KCN Treatment Research Articles

Isozymes of superoxide dismutase from Heliobacillus mobilis

The supernatant of cell lysates from Heliobacillus mobilis contains two superoxide dismutase (SOD) bands as revealed by activity staining of gels from non-denaturing PAGE. These SODs were partially purified by ammonium sulfate fractionation, DEAE-anion exchange, gel-permeation, and hydroxyapatite column chromatographies. Two SOD fractions were separated from each other on DEAE chromatography. The level of total SOD activity is extremely low in cells grown under strictly anaerobic photosynthetic conditions. However, when the cell culture was exposed to air, the total SOD activity of the cells very rapidly increased 4 to 8-fold in 15 - 30 min. When 1 mM paraquat was added in addition, the total activity increased 10 to 12-fold in 15 - 30 min. Increasing the paraquat concentration beyond 1 mM did not increase the SOD activities further. The both SOD activities were not inhibited by H2O2 or by KCN treatment, indicating that these SODs are Mn-SODs.

Induction of cytokine genes and IL-1α by chemical hypoxia in PC12 cells

The role of cytokine in neuronal injury was examined in rat pheochromocytoma (PC12) cells under chemical hypoxia (i.e. KCN) and glucose deprivation. The mRNA levels of interleukin-1alpha (IL-1α), IL-6, and tumor necrosis factor-alpha (TNF-α) were measured by reverse transcription-polymerase chain reaction (RT-PCR) in PC12 cells exposed to 0.5 mM KCN for various time intervals. Cytokine mRNA levels expressed to peak levels 30 minutes after KCN treatment and declined gradually until 240 min. The IL-1α activity reached the highest levels 2 hr after the same KCN treatment. Under parallel conditions, KCN increased cytosolic free calcium concentration ([Ca 2+] i) in the absence of glucose. However, IL-1α mRNA induction by KCN was not altered under calcium-free conditions in PC12 cells, indicating its induction was Ca 2+-independent. However, the phosphatidylcholine (PC)-specific phospholipase C (PLC) inhibitor D609 decreased the KCN-induced IL-1α mRNA and protein in PC12 cells suggests that PC-PLC might play a role in cytokine induction during hypoxia.

Oxygen diffusive barriers of rat distal colon: role of subepithelial tissue, mucosa, and mucus gel layer.

The contributions of subepithelial tissue, mucosa, and mucus gel layer as restraints for oxygen diffusion in rat distal colon in vitro were assessed by comparing oxygen transfer through preparations of isolated submucosa, isolated mucosa with and without the superficial mucus gel layer, and mucosa-submucosa mounted as flat sheets in a diffusion chamber. One side of the chamber was gassed with 95% O2-5% CO2 while the time course of oxygen concentration rise was measured in the continuously stirred opposite side, initially equilibrated with near-zero oxygen solution. The procedure does not affect epithelial viability. Diffusion in isolated mucosa was the same before and after KCN (5 mM) treatment, suggesting that epithelial oxygen consumption does not influence transfer rates. Subepithelial tissue, mucosa, and mucus gel layer are roughly responsible, respectively, for 12%, 56%, and 32% of oxygen diffusive hindrance. Diffusion coefficients range from 13% (mucosa-submucosa) to 54% (isolated submucosa) of that of water. Subepithelial tissue accounts for about 12% of total diffusive restraint.

Differential Susceptibility of Brain Areas to Cyanide Involves Different Modes of Cell Death

We have demonstrated that cyanide (KCN) induces selective degeneration of dopaminergic neurons in mice and apoptotic cell death in cultured neurons. In the present study the mode of cyanide-induced cell death was determined in the susceptible brain areas. Mice were treated with KCN (6 mg/kg ip) or vehicle (saline) twice daily for 1 to 12 days. After 3 days of KCN treatment, two separate lesions were observed in coronal brain sections. Widespread DNA fragmentation in parietal and suprarhinal regions of the motor cortex was observed by thein situterminal deoxynucleotide transferase nick-end labeling (TUNEL) technique. Pyknosis and chromatin condensation, morphological hallmarks of apoptotic cells, were observed in TUNEL-positive regions. On the other hand, in the substantia nigra (SN), KCN produced a progressive, bilateral necrotic lesion that was evident by 3 days of treatment. The SN lesion was circumscribed by a prominent ring of glial infiltration, as determined by glial-acidic fibrillary protein (GFAP) immunostaining. The extent of the SN lesion steadily increased with treatment duration, and DNA fragmentation was not observed over the 1- to 12-day period. On the other hand, cortical apoptosis was not associated with necrotic cell loss or astrogliosis. Pretreatment of animals with the antioxidant α-phenyl-tert-butyl nitrone (PBN) for 7 days prior to and during 3 days of KCN administration markedly reduced cortical DNA fragmentation whereas the PBN treatment did not influence the SN necrosis or astrocytic gliosis. Except for moderate GFAP immunostaining in corpus callosum, other brain areas were not affected by cyanide. It is concluded that KCN-induced neuronal loss involves selective activation of necrosis or apoptosis in different neuronal populations, and involves divergent mechanisms and sensitivity to antioxidants.

Kinetic study of heavy metal salt effects on the activity of L-lactate dehydrogenase in solution or immobilized on an oxygen electrode

A sensitive and convenient biosensor for detection of heavy metal salts has been developed. The method is based on the effects of heavy metal salts on the catalytic activity of L-lactate dehydrogenase (LDH) in solution or coimmobilized with L-lactate oxidase (LOD) on an oxygen electrode. At metal concentrations below 100 μM, the kinetic behavior, with the LDH substrate NADH, showed a competitive inhibition with high affinity during the first 10 s. With increased incubation time, irreversible first order inactivation with respect to enzyme concentration was observed. This irreversible inactivation of LDH in solution was dose dependant. The efficiencies obtained for the different heavy metal salts were: HgCl 2>AgNO 3>Pb(COOCH 3) 2>CuSO 4>ZnCl 2. HgCl 2 and AgNO 3 were effective in the nanomolar range while the other metal salts acted at the micromolar level. LDH is protected by saturating amounts of substrate NADH against the effects of the heavy metal salts studied. The p Ks for LDH catalytic activity and inactivation by heavy metal salts were similar. The results suggest binding of the heavy metal salts to the enzyme active site. Except for lead acetate, all heavy metal detection was in the range of European norms. For AgNO 3, CuSO 4 and HgCl 2, the sensor limit of detection reached the European norm values whereas with ZnCl 2 it was well below. The immobilization of LDH considerably decreased the amount of enzyme consumed by permitting repetitive assays. The efficiency of inactivation by the heavy metal salts was reduced in comparison with LDH in solution. Restoration of activity of the inactivated immobilized enzyme was obtained with DTT, EDTA, KCN and NADH treatment. This opens up possibilities for detection of toxic compounds using simple procedures suitable for assays in a variety of monitoring conditions in environmental and food pollution control.

Preparation of Culn(S xSe 1− x) 2 thin films by sulfurization and selenization

A CuIn(S x Se 1− x ) 2 alloy thin-film was prepared by selenization of CuInS 2: its composition ratio x can be controlled by the number of selenization cycles implemented. Crystallinity of the films was improved by annealing in vacuum. The resistivity of the film was about 1 Ω cm and increased by one to two orders of magnitude after KCN treatment. An 8.1 % efficiency solar cell was obtained by using this annealed alloy thin-film.

The influence of sodium on the properties of CuInS 2 thin films and solar cells

The controlled incorporation of sodium into the absorber layer of CuInS 2 solar cells improved cell performance remarkably. Without toxic KCN treatment, conversion efficiencies of over 6% were achieved by sulfurization of sodium-containing precursors. We also investigated the characteristics of the sodium-incorporated CuInS 2 films by intentional addition and diffusion from a soda-lime glass. The ternary compound semiconductor of NaInS 2 was found to form mainly on the surface of each of the CuInS 2 films.

ChemInform Abstract: Improvement of Electrical Characteristics of (Indium‐Tin Oxide/Silicon Oxide/Polycrystalline n‐Si) Solar Cells by a KCN Treatment.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Improvement of Electrical Characteristics of 〈Indium‐Tin Oxide/Silicon Oxide/Polycrystalline n‐Si〉 Solar Cells by a KCN Treatment

The photovoltage and the fill factor of 〈indium‐tin oxide (ITO)/silicon oxide/polycrystalline n‐Si〉 junction solar cells are increased by immersing Si in a potassium cyanide solution before the deposition of an ITO film. Measurements of the temperature dependence of the dark current‐voltage curves show that the mechanism of the current flow through the Si depletion layer is changed from trap‐assisted multistep tunneling to thermionic‐assisted tunneling by the KCN treatment, indicating a decrease in the density of the trap states in the Si depletion layer. Measurements of the electrode conductance also show that the trap density is greatly reduced by the KCN treatment. The improvement of the electrical characteristics is attributed to the decrease in the trap density and an increase in the barrier height in n‐Si caused by the inclusion of cyanide ions at the oxide/Si interface and/or in the silicon oxide layer.

1] Determination of vitamin B6 vitamers and metabolites in a bioloical sample

This chapter determines sample preparation and analytical techniques appropriate for the determination of all forms of vitamin B6 in a biological sample. For the determination of all B6, compounds except pyridoxic acid 5'-phosphate (PIC-P), the fluorescence spectrophotometer is set at an emission wavelength of 390 nm with an excitation wavelength of 305 nm. For the determination of PIC-P, which is prepared from pyridoxal 5'-phosphate (PLP) by KCN treatment, the fluorescence measurement is carried out at an emission wavelength of 420 nm with an excitation wavelength of 320 nm. An isocratic elution system is adopted to quantitate B6 compounds fluorometrically, because the fluorescence quantum yield of a compound drastically changed, depending on the slight change in ionic strength and pH of the solvent. Two isocratic solvent systems are used for the determination of naturally occurring pyridoxal derivatives, in which most pyridoxal derivatives can be analyzed with nearly the same sensitivity.

Cytoplasmic phosphates in Na(+)-K+ balance in KCN-poisoned rat heart: a 87Rb-, 23Na-, and 31P-NMR study.

The effect on intracellular Na+ ([Na+]i) and Rb+ fluxes if reduced [ATP]/ [ADP] and increased Pi has been investigated by 1 mM potassium cyanide (KCN) or KCl (control) infusion (24 min) in Langendorff perfused rat hearts. 87Rb, 23Na, or 31P nuclear magnetic resonance (NMR) spectra were acquired to measure intracellular Rb+ (a congener for K+, 20% substitution), Na+, and phosphates. KCN infusion (14-24 min) caused decreases in phosphocreatine (34 +/- 12% of initial), ATP (64 +/- 17), and Rb content (71 +/- 7) and increases in Pi (273 +/- 65) and [Na+]i (210 +/- 52). Dimethylamiloride (10 microM) did not change the rate of Na+ accumulation. The rate constant of unidirectional Rb+ efflux (min-1) increased during KCN treatment by 70% (0.061 +/- 0.006 vs. 0.036 +/- 0.004, P = 0.0001). KCN-stimulated Rb+ efflux was inhibited by glibenclamide (Glib, 10 microM. 0.042 +/- 0.009, P = 0.0001 vs. KCN) and alpha-cyano-4-hydroxycinnamate (0.5 mM, 0.047 +/- 0.008, P < 0.002 vs. KCN). KCN moderately decreased the Rb+ influx rate (to 82 +/- 17%, P = 0.01), which was depressed more significantly in the presence of Glib (47 +/- 17%, P = 0.03). We suggest that inhibition of Na(+)-K(+)-adenosinetriphosphatase (ATPase) by Pi is responsible for intracellular Na+ accumulation, whereas K+ loss is associated with both activation of ATP-sensitive K+ channels and the K(+)-lactate-cotransporter and inhibition of Na(+)-K(+)-ATPase.

Solar Cells Based on CuInS2 Thin Films through Sulfurization of Precursors Prepared by Reactive Sputtering with H 2S Gas

CuInS2 films were prepared using a two-stage process in which Cu–In–S precursors were sputtered in H2S/Ar with metal targets (Cu and In) and then annealed in H2S atmosphere. Control of S content in the precursor is essential for fabricating high-quality CuInS2 films and achieving high-efficiency solar cells. When S/(Cu+In) ratio in the precursor was about 0.3, CuInS2 films with good crystallinity and smooth surface were obtained, and consequently a CuInS2 solar cell with an efficiency of 6.3% has been achieved without KCN treatment.

Influence of KCN treatment on CuInS 2 thin films

Electrical and compositional properties as well as solar cell performances were studied on polycrystalline CuInS 2 films synthesized by sulphurization of copper and indium sandwiches. To study the influence of KCN treatment, each of the samples was divided into two pieces, where one was treated with KCN, and their properties were compared. KCN treatment lowered the initial Cu In composition ratio which ranged between 1 and 2.1 to slightly less than 1. Also, it increased the resistivity by two orders of magnitude, which is due to the reduction of the carrier concentration by three orders of magnitude. The X-ray diffraction line width is narrowed as well. These results indicate that some Cu x S and/or copper are etched during the KCN treatment. Solar cells were fabricated with a chemical bath deposited CdS buffer layer and an atom beam sputtered ZnO window on the CuInS 2 thin films. The solar cell conversion efficiency was increased from η = 2.1% (3.9% after vacuum annealing) to η = 5.8%.

Treatment of Wool Fabrics with Potassium Cyanide in Organic Solvent-Water Mixtures

Wool fabrics were treated with 0.08M KCN in water, a 1:3 (v/v) mixture of acetone and water or a 1:3 (v/v) mixture of 2-propanol and water at 50 or 80°C. The wool fabrics were shrunk in two stages (at the KCN treatment and at air-drying) and the thickness of the fabrics was increased by the treatment in mixed solvent systems but the air permeability of the treated fabrics was increased because pin holes were formed at the interseptions of the warp and filling yarns. Scanning electron microscopic observations of the fabrics treated in mixed solvent systems showed that the cross sections of the fibers were much deformed and sometimes fibers adhered each other. Deep longitudinal striations were found at the surfaces of the fibers. Experiments with single wool fibers showed that the bilateral distribution of ortho-and paracortical cells was reversed in relation to the crimps of the fibers by the treatment: orthocortical cells located on the outer side of the crimps before the treatment were located on the inner side after the treatment, and the striations were preferentially distributed on the orthocortical side of the crimps. The changes in the structures of fabrics, yarns and fibers were the most significant when treated with KCN in aqueous 2-propanol in which both hydrophilic and hydrophobic bonds in wool were cleaved the most effectively so that wool fibers swelled the most in this system.

Photoemission study of evaporated CuInS2 thin films. II. Electronic surface structure

The electronic surface structure of evaporated CuInS2 films with different stoichiometries was investigated by photoelectron spectroscopy [x-ray and ultraviolet (XPS and UPS, respectively)]. The Fermi level position is observed to vary from EF−EV=1.3 eV for the In-rich to EF−EV=0.0 eV for the Cu-rich films. Valence band spectra of In-rich films can be interpreted according to theoretical band structure calculations in the literature. The electronic surface structure of Cu-rich films is determined by a CuS phase segregation which is displayed by an additional valence band emission structure. This phase is responsible for the semimetallic character of the Cu-rich films. A comparison of the energy level positions of Cu-rich and In-rich films is given according to a simple model. The removal of CuS by a KCN treatment is indicated by the complete recovery of the CuInS2 valence band structure. As a consequence highly efficient solar-to-energy conversion can be obtained from CuInS2 films of a wide as-deposited Cu-rich composition range.

Chemical modification of octopine dehydrogenase by thiol-specific reagents: evidence for the presence of an essential cysteine at the catalytic site

Thiol-specific reagents, p-cchloromercuricphenyl sulfonic acid (PCMS), 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) and N-ethylmaleimide (NEM), incubated with octopine dehydrogenase resulted in the loss of catalytic activity. The kinetic profile of PCMS inactivated enzyme showed that the reaction followed pseudo-first-order kinetics during the initial phase of inactivation. The reversal of enzyme activity was obtained by thiol-containing reagents. The loss of enzyme activity was prevented only by NADH and not by other substrates. The dissociation constant for NADH calculated from the decrease in the enzyme inactivation rate was 45 μM. Cyanolysis of the DTNB-modified enzyme with KCN led to the release of 5-thio-2-nitrobenzoate (TNB) accompanied by the formation of thio-cyano enzyme. By correlating the enzyme activity with the formation of thio-cyano derivative it was found that no activity was recovered after kCN treatment. These evidences clearly established the critical involvement of the thiol group in catalysis. Double inhibition studies with PCMs and NEM on octopine dehydrogenase showed that the inactivating reagents bind to the same functional thiol present at the catalytic center. pH-dependent inactivation by PCMS indicated that a group with a p K a value of 7.4 is involved in the loss of enzyme activity. These approaches suggested that at least one thiol group present at the coenzyme-binding domain is essential for the catalytic reaction of octopine dehydrogenase.

Characterization of a Polymer-Bound Palladium Acetate Catalyst and Studies on the Selective Hydrogenation of Dienes and Alkynes

Abstract Palladium(II) acetate has been anchored onto a copolymer support containing pyridyl and carboxyl groups. XPS studies showed the Pd 3d binding energies for the recovered catalyst to be less by 1 eV after being used in hydrogenation studies. However, x-ray studies and a chemical test based on KCN treatment failed to reveal any palladium oxide or palladium metal formation in the recovered catalyst. It is presumed that an acetate ligand is lost during hydrogenation, which could be the reason for the lowering of the palladium 3d binding energies in the recovered catalyst. Results of investigations of the hydrogenation of olefins and selectivity of the catalyst toward the hydrogenation of dienes and alkynes are presented. The loss of palladium due to leaching under the reaction conditions employed was found to be very low (<1%/cycle).

Protective effect of the dimer of 16,16-diMePGB1 against KCN-induced mitochondrial failure in hepatocytes.

The dimer and trimer of 16,16-dimethyl-15-dehydroprostaglandin B1 (16,16-diMePGB1) previously have been shown to have protective effects on mitochondrial function. To examine the potential mechanisms involved in protection against mitochondrial failure, we have studied the effects of the dimer of 16,16-diMe-PGB1 (dicalciphor) on mitochondrial function in hepatocytes exposed to KCN. Addition of micromolar concentrations of dicalciphor provided substantial protection against KCN-induced toxicity in a concentration- and time-dependent manner. Dicalciphor, however, had no effect on total or mitochondrial ATP losses in KCN-treated cells. The dimer prevented the marked loss of mitochondrial membrane potential (delta psi) and delta pH that occurs as a result of KCN treatment and prevented KCN-induced loading of phosphate in mitochondria. Furthermore, the dimer of 16,16-diMePGB1 also prevented KCN-induced mitochondrial and cellular swelling. These results demonstrate that dicalciphor protects against KCN-induced damage and that this protection is associated with regulation of specific mitochondrial ion transport functions.

Chromosome aberrations reduced in whole-body irradiated mice by pretreatment with cyanide

Male mice exposed to single, whole-body 60Co irradiation, were injected intraperitoneally with a non-toxic dose of KCN, 2 min or 20 min prior to irradiation. Bone-marrow cells were examined for chromatid breaks and chromosome aberrations (CA) at different times post-irradiation. The 2 min but not the 20 min treated mice had a marked reduction in chromatid breaks and chromosome aberrations. A study was made of mice exposed to 3.0 Gy (1.8 Gy/min), treated with KCN 2 min prior to irradiation and examined 5 min to 30 d post-irradiation. After 5 min there were no significant changes in frequency of CA. Subsequently, the incidence of CA in the KCN-treated group was reduced compared to the irradiated controls. By the 30th day, however, CA frequencies had returned to control levels in all groups. No effect of KCN treatment was observed in the white or red blood cells. The cytogenetic results were posited to be a function of the relative inhibition and recovery times of cyanide affected cytochrome oxidase, DNA synthesis, and ATP.

Glycine cytoprotection during lethal hepatocellular injury from adenosine triphosphate depletion

Glycine protects renal tubule cells from cell death during adenosine triphosphate (ATP) depletion. Although the liver plays a key role in glycine metabolism, information is lacking regarding the effects of glycine on lethal hepatocellular injury. Thus, the aim of this study was to determine the potential cytoprotective role of glycine during ATP depletion of rat hepatocytes. Metabolic inhibition with 2.5 mmol/L potassium cyanide (KCN) was used to produce ATP depletion. Hepatocyte suspensions treated with KCN had a 2-hour viability of 5.9% ± 2.0%, whereas cells treated with KCN in the presence of 2.0 mmol/L glycine had a viability of 80.2% ± 1.5%, which was virtually identical to controls (81.5% ± 1.9%). Glycine cytoprotection was dose dependent and amino acid specific. The cytoprotective effect of glycine was not mediated by protein synthesis, glycine mitochondrial metabolism, cytosolic acidosis, or preservation of either intracellular cellular glutathione or ATP. However, glycine did decrease total cellular proteolysis by 18% ± 2%, 25% ± 3%, and 33% ± 1% after 1, 2, and 3 hours of KCN treatment, respectively (P < 0.01). Inhibition of proteolysis by glycine was dose dependent over the same range as its cytoprotection. The results suggest that glycine protects against hepatocellular injury by inhibiting degradative proteolytic activity. It was concluded that proteolysis may be an important mechanism contributing to lethal injury of hepatocytes during ATP depletion.