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At least 1,711 records · Page 95Linked to original sources
PubMed2003

Sorption and mass fluxes of sulfonated naphthalene formaldehyde condensates in aquifers.

Sulfonated naphthalene formaldehyde condensates (SNFC) and their monomeric analogues were used as superplasticizers for cement suspension injections at two tunnel construction sites that are in direct contact with groundwater. Because in one case the aquifer is an important drinking water resource, the behavior of SNFC in the groundwater was carefully investigated. Chemical analyses showed that SNFC leached to the groundwater in concentrations of up to 58 microg/l of total SNFC at a distance of about 60 m down-gradient from the construction site. Of the individual SNFC components, only monomers and oligomers with up to four units could be detected in the groundwater. Oligomers with more than four units did not leach from the cement paste. The leached oligomers were transported in the groundwater at different velocities, which can be explained by sorption experiments. Mass fluxes of SNFC used at the tunnel construction sites were evaluated. Most SNFC were immobilized in the cement, but 5% (w/w) of the applied SNFC were found to leach into the aquifer. This corresponds to a total amount of leached SNFC of approximately 100 kg, of which about 80% are biodegraded in the aquifer and 20% (20 kg) still remain in the groundwater.

Biodegradation, Environmental↗
PubMed2002

Double mutant and formaldehyde inactivated TSST-1 as vaccine candidates for TSST-1-induced toxic shock syndrome.

Up to now there is no treatment for staphylococcal toxic shock syndrome, a disease mainly induced by toxic shock syndrome toxin-1(TSST-1). There is great demand in finding means to control the disease, one of them is the development of an effective and safe vaccine against TSST-1. In this study we constructed a series of vaccine candidates and investigated their biological activity, toxicity, and potential to invoke an immune response. TSST-1 was isolated from Stahylococcus aureus supernatants and recombinantly expressed as a N-terminal 6x histidine-tagged protein in Escherichia coli. In order to obtain molecules with minimal toxicity we constructed single mutants (G31R and H135A) and one double mutant (G31R/H135A) with both residues exchanged. We also detoxified native TSST-1 isolated from S. aureus, and recombinantly expressed TSST-1 by treatment with formaldehyde. Functional activity of native and recombinant TSST-1 and grade of inocuity of mutants and toxoids was determined by investigating mitogenity, T-cell activation, and cytokine release upon stimulation of human mononuclear cells with the vaccine candidates. All substances were tested in a rabbit immunization study. After primary immunization and three additional boosts all vaccinated animals developed antibody titers against TSST-1 and were protected against challenge with a lethal doses of superantigen potentiated with lipopolysaccharide.

Animals↗
PubMed2003

Formaldehyde-induced gene expression in F344 rat nasal respiratory epithelium.

Formaldehyde (FA), an occupational and environmental toxicant used extensively in the manufacturing of many household and personal use products, is known to induce squamous cell carcinomas in the nasal turbinates of rats and mice and squamous metaplasia in monkey noses. Tissue responses to FA include a dose dependent epithelial degeneration, respiratory cell hypertrophy, and squamous metaplasia. The primary target for FA-induced toxicity in both rodents and monkeys is the respiratory nasal epithelium. FA increases nasal epithelial cell proliferation and DNA-protein crosslinks (DPX) that are associated with subsequent nasal cancer development. To address the acute effects of FA exposure that might contribute to known pathological changes, cDNA gene expression analysis was used. Two groups of male F344 rats received either 40 ul of distilled water or FA (400 mM) instilled into each nostril. Twenty-four hours following treatment, nasal epithelium was recovered from which total RNA was used to generate cDNA probes. Significance analysis of microarrays (SAM) hybridization data using Clontech Rat Atlas 1.2 arrays revealed that 24 of the 1185 genes queried were significantly up-regulated and 22 genes were significantly downregulated. Results for ten of the differentially expressed genes were confirmed by quantitative real time RT PCR. The identified genes with FA-induced change in expression belong to the functional gene categories xenobiotic metabolism, cell cycle, apoptosis, and DNA repair. These data suggest that multiple pathways are dysregulated by FA exposure, including those involved in DNA synthesis/repair and regulation of cell proliferation. Differential gene expression profiles may provide clues that could be used to define mechanisms involved in FA-induced nasal cancer.

Administration, Intranasal↗
PubMed1979

N-mineralization of formaldehyde-releasing N-compounds.

The mineralization of several N-compounds, such as MMU, DMU, and HMT, as well as their respective nitrificide action, have been investigated. It has been proved that the amount of available formaldehyde, as well as its rate of release, are responsible for the specific action of these compounds on the N-mineralization process. Factors affecting the rate of release, namely molecular structure, solubility, and temperature, are discussed as well. Importance of these N-compounds as slow-release N-fertilizers based on a new molecular-microbiological approach is described.

Bacteria↗
PubMed1980

Study of the effect of amines on structure of coacervates formed by photochemical effect on metal ions in presence of formaldehyde.

If an aqueous mixture of ammonium molybdate, diammonium hydrogen phosphate, biological minerals, and formaldehyde is exposed to sunlight, typical "Jeewanu", mixtures are observed. However, if a little solution of p-phenylene diamine, p-nitroaniline, alpha-naphthylamine or beta-naphthyl amine is added to it, a dense white precipitate is obtained. This precipitate, under a microscope at X1200 magnification, appears as large clusters of very tiny cream-coloured spherules. But if the mixture is first exposed to sunlight for four hours, when the formation of typical microstructures appears, and then the amine solution is added, the formation of the precipitate is retarded as the exposure time of amine-free mixture is enhanced, till finally the formation of spherules as precipitate is stopped. Microscopic study in twenty days of exposure of the amine-containing mixture tube shows that the number of typical microstructures decreases; they get larger in size and gradually disintegrate, while the formation of tiny sdpherules is accelerated.

1-Naphthylamine↗
PubMed1980

Synthesis of phospholipids in microstructures, prepared by the interaction of ammonium thiocyanate, minerals, calcium acetate, potassium dihydrogen phosphate, and formaldehyde.

The photochemically formed microstructures, synthesized in sterilized aqueous mixture containing ammonium thiocyanate and formaldehyde in appropriate mineral environment in the presence of ferric chloride, on exposure to sunlight revealed the presence of phospholipids. The microsturctures synthesized in the unexposed mixture showed a less degree of synthesis. The microstructures showed the formation of amino acids, peptides, organic acids, and sugars as well.

Acetates↗
PubMed1978

Standardized fixation of human lung for radiology and morphometry; Description of a "two chamber"-system with formaldehyde vapor inflation.

In order to obtain optimal preservation of lungs for histology, morphometry and radiology a two-chamber system of lung fixation with hot formaldehyde vapor is introduced. Compared with other procedures this system offers small dead space and ensures quick and thorough fixation by imitating "inspiration" and "expiration". Volume- and pressure-regulated "breathing" enables fixation in a stage of the respiration cycle, which can be chosen. This procedure can be used routinely in the autopsy room. The only serious drawback seems to be air pollution, if the chambers are not absolutely insulated.

Air Pollution↗
PubMed1997

Polymerase chain reaction based gene rearrangement studies in the diagnosis of follicular lymphoma--performance in formaldehyde-fixed tissue and application in clinical problem cases.

The diagnostic potential of PCR-based studies on the immunoglobulin heavy chain (IgH) gene rearrangements and the t(14;18) translocation was evaluated in a series of 30 benign and 46 malignant follicular lymphoid lesions including difficult problem cases using formaldehyde-fixed and paraffin-embedded (FFPE) tissue. Clonal IgH gene rearrangement was documented by PCR in 38/46 follicular lymphomas using two alternative (FR3A and FR2A-based) primer systems: all benign hyperplasias showed a polyclonal pattern. The t(14;18) translocation was documented in 20/46 cases, including cases that did not show a clonal IgH gene amplification; a weak signal was seen in 6 benign hyperplasias probably related to the recently described rare non-neoplastic cells carrying the t(14;18) translocation. Of the translocations in follicular lymphomas, 18 involved the major breakpoint region (MBR) and two the minor cluster region (MCR). The diagnosis of follicular lymphoma could be reached with at least one marker in over 90% of the cases. With these tests we diagnosed an incidental follicular lymphoma in the axillary dissection for breast carcinoma, and confirmed benign nature of an extreme follicular hyperplasia with a 2200 g spleen. One diffuse large cleaved cell lymphoma with subsequent follicular small cleaved cell lymphoma was diagnosed to have a similar t(14;18) translocation showing a link between the two seemingly different lymphomas.

Adult↗
PubMed1998

Repeated low-level formaldehyde exposure produces cross-sensitization to cocaine: possible relevance to chemical sensitivity in humans.

Sensitivity to chemicals in humans has been proposed to be an acquired disorder in which individuals become increasingly sensitive to chemicals in the environment. A possible link between the manifestation of psychiatric symptoms in individuals claiming sensitivity to chemicals was investigated based on a leading hypothesis put forth by Bell and co-workers (1992) to explain the amplification of symptoms after chemical exposure. The hypothesis is that chemical sensitivities may be akin to sensitization observed in rodents after repeated psychostimulants. Repeated exposure to psychostimulants enhances behavioral activity and the underlying neurochemical responses in specific limbic pathways; a similar sensitization of limbic pathways has been proposed to occur in individuals who become sensitive to chemicals. To test this hypothesis, female Sprague-Dawley rats were exposed to either air or formaldehyde (Form) for 1 h/day for 7 days or 20 days (5 days/week x 4 weeks). Two to 4 days after the last exposure, rats were given a cocaine challenge (= early withdrawal) followed by an additional cocaine challenge 4-6 weeks later (= late withdrawal). No differences in cocaine-induced locomotor activity were noted between groups after 7 days of exposure. However, after 20 days of exposure to Form, vertical activity was significantly elevated at both early and late withdrawal times. These studies demonstrate that behavioral sensitization occurs after long-term, but not short-term, low-level exposure to Form, and lends support to the limbic system sensitization hypothesis of sensitivity to chemicals in humans.

Anesthetics, Local↗
PubMed1996

Toxicity of formaldehyde and acrolein mixtures: in vitro studies using nasal epithelial cells.

In vitro studies with human and rat nasal epithelial cells were carried out to investigate the combined toxicity of formaldehyde and acrolein and the role of aldehyde dehydrogenases in this process. These studies showed that the toxic effect of mixtures of aldehydes was additive. In addition, aldehyde dehydrogenases were inhibited by disulfiram and acrolein in S9 incubation but disulfiram did not influence the toxicity in vitro (cell culture). This study does not support the idea that aldehyde dehydrogenases play a major role in the detoxification of exogenous aldehydes.

Acrolein↗
PubMed2003

Manufacture of flame retardant foaming board from waste papers reinforced with phenol-formaldehyde resin.

A new flame retardant and waterproof porous fiberboard was manufactured from waste newspapers by using a foaming agent and a reinforcing phenol-formaldehyde resin. To find the optimum conditions for forming fiberboard with high mechanical properties as well as flame retardant and waterproof characteristics, a series of experiments were performed with varying weight percentages of resin (w). The results indicate that the best quality of the fiberboard was obtained for w approximately 11%.

Acrylic Resins↗
PubMed2003

Effect of veneer side wettability on bonding quality of Eucalyptus globulus plywoods prepared using a tannin-phenol-formaldehyde adhesive.

The influence of rotary peeling on the different behaviour of tight and loose sides of Eucalyptus globulus veneers has been studied. The presence of lathe checks on the loose sides favours wettability, the contact angle decreasing more rapidly on these sides than on tight sides. Additionally, pine bark tannins improved wettability due to their surfactant character. Bonding quality tests carried out on plywoods prepared using a tannin-phenol-formaldehyde adhesive showed that fracture almost invariably occurred in a glue line with at least one loose side, where wood failure appeared. This behaviour, confirmed by analysing the glue lines by means of fluorescence microscopy, was due to the large surface alterations of the loose sides which reduced mechanical strength but allowed greater penetration of the adhesive giving rise to high wood failure.

Adhesives↗
PubMed2003

Impregnation of softwood cell walls with melamine-formaldehyde resin.

Melamine-formaldehyde (MF) resin impregnation has shown considerable potential to improve a number of wood properties, such as surface hardness and weathering resistance. In this study, selected factors influencing the uptake of MF resin into the cell wall of softwood were studied. Using UV-microspectroscopy, it could be shown that water soluble MF diffused well into the secondary cell wall and the middle lamella. Concentrations as high as 24% (v/v) were achieved after an impregnation of 20 h. High cell wall moisture content, high water content of the resin used for impregnation, and low extractive content are factors which are favourable for MF resin uptake into the cell wall. For dry cell walls, solvent exchange drying improved resin uptake to a similar extent, as was the case when cell walls were soaked in water.

Construction Materials↗
PubMed2000

Mapping chromosomal proteins in vivo by formaldehyde-crosslinked-chromatin immunoprecipitation.

Gene regulation is a complex process. Numerous factors appear to be required for the accurate temporal and spatial regulation of each gene. Often these factors are assembled into multiprotein complexes, contributing to specific gene regulation events. Understanding how all these factors are organized in the chromosome and how their function is regulated in vivo is a challenging task. One of the most useful techniques for studying this level of gene regulation is the in vivo fixation by formaldehyde crosslinking of proteins to proteins and proteins to DNA, followed by immunoprecipitation of the fixed material.

Animals↗
PubMed2001

Postinfarction ventricular septal perforation repair with endoventricular circular patch plasty using double patches and gelatin-resorcinol-formaldehyde biological glue.

We describe a technique for repairing the ventricular septal perforation 10 days post acute anteroseptal myocardial infarction using the modified infarction exclusion method. The repair involves endoventricular circular patch plasty and application of gelatin-resorcinol-formaldehyde biological glue in the space between a Teflon felt patch on the infarcted septum and a bovine pericardial patch in the left ventricular cavity. Its use in a patient resulted in an almost normal shaped interventricular septum and left ventricular cavity as well as normal left ventricular function.

Aged↗
PubMed1997

Pneumostatic effect of gelatin-resorcinol formaldehyde-glutaraldehyde glue on thermal injury of the lung: an experimental study on rats.

OBJECTIVE: Recently, the use of gelatin-resorcinol formaldehyde-glutaraldehyde (GRFG) glue has been reported in vascular surgery, especially in surgery for acute aortic dissection. However, reports concerning its use in lung surgery are quite rare. Although the strong adhesion and tensile strength of GRFG glue to fresh incisional wounds of the lung has been demonstrated experimentally, the effectiveness of this adhesive on thermal injury with severe tissue degeneration has not yet been reported. METHODS: We experimentally evaluated the ability of GRFG glue to seal air leaks through severely degenerated tissues after thermal injury on rat lung, and compared its performance with two reference adhesives: fibrin glue and EDH-adhesive. RESULTS: The GRFG glue provided complete pneumostasis immediately after the sealing in the presence of positive pressure ventilation, unlike the other two reference adhesives. The fate and biocompatibility of the three glues were examined histologically at 1 h and 3, 8, and 20 days after treatment. The GRFG glue tightly adhered to the degenerated tissue surface and was gradually fragmented and absorbed. The healing process was favorable, indicating good biocompatibility. Local tissue irritability was negligible. CONCLUSIONS: Even in the presence of tissue degeneration and positive pressure ventilation, the GRFG glue has proved efficacious as a surgical adhesive in lung surgery because of its ability to bind tissue rapidly and tightly.

Animals↗
PubMed2002

Characterizing transcription factor binding sites using formaldehyde crosslinking and immunoprecipitation.

In their article, A.S. Weinmann and P.J. Farnham (2002, Methods 26) described new techniques for isolating in vivo binding sites for any DNA-binding protein. In this article, we describe complementary methods for detailed in vivo characterizations of such identified protein-DNA interactions. First, we describe how formaldehyde crosslinking and chromatin immunoprecipitation (ChIP), in conjunction with transient transfections or the use of cell lines containing stably integrated constructs or episomes, can be employed to identify which specific nucleotides of a region of DNA are required for recruitment of a particular transcription factor. In contrast to in vivo footprinting, this method not only specifies which nucleotides are bound, but also identifies the protein(s) involved in binding. Next, we discuss the use of the ChIP assay to study how binding of a transcription factor is altered by passage through the cell cycle, by overexpression or deletion of another factor, or during tumorigenesis. Finally, a look toward the future suggests that the ChIP assay may be combined with Western blot analysis or mass spectrometry to identify additional proteins that interact with a transcription factor of interest.

Animals↗