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PubMed1990

Evaluation of a diffusive sampler for formaldehyde.

A diffusive sampling system, using a commercially available liquid sorbent badge, has been evaluated for the determination of airborne formaldehyde concentrations according to the U.K. Health and Safety Executive protocol. The results of laboratory and field experiments are presented. The results obtained using the diffusive sampler during field measurements were about 10% higher overall than those obtained using a conventional pumped sampler.

Diffusion↗
PubMed2006

Monte Carlo simulation to reconstruct formaldehyde exposure levels from summary parameters reported in the literature.

OBJECTIVES: This study presents a procedure allowing the numerical synthesis of exposure data reported in different ways in the literature, including summary parameters and single measurements. The procedure was applied to literature regarding formaldehyde exposure in the reconstituted wood panels industry, including oriented-strand board (OSB), medium density fibre board (MDF) and particle board (PB). METHODS: For each publication providing summary parameters we estimated geometric means (GM) and geometric standard deviations (GSD) by assuming lognormality of exposure levels. Monte Carlo simulation was performed to re-create datasets from the sample sizes and estimated GMs and GSDs, allowing their subsequent formatting together with the single measurements. The precision and bias of the methods used to estimate GMs and GSDs were evaluated. RESULTS: Altogether, the 13 articles included in our study yielded a final database of 874 data, of which 732 were simulated. For both area and personal data, exposures corresponding to MDF and PB were similar while OSB levels were lower. The most recent available personal levels (1985-1994) were highest in PB for jobs performed in the vicinity of the press (GM=0.63 mg m-3). Corresponding area levels were highest for PB in the main production zone (GM=0.43 mg m-3). Mixed-effects models fitted to area PB data explained 38% of the total variability. A 6-fold decrease in exposures from 1965 to 1995 was estimated. Replication of the simulation process yielded relative standard deviations of the calculated GMs and GSDs between 10 and 20%. The relative biases of the methods used to estimate GMs and GSDs varied across methods and decreased with higher sample sizes (from approximately 15% for n=5 to less than 5% for n=30, in absolute value). The precision also varied across methods and improved with higher sample sizes (from approximately 30% for n=5 to approximately 10% for n=30). DISCUSSION: This methodology constitutes a new meta-analysis tool that should improve the interpretation of industrial hygiene literature data, but needs to be further validated.

Air Pollutants, Occupational↗
PubMed1996

DNA--protein crosslinks, a biomarker of exposure to formaldehyde--in vitro and in vivo studies.

Formaldehyde (FA) is a widely produced industrial chemical. Sufficient evidence exists to consider FA as an animal carcinogen. In humans the evidence is not conclusive. DNA-protein crosslinks (DPC) may be one of the early lesions in the carcinogenesis process in cells following exposures to carcinogens. It has been shown in in vitro tests that FA can form DPC. We examined the amount of DPC formation in human white blood cells exposed to FA in vitro and in white blood cells taken from 12 workers exposed to FA and eight controls. We found a significant difference (P = 0.03) in the amount of DPC among exposed (mean +/- SD 28 +/- 5%, minimum 21%, maximum 38%) than among the unexposed controls (mean +/- SD 22 +/- 6%, minimum 16%, maximum 32%). Of the 12 exposed workers, four (33%) showed crosslink values above the upper range of controls. We also found a linear relationship between years of exposure and the amount of DPC. We conclude that our data indicate a possible mechanism of FA carcinogenicity in humans and that DPC can be used as a method for biological monitoring of exposure to FA.

Biomarkers↗
PubMed1987

The induction of growth-altered cell populations (tumor-initiation sites) in rat tracheal implants exposed to benzo[a]pyrene and formaldehyde.

The effects of exposure to benzo[a]pyrene (BAP) and formaldehyde (HCHO), alone and combined, on the induction of carcinogenesis in rat tracheal implants was determined as the number of growth-altered cell populations (tumor-initiation sites, TIS) per trachea. While exposure twice-weekly for 4.5 months to 0.2% HCHO solution gave only a weak response (0.25 TIS/trachea), 2.37 TIS per trachea were detected after exposure to 20 micrograms BAP in the same regimen. The combination of BAP followed by HCHO had a greater response than either agent alone (7.83 TIS/trachea), while the reverse exposure gave 1.49 TIS per trachea, which was less than BAP alone. Thus, the induction of TIS by combined exposure to BAP and HCHO was dependent on the order of exposure, and could not be predicted from their individual exposures.

Animals↗
PubMed1977

Analysis of formaldehyde in tobacco smoke by high performance liquid chromatography.

Formaldehyde in tobacco smoke is allowed to react with 2,4-dinitrophenylhydrazine to form the dinitrophenylhydrazone. This derivative is extracted with chloroform and concentrated. The residue in methylene chloride is separated and analyzed by high performance liquid chromatography. A column packed with 10-micron silica is used for separation. The internal standard is triphenylene. This method can also be used for the analysis of other carbonyl compounds in tobacco smoke that react to form hydrazone derivatives.

Chromatography, High Pressure Liquid↗
PubMed2001

Preparation of a ribonucleic acid-(polyamidoamine)-(zirconia-urea-formaldehyde resin) high-performance liquid affinity chromatographic stationary phase.

A preparative method for a high-performance liquid affinity chromatographic (HPLAC) stationary phase is described. The 3- to 5-microm nonporous composite spherical microparticles of zirconia and urea-formaldehyde (UF) resin are synthesized through the reaction of zirconyl chloride with hexamethylene tetra-amine and urea, and then it is used as the matrix of the HPLAC stationary phase of which the diameter and structure are determined by scanning electron microscopy. In a methanol medium, the polyamidoamine (PAMAM) starburst dentritic spacer arms are linked with the imido-groups on the surface of the matrix by the Michael addition reaction with methyl acrylate and the amination reaction with ethylene diamine. After repeating these steps in triplets, amine-terminated dentritic spacer arms with a generation of 3 are obtained. The topological structure of the spacer arms is examined by solid-state 13C NMR. The Br-substituted ribonucleic acid (RNA) ligand is obtained by the reaction of liquid bromine with RNA and bonded to the dendritic spacer arms of the matrix in a solution of NaOH (pH 9-11). The binding capacity of RNA is measured by UV spectrophotometry. A new type of stationary phase--RNA-(PAMAM)-(zirconia-UF resin--for HPLAC, which possesses starburst dendritic spacer arms, is synthesized and used for the separation of biological macromolecules.

Adenine Nucleotides↗
PubMed2003

Channelling and formation of 'active' formaldehyde in dimethylglycine oxidase.

Here we report crystal structures of dimethylglycine oxidase (DMGO) from the bacterium Arthrobacter globiformis, a bifunctional enzyme that catalyzes the oxidation of N,N-dimethyl glycine and the formation of 5,10-methylene tetrahydrofolate. The N-terminal region binds FAD covalently and oxidizes dimethylglycine to a labile iminium intermediate. The C-terminal region binds tetrahydrofolate, comprises three domains arranged in a ring-like structure and is related to the T-protein of the glycine cleavage system. The complex with folinic acid indicates that this enzyme selectively activates the N10 amino group for initial attack on the substrate. Dead-end reactions with oxidized folate are avoided by the strict stereochemical constraints imposed by the folate-binding funnel. The active sites in DMGO are approximately 40 A apart, connected by a large irregular internal cavity. The tetrahydrofolate-binding funnel serves as a transient entry-exit port, and access to the internal cavity is controlled kinetically by tetrahydrofolate binding. The internal cavity enables sequestration of the reactive iminium intermediate prior to reaction with tetrahydrofolate and avoids formation of toxic formaldehyde. This mode of channelling in DMGO is distinct from other channelling mechanisms.

Amino Acid Sequence↗
PubMed1998

Formaldehyde in cryoprotectant propanediol and effect on mouse zygotes.

Cryopreservation of human zygotes and embryos has been routinely performed by in-vitro fertilization clinics for many years. Karran and Legge (1996) first reported that formaldehyde (FA) present in the cryoprotective solutions can have a deleterious effect on mouse oocytes. FA is a cytotoxic, carcinogenic and mutagenic chemical. The effect of FA on mouse zygotes was investigated. In addition, the concentrations of FA in propanediol (PROH) obtained from various sources were determined. Pooled 1-cell embryos were dispensed into droplets of modified Ham's F10 or human tubal fluid containing various concentrations of FA. Since bovine serum albumin (BSA) may minimize toxicity additional trials were done as above in the absence of BSA. FA concentration in the standard 1.5 M PROH, from different sources in water, was measured in the same assay using a standard curve of 0-100 microM FA. FA in a complex medium had a significant deleterious effect on embryo development and hatching but only at 1 mM concentration (P < 0.000001; see Tables I-III). There was no significant effect of FA at 100 microM. However, in a simple medium even 50 microM FA decreased embryo hatching. FA was present in 1.5 M PROH from different sources (range 1.0-35.3 microM concentration). It appears that FA concentrations do not increase with storage because FA concentrations were low even after opening and storage for 3 years on the shelf. This suggests that FA is a contaminant during the manufacturing process and may vary from manufacturer to manufacturer and batch to batch. Until further studies are done to confirm the lack of toxicity to embryos during cryopreservation (with or without FA scavengers) it may be prudent to screen all batches of cryoprotectants for FA as part of quality control.

Animals↗
PubMed1993

Retrospective assessment of exposure by experts: the example of formaldehyde, solvents and mineral oils among textile and metal workers.

The validity of retrospective assessment of occupational exposure greatly depends on the amount of detail in the available information, on the knowledge of the specific industrial process by the experts, and on the criteria adopted to define relevant exposure. These criteria are difficult to standardize and are rarely made explicit in published reports, which makes it difficult to interpret inconsistencies among different studies. In two ongoing case-control studies on kidney cancer and, respectively, malignant lymphomas, a detailed occupational history was obtained and supplemented by 19 additional questionnaires, specifically addressing industrial activities where the knowledge of job title alone would have been insufficient for reliable exposure assessment. One further questionnaire was used to collect details of task and environment for all the other activities. These data are used to establish probability, intensity and frequency of exposure to 30 substances known or suspected to be carcinogenic from previous studies. There are two basic steps in the exposure assessment procedure: firstly, general rules are defined for each job within each activity covered by specific questionnaires; secondly the judgement is modulated according to the detailed tasks, working conditions and environment. To illustrate the process and to facilitate comparison with other studies, examples are given for a few common exposures in the textile and metal industries--the two most frequent economic activities in the study area--namely exposure to mineral oils, formaldehyde, aromatic solvents, chlorinated solvents and other organic solvents.

Case-Control Studies↗
PubMed2001

In vitro reaction of barbiturates with formaldehyde.

Barbiturates are widely used as sedatives, hypnotics, and antiepileptics, and, when coupled with their narrow therapeutic index, the probability that their use will result in accidental or intentional death is significant. When barbiturates are implicated in a murder or suicide, analysis for their presence is often required. Under certain conditions, barbiturates are quite stable, but conditions found in vivo immediately after death or after embalming may promote barbiturate decomposition. If extensive decomposition occurs, analysis for them may be difficult or impossible. Here, the stability of three representative barbiturates, under conditions that model those likely to prevail in vivo shortly after death and after embalming, have been studied. Solutions of phenobarbital were found to slowly decompose in water over the pH range of approximately 3.5 to 9.5. More rapid decomposition occurred at higher pH, and 2-phenylbutyric acid was the main decomposition product. Formaldehyde (5-20%) accelerated the decomposition rate 3-10-fold such that phenobarbital decomposition could be complete after 30 days. In contrast, pentobarbital decomposed roughly 10 times more slowly and secobarbital did not detectably decompose under any of the conditions studied. Thus, certain barbiturates may partially or completely decompose in vivo after death, especially after embalming, and thus analysis for them may lead to false negatives. However, this work shows that analysis for the parent barbiturate or its predicted decomposition product may provide data that will reduce the likelihood of false negatives.

Barbiturates↗
PubMed2005

Comparison of UV, fluorescence, and electrochemical detectors for the analysis of formaldehyde-induced DNA adducts.

A high-performance liquid chromatography (HPLC) method for normal and formaldehyde-modified deoxynucleosides after hydrolysis of exposed and unexposed human placental DNA was compared with ultraviolet (UV), fluorescence (FL), and electrochemical (EC) detectors. The lower quantifiable limits (LQL) for UV detection at 254 nm were 10-22 pmol for N(6)-hydroxymethyldeoxyadenosine (N(6)-dA), N(2)-hydroxymethyldeoxyguanosine (N(2)-dG), and N(4)-hydroxymethyldeoxycytidine (N(4)-dC), with N(4)-dC having the highest LQL and the 2 purines the lowest LQL. Similarly, LQLs using FL (excitation: 264 nm; emission: 340 nm) were 14-30 pmol, with N(2)-dG having the lowest LQL and N(6)-dA the highest. The LQL for N(2)-dG by EC detection at +1.10 V was 27 pmol, over 50-fold greater sensitivity than for the other hydroxymethyl deoxynucleosides; deoxyguanosine was similarly detected more sensitively than the other normal deoxynucleosides. Percent relative standard deviations ranged between 6 and 13% for both intra- and interrun assays for all detectors. HPLC-UV allows all the deoxynucleosides to be detected without the flow cell washing and use of fresh solutions necessary for the more selective FL detection, the latter not having enzyme blank interferences. EC allows only deoxyguanosine and N(2)-dG to be detected at pmol levels with no blank interferences. HPLC-UV allowed more sensitive detection of N(2)-dG and N(6)-dA than the other techniques and is recommended. The UV, FL, and EC properties of the hydroxymethyl deoxynucleosides of dA, dG, and dC are reported for the first time.

Chromatography, High Pressure Liquid↗
PubMed1976

Effects of treatment of whole fat soybeans or soy flour with formaldehyde to protect the polyunsaturated fatty acids from biohydrogenation in the rumen.

Full-fat, ground soy flour (GSF) was treated with 37% formaldehyde (HCHO) and evaluated by in vitro and in vivo criteria to determine the protection afforded linoleic acid against ruminal biohydrogenation when the materials described above were fed as a protein supplement to rations for growing lambs. The supplements compared were soybean meal (SBM), uked for 2 hours. Organoleptic evaluations were conducted to determine if any flavor differences in meat from lambs fed these supplements could be detected. Excellent protection of linoleic acid, the major polyunsaturated fatty acid in soybeans, was noted both in vitro and in vivo. Rump, shoulder, kidney knob and omental fat depots of lambs fed the HCHO treated GSF ration had significantly more linoleic acid than lambs fed untreated GSF while lambs fed untreated GSF had significantly, more linoleic acid in their fat depots than lambs fed SBM. Linoleic acid content of intramuscular (loin) fat from lambs fed HCHO treated GSF was not significantly different from lambs fed untreated GSF, but lambs fed untreated GSF had significantly more loin linoleic acid than lambs fed SBM. No significant differences were noted in daily feed intake, feed efficiency or average daily gain for lambs fed growing-finishing rations containing any of the products tested as the protein supplement. A taste panel could not detect any differences in flavor of ground loin among any of the treatments.

Adipose Tissue↗
PubMed1986

Formaldehyde-induced cytotoxic, genotoxic and mutagenic response in human lymphocytes and Salmonella typhimurium.

The incidences of chromatid-type aberrations and sister-chromatid exchanges were significantly increased in human lymphocytes treated with formaldehyde (FA) in vitro. In the presence of the mammalian metabolic activation system, i.e. S9 mix, the yields were reduced, although not to control levels. With S9 mix the structural chromosome damage induced by exposure to 1.0 mM FA was qualitatively and quantitatively identical to that induced by 0.05 mM cyclophosphamide (used as positive control for metabolic activation). Cell proliferation was clearly reduced with or without the presence of S9 mix. In a plate assay with Salmonella typhimurium strain TA100 in the absence and presence of S9 mix, a weak mutagenic response was observed. Using the pre-incubation method, FA induced without S9 mix a 1.6-fold and with S9 mix a 2.7-fold increase of revertant numbers over controls.

Animals↗
PubMed2002

Evaluation of mutagenic effects of formaldehyde in vitro: detection of crosslinks and mutations in mouse lymphoma cells.

Formaldehyde (FA) is known to be a genotoxic substance. FA induces DNA-protein crosslinks (DPC) as the primary DNA lesion. However, the significance of DPC for FA-induced mutations and the mechanism(s) of mutation formation are at present poorly understood. Our previous results indicated that FA-induced DPC seem to be related to cytotoxicity and clastogenicity but do not lead to gene mutations in mammalian cells. We now demonstrate that FA efficiently induces mutations in the mouse lymphoma assay (MLA). Treatment of L5178Y cells with FA for 2 h caused a clear and concentration-related mutagenic effect in the MLA. As this mutagenic effect was mainly due to a strong increase in small colony mutants, we suggest that FA mainly causes mutations by induction of chromosomal aberrations. Molecular characterization of spontaneous and FA-induced mutants by loss of heterozygosity analysis showed an extensive loss of functional tk sequences, supporting a clastogenic mechanism of mutation formation. Whole chromosome fluorescence in situ hybridization was used to further elucidate the mechanism(s) of chromosome mutations. Our results indicate that small-scale chromosomal rearrangements (e.g. deletions or recombinations) are mainly involved in FA-induced mutagenesis in the MLA.

Animals↗
PubMed2006

Genotoxic effects induced by formaldehyde in human blood and implications for the interpretation of biomonitoring studies.

Formaldehyde (FA) was tested for its genotoxicity in human blood cultures. We treated blood samples at the start of the culture to follow FA-induced DNA damage (DNA-protein crosslinks, DPX), its repair and its genetic consequences in form of sister chromatid exchanges (SCE) and micronuclei (MN). Our results clearly indicate that DPX (determined by the comet assay) are induced at FA concentrations of > or =25 microM. DPX induced by FA concentrations up to 100 microM are completely removed before lymphocytes start to replicate. SCE are induced at concentrations >100 microM parallel to the induction of cytotoxicity (measured as reduction of the replication index). MN were not induced by FA concentrations up to 250 microM (the highest analyzable concentration) added at the start of the blood cultures in the cytokinesis-block micronucleus (CBMN) test. FA-induced cytotoxicity (measured as reduction of the nuclear division index) possibly prevented division of damaged cells. MN were only significantly induced in human blood when proliferating cells were exposed to FA during the last cell cycle before preparation. Several human biomonitoring studies reported increased frequencies of SCE and MN in lymphocytes of subjects exposed to FA. Our results characterize the genotoxic potential of FA in cultured lymphocytes and lead to the conclusion that cytogenetic effects of FA are very unlikely to occur in blood cultures of FA-exposed subjects.

Blood Cells↗
PubMed1979

Formation of molecules of biological interest from formaldehyde and hydroxylamine in a modified sea medium.

As reported previously, glycine, serine, aspartic acid, and beta-alanine are the predominant amino acids produced from equimolecular formaldehyde and hydroxylamine in a modified sea medium enriched with essential transition metal ions. The time course of formation of the amino acids, and related substances was studied. Among the amino acids, glycine was produced earlier. Urea was produced initially and disappeared rapidly. Formation of cyanide, glycinenitrile, and glycinamide preceded the formation of amino acids. Probable pathways for the formation of amino acids and urea are suggested.

Amino Acids↗
PubMed1980

Reevaluation of the reaction of formaldehyde at low concentration with amino acids.

Many studies have been reported on the reaction of formaldehyde (FA) with amino acids or proteins, and FA is assumed to react with the alpha-amino group as well as some of the side chain groups. In most of these investigations a large excess of FA relative to amino acids or proteins was employed. In the present study, however, we carried out the reaction with a smaller excess of FA in order to clarify the reactivity, firstly with the alpha-amino groups, and secondly with specific side chain groups. No evidence for so-called Schiff base (-N = CH2) formation was obtained in the reaction with the alpha-amino groups, but the formation of an acid-labile N-hydroxymethyl compound as a major product was suggested by NMR and IR at greater than pH 9.2. There was no indication, however, of the presence of such a product below pH 9.2, and the amount of N-hydroxymethyl product increased in parallel with the reaction pH. The higher the reaction pH (greater than or equal to 9.2), the greater the consumption of FA, up to 2 mol/mol Ala. In addition, the larger the excess of FA, the smaller the amount of free amino group remaining (at pH 9.7). In the assignment of IR spectra, discrete absorption bands of the alpha-carboxyl group of Ala were observed, which reflected ionization states of the alpha-amino group, and these were utilized for analysis of the reaction mechanism. Furthermore, among amino acids with side chain groups, His, Trp, and Arg showed high reactivity and Asn showed moderate reactivity. The products were relatively stable and were purified and subjected to instrumental analyses. Sixteen other amino acids including Tyr and Lys did not yield stable products. The products from Arg were unique because of the non-involvement of the amino group, and were reversibly converted to the original Arg upon acid hydrolysis. The products from His, Trp and Asn all involved amino or amide nitrogen forming cyclic ring structures with methylene derived from FA. The chemical structures of these products were determined on the basis of elemental analyses, MS and NMR.

Amino Acids↗
PubMed1980

Maintaining patency of the ductus-arteriosus for palliation of cyanotic congenital cardiac malformations. The use of prostaglandin E1 and formaldehyde infiltration of the ductal wall.

We have used two methods to maintain ductal ppatency in 13 newborns during surgery for congenital cardiac malformations: prostaglandin E1 (PGE1) infusion for the short-term and formaldehyde infiltration of the ductus arteriosuos (FID) for the longer term. PGE1 increased the arterial oxygen saturation, leading to stable intraoperative hemodynamics in the six infants in whom it was used. FID was used in all 13 patients. Four of these patients died in the hospital, all with the ductus open. Of the nine early survivors, all required an additional shunt procedure. The five long-term survivors had the second palliative operation immediately, three hours, three days, two and one-half months, and four and one-half months after FID. We continue to use PGE1 to maintain ductal atency through operation, but use aortopulmonary anastomosis in the newborn period rather than FID.

Aorta, Thoracic↗

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