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PubMed1979

Reaction of formaldehyde with calf-thymus nucleohistone.

The reactions of formaldehyde with calf thymus nucleohistone were analyzed in the following ways: measurement with fluorescamine of the decrease in primary amino groups resulting from hydroxymethylation and crosslinking reactions, measurement with dodecylsulphate-gel electrophoresis of formation of histone oligomers, measurement of fixation of histones to the DNA in nucleohistone, and measurement of changes in the circular dichroism spectrum in the region of 250--300 nm. In the presence of formaldehyde, the primary amino groups of histones decreased very rapidly, attaining an equilibrium within 60 min, and successively intermolecular crosslinks were also formed between histone molecules, the resulting dimers and oligomers being separable by dodecylsulfate-gel electrophoresis. Whereas the fixation reaction proceeded much more slowly. The extent of fixation could be measured more accurately by dodecylsulfate/sucrose centrifugation analysis than by sulfuric acid extraction. After removal of formaldehyde from the reaction mixture, the fraction of masked amino groups decreased, perhaps due to the reverse reaction, but the extent of fixation of histones continued to increase with time. No specificity was observed among five molecular species of histones in the fixation reaction. With increase in formaldehyde concentration, the ellipticity of nucleohistone decreased to a minimum with about 0.4% formaldehyde, and then increased.

Amino Acids↗
PubMed1989

The role of sodium ions in methanogenesis. Formaldehyde oxidation to CO2 and 2H2 in methanogenic bacteria is coupled with primary electrogenic Na+ translocation at a stoichiometry of 2-3 Na+/CO2.

Cell suspensions of Methanosarcina barkeri were found to oxidize formaldehyde to CO2 and 2H2 (delta G0' = -27 kJ/mol CO2), when methanogenesis was inhibited by 2-bromoethanesulfonate. We report here that this reaction is coupled with (a) primary electrogenic Na+ translocation at a stoichiometry of 2-3 Na+/CO2, (b) with secondary H+ translocation via a Na+/H+ antiporter and (c) with ATP synthesis driven by an electrochemical proton potential. This is concluded from the following findings. Formaldehyde oxidation to CO2 and 2H2 was dependent on Na+ ions, 2-3 mol Na+/mol formaldehyde oxidized were extruded. Na+ translocation was inhibited by Na+ ionophores, but not affected by protonophores of Na+/H+ antiport inhibitors. Formaldehyde oxidation was associated with the build up of a membrane potential in the order of 100 mV (inside negative), which could be dissipated by sodium ionophores rather than by protonophores. Formaldehyde oxidation was coupled with ATP synthesis, which could be inhibited by Na+ ionophores, Na+/H+ antiport inhibitors, by protonophores and by the H+-translocating-ATP-synthase inhibitor, dicyclohexylcarbodiimide. With cell suspensions of Methanobacterium thermoautotrophicum similar results were obtained.

Adenosine Triphosphate↗
PubMed1990

Quantitative cancer risk estimation for formaldehyde.

Of primary concern are irreversible effects, such as cancer induction, that formaldehyde exposure could have on human health. Dose-response data from human exposure situations would provide the most solid foundation for risk assessment, avoiding problematic extrapolations from the health effects seen in nonhuman species. However, epidemiologic studies of human formaldehyde exposure have provided little definitive information regarding dose-response. Reliance must consequently be placed on laboratory animal evidence. An impressive array of data points to significantly nonlinear relationships between rodent tumor incidence and administered dose, and between target tissue dose and administered dose (the latter for both rodents and Rhesus monkeys) following exposure to formaldehyde by inhalation. Disproportionately less formaldehyde binds covalently to the DNA of nasal respiratory epithelium at low than at high airborne concentrations. Use of this internal measure of delivered dose in analyses of rodent bioassay nasal tumor response yields multistage model estimates of low-dose risk, both point and upper bound, that are lower than equivalent estimates based upon airborne formaldehyde concentration. In addition, risk estimates obtained for Rhesus monkeys appear at least 10-fold lower than corresponding estimates for identically exposed Fischer-344 rats.

Air Pollutants↗
PubMed2002

Purification and characterization of formate oxidase from a formaldehyde-resistant fungus.

A formate oxidase activity was found in the crude extract of a formaldehyde-resistant fungus isolated from soil. The fungus was classified and designated as Aspergillus nomius IRI013, which could grow on a medium containing up to 0.45% formaldehyde and consumed formaldehyde completely. The specific activity of formate oxidase in the extract of the fungus grown on formaldehyde was found to be considerably higher than that in the extracts of the fungus grown on formate and methanol. Formate oxidase from the fungus grown on formaldehyde was purified to homogeneity. The enzyme had a relative molecular mass of 100000 and was composed of two apparently identical subunits that had a relative molecular mass of 59000. The enzyme showed the highest activity using formate as substrate. Hydrogen peroxide was formed during the oxidation of formate. The Michaelis constant for formate was 15.9 mM; highest enzyme activity was found at pH 4.5-5.0. The enzyme activity was strongly inhibited by NaN(3), p-chloromercuribenzoate and HgCl(2).

Aspergillus↗
PubMed1998

Formation of formaldehyde and peroxides by air oxidation of high purity polyoxyethylene surfactants.

Ethoxylated alcohols are non-ionic surfactants. The majority are used in household cleaners, laundry products, toiletries and in industrial and institutional cleaners. In previous studies, an ethoxylated non-ionic surfactant of technical quality showed allergenic activity in guinea pig experiments. Chemical analysis revealed a content of formaldehyde, a well-known contact allergen, and peroxides in the surfactant. Most cases of occupational contact dermatitis are considered to be of irritant origin, caused by contact with water and surfactants, but if allergenic autoxidation products can be formed, allergic contact dermatitis cannot be excluded. The sensitizing potential of a chemically defined high purity ethoxylated alcohol was investigated and oxidation under various storage and handling conditions was studied for this and a homologous product. The pure surfactant showed no significant allergenic activity on predictive testing in guinea pigs. When ethoxylated alcohols were stored in the refrigerator, their deterioration was limited. At room temperature, their content of peroxides and formaldehyde increased with time. Levels of formaldehyde above those capable of causing positive patch test reactions were found. Since such surfactants have wide applications, resulting exposure to formaldehyde could be more frequent than is generally realized, contributing to persistence of dermatitis in individuals allergic to formaldehyde.

Aerobiosis↗
PubMed1986

Monoclonal antibodies to GFAP epitopes available in formaldehyde fixed tissue.

We have recently demonstrated that one of our monoclonal antibodies (MAB's) to glial fibrillary acidic protein (GFAP) recognizes an epitope on this molecule which is to a large degree blocked during fixation with formaldehyde or crosslinking with Dithiobis (Succinimidyl) Propionate (DTSP). This was shown to be due to the crossbinding of a single or a number of proteins to the GFAP and is not due to a change in the epitope on GFAP induced by the fixation itself. In an attempt to produce further MAB's capable of recognizing epitopes on the GFAP molecule available following formaldehyde fixation, we immunized BALB-C mice with cytoskeletal preparations of human glioma cells which contain GFAP where the blocking protein or proteins were crossbound by DTSP or formaldehyde to the GFAP. Following fusion of the spleen lymphocytes to Sp 2/0 myeloma cells we have cloned hybridomas which produce antibodies that recognize GFAP in formaldehyde fixed tissues. This method presents the antigen in its native "fixed" state for the mouse's immune system and avoids the production of MAB's which (although excellent for immunochemical studies) do not recognize any epitopes available on the molecule in question in formaldehyde fixed tissues. Antibodies so produced are of great interest in routine pathology where most tissues are still, unfortunately, undiscriminately fixed in formalin. The results also show that GFAP varies immunologically in different species (i.e. human v. rat/mouse) and confirm that the GFAP of the PNS is immunologically distinct and/or associated with different proteins from that found in the CNS.

Acetone↗
PubMed2004

Protein cross-linkage induced by formaldehyde derived from semicarbazide-sensitive amine oxidase-mediated deamination of methylamine.

Semicarbazide-sensitive amine oxidase (SSAO) catalyzes the conversion of methylamine to formaldehyde. This enzyme is located on the surface of the cytoplasmic membrane and in the cytosol of vascular endothelial cells, smooth muscle cells, and adipocytes. Increased SSAO activity has been found in patients with diabetes mellitus, chronic heart failure, and multiple types of cerebral infarcts and is associated with obesity. Increased SSAO-mediated deamination may contribute to protein deposition, the formation of plaques, and inflammation, and thus may be involved in the pathophysiology of chronic vascular and neurological disorders, such as diabetic complications, atherosclerosis, and Alzheimer's disease. In the present study, we demonstrate the induction of cross-linkage of formaldehyde with the lysine moiety of peptides and proteins. Formaldehyde-protein adducts were reduced with sodium cyanoborohydride, hydrolyzed in hydrochloric acid, and the amino acids in the hydrolysates were derivatized with fluorenylmethyl chloroformate and then identified with high-performance liquid chromatography. We further demonstrate that incubation of methylamine in the presence of SSAO-rich tissues, e.g., human brain meninges, results in formaldehyde-protein cross-linkage of particulate bound proteins as well as of soluble proteins. This cross-linkage can be completely blocked by a selective inhibitor of SSAO. Our data support the hypothesis that the SSAO-induced production of formaldehyde may be involved in the alteration of protein structure, which may subsequently cause protein deposition associated with chronic pathological disorders.

Amine Oxidase (Copper-Containing)↗
PubMed1972

Sporostatic and sporocidal properties of aqueous formaldehyde.

Aqueous formaldehyde is shown to exert both sporostatic and sporocidal effects on Bacillus subtilis spores. The sporostatic effect is a result of the reversible inhibition of spore germination occasioned by aqueous formaldehyde; the sporocidal effect is due to temperature-dependent inactivation of these spores in aqueous formaldehyde. The physicochemical state of formaldehyde in solution provides a framework with which to interpret both the sporostatic and sporocidal properties of aqueous formaldehyde.

Bacillus subtilis↗
PubMed1985

Sodium ions and an energized membrane required by Methanosarcina barkeri for the oxidation of methanol to the level of formaldehyde.

Methanogenesis from methanol by cell suspensions of Methanosarcina barkeri was inhibited by the uncoupler tetrachlorosalicylanilide. This inhibition was reversed by the addition of formaldehyde. 14C labeling experiments revealed that methanol served exclusively as the electron acceptor, whereas formaldehyde was mainly oxidized to CO2 under these conditions. These data support the hypothesis (M. Blaut and G. Gottschalk, Eur. J. Biochem. 141: 217-222, 1984) that the first step in methanol oxidation depends on the proton motive force or a product thereof. Cell extracts of M. barkeri converted methanol and formaldehyde to methane under an H2 atmosphere. Under an N2 atmosphere, however, formaldehyde was disproportionated to CH4 and CO2, whereas methanol was metabolized to a very small extent only, irrespective of the presence of ATP. It was concluded that cell extracts of M. barkeri are not able to oxidize methanol. In further experiments, the sodium dependence of methanogenesis and ATP formation by whole cells was investigated. Methane formation from methanol alone and the corresponding increase in the intracellular ATP content were strictly dependent on Na+. If, in contrast, methanol was utilized together with H2, methane and ATP were synthesized in the absence of Na+. The same is true for the disproportionation of formaldehyde to methane and carbon dioxide. From these experiments, it is concluded that in M. barkeri, Na+ is involved not in the process of ATP synthesis but in the first step of methanol oxidation.

Adenosine Triphosphate↗
PubMed2001

Membrane-associated quinoprotein formaldehyde dehydrogenase from Methylococcus capsulatus Bath.

A membrane-associated, dye-linked formaldehyde dehydrogenase (DL-FalDH) was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 micromol of Cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. Soluble NAD(P)(+)-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane monooxygenase (Tate and Dalton, Microbiology 145:159-167, 1999; Vorholt et al., J. Bacteriol. 180:5351-5356, 1998). The membrane-associated enzyme is a homotetramer with a subunit molecular mass of 49,500 Da. UV-visible absorption, electron paramagnetic resonance, and electrospray mass spectrometry suggest the redox cofactor of the DL-FalDH is pyrroloquinoline quinone (PQQ), with a PQQ-to-subunit stochiometry of approximately 1:1. The enzyme was specific for formaldehyde, oxidizing formaldehyde to formate, and utilized the cytochrome b(559/569) complex as the physiological electron acceptor.

Aldehyde Oxidoreductases↗
PubMed1990

Fundamental study on the mechanism of DNA degradation in tissues fixed in formaldehyde.

The mechanism of DNA degradation and its clinical applications were examined. When purified lambda phage and extracted liver DNA were fixed in phosphate buffered formaldehyde, the DNA did not degrade, but there was incomplete digestion with endonuclease. Rat liver tissues were fixed under various conditions and DNA extracted. Immediate fixation with buffered formaldehyde at low temperature, or the addition of EDTA to buffered formaldehyde blocked the DNA degradation. Analysis of pulsed field gel electrophoresis also showed that DNA was degraded before extraction. These results suggest that tissue nuclease has an important role in DNA degradation in tissue. Furthermore, formaldehyde fixation at low temperature, which may take time and which decreases slightly the staining capacity, is useful for the extraction of intact DNA. For clinical application, the detection of provirus was examined. Genomic DNA was extracted from a necropsy sample of adult T cell leukaemia fixed in formaldehyde; human T cell leukaemia virus type-I (HTLV-I) provirus was successfully detected by Southern blotting.

Animals↗
PubMed1990

Nasal mucosa in workers exposed to formaldehyde: a pilot study.

This study evaluates the histological changes, especially the presence of possible precancerous lesions, in the nasal mucosa of workers exposed to formaldehyde. Nasal biopsies of 37 workers occupationally exposed to formaldehyde for more than five years and 37 age matched referents showed a higher degree of metaplastic alterations in the former group. In addition, three cases of epithelial dysplasia were observed among the exposed. These results indicate that formaldehyde may be potentially carcinogenic to man. Combination of this finding with the inconclusive epidemiological studies suggests that formaldehyde is a weak carcinogen and that occupational exposure to formaldehyde alone is insufficient to induce nasal cancer.

Adult↗
PubMed1993

Distribution of radioactivity from 14C-formaldehyde in pregnant mice and their fetuses.

The distribution of 14C after the administration of 14C-formaldehyde was studied in pregnant mice by a whole body low temperature autoradiographic technique. The concentrations of formaldehyde and its metabolites in maternal and fetal blood and tissues were determined in unsectioned tissues by liquid scintillation spectrophotometry. The binding of 14C from 14C-formaldehyde to cells and DNA in maternal and fetal mouse liver was also measured. Radioactivity of 14C deriving from 14C-formaldehyde was found immediately after injection, and showed strong accumulation and retention three hours after injection. The organs that had high concentrations at all studied survival intervals were maternal liver, intestinal mucosa, bone marrow, kidneys, and salivary glands. Considerable amounts of radioactivity were found in the fetuses at six hours after injection, and the concentrations were almost the same as in the maternal tissues. The elimination of 14C-formaldehyde and metabolites from the placenta and fetus occurred more slowly than from maternal tissue.

Animals↗
PubMed1995

Increased IgE antiovalbumin level in mice exposed to formaldehyde.

The effect of formaldehyde exposure on the sensitization of mice to ovalbumin was investigated. Significantly increased IgE antiovalbumin titers were found in mice sensitized intranasally to ovalbumin and exposed for 10 days to 2 mg/m3 of formaldehyde. In contrast, mice not exposed to formaldehyde or exposed once a week produced low levels of this antibody. The exposure of mice, sensitized intraperitoneally with ovalbumin, to formaldehyde did not increase sensitization. It was concluded that formaldehyde facilitates sensitization of mice to ovalbumin by changes that occur in the respiratory tract.

Allergens↗
PubMed1988

Release of formaldehyde from dental composites.

Polymeric composite materials may contain releasable degradation products or unreacted constituents. Release of formaldehyde from nine different composites was investigated by means of HCHO-hydrazone derivative analyzed with high-performance liquid chromatography. Formation of formaldehyde was found in all the investigated materials. The highest concentrations were observed in specimens polymerized in contact with air. A correlation coefficient, r = 0.83, was found between released formaldehyde and the thickness of the unpolymerized surface inhibition layer. The formaldehyde concentrations were reduced when the inhibition layer was removed prior to testing. A continuous release of formaldehyde was evident during the first ten days. The release decreased with time, but was still detectable after 115 days.

Chromatography, High Pressure Liquid↗
PubMed1990

Pathology and cell proliferation induced by intra-nasal instillation of aldehydes in the rat: comparison of glutaraldehyde and formaldehyde.

The relative toxicities of formaldehyde and glutaraldehyde to the rat nasal epithelium were determined following intra-nasal instillation of aqueous solutions of these compounds into one nostril of male Fischer 344 (F-344) rats. Lesions identical in appearance to those resulting from acute inhalation exposure to formaldehyde were induced by both compounds in a concentration-dependent manner. Treatments included India ink or 1 M methylene blue (for instillation deposition studies); sterile saline (vehicle control); 40, 200, 400, and 800 mM formaldehyde; and 10, 20, and 40 mM glutaraldehyde. Dye-treated rats were sacrificed immediately, and nasal passages were examined to determine the localization of instilled materials. Three days after treatment, all other animals received a single ip injection of 5-bromo-2'-deoxyuridine 2 hr prior to sacrifice, and the nasal passages were prepared for histopathology and cell proliferation studies. While sterile saline and 10 mM glutaraldehyde induced no significant epithelial changes, 20 and 40 mM glutaraldehyde induced extensive lesions in the treated side of the nose. Aldehyde-induced lesions included inflammation, epithelial degeneration, respiratory epithelial hypertrophy, and squamous metaplasia in association with marked increases (3-8-fold) in labeling index for both compounds. Formaldehyde induced similar lesions but required concentrations of 200 mM or more to elicit a toxic response. Thus, glutaraldehyde is approximately an order of magnitude more toxic to the nasal epithelium than formaldehyde. These studies also indicate that the nose is very resistant to the aldehydes studied, requiring instillation of millimolar concentrations before toxic responses occurred.

Administration, Intranasal↗
PubMed1987

Formaldehyde sensitivity of a GFAP epitope, removed by extraction of the cytoskeleton with high salt.

We have used cytofluorometry to examine the formaldehyde sensitivity of the binding of a monoclonal antibody (MAB) to its epitope on glial fibrillary acidic protein in human malignant glioma cells in culture. When acetone-extracted whole cells or cytoskeletons, made by extracting with Triton in stabilizing buffer (Tsb), are fixed with formaldehyde, binding of the MAB Tp-GFAP1 to GFAP is abolished or greatly reduced. Fixation with the bifunctional protein crosslinking reagent dithiobis (succinimidyl propionate) (DTSP) has the same negative effect as formaldehyde. If cytoskeletons are further extracted with Tsb containing 250 mM ammonium sulfate (Thsb), fixation with formaldehyde or DTSP has reduced or no effect on the binding of Tp-GFAP1. The data are consistent with the hypothesis that aldehyde sensitivity of Tp-GFAP1 is caused by the crosslinking of a second protein to GFAP that blocks the binding of the MAB to its epitope. This putative blocking protein is part of the Triton-insoluble cytoskeleton, but it begins to be solubilized in 50 mM ammonium sulfate and it is largely removed in 250 mM ammonium sulfate (Thsb). SDS-PAGE shows that extraction with Thsb also removes a large number of proteins from the cytoskeleton, one of which could be the blocking protein. A second antibody to GFAP, designated Tp-GFAP3, was raised against cytoskeletons which had been fixed with DTSP and in which the epitope recognized by Tp-GFAP1 was presumably blocked. Tp-GFAP3 is not sensitive to fixation by either formaldehyde or DTSP.

Antibodies, Monoclonal↗
PubMedDate not supplied

Control of workers' exposure to airborne endotoxins and formaldehyde during the use of metalworking fluids.

The study evaluated the effects of triazine use and machine enclosure on workers' exposure to bacteria, endotoxins, and formaldehyde in the use of metalworking fluids (MWF). Concentrations of triazine and bacterial contaminants were monitored in bulk samples of MWF from two machines in one workplace. One of the machines was used normally; triazine was added to the other when needed. Air sampling was used to estimate workers' exposure to endotoxins at 18 workplaces near enclosed and open machines. Concentrations of triazine in MWF and formaldehyde in the air were measured. Some recirculating local exhaust ventilation systems were also tested. The endotoxin and bacteria concentrations in the biocide test of MWF rapidly increased when the biocide levels decreased below 500 ppm. Airborne concentrations of endotoxins were substantially lower near enclosed machines than near open ones. Concentrations of airborne formaldehyde were below the Finnish occupational exposure limit at the existing levels of triazine in MWF. Concentrations of triazine in MWF correlated well with those of formaldehyde in the air near the machines (correlation coefficient r=.69). The results showed that the triazine levels in MWF should continuously be kept high enough (>500 ppm) to prevent workers' exposure to endotoxins and bacteria. Overdosing with triazine, however, should be avoided, so that the levels of airborne formaldehyde remain low. Triazine levels in MWF can be followed by the method described in this article. Workers' exposure to contaminants of MWF can be reduced substantially by enclosing the machines and equipping them with local exhausts.

Aerosols↗