contamination and the concentration of volatile organic compounds (VOC). The Airbus types A310 of Swissair and A340 of Lufthansa were used for measurements. The particles were found to be mainly emitted by the passengers, especially by smokers. Depending on recirculation filter efficiency the recirculation air contained a lower or equal amount of particles compared to the fresh air, whereas the amount of bacteria exceeded reported concentrations within other indoor spaces. The detected species were mainly non-pathogenic, with droplet infection over short distances identified as the only health risk. The concentration of volatile organic compounds (VOC) were well below threshold values. Ethanol was identified as the compound with the highest amount in cabin air. Further organics were emitted by the passengers--as metabolic products or by smoking--and on ground as engine exhaust (bad airport air quality). Cleaning agents may be the source of further compounds.     

Commercial Odor-Reducing Agents for Minimizing the Odor Potential of Asphalt Binders

Odors arising from hot mix asphalt (HMA) production and application are a serious problem due to the proximity of HMA production to human habitation. One possible solution to this problem is the use of odor-reducing agents, which are intended to suppress the production of malodorous compounds. In this study, the ability of seven odor-reducing agents to reduce the odor compounds produced by 22 different HMA binders was quantified. Some odor-reducing agents produced only modest reductions in odors and were inconsistent in performance. Results indicate that terpine and essential oil based odor reducing agents did not appear to be effective in reducing odors. The aldehyde based agents attained the highest degree of odor reduction and appeared to be the most consistent performer over the spectrum of asphalt binders tested. Aldehydes produced reductions in odor potential that consistently exceeded 50% in odor-related volatile organic compounds. The odor reduction seen with the aldehydes is similar to those obtained with a nitrogen purge, leading to the hypothesis that these type of agents act as an oxygen scavenger.     

Recognition of novel artifacts produced during the microsomal incubation of secondary alicyclic amines in the presence of cyanide

1. During the in vitro microsomal metabolism of the secondary alicyclic amines, nornicotine, anabasine or 4-benzylpiperidine in the presence of cyanide, a new product was formed. 2. Comparison of these new products with authentic compounds by hplc and ms showed they were the corresponding 1'-N-cyanomethyl compounds. 3. The source of the methylene group was shown to be formaldehyde, arising during incubation, from either microsomal lipid and/or glycerol used to store microsomes for long periods at low temperature. 4. The formation of the 1'-N-cyanomethyl compounds was enhanced in the presence of substrates producing formaldehyde during their metabolism, in direct relationship to the amount of formaldehyde generated. 5. The results indicate that care should be taken in interpreting data obtained from incubates containing secondary amines and cyanide, especially in the presence of substrates capable of donating formaldehyde.     

Evaluation of sink effects on VOCs from a latex paint

The sink strength of two common indoor materials, a carpet and a gypsum board, was evaluated by environmental chamber tests with four volatile organic compounds (VOCs): propylene glycol, ethylene glycol, 2-(2-butoxyethoxy)ethanol (BEE), and Texanol. These oxygenated compounds represent the major VOCs emitted from a latex paint. Each chamber test included two phases. Phase 1 was the dosing/sorption period during which sink materials (pieces of carpet and gypsum board samples) were exposed to the four VOCs. The sink strength of each material tested was characterized by the amount of the VOCs adsorbed or absorbed. Phase 2 was the purging/desorption period during which the chambers with the dosed sink materials were flushed with purified air. The reemission rates of the adsorbed VOCs from the sinks were reflected by the amount of the VOCs being flushed. Phase 1 results indicated that the sink strength for the four target compounds is more than 1 order of magnitude higher than that for other VOCs previously tested by the U.S. Environmental Protection Agency (EPA). The high sink strength reflected the unusually high sorption capacity of common indoor materials for the four VOCs. Phase 2 results showed that reemission was an extremely slow process. If all the VOCs adsorbed were reemittable, it would take more than a year to completely flush out the VOCs from the sink materials tested. The long reemission process can result in chronic and low-level exposure to the VOCs after painting interior walls and surfaces.     

Changes of lipoxygenase and fatty acid hydroperoxide lyase activities in bell pepper fruits during maturation

Developmental changes in fatty acid hydroperoxide lyase (HPO lyase) and lipoxygenase (LOX) during the maturation of bell pepper fruits (Capsicum annuum L. cv. Kyonami) were examined by means of activity measurements, immunological detection of both the enzymes, and analysis of the volatile compounds formed upon homogenization of the fruits. Both the enzyme activities decreased with maturation, and immunological studies showed that the amounts of the enzymes concomitantly decreased. The amounts of six-carbon aldehydes and alcohols formed from bell pepper fruits upon homogenization also decreased during maturation, and with the fully ripened red fruits, these volatile compounds were hardly detectable. These results suggest that the major factor contributing to the changes in the composition of volatile compounds during the maturation of bell pepper fruits was changes in the amounts of HPO lyase and LOX.