Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Formaldehyde”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources
PubMed1988

Benzo[a]pyrene- and formaldehyde-induced DNA damage and repair in rat tracheal epithelial cells.

The single and combined effects of 2 environmental carcinogens, benzo[a]pyrene (BAP) and formaldehyde (HCHO), on cell growth and DNA damage were assessed in a rat tracheal epithelial cell line, C18. Treatment of C18 cells with HCHO for 90 min reduced the calculated growth index at the highest concentration tested, 400 microM, while no growth effects were observed with BAP treatments. Combination treatments reduced the growth index to 75% of control values. Alkaline elution analysis of C18 cell DNA detected both DNA-protein crosslinks (DPC) and single-strand breaks (SSB) as a result of HCHO treatment, while BAP caused only SSB. HCHO-induced SSB were repaired within 2 h, whereas BAP-induced SSB persisted for at least 48 h. Combination treatment of cells with BAP followed by HCHO enhanced the number of SSB, but reduced DPC. The results are discussed in reference to earlier work which demonstrated the interaction in vivo between BAP and HCHO with respect to their carcinogenicity in rat tracheal implants.

Animals↗
PubMed1995

Evaluation of contact sensitivity to formaldehyde and tetramethylthiuram monosulfide using a modified lymphocyte transformation test.

To examine the validity of a modified lymphocyte transformation test for evaluating contact hypersensitivity from weak sensitizers, guinea pigs were sensitized with formaldehyde (F) or tetramethylthiuram monosulfide (TMTM) using the maximization test procedure. Lymph node cells from the animals were then cultured with F or TMTM, in the presence or absence of epidermal cells (EC). Transformed lymphocyte counts were evaluated by uptake of 3H-thymidine. Nonsensitized guinea pigs were used as controls. The lymphocytes from sensitized guinea pigs showed stronger blastogenesis when cultured with F or TMTM in the presence of EC than when the sensitizers were not added to the culture and the response depended on the concentration of F or TMTM. Cultures in the absence of EC also showed significant enhancement of blastogenesis by F or TMTM, but the responses were significantly weaker than those in the presence of EC. Lymphocytes from the control animals did not show significantly enhanced blastogenesis in response to F or TMTM, even when EC was added to the cultures. The results suggested that contact sensitivity for weak sensitizers can be evaluated by this modified lymphocyte transformation test, especially when lymph node cells were co-cultured with EC.

Analysis of Variance↗
PubMed1977

A possible prebiotic synthesis of thymine: uracil-formaldehyde-formic acid reaction.

When uracil is reacted with formaldehyde and formic acid in dilute aqueous solutions at 100-140 degrees C, 5-hydroxymethyluracil (5-HMU), methylenebiuracil (MBU) and thymine are formed. It has been shown that 5-HMU is an intermediate in the formation of MBU and thymine. In the presence of formic acid, 5-HMU gives MBU, thymine and in some cases uracil. The formation of thymine is generally favoured under acidic conditions, although small amounts of this base could also be obtained when the reactions were carried out under mildly basic conditions. A hydride ion transfer mechanism is suggested for some of these reactions. These results have relevance to the formation of thymine under prebiotic conditions.

Chemical Phenomena↗
PubMedDate not supplied

The detection of DNA-protein cross-links in rat tracheal implants exposed in vivo to benzo[a]pyrene and formaldehyde.

The DNA damage associated with benzo(a)pyrene (B[a]P) and formaldehyde (HCHO) exposure in rat tracheal implants was determined by alkaline filter elution adapted to measure DNA-protein cross-links (DPC) in vivo. In addition, histopathological responses of the tracheal epithelium were quantitated after multiple exposures to 20 micrograms B[a]P and 0.2% HCHO. Compared to either agent alone, combined exposure for 1-4 weeks caused an increase in cellular atypia and greater thickness of hyperplastic and metaplastic lesions. HCHO exposure resulted in a dose-dependent increase in DPC with a maximal response of 85% DNA filter retention at 0.2% HCHO, which were mostly removed by 72 h. B[a]P did not cause DPC, but when tracheas were pre-exposed to 20 micrograms B[a]P followed by 0.05% HCHO there was a 15% decrease in HCHO-induced DPC. This competition between B[a]P and HCHO for sites presumably on DNA does not offer a clear explanation for their markedly enhanced cocarcinogenicity observed in previous studies, but does demonstrate the interaction between the two agents in tracheal epithelium.

Animals↗
PubMed1977

Uptake and degradation of formaldehyde-treated 125I-labelled human serum albumin in rat liver cells in vivo and in vitro.

The uptake of formaldehyde-treated 125I-labelled human serum albumin in rat hepatocytes and nonparenchymal liver cells was measured in vivo and in vitro. Isolated liver cells were prepared by treating the perfused liver with collagenase. Purified hepatocytes and nonparenchymal cells were obtained by differential centrifugation. Human serum albumin was found to be taken up exclusively or almost exclusively by nonparenchymal cells in vitro and in vivo (after intravenous injection). The maximal rate of human serum albumin-uptake in vitro was comparable to that in vivo. Nonparenchymal cells degraded human serum albumin in vitro as indicated by release of trichloroacetic acid-soluble radioactivity. Degradation started about 20-30 min after addition of human serum albumin to cells and rate of degradation was proportional to rate of uptake. Human serum albumin-degradation could be studied without interference of concurrent uptake by separating cells that had been preincubated with human serum albumin from the medium and then reincubating them with human serum albumin-free medium. The lag phase before human serum albumin-degradation starts and the inhibitory effect of chloroquine on degradation indicate that human serum albumin is degraded in lysosomes. The data obtained show that enzymatically prepared nonparenchymal liver cells retain their endocytic activity in vitro. Denatured human serum albumin should be useful both as a marker for rat liver macrophages and for the study of intracellular proteolysis in these cells.

Animals↗
PubMed1988

Studies on dopamine-, tyrosine hydroxylase- and aromatic L-amino acid decarboxylase-containing cells in the rat diencephalon: comparison between formaldehyde-induced histofluorescence and immunofluorescence.

The morphology, number and distribution of catecholaminergic neurons, as visualized either with the aluminum-catalysed formaldehyde method for catecholamines or with the immunohistochemical method for the catecholamine-synthesizing enzymes tyrosine hydroxylase and aromatic L-amino acid decarboxylase, respectively, were analysed within the rat dorsal hypothalamus, ventral thalamus and adjoining regions (A11 and A13 cell groups). Both polyclonal rabbit and monoclonal mouse tyrosine hydroxylase antibodies were used in elution-restaining and double-staining experiments, respectively. Some of the animals also received spinal injections of the fluorescent tracer True Blue in order to retrogradely label cells projecting to the spinal cord. With respect to the number and distribution of catecholaminergic neurons in the A11 and medial A13 cell groups, including the spinal-projecting subpopulation, the results obtained with the two methods were very similar, indicating that within these regions of the CNS the two methods in principle visualize identical cell populations. However, the catecholaminergic cells were distinctly larger and their processes appeared more extensive with the immunohistochemical method. Animals processed for immunohistochemistry exhibited a lower total number of retrogradely labelled cells in the A11 area than those analysed with aldehyde-induced fluorescence despite the fact that both methods revealed similar numbers of retrogradely labelled tyrosine hydroxylase-positive and catecholamine-containing cells, respectively. The reason for these discrepancies, which are probably of methodological nature, are discussed. While this study shows that the results obtained with the two methods within the A11 and medial A13 cell group are very similar and thus strengthens the earlier proposed concept of the organization of the diencephalospinal dopaminergic system, it also documents that in intermingling and nearby CNS regions there are cell bodies which cannot be demonstrated with the aldehyde fluorescence method, but which still contain tyrosine hydroxylase and/or aromatic L-amino acid decarboxylase-like immunoreactivity. One explanation is low levels of enzyme and/or dopamine combined with a comparatively low sensitivity of the histochemical method. Thus, neurons containing both enzymes are probably dopaminergic, even if catecholamine fluorescence cannot be demonstrated. Neurons containing tyrosine hydroxylase, but lacking both aldehyde induced fluorescence and aromatic L-amino acid decarboxylase, may also still be dopaminergic.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMedDate not supplied

Changes in formaldehyde-induced fluorescence of the hypothalamus and pars intermedia in the frog, Rana temporaria, following background adaptation.

Adaptation of the frog, Rana temporaria, to a white background for 12 hr has resulted in an intense formaldehyde-induced fluorescence (FIF) in the neurons of the preoptic recess organ (PRO), paraventricular organ (PVO), nucleus infundibularis dorsalis (NID) and their basal processes permitting visualization of the PRO- and PVO-hypophysial tracts that extend into the median eminence (ME) and pars intermedia (PI); the FIF is reduced in all the structures by 3 days. In frogs adapted to a black background, for 12 hr and 3 days, there was a general reduction in the FIF of the PRO neurons and PRO-hypophysial tract. By 12 hr black background adaptation, the PVO/NID neurons and only their adjacent basal processes show FIF which was sharply reduced by 3 days, making the PVO-hypophysial tract undetectable. In the PI fibers the fluorescence was more intense in black-adapted frogs than in white-adapted ones at both the intervals studied. The simultaneous changes in the FIF of the hypothalamic nuclei, tracts and PI suggest that the PRO and PVO/NID neurons participate in PI control through release of neurotransmitter(s) at the axonal ends.

Animals↗
PubMed1992

Excretion of formaldehyde, malondialdehyde, acetaldehyde and acetone in the urine of rats in response to 2,3,7,8-tetrachlorodibenzo-p-dioxin, paraquat, endrin and carbon tetrachloride.

Formaldehyde (FA), acetaldehyde (ACT), malondialdehyde (MDA) and acetone (ACON) were simultaneously identified in urine, and their excretion quantitated in response to chemically induced oxidative stress. Urine samples of female Sprague-Dawley rats were collected over dry ice and derivatized with 2,4-dinitrophenylhydrazine. The hydrazones of the four lipid metabolic products were quantitated by high-performance liquid chromatography on a Waters 10-microns mu-Bondapak C18 column. The identities of FA, ACT, MDA and ACON in urine were confirmed by gas chromatography-mass spectrometry. An oxidative stress was induced by orally administering 100 micrograms/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin, 75 mg/kg paraquat, 6 mg/kg endrin or 2.5 ml/kg carbon tetrachloride to rats. Urinary excretion of FA, ACT, MDA and ACON increased relative to control animals 24 h after treatment with all xenobiotics. The system has wide-spread applicability to the investigation of altered lipid metabolism in disease states and exposure to environmental pollutants.

Acetaldehyde↗
PubMed1993

Gas chromatographic-mass spectrometric screening procedure for the identification of formaldehyde-derived tetrahydroisoquinolines in human urine.

A gas chromatographic-mass spectrometric method has been developed for the identification of 1,2,3,4-tetrahydroisoquinoline and six metabolites extracted from urine in the picogram range. The derivatization procedure for the substances, formed by reaction of formaldehyde with biogenic amines, employs propionic anhydride and can take place in aqueous medium. In this way artificial formation of these compounds via condensation of biogenic amines with aldehydes or alpha-keto acids during the work-up procedure is eliminated. The procedure results in hydrophobic compounds, which are quantitatively extractable by liquid-liquid extraction with organic solvents. Further clean-up was performed by solid-phase extraction on C18 sample preparation columns.

Formaldehyde↗
PubMed1993

Gas chromatographic-mass spectrometric screening procedure for the identification of formaldehyde-derived tetrahydro-beta-carbolines in human urine.

A gas chromatographic-mass spectrometric method for the identification of 1,2,3,4-tetrahydro-beta-carboline and four metabolites extracted from urine is described. In a first step the substances, formed by reaction of formaldehyde with biogenic amines, were derivatized in aqueous solution with methyl chloroformate to eliminate an artificial formation of these compounds via condensation of endogenous indole ethylamines with aldehydes or alpha-keto acids during the work-up procedure. This initial derivatization formed stable hydrophobic compounds and improved the extractability for a liquid-liquid extraction. Further clean-up was performed by solid-phase extraction on C18 sample preparation columns. The method can identify these compounds in the picogram range.

Carbolines↗
PubMed1996

Formaldehyde-derived tetrahydroisoquinolines and tetrahydro-beta-carbolines in human urine.

Human urine samples were examined for the occurrence of formaldehyde-derived tetrahydroisoquinolines and tetrahydro-beta-carbolines generated by condensation of the methanol oxidation product with biogenic amines. Positive results were obtained for the tryptamine condensation product 1,2,3,4-tetrahydro-beta-carboline and the serotonine condensation product 6-hydroxy-1,2,3,4-tetrahydro-beta-carboline as well as for the condensation products with tyramine, dopamine, adrenaline and noradrenaline 1,2,3,4-tetrahydroisoquinoline, 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, N-methyl-4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline, 4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline, and the metabolite 6-methoxy-7-hydroxy-1,2,3,4-tetrahydroisoquinoline. Negative results were obtained for N-methyl-1,2,3,4-tetrahydroisoquinoline and 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline, N-methyl-1,2,3,4-tetrahydro-beta-carboline, 6-methyl-1,2,3,4-tetrahydro-beta-carboline, and 6-methoxy-1,2,3,4-tetrahydro-beta-carboline in samples of chronic alcoholics as well as in the urine of healthy volunteers. No correlation between alcohol ingestion or state of alcoholization could be demonstrated.

Alcoholism↗
PubMed1988

Routine synthesis of N-[11C-methyl]scopolamine by phosphite mediated reductive methylation with [11C]formaldehyde.

A synthesis of [11C]scopolamine capable of clinical delivery of this agent in high specific activity is described. The precursor [11C]formaldehyde was produced by catalytic oxidation of [11C]CH3OH over metallic silver and was used to N-11C-methylate norscopolamine using aqueous neutral potassium phosphite as the reducing agent. The labeling reaction was complete after 5 min at 75-80 degrees C and the [11C]scopolamine (99% radiochemical purity) was isolated by preparative HPLC. Total synthesis time is less than 45 min. Decay corrected radiochemical yields from [11C]CO2 are presently 20-43%.

Carbon Radioisotopes↗
PubMed1987

Effects of various basic compounds on the degradation of formaldehyde-treated 125I-labeled bovine serum albumin in mouse liver lysosomes.

The effect of various basic compounds on degradation of formaldehyde-treated 125I-bovine serum albumin (denatured 125I-BSA) in livers of mice was studied in detail. Five basic compounds (BTTB, chloroquine, methylamine, ammonium chloride, and vinblastine) were tested. All the basic compounds inhibited the degradation of exogenous protein in lysosomes. When p-biphenylmethyl-(dl-tropyl-alpha-tropinium)bromide (BTTB) was used, the most effective inhibition was obtained at the concentration of 3.2 mM. Also, vinblastine, a well-known inhibitor of microtubular function, inhibited the degradation of an exogenous protein to the similar extent as that of chloroquine. The inhibition of protein degradation caused by BTTB closely related to the uptake of BTTB into lysosomes. It is supposed that BTTB accumulates in lysosomes and that it inhibits the hydrolytic enzyme by neutralizing intralysosomal pH. Furthermore, it is supposed that BTTB, a quaternary ammonium compound, becomes a useful tool in the study of protein degradation in lysosomes as well as the typically lysosomotropic compounds (chloroquine, ammonium chloride, and methylamine).

Acid Phosphatase↗
PubMed1991

Cross-adaptive response in Escherichia coli caused by pretreatment with H2O2 against formaldehyde and other aldehyde compounds.

A cross-adaptive response (CAR), defined as a reduction of the effects of an agent by pretreatment with another agent, was demonstrated when E. coli WP2 cells were pretreated with hydrogen peroxide (H2O2) followed by challenging treatment with aldehyde compounds. Pretreatment with a sublethal dose (60 microM) of H2O2 for 30 min made WP2 cells resistant to the killing effects of formaldehyde (FA), and 4 other mutagenic aldehydes: glutaraldehyde, glyoxal, methyl glyoxal and chloroacetaldehyde. CAR was also observed in WP2uvrA (uvrA-) and ZA12 (umuC-) cells, but not in ZA60 (recA-) and CM561 (lexA- (Ind-] cells. A role of recA and lexA in CAR was further suggested by the lack of beta-galactosidase induction in recA- and lexA- cells by H2O2. CAR and beta-galactosidase induction, however, were found to be separate events since CAR was recovered by introducing the recA+ gene into lexA- cells, but no induction of beta-galactosidase by H2O2 was observed in cells with the same gene transfer. These results suggest that H2O2 has the capacity to induce a function which reduces the killing effects of aldehydes, and the function is controlled by the recA gene without involvement of SOS response.

Acclimatization↗
PubMed1995

Adult respiratory distress syndrome following closure of a chronic ventricular septal defect: possible relationship to the use of intracardiac gelatin-resorcin-formaldehyde glue.

Gelatin-resorcin-formaldehyde glue is now widely used in cardiac surgery, particularly in Europe. A case is reported where its use may have contributed to the pulmonary dysfunction seen postoperatively after elective closure of a postinfarct ventricular septal defect. It is believed that this is a result of a relatively high exposure of the pulmonary circulation to the glue, in particular to formalin. Although not proven, the authors advise caution when using the glue within the cardiac chambers.

Aged↗
PubMed2005

Sequence specificity of formaldehyde-mediated covalent binding of anthracycline derivatives to DNA.

Daunorubicin (DRB) and doxorubicin (DOX) in the presence of formaldehyde (CH2O) form covalent adducts with DNA. A G-specific adduct is formed by producing an aminal bridge between the C-3' of daunosamine and the C-2 of guanine. New derivatives of DRB, DOX and epidoxorubicin (EDOX) with an amidine group bonded to the C-3' of the daunosamine moiety, with either a morpholine or hexamethyleneimine ring attached to the amidine group, were studied in this paper. DNase I footprinting and analyses with restriction endonucleases were applied to compare the specificity of adduct formed by the amidine derivatives and their parent compounds. These approaches provide consistent results, proving that a GC pair is required for covalent binding of anthracycline derivatives to DNA and that different flanking sequences are able to modify the sequence preference of the drugs. The 5'-GC-3', 5'-CG-3' and 5'-TC-3' sequences were protected most efficiently by the parent compounds and their morpholine derivatives and some increased protection of 5'-TC-3' sequence was observed for morpholine analogues. Hexamethyleneimine derivatives bind to DNA with much lower efficiency. Finally, the sequence specificity of anthracycline derivatives was correlated with their ability to inhibit binding of transcription factors Sp1 and AP-1 to their DNA recognition sequences. The anthracycline derivatives were more potent in inhibiting Sp1 binding to its cognate GC box than in preventing AP-1 from binding to its mixed A.T and G.C site. Overall, the results indicate that the amidine derivatives of anthracyclines show similar, but not identical sequence specificity as parent compounds, though they exert their effect at a higher concentration.

Anthracyclines↗
PubMed2006

Adsorption of phenol on formaldehyde-pretreated Pinus pinaster bark: equilibrium and kinetics.

This work studies phenol adsorption on Pinus pinaster bark that has been previously treated with formaldehyde in acid medium. The influence of several variables such as solid/liquid ratio, pH and initial concentration of phenol in the solution on the adsorption capacity of the bark has been analysed. A kinetic model based on phenol diffusion within the pores of the adsorbent was in agreement with the results obtained for high initial concentrations of phenol, allowing the determination of diffusion coefficients. Adsorption equilibrium data were fitted by the Freundlich and BET isotherms. From their parameters phenol adsorption capacity and intensity, as well as the specific surface (BET) of the adsorbent, were determined.

Adsorption↗
PubMed2004

Long-term exposure to low levels of formaldehyde increases the number of tyrosine hydroxylase-immunopositive periglomerular cells in mouse main olfactory bulb.

Multiple chemical sensitivity (MCS) in response to a long-term low-level chemical exposure is as yet an unclarified disorder. To determine the role of olfactory function in the induction of MCS, immunocytochemical analysis of the main olfactory bulb (MOB) was performed after exposure of mice to low levels of formaldehyde. A long-term exposure resulted in an increase in the number of tyrosine hydroxylase-immunopositive periglomerular cells and may affect the neuronal function of the MOB.

Animals↗