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PubMed1989

A colorimetric method for the enzymatic analysis of gases: the determination of ethanol and formaldehyde vapors using solid alcohol oxidase.

A novel enzymatic approach to the direct determination of ethanol vapors in the gas phase is described. The system is composed of alcohol oxidase, peroxidase, and the color indicator 2,6-dichloroindophenol dispersed on microcrystalline cellulose (avicel). Simple devices are developed for the semiquantitative determination of ethanol in the breath. The devices are optimized to produce a sharp color change at a set time of 1 min for ethanol concentrations above the legal limit for driving (kinetic method) or a stable final color after 5 min (equilibrium method). Such color changes are detectable by simple visual observation. Using TLC plastic sheets and a transmittance densitometer, the system can also be used as a quantitative method for the determination of ethanol or formaldehyde vapors. Dehydrated enzymes may be useful for the analysis of hazardous gases.

2,6-Dichloroindophenol↗
PubMed1991

A simplified formaldehyde fixation and immunoprecipitation technique for studying protein-DNA interactions.

Using the single cell eukaryote Tetrahymena thermophila, a simple method was developed for studying protein-DNA associations by cross-linking proteins to DNA with formaldehyde and immunoprecipitating the solubilized chromatin fragments with a specific antiserum. The protocol uses crude antiserum and involves only three steps: cross-linking, shearing to solubilize the chromatin, and immunoprecipitation. Methods for optimizing certain critical parameters, such as fixation time and NaCl concentration, are described. The method is likely to be generally useful for a variety of nuclear antigens.

Animals↗
PubMed1988

A receptor for formaldehyde-treated serum albumin on human placental brush-border membrane.

Formaldehyde-treated serum albumin (f-Alb) is known to be taken up and degraded by sinusoidal liver cells via receptor-mediated endocytosis. We report that 125I-labeled f-Alb (125I-f-Alb) binding to human placental brush-border membranes also occurs. This binding reached equilibrium within 40 min at 37 degrees C. Kinetic studies demonstrated the presence of saturable binding with an apparent Kd of 2.1 micrograms of f-Alb/ml and a maximal binding of 2.3 micrograms/mg of membrane protein at pH 7.5. Maximal binding was observed at between pH 7.5 and 8.0. 125I-f-Alb binding to the membranes was little inhibited by a 1000-fold molar excess of ovalbumin, human apo-transferrin and native bovine serum albumin. No binding was observed with membranes which had been pretreated with proteinase or trypsin. This f-Alb receptor was extremely heat-stable, since the binding was not abolished even by pretreatment of the membranes at 78 degrees C for 30 min. EDTA, Ca2+ and Mg/4 had no effect on 125I-f-Alb binding, so the binding was independent of divalent cations. These data suggest that a receptor specific for f-Alb exists on human placental brush-border membranes of syncytial trophoblasts.

Cations, Divalent↗
PubMed1985

Purification of DNA from formaldehyde fixed and paraffin embedded human tissue.

The ability to isolate DNA from preserved human tissues would provide numerous experimental opportunities. In this report it is shown that DNA can be extracted from tissues prepared for routine histopathological examination (i.e., fixed with formaldehyde and embedded in paraffin). Although the extracted DNA is not intact, it is double stranded, cleavable with restriction endonucleases, and suitable for a variety of standard techniques used in molecular biology.

Carcinoma↗
PubMed1975

Influence of centrifugal sinus nerve activity on carotid body catecholamines: microphotometric analysis of formaldehyde-induced fluorescence.

The effects of centrifugal activity in the carotid sinus nerve (CSN) on the intensity of formaldehyde-induced fluorescence of carotid body were examined in cat. Measurements of intensity were obtained from 21 to 56 sections of each carotid body with a microscope photometer attached to a fluorescence microscope. Comparisons were made between the two carotid bodies removed from each cat. In one series of experiments, one carotid body (CSN intact) served as control, while the experimental carotid body was on the side on which centrifugal activity was increased by electrical stimulation of the peripheral end of the cut CSN. In a second series, centrifugal CSN activity was increased by hypoxemia; one CSN was transected (control) and the other was left intact (experimental). In untreated cats, fluorescence intensity was significantly higher on the side with increased centrifugal CSN activity. In cats treated with either MK486, which inhibits conversion of L-DOPA to dopamine, or reserpine, increased centrifugal CSN activity caused a significant decrease in intensity of type I cells. These findings indicate that centrifugal discharges regulate, in part, the synthesis and release of catecholamines by type I cells of the carotid body.

Carbidopa↗
PubMed1986

A priori predictions of the rotational constants for protonated formaldehyde and protonated methanol.

Protonated formaldehyde and protonated methanol are candidate interstellar molecules and models for classes of protonated oxygen compounds. Ab initio molecular orbital theory has been used to compute rotational constants to guide spectroscopic searches both in the laboratory and in space. The ab initio results are empirically corrected to account for systematic deficiencies in the theory and zero-point vibrational effects; they are expected to be accurate to approximately +/-2%. For H2COH+ the resultant constants are (in GHz) A = 194.3, B = 34.28, and C = 29.14; for H3COH2+ A = 103.7, B = 21.18, and C = 20.30.

Astronomical Phenomena↗
PubMed1982

The reaction of nitro-blue tetrazolium with d,l-L-tetrahydrofolate: The effect of pH, oxygen, formaldehyde and palladium (II).

d,l-L-Tetrahydrofolate (d,l-L-FH4) transfers two electrons to nitro-blue tetrazolium (NBT) in oxygen-free buffers to form the highly coloured nitro-blue formazan and oxidized folate. Both the rate and extent of this reaction are affected by the pH, the nature of the buffer and the oxygen concentration. Inhibition of both the rate and extent of this reaction in air-saturated solutions by superoxide dismutase (SOD) indicates that the superoxide anion is an intermediate in the reaction so that formazan can be produced by both superoxide independent and superoxide dependent routes in air-saturated solutions. In oxygen-free solutions several lines of evidence can be interpreted to mean that the reduced pteridine ring of tetrahydrofolate is the electron donor in the reaction with NBT. Ionization of the amide hydrogen of the pteridine ring and subsequent increase in electron density of that ring might explain the large increases observed in the rate and extent of the reaction of tetrahydrofolate with NBT as the pH increases. Formaldehyde reacts non-enzymatically with tetrahydrofolate to form a methylene bridge between nitrogens 5 and 10 of methylenetetrahydrofolate. This molecule is much less reactive with nitro-blue tetrazolium than tetrahydrofolate. Complexes formed between tetrahydrofolate and palladium (II) ions are also less reactive with NBT than the tetrahydrofolate alone. This result provides added evidence than palladium (II) ions interact with tetrahydrofolate at the nitrogen 5, nitrogen 10 site of the molecule.

Chemical Phenomena↗
PubMed1985

Formaldehyde complaint investigations in mobile homes by the Texas Department of Health.

The Texas Department of Health sampled for formaldehyde (HCHO) in 443 mobile homes between April, 1979, and May, 1982, at the request of the occupants. Colorimetric detector tubes were used most frequently for sample acquisition. HCHO concentrations ranged from below detectable limits (less than 0.5 ppm) to 8.0 ppm. Twenty-seven percent of homes one year of age or less had mean concentrations equal to or greater than 2.0 ppm while 11.5% of older homes had concentrations of 2.0 ppm or more. An inverse relationship is demonstrated between home age and HCHO level. The primary health complaints reported were headaches, respiratory discomfort, and ocular irritation. Evidence of a dose-response relationship was not present.

Air Pollutants↗
PubMed1986

Prolonged discharge of wide-dynamic-range spinal neurons evoked by formaldehyde injected in their cutaneous receptive fields.

In decerebrate, unanesthetized cats, subcutaneous injection of formaldehyde solutions (0.05 ml, 2.5%) in the receptive fields of spinal wide-dynamic-range neurons elicited an immediate and continuous discharge or burst activity in the neurons that lasted 10 to 55 min. This discharge was reduced by conditioning stimulation of the medial raphe nucleus and was completely abolished by morphine (3 mg/kg, i.v.). Low-threshold cutaneous mechanoreceptive neurons in the dorsal horn and dorsal column nuclei did not show a sustained response.

Animals↗
PubMed1984

Syntheses with isotopically labelled carbon. Methyl iodide, formaldehyde and cyanide.

Many of the uniquely labelled synthetic precursors currently employed in the design of sophisticated radiolabelled compounds have their origins in the field of hot atom chemistry. Particularly, the development during the past few years of automated, on-line synthetic procedures which combine the nuclear reaction, hot atom and classical chemistry, and rapid purification methods has allowed the incorporation of useful radionuclides into suitable compounds of chemical and biochemical interest. The application of isotopically labelled methyl iodide, formaldehyde, and cyanide anion as synthetic intermediates in research involving human physiology and nuclear medicine, as well as their contributions to other scientific methodology, is reviewed.

Amines↗
PubMed1986

RNA molecular weight determination by agarose gel electrophoresis using formaldehyde as denaturant: comparison of RNA and DNA molecular weight markers.

Reliable molecular weight measurements of RNA molecules as large as 4.0 X 10(6) dalton can be made on agarose gels containing 2.2 M formaldehyde as denaturant (Lehrach et al., 1977). Both eucaryotic and procaryotic ribosomal RNAs have generally been used as molecular weight markers. However, Maniatis et al. (1982) have suggested the use of restriction fragments of DNA as convenient molecular weight markers for RNA samples run in formaldehyde/agarose gels. This communication compares RNA and DNA molecular weight markers run under identical conditions.

Bacteriophage lambda↗
PubMed1986

Receptor mediated endocytosis of formaldehyde treated albumin, yeast invertase and chondroitin sulfate in suspensions of rat liver endothelial cells.

Isolated rat liver endothelial cells take up and degrade formaldehyde serum albumin (FSA), invertase and chondroitin sulfate (CS) efficiently. Degradation products start to appear in the medium after 5-30 min. Calcium was necessary for binding of invertase to the cells, but not for the two other ligands. Ammonia and monensin inhibited uptake as well as degradation of all three ligands, whereas leupeptin only inhibited the degradation of FSA and invertase. Uptake of CS was strongly inhibited in the presence of 1 microM FSA. The possibility that these two ligands bind to a common receptor is discussed.

Animals↗
PubMed1994

High-performance liquid chromatographic method for the simultaneous detection of malonaldehyde, acetaldehyde, formaldehyde, acetone and propionaldehyde to monitor the oxidative stress in heart.

Lipid peroxidation (LPO) is the oxidative deterioration of polyunsaturated fatty acids (PUFA) with the production of lipid hydroperoxides, cyclic peroxides, cyclic endoperoxides, and finally fragmentation to ketones and aldehydes (including malonaldehyde, MDA). Estimation of LPO through MDA formation measured by assaying thiobarbituric acid (TBA) reactive products remains the method of choice to study the development of oxidative stress in tissues. However, MDA estimation by TBA reactive products is non-specific and often gives erroneous results. In this report we describe a method using high-performance liquid chromatographic separation to estimate MDA, formaldehyde (FDA), acetaldehyde (ADA), acetone, and propionaldehyde (PDA), the degradation products of oxygen-derived free radicals (ODFR) and PUFA, as presumptive markers for LPO. Oxidative stress was induced in the tissue by perfusing an isolated rat heart with hydroxyl radical generating system (xanthine + xanthine oxidase + FeCl3 + EDTA). The coronary effluents were collected, derivatized with 2,4-dinitrophenylhydrazine (DNPH), and extracted with pentane. Aliquots of 25 microliters in acetonitrile were injected onto a Beckman Ultrasphere C18 (3 microns) column. The products were eluted isocratically with a mobile phase containing acetonitrile-water-acetic acid (40:60:0.1, v/v/v), measured at three different wavelengths (307, 325 and 356 nm) using a Waters M-490 multichannel UV detector and collected for gas chromatography-mass spectrometry (GC-MS) analysis. The peaks were identified by cochromatography with DNPH derivatives of authentic standards, peak addition, UV pattern of absorption at the three wavelengths, and by GC-MS. The retention items of MDA, FDA, ADA, acetone, and PDA were 5.3, 6.6, 10.3, 16.5, and 20.5 min, respectively. The results of our study indicated progressive increase of all five lipid metabolites as a function of the duration of ODFR perfusion. Hydroxyl radical scavengers, superoxide dismutase plus catalase, completely inhibited the formation of these lipid metabolites, demonstrating that the release of lipid metabolites from the isolated heart was indeed in response to oxidative stress. Since MDA, FDA, ADA, acetone, and PDA are the products of ODFR-PUFA interactions, this method allows proper estimation of LPO which monitors the oxidative stress developed during the reperfusion of ischemic myocardium.

Acetaldehyde↗
PubMed1989

Infrared spectrum of the complex of formaldehyde with carbon dioxide in argon and nitrogen matrices.

The complex of formaldehyde with carbon dioxide has been studied by infrared spectroscopy in argon and nitrogen matrices. The shifts relative to the free species show that the complex is weak and similar in argon and nitrogen. The results give evidence for T-shaped complexes, which are isolated in several configurations. Some evidence is also presented which indicates that, in addition to the two well-known sites in argon, carbon dioxide can be trapped in a third site.

Argon↗
PubMed1976

Formaldehyde induced DNA-protein crosslinks in Escherichia Coli.

Exposure of Escherichia coli to low doses of formaldehyde induces interstrand cross-links in the cellular DNA, at least 50% of which involve protein "bridges" between the DNA strands. The biological importance of these cross-links is suggested by both the high yield of formation and by the inability of some sensitive repair deficient mutants to completely remove cross-links and bound protein from the DNA during post treatment incubation.

Bacterial Proteins↗
PubMed1978

Biochemical analysis of damage induced in yeast by formaldehyde. I. Induction of single-strand breaks in DNA and their repair.

Analysis of sedimentation profiles in alkaline sucrose gradients showed that, through a metabolic process, formaldehyde (FA) produced single-strand breaks in DNA of exponential phase cells of haploid wild-type Saccharomyces cerevisiae. The production of this type of lesion was dose-dependent. Strains defective in excision-repair of pyrimidine dimers induced by ultraviolet (UV) irradiation showed a reduced capacity to undergo single-stand breaks after treatment with FA. This indicates that the repair pathways of damage induced by UV and FA share a common step. Post-treatment incubation of wild-type cells in growth medium indicate a lag in cell division during which a slow recovery of DNA with a normal size was observed.

DNA↗
PubMed1979

Survival and herpes virus production of normal and xeroderma pigmentosum fibroblasts after treatment with formaldehyde.

The survival of excision-deficient and of excision-proficient (variant) skin fibroblasts from xeroderma pigmentosum (XP) donors was about 5 times and twice, respectively, more sensitive to formaldehyde (FA) treatment than that of skin fibroblasts from healthy and XP heterozygote donors. The capacity of FA-treated host cells to further support Herpes virus (HSV) replication was also more sensitive to FA in XP12BE (group A) than in normal (KD) cells. An important recovery of this capacity occurred in both cell types when they were infected at increasing times (up to 36 h) after FA treatment. This contrasts with the decreasing capacity observed in XP12BE when similarly infected at increasing times after exposure to ultraviolet. In addition, the survival of FA-treated HSV was comparable in KD and XP12BE cells, whereas that of UV-irradiated HSV was much lower in XP12BE than in KD cells.

Cell Line↗