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PubMed1980

Nitrogen balance, abomasal crude protein and amino acids in wethers fed formaldehyde-treated coastal bermudagrass and infused with methionine, glucose or monensin.

A 5 X 5 Latin square design was used to study the effects on nitrogen balance, wool growth and plasma amino acids of infusing methionine and (or) glucose into the abomasum of growing wethers fed formaldehyde-treated Coastal bermudagrass (F-CBG) or untreated Coastal bermudagrass hay. Daily treatments were: (1) CBG; (2) F-CBG + 3 g methionine (met); (4) F-CBG + 96 g glucose and (5) F-CBG + 3 met + 96 g glucose. Glucose infusion decreased (P < .005) moles/100 g of total essential amino acids in plasma; moles/100 g of lysine, valine, leucine and isoleucine were also reduced (P < .005). Moles/100 g of methionine in plasma were increased significantly by methionine infusion, but nitrogen retention was not affected (P > .10). The grams digestible protein to megacalorie digestible energy (DE) ratio was 36.6, 35.9 and 32.4 for CBG, F-CBG and F-CBG + glucose, respectively. The decrease (36.6 to 32.4) resulted in increased nitrogen retained (P < .05), increased percentage nitrogen intake retained (P < .05) and increased percentage digested nitrogen retained (P < .01). Urinary nitrogen excretion was lower (P < .01) in wethers receiving the F-CBG + glucose treatment than in those receiving the F-CBG treatment (3.60 vs 5.09 g/day). Effects of formaldehyde treatment of CBG and rumen infusion of monensin on quantities of various crude protein (CP) components reaching the abomasum were also determined in a 4 X 4 Latin square design experiment. Total CP reaching the abomasum increased (P < .01) with formaldehyde treatment and resulted in increased quantities of amino acids reaching the abomasum (P < .05). Monensin had no effect on these two parameters, and no interaction between monensin and formaldehyde was observed. Dietary CP reaching the abomasum increased with formaldehyde treatment (P < .005) and with infusion of monensin (P < .025). Total microbial protein (MP) and MP reaching the abomasum per 100 g dry matter digested were not influenced by either formaldehyde or monensin.

Abomasum↗
PubMed1980

Release of formaldehyde from denture base polymers.

The release of formaldehyde in an aqueous environment at 37 degrees C from the surface of heat-polymerized, and auto-polymerized dough and pour type acrylic denture base materials was determined quantitatively. The analytical method used was based on determination of the reaction product of formaldehyde and dimedone by means of high performance liquid chromatography (HPLC), i.e. the method is spesific for formaldehyde. Chemical model reactions were carried out to simulate possible reaction mechanisms for the formation of formaldehyde in denture base polymers. The quantities of released formaldehyde was dependent on the processing conditions and composition of the material. Heat-polymerized denture base materials released considerably less formaldehyde than the auto-polymerized dough and pour types of materials.

Acrylic Resins↗
PubMedDate not supplied

Histological changes in the nasal mucosa in persons occupationally exposed to formaldehyde alone and in combination with wood dust.

In the nasal mucosa of rodents, both formaldehyde and wood dust have proved to be carcinogenic. Wood dust is also a well-known nasal carcinogen in man. The effects of long-term exposure of humans to formaldehyde, however, are more obscure. In this investigation two groups of workers with well-defined exposure to formaldehyde and to formaldehyde and wood dust, respectively, were compared with a control group regarding histological changes in nasal specimens from the middle turbinate. Significant changes were found in the formaldehyde group but not in the group exposed to both formaldehyde and wood dust. No correlation was found between histological changes and duration of exposure, doses of exposure or smoking habits.

Adult↗
PubMed1982

Formaldehyde metabolism by the rat: a re-appraisal.

1. The metabolism of [14C]formaldehyde has been investigated in the male Sprague-Dawley rat. It is extensively oxidized to CO2 and formate, which is excreted in the urine. 2. Two radioactive compounds isolated from the urine of rats dosed with [14C]formaldehyde have been identified as N-hydroxymethylurea and N,N'-bis-(hydroxymethyl)urea, and shown to be urinary artefacts. 3. Previous studies of the metabolism of formaldehyde by rats have been re-appraised. Differences in the rate of oxidation of formaldehyde in various strains of rats result in the excretion of different urinary metabolites and, in some cases, formaldehyde. Excretion of formaldehyde leads to the formation of several artefacts depending on the components present in the urine.

Animals↗
PubMed1996

The role of DNase and EDTA on DNA degradation in formaldehyde fixed tissues.

Degradation and extraction of high molecular weight DNA from formaldehyde fixed tissues suitable for gene analysis are presented. We previously reported that DNase might play an important role in the degradation of DNA extracted from formaldehyde fixed tissues (Tokuda et al. 1990). In the present study, DNase activity of the supernatant from rat tissues fixed in buffered formaldehyde at room temperature was negligible within 3 hr. Analysis of DNA extracted from reconstituted chromatin revealed that the degradation increased in the absence of DNase depending on the duration of the formaldehyde fixation. Furthermore, high molecular weight DNA could be extracted from tissues devoid of DNase activity fixed in buffered formaldehyde containing EDTA. These results demonstrated that DNA degradation was due mainly to a mechanism other than DNAse which was inhibited by EDTA. For clinical application, v-H-ras gene was successfully detected by Southern blotting from rat spleen tissues fixed in buffered formaldehyde especially at 4 C. Fixation at low temperature is useful for gene analysis.

Animals↗
PubMed1998

Detection of formaldehyde-induced crosslinking in soft elastic gelatin capsules using near-infrared spectrophotometry.

The purpose of this research was to monitor the migration of formaldehyde from a polyethylene glycol (PEG) fill into the gelatin shell of a soft elastic gelatin capsule (SEGC) using near-infrared (NIR) spectrophotometry. SEGCs were filled with five solutions of aqueous formaldehyde in PEG (0, 0.05, 0.10, 0.20, and 0.40 v/v%), stored at ambient conditions for 48 hr, emptied, and scanned in NIR spectrophotometer. Principal component regression (PCR) was employed to analyze the spectra of the empty capsules. Good correlation was established (r2 = 0.988) when actual concentrations of formaldehyde in the PEG fill of the capsules were regressed against the principal component (PC) values from NIR spectra of the emptied and washed capsules. The loadings of the first PC describe a baseline shift in the spectra that arises from a change in water concentration. Lower PC loadings reveal the presence of signals at 1780 and 2200 nm that are not due to water absorbance, confirming the hypothesis that chemical bonds are formed during the formaldehyde-induced crosslinking of the gelatin in SEGCs. Gelatin crosslinking, initiated by formaldehyde migration from the PEG fill into the shell of an SEGC, was detected by NIR spectrophotometry. When NIR was coupled to principal component analysis, a linear relationship was found between the NIR spectra of empty SEGCs and the amount of crosslinking induced by concentrations of formaldehyde in the original fill material.

Capsules↗
PubMed1984

Effects of particle size and formaldehyde treatment of soybean meal on milk production and composition for dairy cows.

Twenty-four lactating dairy cattle were used to study the effects of formaldehyde treatment and reduction of particle size of soybean meal on milk production and composition. Cows were fed diets containing one of the following soybean meals: 1) untreated, coarse; 2) untreated, fine; 3) formaldehyde-treated, fine. Formaldehyde reduced the solubility of soybean meal protein from 22.7 to 2.9%. Grinding soybean meal reduced particle size from 842 to 249 micron. Formaldehyde treatment did not affect intake or milk production but resulted in higher efficiency of milk production (1.43 versus 1.46 kg fat-corrected milk/kg dry matter intake). Milk protein (3.08 versus 2.85%) and solids-not-fat (8.51 versus 8.35%) contents were reduced by formaldehyde. Cows fed fine soybean meal had higher dry matter intakes (22.0 versus 20.8 kg dry matter/day) and gained more body weight; however, milk production was not affected by particle size. Grinding soybean meal reduced production efficiency (1.47 versus 1.42 kg milk/kg dry matter intake) and milk fat (3.70 versus 3.33%). Lack of production response and reduced milk protein from formaldehyde treatment suggests possible overprotection of protein. Fine grinding of soybean meal appeared to favor body weight gain rather than milk production.

Animals↗
PubMed1990

Formaldehyde exposure and respiratory cancer among woodworkers--an update.

Respiratory cancer was examined in relation to occupational formaldehyde exposure in a case-referent study (136 cases, 408 referents) nested in a woodworker cohort. Plant- and time-specific job-exposure matrices were constructed for formaldehyde exposure. Over 3 ppm-months of formaldehyde exposure was associated with an odds ratio of 1.4 [90% confidence interval (90% CI) 0.5-4.1]. The odds ratios for lung cancer were near unity, the excess risk concentrating on the upper respiratory tract. That for combined exposure to formaldehyde-phenol exposure (all respiratory cancers) was 1.6 (90% CI 0.6-4.4) but 1.0 for formaldehyde only. No consistent exposure-response patterns emerged for the level, duration, or cumulative exposure. The results are hardly more than debatable support for the hypothesis concerning formaldehyde as a carcinogen in humans, the possible risk seemingly concentrating on the upper respiratory tract rather than the lung.

Case-Control Studies↗
PubMed2004

[Exposure to formaldehyde during an anatomy dissecting course].

Formaldehyde is a flammable, colorless and readily polymerized gas at ambient temperature, and is one of the major pollutants in indoor air. Medical students during their dissection course are exposed to formaldehyde, whose exposure is recently considered to be one of the causes of multiple chemical sensitivity. To understand the system that produces exposures and to plan for implementing control options, this study examined formaldehyde exposures that occurred in the gross anatomy laboratory. Formaldehyde in air was sampled by an active 2,4-dinitrophenylhydrazine (DNPH)-silica gel cartridge, extracted with acetonitrile and analyzed with an high performance liquid chromatograph-ultraviolet(HPLC-UV)detector. The geometric mean formaldehyde concentration was 20-93 ppb in the anatomy laboratory before starting the anatomy dissecting. After beginning the dissecting, however, the highest geometric mean concentrations were 1012-1380 ppb. Significant differences were observed during the exposed period for symptoms of "unusual thirst", "burning eyes", "itchy eyes", "bad feeling", "fatigue", etc. in comparison with the non-exposed period. These results show that medical schools should take more concrete measures to reduce exposure to formaldehyde.

Air Pollution, Indoor↗
PubMed1976

Sublimation of formaldehyde in freeze-drying.

Formaldehyde solution, commonly used to inactivate bacterial, rickettsial and viral suspensions during the preparation of vaccines, is known to have a deleterious effect on many antigens during freeze-drying. Sublimation of formaldehyde in shell-frozen and plug-frozen aqueous samples was investigated by measuring the residual formaldehyde periodically during the freeze-drying procedure. It was found that formaldehyde, even while subliming, concentrated on a volume basis. This was more apparent with the plug-frozen than with the shell-frozen material. Moreover, in the preparations taken to dryness, the formaldehyde polymerized to form paraformaldehyde. It was found that the addition of methanol not only prevented polymerization, but also significantly increased the sublimation of formaldehyde without concentration of the latter.

Acetals↗
PubMedDate not supplied

Growth inhibition, nuclear uptake, and retention of anthracycline-formaldehyde conjugates in prostate cancer cells relative to clinical anthracyclines.

Recent data indicate that the clinical anthracycline anti-tumor drugs, doxorubicin (DOX), daunorubicin (DAU), and epidoxorubicin (EPI), catalyze the production of formaldehyde through induction of oxidative stress and bind the formaldehyde to form a metabolite which covalently bonds to DNA. Based upon this discovery, anthracycline-formaldehyde conjugates were synthesized and evaluated in three metastatic prostate cancer cell lines, LNCaP, PC-3, and DU-145. The doxorubicin-formaldehyde conjugate, Doxoform (DOXF), inhibits the growth of PC-3 and DU-145 cells 50- and 80-fold better, respectively, than the corresponding clinical drug, DOX. Daunorubicin- and epidoxorubicin-formaldehyde conjugates, Daunoform and Epidoxoform (DAUF and EPIF), inhibit the growth about 6 to 10-fold better than the clinical drugs, DAU and EPI. In addition, DAUF, DOXF, and EPIF are 2- to 20-fold more toxic to the doxorubicin-sensitive metastatic prostate cancer cell line, LNCaP. Fluorescence microscopy indicates that the nucleus is the major target for all six drugs. Flow cytometry together with fluorescence microscopy shows that DOXF and EPIF are taken up more rapidly and more abundantly and are retained in the nucleus longer than DOX and EPI, respectively, especially in DU-145 cells. The enhanced toxicity of the anthracycline-formaldehyde conjugates is attributed to their increased nuclear uptake and retention and suggests that DOXF, DAUF, and EPIF are prodrugs to the active metabolites of the clinical drugs DOX, DAU, and EPI.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Formaldehyde treatment suppresses ruminal degradation of phytate in soyabean meal and rapeseed meal.

Most of the P in oilseed meal is in the form of phytate P, and phytate forms complexes with protein. Phytate P has been considered to be absorbed easily in ruminants because of phytate degradation in the rumen. Treatment of oilseed meals with formaldehyde improves the nutritional value of protein through suppressing its ruminal degradation. The present experiment was conducted to study the effects of formaldehyde treatment on phytate degradation in the rumen. The ruminal degradation of phytate in formaldehyde-treated soyabean meal or rapeseed meal was determined by a nylon-bag technique in sheep. Soyabean meal and rapeseed meal were treated with formaldehyde at levels of 3, 5 or 10 g/kg. Treatment with formaldehyde suppressed phytate and protein degradation in both the oilseed meals. Compared with the regular soyabean meal, the regular rapeseed meal showed lower degradability of phytate in the rumen. These results suggest that treatment with formaldehyde suppresses ruminal degradation of phytate in oilseed meal. Thus, the absorption of P from oilseed meal is probably decreased by this treatment in ruminants.

Analysis of Variance↗
PubMed2001

[Formaldehyde fixation in the third millennium].

This review deals with the general principles and problems of formaldehyde fixation. After a short description of 1) formaldehyde methods of production, 2) chemical properties of formaldehyde solution, and 3) kinetic of formaldehyde binding in tissue, formaldehyde reactivity with the tissue biopolymers, proteins and cucleic acids mainly, are described. How formaldehyde fixation of tissues adversely affects the reactivity of cellular proteins with their respective specific antibody and the ways the most commonly used retrieval techniques in immunohistochemistry act are, thereafter, discussed. Finally, concerns that need to be dealt with when formalin-fixed specimens are used for genomic analysis and studies of DNA expression are highlighted.

DNA↗
PubMed2001

Occupational exposure to wood, formaldehyde, and solvents and risk of nasopharyngeal carcinoma.

Our objective was to evaluate the link between occupational exposures to wood dust, formaldehyde, and solvents and the development of nasopharyngeal carcinoma (NPC). A case-control study was conducted among 375 newly diagnosed cases of NPC in Taipei, Taiwan, and 325 community controls matched to cases on sex, age, and geographical residence (99 and 87% response rates, respectively). Most cases (>90%) were diagnosed with WHO Types 2 or 3 (nonkeratinizing and undifferentiated carcinomas), whereas the remaining cases were diagnosed with WHO Type 1 (squamous cell carcinomas). A complete occupational history was obtained via a personal interview and blindly assessed by an industrial hygienist for intensity and probability of exposure to wood dust, formaldehyde, and solvents. Information on socio-demographic characteristics, cigarette smoking, dietary consumption of nitrosamines, and other potential confounding factors was obtained via a personal interview. Blood specimens were tested for human leukocyte antigen class I/II genotypes, polymorphisms in cytochrome P450 2E1 genotype, and various anti-EBV antibodies known to be associated with NPC. Analysis was performed using logistic regression; relative risk (RR) estimates and 95% confidence intervals (CI) were calculated. Individuals exposed to wood dust had an adjusted RR of 1.7 (95% CI = 1.0-3.0). Those exposed to wood dust for >10 years had an adjusted RR of 2.4 (95% CI = 1.1-5.0; p(trend) = 0.02). Risk was strongest for those first exposed before the age of 25 years and those seropositive to EBV. Individuals exposed to formaldehyde were at a more modest and nonsignificant increased risk of NPC (RR = 1.4; 95% CI = 0.93-2.2). Those exposed to formaldehyde for >10 years had an adjusted RR of 1.6 (95% CI = 0.91-2.9). The association between formaldehyde and NPC was stronger in analyses restricted to EBV seropositive individuals (RR = 2.7; 95% CI = 1.2-5.9). However, no dose response was observed with increasing duration or cumulative use. No association was observed between solvent exposure and NPC (RR = 1.2; 95% CI = 0.86-1.7). Occupational exposure to wood dust is likely to be involved in the development of NPC, a finding that is consistent with the known link between wood exposure and nasal adenocarcinomas. Formaldehyde exposure is less clearly linked to NPC, whereas exposure to solvents is unlikely to be involved in NPC pathogenesis.

Adolescent↗
PubMed1976

The generation of formaldehyde from methenamine. Effect of urinary flow and residual volume.

The antimicrobial effect of methenamine in urine is dependent upon: (i) the rate of generation of formaldehyde; (ii) the concentration of formaldehyde achieved; and (iii) the duration of bacterial exposure to formaldehyde. Studies utilizing an in vitro model which simulates the dynamics of the urinary tract showed that bacteriostatic concentrations of formaldehyde (greater than or equal to 25 mug per ml) were obtained from attainable concentrations of methenamine at urine pH 5.7 to 5.85. Reduced urinary flow rates and large residual volumes increased formaldehyde concentrations and would appear to provide prolonged bacterial exposure to the formaldehyde.

Formaldehyde↗
PubMed1977

Methenamine and its salts as urinary tract antiseptics: variables affecting the antibacterial activity of formaldehyde, mandelic acid, and hippuric acid in vitro.

The activities of formaldehyde and of mandelic and hippuric acids, alone and in combination, have been tested against some 300 strains of bacteria typical of those causing urinary tract infections. In a chemically defined medium, which resembles urine in many respects, formaldehyde had a mean minimal inhibitory concentration of 13 mug per ml. Activity was several fold lower in media (nutrient agar and tryptic soy agar) that contained significant amounts of protein. The activity of formaldehyde is virtually unaffected by pH in the range of 5 to 8. Mandelic and hippuric acids (2 mg per ml) have limited antimicrobial activity at acid pH values only. The combination of formaldehyde with mandelic acid (2 mg per ml) was additive, most markedly at pH 5; the formaldehyde-hippuric acid combination, however, did not appear to be additive. Our findings suggest that, at pH values between 5 and 6, an antibacterial concentration of formaldehyde will be generated from methenamine within approximately 1 hr after being excreted into the urine.

Anti-Infective Agents, Urinary↗
PubMed2003

Formaldehyde inhalation & open field behaviour in rats.

BACKGROUND & OBJECTIVES: It has been shown in animal studies that repeated exposure to formaldehyde vapour alters behaviour and memory. Since information is not available on the behavioural consequences of acute formaldehyde exposure, this study was conducted to investigate the influence of single inhalative exposure to formaldehyde on the explorative and locomotor behaviour of adult male and female rats. METHODS: Rats were exposed to different concentrations of formaldehyde vapour (0.5, 1.0, 2.5%, corresponding to inhalation chamber concentrations of 1.0, 2.5, and 5.0 ppm, respectively) for 2 h and an open field test was carried out 2 h after the end of exposure (first test) and repeated 24 h thereafter (second test). The parameters examined were crossing of floor squares, sniffing, grooming, rearing, climbing, and defaecation. RESULTS: In exposed male rats, significant reduction of crossed floor squares, grooming, and wall climbing, and increase in floor sniffing and rearing were observed in the first test. During the second test, males in the groups exposed to 2.5 ppm and 5 ppm crossed significantly higher numbers of squares when compared to controls. Air sniffing, wall climbing, and rearing were altered in all exposed males. Control males showed higher incidence of defaecation in comparison to the values of first test. The formaldehyde-exposed female rats crossed significantly decreased numbers of floor squares in the first test. In females in the 2.5 ppm and 5 ppm groups, decreased grooming and enhanced floor sniffing were observed. In the second test, all exposed females crossed higher numbers of floor squares than controls. Frequencies of air and floor sniffing were higher in females exposed to 2.5 ppm and lower in those exposed to 1 ppm. Defaecation was enhanced in females in the 2.5 ppm group in comparison to the first test. INTERPRETATION & CONCLUSION: The results show that formaldehyde inhalation in the concentrations and duration of exposure used in the present experiments significantly influences the locomotor and explorative behaviour of rats after a single exposure in a gender-related manner and that various behavioural components in the exposed animals remains altered even after 24 h.

Animals↗
PubMed2004

[Study on the acquiring data time and intervals for measuring performance of air cleaner on formaldehyde].

OBJECTIVE: The measuring time and measuring intervals to evaluate different type of air cleaner performance to remove formaldehyde were provided. METHODS: The natural decay measurement and formaldehyde removal measurement were conducted in 1.5 m3 and 30 m3 test chamber. RESULTS: The natural decay rate was determined by acquiring formaldehyde concentration data at 15 minute intervals for 2.5 hours. The measured decay rate was determined by acquiring formaldehyde concentration data at 5 minute intervals for 1.2 hours. When the wind power of air cleaner is smaller than 30 m3/h or measuring performance of no wind power air clearing product, the 1.5 m3 test chamber can be used. Both the natural decay rate and the measured decay rate are determined by acquiring formaldehyde concentration data at 8 minute intervals for 64 minutes. CONCLUSION: There were different measuring time and measuring intervals to evaluate different type of air cleaner performance to remove formaldehyde.

Air Pollutants↗