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PubMed1979

Application of the aluminum-formaldehyde (ALFA) histofluorescence method for demonstration of peripheral stores of catecholamines and indolamines in freeze-dried paraffin-embedded tissue, cryostat sections and whole-mounts.

This paper describes new procedures for highly sensitive visualization of monoamine stores in peripheral tissues, taking advantage of the recently introduced aluminum-catalysed formaldehyde (ALFA) reaction. The tissues are exposed to an aluminum sulphate solution (with or without formaldehyde fixation) in a perfusion and/or immersion step, followed by formaldehyde vapour treatment. Procedures are described for freeze-dried, paraffin embedded tissue, cryostat sections and whole mount preparations. For all these tissue preparations the ALFA method gives a highly sensitive and precise demonstration of catecholamine-containing neurons and 5-HT-containing cells in a variety of peripheral tissues. For freeze-dried tissue and cryostat sections the ALFA method represents an improvement in comparison with other available methods. This is particularly noticeable for the very delicate adrenergic nerves in such organs as the thyroid, ovary, pancreas and the gastrointestinal tract.

Aluminum↗
PubMed1992

Purification and characterization of an NAD(+)-linked formaldehyde dehydrogenase from the facultative RuMP cycle methylotroph Arthrobacter P1.

When Arthrobacter P1 is grown on choline, betaine, dimethylglycine or sarcosine, an NAD(+)-dependent formaldehyde dehydrogenase is induced. This formaldehyde dehydrogenase has been purified using ammonium sulphate fractionation, anion exchange- and hydrophobic interaction chromatography. The molecular mass of the native enzyme was 115 kDa +/- 10 kDa. Gel electrophoresis in the presence of sodium dodecyl sulphate indicated that the molecular mass of the subunit was 56 kDa +/- 3 kDa, which is consistent with a dimeric enzyme structure. After ammonium sulphate fractionation the partially purified enzyme required the addition of a reducing reagent in the assay mixture for maximum activity. The enzyme was highly specific for its substrates and the Km values were 0.10 and 0.80 mM for formaldehyde and NAD+, respectively. The enzyme was heat-stable at 50 degrees C for at least 10 min and showed a broad pH optimum of 8.1 to 8.5. The addition of some metal-binding compounds and thiol reagents inhibited the enzyme activity.

Aldehyde Oxidoreductases↗
PubMed1982

Beware of formaldehyde in disguise.

The toxic potential of formaldehyde has recently been widely discussed, including the consequences of its release from certain building materials. The action of methenamine, used in the treatment of urinary infections, is based on the release of formaldehyde in the body. Various aspects of formaldehyde toxicity are discussed as a basis for reevaluation of methenamine and reconsideration of its safety.

Biotransformation↗
PubMedDate not supplied

Differentiating the effects of microwave and heat on tissue proteins and their crosslinking by formaldehyde.

Alkaline phosphatase activity in mouse liver blocks, cooled by an ice-bath, decreased by 50% in 5 min of microwave irradiation (280 W). This loss of protein tertiary structure has been mirrored by ultrastructural changes in the same tissue. Microwave irradiation did not produce cleavage or polymerization of lysozyme or haemoglobin. Protein formaldehyde reaction mixtures produced protein polymers between 0 degree and 40 degrees C which could be separated by SDS-polyacrylamide gel electrophoresis. Microwave irradiation of lysozyme or haemoglobin plus formaldehyde on ice-bath up to 30 min produced a similar electrophoretic pattern. When lysozyme or haemoglobin plus formaldehyde was heated to 60 degrees C for 30 min, the protein polymers migrated faster on electrophoresis, suggesting a smaller hydrodynamic volume than expected due to intramolecular crosslink formation, not opened up under the conditions of electrophoresis.

Alkaline Phosphatase↗
PubMed1984

Comparative study of infectious and formaldehyde-inactivated tick-borne encephalitis virus particles.

The structure and properties of infectious and formaldehyde-treated particles of tick-borne encephalitis virus, concentrated and purified by chromatography on macroporous glass, were studied. In addition to complete virions, such preparations contain some incomplete forms that differ in density, morphology and protein composition (incomplete forms do not contain nucleocapsid protein). The physico-chemical analysis of complete virions showed that formaldehyde treatment causes a) the formation of glycoprotein dimers and b) a portion of nucleocapsid protein to become tightly cross-linked with viral RNA. Formaldehyde treatment of incomplete forms resulted only in the formation of a small amount of glycoprotein dimers. Incomplete forms and glycoprotein extracted from inactivated preparations had protective and antigenic activity.

Antibodies, Viral↗
PubMed1994

Archean geochemistry of formaldehyde and cyanide and the oligomerization of cyanohydrin.

The sources and speciation of reduced carbon and nitrogen inferred for the early Archean are reviewed in terms of current observations and models, and known chemical reactions. Within this framework hydrogen cyanide and cyanide ion in significant concentration would have been eliminated by reaction with excess formaldehyde to form cyanohydrin (glycolonitrile), and with ferrous ion to form ferrocyanide. Natural reactions of these molecules would under such conditions deserve special consideration in modeling of primordial organochemical processes. As a step in this direction, transformation reactions have been investigated involving glycolonitrile in the presence of water. We find that glycolonitrile, formed from formaldehyde and hydrogen cyanide or cyanide ion, spontaneously cyclodimerizes to 4-amino-2-hydroxymethyloxazole. The crystalline dimer is the major product at low temperature (approximately 0 degrees C); the yield diminishes with increasing temperature at the expense of polymerization and hydrolysis products. Hydrolysis of glycolonitrile and of oxazole yields a number of simpler organic molecules, including ammonia and glycolamide. The spontaneous polymerization of glycolonitrile and its dimer gives rise to soluble, cationic oligomers of as yet unknown structure, and, unless arrested, to a viscous liquid, insoluble in water. A loss of cyanide by reaction with formaldehyde, inferred for the early terrestrial hydrosphere and cryosphere would present a dilemma for hypotheses invoking cyanide and related compounds as concentrated reactants capable of forming biomolecular precursor species. Attempts to escape from its horns may take advantage of the efficient concentration and separation of cyanide as solid ferriferrocyanide, and most directly of reactions of glycolonitrile and its derivatives.

Acetonitriles↗
PubMed1997

The effect of formaldehyde on the growth of Candida diddensii 74-10 and Candida tropicalis R-70.

The effects of formaldehyde on the growth of two strains of fodder yeasts Candida diddensii 74-10 and Candida tropicalis R-70 were investigated using the method of continuous cultivation under conditions of carbon limitation and at dilution rates of 0.1/h and 0.25/h. The results indicate that formaldehyde induces a decrease in the yield of biomass, but stimulates the synthesis of protein and RNA. The authors studied the activities of the following enzymes: NADPH-linked glutamate dehydrogenase, NADH-linked glutamate dehydrogenase, alanine dehydrogenase, glutamine synthetase, and glutamate synthase, which are utilized in nitrogen metabolism. The data obtained showed an increase in the activity of the glutamate dehydrogenase pathway of ammonium assimilation. It was also established that formaldehyde caused considerable changes in the micro-organisms at the higher dilution rate.

Biomass↗
PubMed1994

Metabolism of dichloromethane (methylene chloride) to formaldehyde in human erythrocytes: influence of polymorphism of glutathione transferase theta (GST T1-1).

Human hemolysate was incubated in vitro with different concentrations of dichloromethane (methylene chloride). The resulting enzymatically mediated production of formaldehyde was determined by two independent analytical methods (Nash-reaction/colorimetry or HPLC). The formation of formaldehyde from dichloromethane is influenced by the polymorphism of glutathione-S-transferase (GST) Theta, in the same way as the metabolism of methyl bromide, methyl chloride, methyl iodide and ethylene oxide. Three quarters of the population ("conjugators") possess, whereas one quarter ("non-conjugators") lack this enzyme activity in human erythrocytes. The metabolism of dichloromethane in hemolysate in vitro can be described by Michaelis-Menten kinetics; for an individual with high GST T1-1 enzyme activity, the maximum velocity of formaldehyde production was calculated to be approximately 180 pmol/min per mg Hb, the kM being approximately 60 mM dichloromethane. Carcinogenicity of dichloromethane in long-term inhalation exposure of rodents has been attributed to metabolism of the compound via the GST-dependent pathway. Extrapolation of the results to humans for risk assessment should consider the newly discovered polymorphic enzyme activity of GST Theta. Furthermore, the possible existence of a "high-risk" population among humans should be considered in epidemiological research.

Erythrocytes↗
PubMed1997

Asthma and the indoor environment: the significance of emission of formaldehyde and volatile organic compounds from newly painted indoor surfaces.

As a part of the worldwide European Community Respiratory Health Survey, possible relations between asthma and emissions from newly painted indoor surfaces were studied. The participants (n = 562) answered a self-administered questionnaire, with questions on symptoms and indoor exposures, including indoor painting, during the last 12 months. The participants also underwent a structured interview, spirometry, peak flow measurements at home (PEF), methacholine provocation test for bronchial hyper-responsiveness (BHR), and skin prick tests. In addition, serum concentration of eosinophilic cationic protein (S-ECP), blood eosinophil count (B-EOS), and total immunoglobulin E (S-IgE) were measured. Current asthma was defined as a combination of BHR and at least one asthma-related symptom (wheezing and attacks of breathlessness). The information gathered on indoor painting was compared with exposure measurements of formaldehyde and volatile organic compounds (VOC) performed in a selected sample of the dwellings (n = 62). Relations between exposures, asthma and clinical signs were calculated by multiple linear or logistic regression, adjusting for possible influence of age, gender and tobacco smoking. The prevalence of asthma was increased among subjects with domestic exposure to newly painted surfaces (OR = 1.5; 95% CI 1.0-2.4), particularly newly painted wood details (OR = 2.3; 95% CI 1.2-4.5) and kitchen painting (OR = 2.2; 95% CI 1.1-4.5). Moreover, blood eosinophil concentrations were significantly elevated among subjects living in newly painted dwellings. A significantly increased prevalence of symptoms related to asthma, but not BHR, was observed in relation to workplace exposure to newly painted surfaces. The indoor concentration of aliphatic compounds (C8-C11), butanols, and 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) was significantly elevated in newly painted dwellings. The total indoor VOC was about 100 micrograms/m3 higher in dwellings painted in the last year. A significant increase in formaldehyde concentration was observed in dwellings with newly painted wood details. Our results indicate that exposure to chemical emissions from indoor paint is related to asthma, and that some VOCs may cause inflammatory reactions in the airways. To improve asthma management, and to counteract the increasing frequency of asthma, the significance of the indoor environment should not be neglected. Our study suggests that the contribution of emissions from paint to indoor concentrations of formaldehyde and VOCs should be as low as possible.

Adult↗
PubMed1993

Biophysical properties of the gelatin-resorcin-formaldehyde/glutaraldehyde adhesive.

Refixation of dissected aortic layers with gelatin-resorcin-formaldehyde/glutaraldehyde (GRFG) adhesive represents a new option in the surgical treatment of aortic dissection. Because of its ability to reinforce the delicate structures of the acutely dissected aortic wall, GRFG has been used increasingly in recent years. However, the biomechanical properties of the adhesive are still unclear, and little is known regarding the optimal mode of its application. In an ex vivo study, aortic specimens from sheep were glued with warm (45 degrees C) adhesive under wet and dry conditions and submitted to defined degrees of compression (5 Newtons [N], 20 N). Bonded specimens were retracted to assess tensile strength and elasticity compared with two reference adhesives: cyanoacrylate gel and fibrin glue. Gelatin-resorcin-formaldehyde/glutaraldehyde and cyanoacrylate gel showed similar results at 5 N. Both provided better adhesion when applied under dry conditions (GRFG 5 N: dry, 3.5 +/- 1.6 N/cm2; wet, 1.4 +/- 1.0 N/cm2; cyanoacrylate gel 5 N: dry, 4.8 +/- 1.8 N/cm2; wet, 3.2 +/- 1.3 N/cm2). At 20 N, GRFG tensile strength was significantly increased for either condition compared with values at 5 N (GRFG 20 N: dry, 17.1 +/- 4.2 N/cm2; wet, 4.8 +/- 1.8 N/cm2). Fibrin glue demonstrated only weak adhesive properties even under dry conditions (fibrin glue 5 N: dry, 0.8 +/- 0.3 N/cm2). Gelatin-resorcin-formaldehyde/glutaraldehyde has good adhesive properties both in wet and dry tissue. Bonding capacity can be substantially increased when applied on dry surfaces and at increased pressures.

Adhesiveness↗
PubMed1979

Steady-state kinetics of formaldehyde dehydrogenase and formate dehydrogenase from a methanol-utilizing yeast, Candida boidinii.

Initial velocity studies and product inhibition studies were conducted for the forward and reverse reactions of formaldehyde dehydrogenase (formaldehyde: NAD oxidoreductase, EC 1.2.1.1) isolated from a methanol-utilizing yeast Candida boidinii. The data were consistent with an ordered Bi-Bi mechanism for this reaction in which NAD+ is bound first to the enzyme and NADH released last. Kinetic studies indicated that the nucleoside phosphates ATP, ADP and AMP are competitive inhibitors with respect to NAD and noncompetitive inhibitors with respect to S-hydroxymethylglutathione. The inhibitions of the enzyme activity by ATP and ADP are greater at pH 6.0 and 6.5 than at neutral or alkaline pH values. The kinetic studies of formate dehydrogenase (formate:NAD oxidoreductase, EC 1.2.1.2) from the methanol grown C. boidinii suggested also an ordered Bi-Bi mechanism with NAD being the first substrate and NADH the last product. Formate dehydrogenase the last enzyme of the dissimilatory pathway of the methanol metabolism is also inhibited by adenosine phosphates. Since the intracellular concentrations of NADH and ATP are in the range of the Ki values for formaldehyde dehydrogenase and formate dehydrogenase the activities of these main enzymes of the dissimilatory pathway of methanol metabolism in this yeast may be regulated by these compounds.

Adenine Nucleotides↗
PubMed1981

The role of formaldehyde in methylene dimethanesulphonate-induced DNA cross-links and its relevance to cytotoxicity.

The interaction of the antitumour dialkanesulphonate ester, methylene dimethanesulphonate (MDMS) with the DNA of Yoshida sarcoma cells has been studied using the technique of alkaline elution. A marked retention which was reversed by proteolytic treatment indicated the presence of DNA-protein cross-links. A small proteinase-resistant retention was also observed which indicated that a low level of DNA-DNA interstrand cross-links also occurred. Treatment of cells with the amounts of formaldehyde expected by hydrolysis of the drug showed proteinase-reversible DNA-protein cross-linking which on proteolytic removal revealed a small number of single-strand breaks. Thus, MDMS causes both DNA-protein and DNA-DNA interstrand cross-links, the former component being attributed totally to the formaldehyde produced on the drug's hydrolysis. Cell survival data showed formaldehyde to be comparatively non-cytotoxic, providing evidence that DNA-DNA cross-links observable by this technique may be associated with the cytotoxicity of MDMS.

Alkylating Agents↗
PubMed1984

Relationships between formaldehyde metabolism and toxicity and glutathione concentrations in isolated rat hepatocytes.

The metabolism and toxicity of formaldehyde (CH2O) in isolated rat hepatocytes was found to be dependent upon the intracellular concentration of glutathione (GSH). Using hepatocytes depleted of GSH by treatment with diethyl maleate (DEM), the rate of CH2O (5.0 mM) disappearance was significantly decreased. Formaldehyde decreased the concentration of GSH in hepatocytes, probably by the extrusion of the CH2O-GSH adduct, S-hydroxymethylglutathione. Formaldehyde toxicity was potentiated in cells pretreated with 1.0 mM DEM as measured by the loss of membrane integrity (NADH stimulation of lactate dehydrogenase (LDH) activity) and an increase in lipid peroxidation (formation of thiobarbituric acid-reactive compounds). This potentiation of toxicity was both CH2O concentration-dependent and time-dependent. There was an excellent correlation between the increase in lipid peroxidation and the decrease in cell viability. L-Methionine (1.0 mM) both protected the cells from toxicity caused by the combination of 8.0 mM CH2O and 1.0 mM DEM and increased the cellular GSH concentration. The antioxidants, ascorbate, butylated hydroxytoluene (BHT) and alpha-tocopherol (10, 25 and 125 microM), all exhibited dose-dependent protection against toxicity produced by 8.0 mM CH2O and 1.0 mM DEM. At toxic concentrations of CH2O (10.0-13.0 mM), administered by itself, lipid peroxidation did not increase concomitantly with the decrease in cell viability and the addition of antioxidants (125 microM) did not influence CH2O toxicity. These results suggest that CH2O toxicity in GSH-depleted hepatocytes may be mediated by free radicals as a result of the effect of CH2O on a critical cellular pool of GSH. However, cells with normal concentrations of GSH are damaged by CH2O by a different mechanism.

Animals↗
PubMed1986

Utility of formaldehyde fixation for flow cytometry and inactivation of the AIDS associated retrovirus.

To maximize safety in the setting of an increasing number of requests for flow cytometric analysis of specimens potentially contaminated with the AIDS retrovirus, we evaluated some commonly used fixatives for their ability to inactivate the infectious potential of the virus. We found that both formaldehyde (0.37% v/v) and paraformaldehyde (0.5% w/v) completely inactivated the infectious activity of both free and cell-associated lymphadenopathy associated virus (LAV), the etiologic agent for the acquired immunodeficiency syndrome (AIDS). Based on encouraging preliminary results we formally evaluated the effect of formaldehyde fixation on flow cytometric parameters. In addition to inactivating LAV, 0.37% formaldehyde in phosphate buffered saline preserved light scatter and fluorescence properties of cells stained with fluorescein isothiocyanate (FITC) and beta-phycoerythrin (PE) conjugated monoclonal antibodies. These findings suggest that formalin fixation may be useful for laboratories performing flow cytometric analysis of specimens potentially contaminated with the AIDS virus.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1994

Leaching and cytotoxicity of formaldehyde and methyl methacrylate from acrylic resin denture base materials.

Acrylic resin dentures have the potential to elicit irritation, inflammation, and an allergic response of the oral mucosa. Studies of substances leachable from acrylic resins, their cytotoxicity to cultured cells, and means of reducing their leaching were systematically conducted. Under in vivo and in vitro conditions, formaldehyde and methyl methacrylate were significantly leached into human saliva and saliva-substitute buffer, especially from autopolymerized resins. Both leachable substances showed cytotoxic potentials in the range of their leaching concentrations. Formaldehyde was cytotoxic at lower concentrations than methyl methacrylate. Preleaching in water reduced subsequent leaching of both formaldehyde and methyl methacrylate, and the amount of reduction depended on an increase in the preleaching temperatures. Immersion of acrylic resin dentures in hot water (50 degrees C) before insertion is recommended, especially for autopolymerized resins used either for rebasing or as denture base materials, to minimize the risk of adverse reactions in patients who wear acrylic resin dentures.

Cell Count↗
PubMed1976

Genetic effects of formaldehyde in yeast. II. Influence of ploidly and of mutations affecting radiosensitivity on its lethal effect.

Haploid and diploid cells of Saccharomyces cerevisiae have the same sensitivity to formaldehyde, exponentially growing cells being more sensitive than stationary phase cells for both degrees of ploidy. Strains defective (rad 1-3) or with a reduced capacity (p-, cytoplasmic respiratory deficient mutants) in excision repair of ultraviolet-induced pyrimidine dimers show a greater sensitivity to formaldehyde than the corresponding wild type. A mutant defective in radiation-induced gene conversion (rec5) shows the same sensitivity as the wild-type strain. It appears that the excision-repair system plays an important role, especially in stationary phase cells, in repairing a fraction of formaldehyde-induced lesions.

DNA Repair↗
PubMed1983

A 26-week inhalation toxicity study with formaldehyde in the monkey, rat, and hamster.

This inhalation study involved simultaneous exposure of five groups of 6 male Cynomolgus monkeys, 20 male and 20 female Fischer 344 rats, and 10 male and 10 female Syrian golden hamsters for 22 hr per day, 7 days per week for 26 weeks to formaldehyde gas. The cumulative mean exposure concentrations were 0, 0, 0.19, 0.98, and 2.95 ppm for the two control groups, low-, mid-, and high-level exposure groups, respectively. There was no treatment-related mortality during the study. In monkeys, the most significant findings were hoarseness and congestion and squamous cell metaplasia in the nasal turbinates of the 2.95-ppm exposure group. There were no signs of toxicity in the lower-level exposure groups. In the rat, the only observations of possible responses to exposure were found in the 2.95-ppm exposure group. These findings consisted of squamous metaplasia in the nasal turbinates, decreased body weights starting during the second week of the study, and decreased liver weights. In contrast to monkeys and rats, hamsters did not show any significant responses to exposure even at 2.95 ppm. It was concluded that nearly continuous exposure of monkeys and rats for six months at a level of 2.95 ppm of formaldehyde clearly elicited an effect while exposures below this level did not appear to demonstrate an effect. It further appeared that the monkey and rat were more sensitive to formaldehyde exposure than the hamster.

Animals↗
PubMed1987

Further studies of the metabolic incorporation and covalent binding of inhaled [3H]- and [14C]formaldehyde in Fischer-344 rats: effects of glutathione depletion.

Glutathione (GSH) is required for the oxidation of formaldehyde (HCHO) to formate catalyzed by formaldehyde dehydrogenase (FDH). The effects of GSH depletion on the mechanisms of labeling of macromolecules in the rat nasal mucosa and bone marrow by 3HCHO and H14CHO were investigated. Male rats were exposed for 3 hr to atmospheres containing 3HCHO and H14CHO at concentrations of 0.9, 2, 4, 6, or 10 ppm, 1 day after a single 3-hr preexposure to the same concentration of unlabeled HCHO. Two hours prior to the second exposure, the animals were injected either with phorone (300 mg/kg, ip) or with corn oil. The concentration of nonprotein sulfhydryls in the nasal respiratory mucosa of phorone-injected rats was decreased to 10% of that of corn oil-injected rats. The metabolic incorporation of 3HCHO and H14CHO into DNA, RNA, and proteins in the respiratory and olfactory mucosa and bone marrow (femur) was significantly decreased, and DNA-protein crosslinking was significantly increased in the respiratory mucosa of phorone-injected relative to corn oil-injected rats at all HCHO concentrations. DNA-protein crosslinks were not detected in the respiratory mucosa of corn oil-injected rats at 0.9 ppm. Evidence was obtained for the formation of adducts of HCHO with the RNA from the nasal respiratory mucosa of phorone-injected rats at concentrations above 0.9 ppm. Covalent binding of HCHO to macromolecules in the bone marrow was not detected. These results indicate that the GSH-dependent oxidation of HCHO catalyzed by FDH is an important defense mechanism against the covalent reactions of HCHO with nucleic acids in the respiratory mucosa. Experiments using phorone-injected rats exposed to 10 ppm of [3H]- and [14C]formaldehyde showed that the DNA from the respiratory mucosa was enriched in 3H relative to 14C in comparison to the inhaled vapor. The enrichment is explained by an isotope effect in the oxidation of 3HCHO and H14CHO (H. d'A, Heck and M. Casanova (1987). Toxicol. Appl. Pharmacol. 89, 122-134), which results in 3H enrichment of the residual (unoxidized) HCHO that binds to DNA. A non-linear pharmacokinetic model is proposed that depicts the potential effects of FDH saturation on the relative concentrations of intracellular to extracellular HCHO.

Administration, Inhalation↗