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PubMed1982

A simplified Timm stain procedure compatible with formaldehyde fixation and routine paraffin embedding of rat brain.

A simplified sulphide/silver technique for visualizing transitional metals in rat brain is described. It consists of: (1) sulphide perfusion before formaldehyde perfusion, (2) routine paraffin embedding and sectioning, and (3) silver staining with physical developer. This method is compatible with formaldehyde fixation, eliminates the need for post-fixation in Carnoy's solution before embedding and does not require low paraffin temperatures during embedding. Once embedded, brains can be stored for months before sectioning without loss of stain quality.

Animals↗
PubMed1984

Cytogenetic analysis of lymphocytes from rats following formaldehyde inhalation.

Male and female Fischer-344 rats were exposed to target concentrations of 0.5, 6, or 15 ppm formaldehyde by inhalation for 6 h/day for 5 days. Blood was removed by cardiac puncture within 1 h following termination of exposures and cultured in the presence of 5-bromodeoxyuridine (BrdU) (4 microM) for analyses of sister-chromatid exchange (SCE) and chromosome breakage. Formaldehyde did not cause a statistically significant increase in either SCE frequency or in the number of metaphases displaying chromosome aberrations.

Animals↗
PubMed1986

Effects of formaldehyde in the rat and dog following oral exposure.

Formaldehyde was administered orally (p.o.) to groups of rats and dogs at dosages up to 150 and 100 mg/kg/day, respectively, for 91 consecutive days. Significant body weight changes were observed at the higher dosages tested in both species. Decreased water consumption was observed in a dose-related pattern in all treated groups of rats. Food consumption and feed efficiency were decreased at higher dosage levels in dogs. Results of other clinical studies and microscopic pathology revealed no specific, treatment-related effects on any organ or tissue examined. These findings suggest that formaldehyde possesses little subacute toxicity following oral exposure.

Administration, Oral↗
PubMed1991

Formation of formaldehyde adducts from various drugs by use of methanol in a toxicological screening procedure with gas chromatography-mass spectrometry.

Use of methanol as a solvent in a toxicological screening procedure with gas chromatography-mass spectrometry may be associated with artifact formation. Artifacts with a molecular ion of [M + 12]+ are formed from various drugs, such as amphetamine, propafenone, flecainide, beta-blockers and prilocaine. The mechanism of artifact formation was studied by mass spectral techniques, labelling and nuclear magnetic resonance spectroscopy. It was shown that the artifacts were generated by the addition of formaldehyde and subsequent loss of water. Formaldehyde is probably formed by thermal dehydrogenation of methanol in the injection port of the gas chromatograph.

Adrenergic beta-Antagonists↗
PubMed1991

Measurements of oxygen consumption in Mytilus edulis during exposure to, and recovery from, high sublethal concentrations of formaldehyde, benzene and phenol.

1. The rate of oxygen consumption has been monitored continuously in M. edulis during acute exposure to high sublethal concentrations of formaldehyde, phenol and benzene and subsequent recovery periods of 96 hr. 2. The results are discussed in relation to changes in the electrochemical potential difference of sodium, the content of ATP and the tissue concentration of strombine. 3. After exposure to benzene and phenol, an increase in the rate of oxygen consumption that could not be explained by oxygen debt from the exposure period was observed. 4. Depression of the rate of oxygen consumption after exposure to formaldehyde may be explained by a reduced ability to extract oxygen from the water. 5. The pattern of oxygen consumption and behavioural responses, as well as the combined changes in the biochemical markers, were distinctly different in the three cases.

Animals↗
PubMed1995

Preparation of [11C]formaldehyde using a hollow fiber membrane bioreactor.

A bioreactor consisting of the enzymes alcohol oxidase and catalase immobilized onto a hollow fiber membrane was used to convert [11C]methanol to [11C]formaldehyde. Using an alcohol oxidase:catalase ratio of 1:500 U, conversion yields of 90-95% were obtained allowing the production of up to 7400 MBq (200 mCi) of [11C]formaldehyde in 5 min. The hollow fiber bioreactor allowed for a convenient, rapid synthesis with yields significantly higher than the standard chemical procedures, has demonstrable advantages over glass bead immobilized systems (primarily due to convective flow), and was amenable to hot cell conditions.

Alcohol Oxidoreductases↗
PubMed2005

Properties of resorcinol-tannin-formaldehyde copolymer resins prepared from the bark extracts of Taiwan acacia and China fir.

Resorcinol-tannin-formaldehyde copolymer resins (RTF) were prepared by using the bark extracts of Taiwan acacia (Acacia confusa) and China fir (Cunninghamia lanceolata) to substitute part of the resorcinol. From the results, the content of reactive phenolic materials in Taiwan acacia and China fir bark extracts were 51.6% and 46.5%, respectively. Aromatic compounds were the main components in the bark extracts showed by FT-IR analysis. The conventional synthesis condition used for RF resin was certainly not suitable for the RTF copolymer resin. It should be formed the novolak RF prepolymer by reacting the resorcinol with formaldehyde at the first stage, and then the bark extracts added and underwent the copolymerization reaction under acidic condition at the second-stage. The RTF copolymer resins prepared had cold-setting capability. They had higher viscosity, shorter gel time as compared with the RF resin. The RTF copolymer resins could be carried out the gluing application immediately after the hardener was added and had bonding strength the same as RF resin. But the RTF copolymer resins had worse stability and shorter shelf life than RF resin.

Acacia↗
PubMed2005

Process model and economic analysis of itaconic acid production from dimethyl succinate and formaldehyde.

A complete process model and economic analysis has been developed for itaconic acid production via catalytic condensation of dimethyl succinate and formaldehyde. The process model is based on experimental yields and selectivities obtained for the condensation reaction and on recovery schemes for itaconic acid developed in our laboratory. For an 18 million kg/yr (40 million lb/yr) itaconic acid production facility with a 10-year lifetime, the model predicts a capital investment of $40 million and an itaconic acid selling price of $2.34/kg ($1.06/lb) to achieve 30% annual return on investment. Feedstock cost is the largest contributor to the price of itaconic acid; succinate conversion and selectivity to the intermediate citraconic acid therefore most strongly influence process economics. Results of these analyses indicate that itaconic acid can be produced catalytically from succinic acid and formaldehyde at lower cost than via the current fungal fermentation route.

Costs and Cost Analysis↗
PubMed2006

Physico-chemical characterization of lignins from different sources for use in phenol-formaldehyde resin synthesis.

During the last decades lignin has been investigated as a promising natural alternative to petrochemicals in phenol-formaldehyde (PF) resin production, due to their structural similarity. Physico-chemical characterization of three types of lignin, namely kraft pine lignin (L1), soda-anthraquinone flax lignin (L2), and ethanol-water wild tamarind lignin (L3) has been evaluated to determine which one is the most suitable chemical structure for above purpose. Characterization has been performed using Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectrometry ((1)H NMR) to analyse the chemical structure, gel permeation chromatography (GPC) for determining molecular weight (MW) and molecular weight distribution (MWD), differential scanning calorimetry (DSC) to measure the glass transition temperature and thermogravimetric analysis (TGA) to follow the thermal degradation. Both structural and thermal characteristics suggest that kraft pine lignin (L1) would be a better phenol (P) substitute in the synthesis of lignin-phenol-formaldehyde (LPF) resins, as it presents higher amounts of activated free ring positions, higher MW and higher thermal decomposition temperature.

Calorimetry, Differential Scanning↗
PubMed2005

Functional coupling between vanillate-O-demethylase and formaldehyde detoxification pathway.

Pseudomonas putida vanillate-O-demethylase consisting of VanA and VanB was expressed in Escherichia coli strain K-12. Recombinant E. coli strain K-12 cells expressing VanAB efficiently converted vanillate into protocatechuate with glucose consumption. Mutant lacking either pgi or zwf showed higher or lower converting activity than the parental strain, respectively. Formaldehyde, which is the by-product of the demethylation, was converted into formate in the cellular reaction. Formate accumulation was blocked by gene disruption of the E. coli frmA that coded glutathione-dependent formaldehyde dehydrogenase.

DNA, Recombinant↗
PubMed2005

Vitamin E against oxidative damage caused by formaldehyde in frontal cortex and hippocampus: biochemical and histological studies.

Formaldehyde (FA) can cause severe central nervous system impairment. But, there are only a few studies about biochemical and histopathological changes of frontal cortex and hippocampal tissue caused by FA toxicity. The aim of our study was to investigate these changes occurring after chronic formaldehyde toxicity in frontal cortex and hippocampal tissues, and protective effect of Vitamin E (vit E) against oxidative damage. Eighteen rats were divided into three groups: (1) control, (2) treated with FA (FAt), and (3) treated with FA and vit E (FAt+vit E) groups. After the treatment, the animals were sacrificed and frontal cortex and hippocampal tissues were removed for biochemical and histopathological investigation. FA significantly increased tissue malondialdehyde (MDA) and protein carbonyl (PC) levels and also decreased superoxide dismutase (SOD) and catalase (CAT) enzyme activities in frontal cortex and hippocampal tissue compared to control. Vit E treatment decreased MDA and PC levels and prevented inhibition of SOD and CAT enzymes in the tissues. In the FAt group, the neurons of both tissues became extensively dark and degenerated with picnotic nuclei. The morphology of neurons in FAt+vit E group was protected well, but not as neurons of the control group. The number of neurons in frontal cortex and hippocampal tissue of FAt group was significantly less than both control and FAt+vit E groups. It was concluded that vit E treatment might be beneficial in preventing FA-induced oxidative frontal cortex and hippocampal tissue damage, therefore, shows potential for clinical use.

Animals↗
PubMed2006

Direct trapping of formaldehyde formed via oxidative N-demethylation of N,N-dialkylarylamines by Bacillus megaterium using cysteamine derivatization.

Oxidative N-demethylation was measured by incubation experiments using Bacillus megaterium isolated from topsoil as a biocatalyst for the N-demethylation of the N,N-dialkylarylamines N,N-dimethylaniline and N-ethyl-N-methylaniline. Formed formaldehyde, normally difficult to analyse in biological systems because of further metabolization, was successfully trapped and converted into thiazolidine by addition of cysteamine into the incubation media. Studies using N,N-di-(trideutero-methyl)-aniline and N-ethyl-N-(trideuteromethyl)-aniline as well as N,N-di-[methyl-(13)C]-aniline and N-ethyl-N-[methyl-(13)C]-aniline were performed to confirm that the N-demethylation proceeds via formaldehyde.

Aniline Compounds↗
PubMed1997

Gelatin-resorcinol-formaldehyde-glutaraldehyde glue-spread stapler prevents air leakage from the lung.

BACKGROUND: To reinforce the staple line of the emphysematous lung and thereby prevent air leakage during thoracoscopic operations, we have developed a procedure of lung excision that uses a gelatin-resorcinol-formaldehyde-glutaraldehyde (GRFG) glue-spread stapler. METHODS: Formaldehyde-glutaraldehyde (FG) jelly is prepared by mixing FG fluid with 2.5% sodium carboxymethyl cellulose. The FG jelly is placed in the stapler groove and staple holes, and a gelatin-resorcinol (GR) mixture is applied. The GRFG glue-spread stapler was applied to emphysematous lung cutting during thoracoscopic operations in 10 cases. RESULTS: An adhesion-strength test showed no difference in glue adhesion between FG fluid and FG jelly. An experiment using swine lung showed that with this newly developed stapler, no resistance in firing occurred, and GRFG glue covered every staple hole. Clinical application in 10 cases with emphysematous lung demonstrated no air leakage from the staple line, even long after the operation. CONCLUSIONS: Emphysematous lung excision using the GRFG glue-spread stapler during thoracoscopic operations is useful in preventing air leakage from the staple line and is a simple, safe, and low-cost procedure.

Drug Combinations↗
PubMed1999

Gelatin-resorcinol-formaldehyde-glutaraldehyde glue for sealing pulmonary air leaks during thoracoscopic operation.

BACKGROUND: Intraoperative pulmonary air leakage is one of the most troublesome complications in video-assisted thoracoscopic surgical procedures. We developed a sealing procedure using gelatin-resorcinol-formaldehyde-glutaraldehyde (GRFG) glue for pulmonary air leaks during such operations. METHODS: Formaldehyde-glutaraldehyde (FG) jelly is prepared by mixing FG fluid with 2.5% sodium carboxymethyl cellulose to make the FG fluid viscous. We performed an adhesion-strength test to determine the optimum ratio of gelatin-resorcinol mixture to FG jelly and then conducted an air leakage test on swine lung to compare the sealing effect between fibrin and GRFG glues. To study the histotoxicity of the GRFG glue, the sealant was applied to injured rabbit lung, and the rabbits were followed for 1 day to 188 days. For clinical studies, we developed an endosyringe to apply the GRFG glue on the target site during video-assisted thoracoscopic surgical procedures and used this technique in 21 patients with intraoperative air leaks. In addition, the side effects of GRFG glue application were studied in 52 patients in whom glue was used in several ways during lung operations. RESULTS: The results of the adhesion-strength test favored a 2:1 gelatin-resorcinol to FG ratio. The mean pressure required to produce air leakage was significantly higher with GRFG glue than with fibrin glue (p<0.001). No critical histologic damage was seen in the rabbit lung, and the glue persisted on the lung surface for 188 days after sealing. Clinical application of the glue in 21 patients resulted in complete stoppage of air leakage during operation and long afterward, except in 1 patient with a late-onset lung fistula. The FG jelly helped prevent glue spillage at the target site, regardless of angle. A transient rise in temperature up to 38.60C was observed as a side effect 7 days after operation in 5 (9.6%) of the 52 patients. CONCLUSIONS: A GRFG glue using FG jelly seals pulmonary air leaks effectively, simply, and safely during video-assisted thoracoscopic surgical procedures.

Animals↗
PubMed1996

Structure and mechanism of formation of a new adduct from formaldehyde and guanosine.

Reactions between formaldehyde and guanosine in the range pH 4-10 gave N2-hydroxymethylguanosine 1, bis-N2-guanosinylmethane 2 and 7-[7-(beta-D-ribofuranosyl)-purin-6(7H)- on-2-yl]-3-(beta-D-ribofuranosyl)-5,6,7,8-tetrahydro-sym-triazino[ 1,2-alpha] purin-10(3H)-one 3a. The latter is a new adduct, the formation of which occurs in neutral solution, is favoured at higher pH and can be rationalised by a sequence of condensations involving two molecules each of guanosine and formaldehyde.

DNA Adducts↗
PubMed2000

Simultaneous supercritical fluid derivatization and extraction of formaldehyde by the Hantzsch reaction.

A study where the Hantzsch reaction is used to produce the chemical derivatization of formaldehyde in a supercritical medium is presented in this paper. Pressure, temperature and other parameters such as static and dynamic extraction time must be optimized to increase the yield of this kinetically controlled reaction. A 2(5-1) (resolution V) factorial design was used to study the significant parameters affecting the supercritical process in terms of resolution and sensitivity. A subsequent central composite design was employed to find the conditions of maximum response. Ultraviolet-visible spectrophotometry was used as the detection technique. The optimum conditions were used for the determination of formaldehyde in real finger-paints by means of the previous addition of known quantities of this analyte to the paint. Results were compared with those obtained with supercritical fluid extraction and subsequent chemical derivatization and an improvement of sensitivity as well as a reduction of time of analysis, solvent waste and reagents consumption were observed.

Chromatography↗
PubMed1999

High-performance liquid chromatography of methanol released from pectins after its oxidation to formaldehyde and condensation with 2,4-dinitrophenylhydrazine.

A procedure was developed to measure the content of methanol in pectins after the base-catalysed hydrolysis of galacturonic acid methyl esters and oxidation of released methanol with potassium permanganate followed by condensation of the resulting formaldehyde (HCHO) with 2,4-dinitrophenylhydrazine (DNPH) dissolved in acetonitrile. The constant yields of resultant formaldehyde 2,4-dinitrophenylhydrazone (HCHO-DNPH derivative) were obtained at molar ratios of DNPH/HCHO higher than 5. The separation of the HCHO-DNPH derivative from DNPH reagent was achieved by isocratic reversed-phase HPLC equipped with the spectrophotometric detector set at a wavelength of 351 nm. The calibration curve was linear in the methanol concentration range between 0.04 and 15 micromol/ml (R=0.9995). The total recovery from pectin solutions spiked with methanol was equal to 100.6+/-5.1%.

Acetonitriles↗