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PubMed1986

Calcification of subcutaneously implanted type I collagen sponges. Effects of formaldehyde and glutaraldehyde pretreatments.

Although collagen-containing implants are widely used in various surgical applications, there has been relatively little attention paid to the possibility that this type of biomaterial may undergo pathologic calcification which could compromise its function. The present study reports for the first time the calcification of a series of implants of purified collagen sponges prepared with graded degrees of aldehyde-induced cross-linkages (assessed by shrinkage-temperature, wetting time, and collagenase digestibility). Type I collagen sponges were pretreated with either glutaraldehyde (0.1% to 2.0% aqueous solution, for 5-180 minutes) or formaldehyde (as vapors for 15 minutes to 15 hours), and implanted subcutaneously for 21 days in weanling rats. Although specimens not pretreated with either aldehyde reagent and the formaldehyde sponges pretreated for 15 minutes were resorbed without evidence of calcification, all other aldehyde-pretreated implants mineralized. The degree of calcification did not correlate with extent of cross-linking. Formaldehyde-pretreated implants calcified more extensively (Ca2+ = 87.8 +/- 2.8 micrograms/mg, mean +/- standard error of the mean; n = 58) than did glutaraldehyde-pretreated implants (Ca2+ = 40.9 +/- 1.4 micrograms/mg; n = 52). It is concluded that both glutaraldehyde- and formaldehyde-pretreated Type I collagen sponges calcify after subdermal implantation in young rats. Although aldehyde pretreatment of Type I collagen sponge implants is a prerequisite for their eventual mineralization, the threshold level of aldehyde-induced cross-linking required to potentiate their maximal pathologic calcification is low.

Aldehydes↗
PubMedDate not supplied

[The role of rat liver microsomes in the metabolism of methylmethacrylate to formaldehyde].

Rat liver microsomal carboxylesterase catalyzed hydrolysis of butyl methacrylate (BMA), butyl acrylate (BA), methyl acrylate (MA) and methyl methacrylate (MMA). The rate of butanol formation from BA and BMA was 4-fold higher as compared with methanol production from MA and MMA. Methanol was oxidized to formaldehyde at the next step of microsomal metabolism. The rate of methanol oxidation was increased 2.2-fold after addition of the NADPH-generating system into the incubation medium. In the mixture containing MMA, NADPH-generating system and liver microsomes, preinduced with phenobarbital or methyl cholanthrene, the rate of formaldehyde generation was increased 7- and 2-fold, respectively, as compared with the analogous experiments involving liver microsomes of control rats. Production of methanol and generation of formaldehyde were not detected after incubation of MMA with inactivated microsomes. The microsomal MMA-methanol oxidizing system was inhibited by CO or after addition of microsomes from rats pretreated with CoCL2. Sodium azide (0.05 mM) decreased 8-fold the rate of formaldehyde generation.

Animals↗
PubMed1988

[Formaldehyde and phthalic anhydride asthma. Demonstration of specific IgE antibodies with RAST].

Two patients with positive formaldehyde RAST and 3 with positive phthalic anhydride RAST are described, of whom 3 presented with a typical history of occupational asthma and one had only work-related rhinitis. The fifth case with specific IgE antibodies to formaldehyde had only a domestic exposure-effect relationship; asthmatic symptoms had first started some weeks after renovation of the patient's apartment. Thus far, failing proof of specific IgE antibodies, a true allergic reaction to formaldehyde in particular has been doubted. Presenting respiratory symptoms were considered to be probably due to irritant effects. The reported cases indicate that formaldehyde and phthalic anhydride may also exert their effect through immunologic mechanisms.

Adult↗
PubMed1988

[Action of exogenous formaldehyde in acute cerebral ischemia at the level of membrane structures].

The data presented are indicative of the general stabilizing action of exogenous formaldehyde on membrane structures and specific retention of macromolecular structures in membrane complexes in the presence of exogenous formaldehyde in acute cerebral ischemia. It is assumed that stabilizing effect of exogenous formaldehyde might be accounted for by its influence on the activity of lipid peroxidation in the brain tissue. High lipid content in the brain tissue resulting from exogenous formaldehyde presence in cerebral ischemia is thought to influence the stabilizing effect on the membrane structures.

Acute Disease↗
PubMed1987

Nasopharyngeal cancer, sinonasal cancer, and occupations related to formaldehyde: a case-control study.

Formaldehyde vapor induces cancer of the nasal passages in laboratory animals. In this case-control epidemiologic study, occupational information was obtained for 198 persons with sinonasal cancer (SNC), for 173 with nasopharyngeal cancer (NPC) identified as incident cases by the Connecticut Tumor Registry over 41 years among Connecticut males dying of any cause, and for 605 controls sampled from Connecticut death certificates. City directories and death certificates provided information on job, industry, employer, and year of employment for exposure classification. Without knowledge as to case-control status, an industrial hygienist particularly experienced in epidemiologic studies of formaldehyde classified each study subject with respect to probability and degree of formaldehyde exposure. For those with probable exposure to the high level 20+ years prior to death the odds ratio for NPC was 2.3 [95% confidence limits (CL): 0.9, 6.0], and for those with this same risk factor among men dying at age 68+ (the median study age at death or older) the odds ratio was 4.0 [95% CL: 1.3, 12.0--with two-sided P = .015, unadjusted for multiple significance tests, and with two-sided P = .129 in testing for interaction between this risk factor (never any exposure vs. probable exposure to high level 20+ years prior to death) and age (age less than 68 yr vs. age 68+ yr)]. Odds ratios were close to unity for 9 of 13 industries. Formaldehyde-related occupations in printing appeared to be associated with any type of nasal cancer (either SNC or NPC).

Formaldehyde↗
PubMed1987

Occupational formaldehyde exposure and the nasal mucosa.

This study was undertaken to evaluate the possible cytotoxic effect of formaldehyde on the nasal mucosa in man. 38 men with an average age of 38 years and average exposure time of 10.5 years were studied. They were exposed to formaldehyde when processing laminae. All men passed a medical examination and a nasal biopsy. The histological findings were scored, 0-8, according to a system proposed by Torjussen. The findings were compared with a non-exposed reference group of 25 men (mean age 35 years). 35% of the exposed were smokers compared to 48% of the nonexposed. The average histological score was 2.8 for the exposed versus 1.8 for the non-exposed (p less than 0.05, Wilcoxon). The more common findings in the exposed were loss of cilia, goblet cell hyperplasia and squamous metaplasia. In four cases (11%) there was a mild dysplasia. Smoking had a slight modifying effect on the histological picture. The results indicate that the suspected precancerous findings in animal studies after exposure to formaldehyde might be present in workers exposed to formaldehyde at relatively low levels.

Adult↗
PubMed1986

Ultrastructural evaluation of acute nasal toxicity in the rat respiratory epithelium in response to formaldehyde gas.

Ultrastructural lesions were induced by formaldehyde (HCHO) gas in the rat nasal respiratory epithelium. Male F-344 rats, 7-9 weeks old, were exposed to 0.5 or 2 ppm (6 hr/day) for 1 or 4 days and to 6 ppm (6 hr/day) of HCHO for 1 day and sacrificed immediately or 18 hr after 1, 2, or 4 days of exposure. Other groups were exposed to 15 ppm (6 hr/day) of HCHO for 1 and 2 days. Ultrastructural changes to 0.5 or 2 ppm were limited to altered cilia with wing-like projections occasionally seen on the tips of the ciliary shafts. Autophagic vacuoles were present in some of the basal cells while neutrophils were seen in the basal and suprabasal layers after 1 day exposure to 6 ppm of formaldehyde. Hypertrophy of goblet and ciliated cells were noted in animals exposed to 6 ppm of formaldehyde and sacrificed 18 hours after 1, 2, or 4 days of exposure. Some nonciliated cells formed apical blebs containing an abundance of SER. Ciliated-mucous cells were observed after 2 and 4 days of exposure to 6 ppm of formaldehyde. Nonkeratinized squamous cells containing microfilaments were seen as early as 4 days after exposure to 6 ppm and at 1 and 2 days after exposure to 15 ppm. Loss of microvilli in ciliated cells occurred in all exposure levels. At 15 ppm for 1 and 2 days, nucleolar segregation was observed in basal and cuboidal cells and internalized cilia were noted. These results demonstrate that short-term exposure to 6 or 15 ppm of HCHO caused respiratory epithelial injury which was not cell specific, but was dose related in severity.

Animals↗
PubMed1987

Formaldehyde: toxicology and hazards.

The widespread use of formaldehyde-based resins had led to the observation of consumer annoyance and health problems associated with its release. Formaldehyde vapor now is known to off-gas from many of these products. Vapor exposure of humans results in symptoms of eye and upper respiratory tract irritation. Inhaled formaldehyde also produces nasal carcinomas in rats and mice (following exposure to 14.1 ppm in mice and 5.6 ppm in rats for 6 hr/day, 5 days/week for 24 mo). These findings resulted in intensified concern over the amount of formaldehyde released into the indoor environment from various laboratory and consumer products.

Air Pollutants↗
PubMed1978

[Study on the effect of formaldehyde on the immunological reactivity and morphology of hepatitis B-antigen (author's transl)].

Treatment of purified HB-antigen with formaldehyde solution changes its immunological reactivity and its morphology. A decrease in antigen activity by formaldehyde treatment could be demonstrated by radial immunodiffusion and by radioimmunoassay (Fig. 1). Electron microscopic studies revealed a segmentation of tubular HBAg particles into small round forms (Fig. 3) and a shift of the ratio tubular forms: spherical forms in favour of the spherical particles (Table 1). These findings support the hypothesis that 20 nm particles originate from a division of tubular forms. Round forms became smaller after formaldehyde treatment (Fig. 4). The treatment with formaldehyde changed neither the density of HBsAg testes in CsCl gradients, nor the immunologic identity tested in immunodiffusion tests (Fig. 2). All prescribed effects were observed only in the high concentrations of formalin (10 and 1%), whereas in the concentration of 0.1%, which is usually used for inactivations in the development of vaccines, no immunological and morphological changes of the HBAg could be seen.

Densitometry↗
PubMed1979

Shrinkage of the brain during histological procedures with fixation in formaldehyde solutions of different concentrations.

The purpose of this study was to measure the shrinkage of the brain during fixation and the subsequent histological procedures. In neuropathology formaldehyde solutions are the most common fixative, but different concentrations are used. This may lead to uncertainty in connection with quantitative comparative studies, because of the possibility of different degrees of shrinkage. Three groups of five brains each were fixed in three different formaldehyde solutions containing 4% buffered solution, 10% and 12% solutions without additives, respectively. The further procedure to the final histological preparation was the same in all groups. The total shrinkage in volume was 48%, with no significant difference between the three groups. A significant difference appears in relation to the duration of fixation in the most concentrated formaldehyde solution. In all three groups the shrinkage due to the fixation was more than half of the total shrinkage. Finally, it is concluded that comparative quantitative studies on brains can be performed without regard to the technique after fixation in any of the concentrations of formaldehyde investigated.

Adult↗
PubMed1983

Acute symptoms secondary to formaldehyde exposure in a pathology resident.

Formaldehyde is ubiquitous and found at work and at home. The National Institute of Occupational Safety and Health (NIOSH) lists fifty-two occupations with substantial formaldehyde exposure. Pathology is one such occupation. This report describes the incapacitating symptomatology that developed from formaldehyde exposure in a pathology resident. Diagnosis and management of formaldehyde hypersensitivity are discussed and the literature reviewed.

Adult↗
PubMed1984

[Effect of formaldehyde on the protection of proteins in the silage of the peanut plant (Arachis hypogaea)].

An experiment was performed to study the formaldehyde protective effect on the ensilaged whole peanut plant protein (21.5% CP). The experimental design consisted in four treatments 5, 10, 15 and 20% formaldehyde, which was added in the proportion of 5 lt, per ton. A control group without any formaldehyde was also included. There were no significant differences in regard to pH among treatments (5.56 to 5.70). Ammonia concentration dropped significantly in all treatments, a finding which suggests a protective effect on protein nitrogen degradation to non-protein nitrogen (NH3). A lactic acid fermentation was observed, without any difference between treatment and the control group. Nevertheless, there was a reduction in propionic acid and ethanol concentration in all the silages. Therefore, it is concluded that there was an inhibition of the fermentation process in all the silages treated, and that the addition of formaldehyde at the 5% level is a satisfactory way of protecting this type of feed.

Ammonia↗
PubMed1983

Weak promotion of C3H/10T1/2 cell transformation by repeated treatments with formaldehyde.

C3H/10T 1/2 cells were treated with N-methyl-N'-nitro-N-nitrosoguanidine and then repeatedly exposed to formaldehyde (0.1 to 2.0 micrograms/ml). Exposure of N-methyl-N'-nitro-N-nitrosoguanidine-initiated cultures to formaldehyde concentrations of 0.5 or 1.0 micrograms/ml in a variety of treatment regimens resulted in focus formation in up to 9% of the treated dishes. Transformed foci were observed in 2% or less of the cultures treated with N-methyl-N'-nitro-N-nitrosoguanidine or formaldehyde alone. Formaldehyde thus appears to be only a weak tumor promoter for C3H/10T 1/2 cell transformation.

Animals↗
PubMed1983

Carcinogenicity of formaldehyde in rats and mice after long-term inhalation exposure.

Groups of approximately 120 male and 120 female Fischer 344 rats and C57BL/6 X C3H F1 mice were exposed by inhalation to 0, 2.0, 5.6, and 14.3 ppm of formaldehyde gas 6 hr/day, 5 days/week, for 24 months. This exposure period was followed by up to 6 months of nonexposure. Interim sacrifices were conducted at 6, 12, 18, 24, 27, and 30 months. Significant formaldehyde-induced lesions were restricted to the nasal cavity and proximal trachea. The distribution and severity of these lesions were concentration dependent. Rhinitis, epithelial dysplasia, and squamous metaplasia occurred in all exposure groups of rats and in the intermediate and high exposure groups of mice. There was regression of rhinitis, dysplasia, and metaplasia at 27 months (3 months postexposure) in the 14.3- and 5.6-ppm groups of mice and in the 2.0- and 5.6-ppm groups of rats. Squamous cell carcinomas were observed in the nasal cavities of 103 rats (52 females and 51 males) and 2 male mice exposed to 14.3 ppm and in 2 rats (one male and one female) exposed to 5.6 ppm of formaldehyde gas. Formaldehyde inhalation was also weakly associated with an increase in the frequency of polypoid adenomas in the nasal cavity of male rats.

Animals↗
PubMed1980

Identification of mononuclear cells in human blood. II. Evaluation of morphological and immunological aspects of native and formaldehyde-fixed cell populations.

The presence of surface-associated immunoglobulins and Fc receptors on mononuclear cells from normal human blood was investigated by the direct immunofluorescence technique combined with phase-contrast microscopy. Formaldehyde-fixed cells were compared to unfixed cells and to cells preincubated at 37 degrees C. In the unfixed samples a separate population which showed Fc receptors in an immunofluorescence technique using a labelled antigen--antibody complex was detected. This cell population showed an atypical, i.e. not clearly membrane-associated, pattern of fluorescence with anti-Fab conjugates. This interaction most probably is due to autologous IgG molecules taken up by these cells from the donor serum. Using phase-contrast microscopy, these cells were morphologically distinct from lymphocytes and mature monocytes. They will be referred to as 'undefined mononuclear cells' (UMC). After formaldehyde fixation or preincubation at 37 degrees C the interaction of the UMC with anti-Fab conjugates could no longer be demonstrated. Mature monocytes show the same atypical fluorescence pattern with anti-Fab conjugates, but in contrast to the UMC the interaction persists after formaldehyde fixation or preincubation at 37 degrees C. No evidence was found for passive uptake of labelled IgG from conjugates by any mononuclear cell F(ab')2 fragments of IgG from antisera gave results similar to those obtained with intact IgG fractions. The morphology of the different cell subpopulations is described and their relative numbers in normal blood are given. Formaldehyde fixation proved to be a simple and useful procedure, especially for the determination of the number of B lymphocytes, because the Fc receptor of the undefined mononuclear cell does not give rise to confusion.

Antigen-Antibody Complex↗
PubMed1982

[Role of folic acid and its amino derivatives in the mechanism of action of low doses of formaldehyde on the organs].

The presence of the relationship between the content of formaldehyde and folic acid in solution and tissue has been studied. It has been demonstrated that folic acid and its amino derivatives reduce the content of formaldehyde in solution by over 50%. During the build up of the increased content of folic acids and its analogs, there takes place diminution of the content of exogenous formaldehyde in all the test organs. This was interpreted as evidence of a close interplay with folic acid metabolism as regards the mechanism of action of exogenous formaldehyde introduced with a purpose of organ conservation.

Aminopterin↗
PubMedDate not supplied

[Kinetics of the reaction between formaldehyde and proteins].

The reaction between formaldehyde and protein has been studied with the use of a radioactive indicator. In the presence of excess formaldehyde the reaction is kinetically of the first order. The accordance of experimental results to the kinetic scheme of a biphasic process was shown. On this basis experimental and veritable rate constants, equilibrium constants of mono- and dimetilol derivatives formation, the energy of activation and pseudothermodynamic parameters were determined. The dependence of reaction rate and degree of protein modification from formaldehyde concentration and temperature are discussed. Given results permit to optimize and control the process of interaction between formaldehyde and proteins.

Formaldehyde↗
PubMed1995

[Formaldehyde determination in shampoos, bath preparations and dish washing liquids by colorimetric methods].

In the years 1992-1993 in cooperation with Province Sanitary-Epidemiological Stations 2415 samples of shampoos and bath preparations for adults and children as well as of dish washing liquids, imported and produced in Poland, were analysed. The colorimetric method either with the chromotropic acid or acetylacetone was used. Among polish preparations, only in 6% samples of cosmetic products for children the level of formaldehyde exceeded permitted level of 50 mg/kg. In all cosmetic products for adults as well as in all samples of dish washing liquids the content of formaldehyde was below permitted level 500 mg/kg. Among imported products, 40% of samples of cosmetics for children, 3%--for adults and 2% of dish washing liquids revealed formaldehyde level above permitted values. It is advisable to determine periodically formaldehyde content in particular cosmetic products, such as shampoos and bath preparations, mainly used by children.

Adult↗