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PubMed1992

Preservation of RNA for in situ hybridization: Carnoy's versus formaldehyde fixation.

Tissues fixed with organic solvent fixatives such as Carnoy's solution are known to give poor and erratic results with in situ hybridization, whereas those fixed with paraformaldehyde produce more consistent results. To understand this difference and to improve the utility of Carnoy's-fixed tissue for in situ hybridization, we explored several parameters of RNA integrity and preservation. Carnoy's-fixed, paraffin-embedded livers and paraformaldehyde-fixed, paraffin-embedded livers of mice were compared for RNA extractability, degradation, and hybridizability. In addition, retention of RNA in tissue sections after sequential in situ hybridization treatments was compared. RNA was found to be easily extractable from Carnoy's-fixed liver and was well preserved, with only slight degradation of high molecular weight RNA. Conversely, only a small percentage of the RNA was extractable from paraformaldehyde-fixed liver unless the tissue was digested with protease. The extracted RNA was well preserved, without detectable degradation. Sections of tissue fixed in Carnoy's solution subjected to in situ hybridization retained only about 10% of their original RNA content and gave correspondingly weak in situ hybridization signals. Formaldehyde-fixed tissues retained much more of the RNA (about 45%) and produced strong in situ hybridization signals. Treatment of Carnoy's-fixed tissue sections with vaporous formaldehyde increased retention of RNA and provided in situ hybridization signals comparable with those of paraformaldehyde-fixed tissues.

Acetates↗
PubMed2001

The effects of newly synthesized pyrazole derivatives on formaldehyde-, carrageenan-, and dextran-induced acute paw edema in rats.

The antiinflammatory effects of 10 newly synthesized pyrazole derivatives on formaldehyde-induced rat paw edema were investigated. The most effective of them (K-3) was investigated again in dextran- and carrageenan-induced paw edema. In formaldehyde-induced paw edema, K-3 50, 100, and 200 mg/kg p.o. inhibited the edema by 48.9% (p<0.002), 68.7% (p<0.001), and 79.1% (p<0.001), respectively, 3 h after administration. In dextran-induced paw edema, the same dose of K-3 produced 27.1% (p<0.05), 46.8% (p<0.01), and 63.8% (p<0.002) inhibition, respectively. In the carrageenan-induced paw edema test, K-3 100 mg/kg decreased the inflammatory response by 52.0% after 4 h. Acute toxicity studies revealed that K-3 was nontoxic up to an oral dose of 2500 mg/kg.

Animals↗
PubMed1994

Formaldehyde-fixed cells infected with pseudorabies virus conferred resistance against Aujeszky's disease.

Cells infected with Pseudorabies virus (PrV) and fixed with formaldehyde were evaluated as a vaccine against Aujeszky's disease. Mice and pigs inoculated with fixed cells showed no clinical signs. In a challenge test, all fixed cells conferred protection on mice and pigs. Although pigs showed slight symptoms, they were restored to normal health within a few days. These results demonstrate that PrV-infected cells fixed with formaldehyde function as a vaccine against Aujeszky's disease and serve as a novel type of vaccine which is easy to make, and is both safe and effective.

Animals↗
PubMed1976

Homogenous and heterogenous bone implants preserved by formaldehyde: a histologic study.

Small bone sticks from a rat and a dog, fixed in formaldehyde from one to several weeks, were used as homografts and heterografts in defects created in the mandibles of rats. The animals were killed 30, 60, 90, and 150 days after the graft implantation procedure. Histologic study showed that although the homografts induced a distinct osteogenic activity and were incorporated by the host in less than 90 days, the heterografts behaved as foreign bodies and became encapsulated by connective tissue and remained unresorbed up to 150 days. Therefore, the clinical applicability of formaldehyde-fixed homografts should be considered.

Animals↗
PubMedDate not supplied

Reactions of substituted arenediazonium chlorides with methylamine-formaldehyde premix revisited: reactivity and transformations of methylolamine intermediates and their biological significance.

Modulation of the N-azo coupling between ring-substituted arenediazonium chlorides and premixed methylamine-formaldehyde leads not only to 1-aryl-3-hydroxymethyl-3-methyltriazenes and their dimers, but also to unexpected cyclic and complex products. The syntheses comprise reactions with arenediazonium chlorides bearing both -M and +M substituents at para and ortho/para positions of the phenyl ring. One of the major constituents isolated from a mixture of products is the O-acetate of 3-hydroxymethyl-3-methyl-1-(2,4,6-trichlorophenyl)triazene. This product was obtained from the reaction of 2,4,6-trichlorobenzenediazonium chloride and methylamine-formaldehyde mixture which was then stabilized by acetylation. The structures of the isolated products could be derived from reactive methylolamines and electrophilic intermediates that possible occur in vivo and thereby offer a plausible mechanistic explanation for the carcinogenic and tumour-inhibitory activity associated with the open-chain triazene compounds in the living cell.

Diazonium Compounds↗
PubMed1994

Improvement of urinary delta-aminolevulinic acid determination by HPLC and fluorescence detection using condensing reaction with acetylacetone and formaldehyde.

We improved the method for determining urinary delta-aminolevulinic acid (ALA) by HPLC-fluorometer after pre-column derivatization with acetylacetone and formaldehyde, and a stable ALA derivative was obtained without any effect from various urinary components as demonstrated by the complete recovery of ALA (100.9 +/- 5.5%, n = 85) from the urine samples. The modified procedure was as follows: Twenty microliters of urine sample, 5 ml of acetylacetone solution (acetylacetone/ethanol/distilled water containing 4 milligrams of NaCl; 15/10/75), and 0.45 ml of 9.3% formaldehyde solution were mixed and boiled for 15 min. The fluorescent derivative of ALA was separated and analyzed by HPLC with the fluorometer at Ex 246 nm and Em 458 nm. Using a gradient program, the retention time of the ALA derivative was 7.3 min and the analysis could be repeated at 13 min intervals. Concentrations of ALA in urine samples measured by this method were significantly correlated with those measured by the Mauzerall-Granick (M-G) method (n = 85, r = 0.993, p < 0.001). The values obtained by our method were, however, lower than those obtained by the M-G method. Urinary ALA concentrations of 40 non-lead workers ranged from 0.1 to 2.3 mg/g creatinine with the mean +/- SD of 1.1 +/- 0.4 mg/g creatinine as measured by the present method.

Adult↗
PubMed1983

Detection of metastatic neuroblastoma cells in bone marrow aspirates by formaldehyde induced fluorescence histochemistry.

Metastatic neuroblastoma cells in bone marrow aspirates were examined by the formaldehyde induced fluorescence histochemical method. With this method we could easily identify abnormal cells as metastatic neuroblastoma cells by observing catecholamine green colored fluorescence in their cytoplasma. This formaldehyde induced fluorescence histochemical method is significantly useful for the diagnosis of metastatic neuroblastoma of the bone marrow.

Bone Marrow↗
PubMed1997

Results of a 28-month chronic inhalation toxicity study of formaldehyde in male Fisher-344 rats.

Male F-344 rats were exposed by inhalation to gaseous formaldehyde at 0.3, 2, and 15 ppm 6 h/day, 5 days/week for 28 months. Nasal tumors were macroscopically evident in the 15 ppm group from the 14th month and 8 of 32 rats bore such tumors at the 24th month. Histopathological examination revealed both squamous cell papillomas and carcinomas. No nasal tumors were observed in the lower exposure groups (0.3 and 2 ppm groups). In the high exposure group (15 ppm group), frequent face washing, coughing and/or crouching position, lacrimation, nasal discharge, and yellow discoloration of the haircoat were observed. Significant decrease in food consumption and body weight was noted, and 20 (88.3%) rats died by the 24th month. Reduced triglyceride levels and liver weights, presumed to be related to the drop in food intake, were also seen in the 15 ppm group. Epithelial cell hyperplasia, hyperkeratosis, and the squamous metaplasia were apparent in all exposure groups. Inflammatory cell infiltration, erosion or edema were evident in all groups, including the 0 ppm and room (RC group) controls. In this study, a no effect level of formaldehyde vapor could not be obtained because toxicological signs were obvious even with the low exposure group. The benchmark doses for squamous metaplasia and epithelial hyperplasia were 0.25 and 0.24 ppm, respectively.

Administration, Inhalation↗
PubMed1992

Effect of formic acid or formaldehyde treatment of alfalfa silage on nutrient utilization by dairy cows.

Third-cutting alfalfa with 37% DM was ensiled untreated or treated with either 2.8 g of formic acid/100 g of DM or .31 g of formaldehyde/100 g of DM and fed to lactating dairy cows in two experiments. Silage treated with formic acid had the lowest pH and concentrations of NPN, NH3, and total free AA. Both treatments decreased rumen in vitro protein degradability but did not affect in vitro rumen plus pepsin digestibility. In trial 1, part 1, 22 Holstein cows received a standard diet for 18 d postpartum and then were fed for 6 wk one of three diets containing 98% alfalfa silage DM. Although DMI was comparable, yields of milk, SCM, fat, protein, lactose, and SNF were higher when treated silages were fed. Plasma concentrations of branched-chain, essential, and total AA increased when formic acid-treated silage was fed. Rumen pH and concentrations of NH3 and VFA were similar for all diets. Rumen escape protein, estimated using 15N as a microbial protein marker, was increased more by formic acid than by formaldehyde treatment. In trial 1, part 2, supplementation with 4.8% fish meal increased concentration of milk protein and yields of milk, protein, lactose, and SNF. Milk urea concentration was higher on the untreated silage diet. Total tract apparent DM and N digestibilities were not affected by silage treatment, although fish meal decreased apparent DM digestibility. In trial 2, 80:20 alfalfa silage:ground corn diets were fed to 12 midlactation cows in a 3 x 3 Latin square study. Milk production was unaffected, but milk protein concentration and DMI were higher when treated silages were fed. Feeding treated silages increased plasma concentrations of branched-chain AA, essential AA, and total AA. Formaldehyde and especially formic acid treatment effectively improved utilization of nutrients in alfalfa silage by lactating dairy cows.

Amino Acids↗
PubMed1989

The importance of formaldehyde purity in studies on the electrokinetic charge of human red cells.

Electrokinetic measurements and rheological studies conducted in parallel have previously shown red cell surface charge to play a role in governing aggregative behavior and bulk flow properties of red cell suspensions. For these and other types of model investigations, aldehyde stabilized cells have been widely used. In this communication, the influence of the purity of formaldehyde was investigated. It was found that (a) the direct dissolution of commercially available paraformaldehyde in water or suitably buffered saline results in impure solutions which, if utilized in the fixation of human erythrocytes, produces cells which have significantly different electrophoretic properties from native cells; (b) the basis for the differences is the presence of metallic impurities in some commercially available paraformaldehyde preparations; (c) the impurities and thus the anomalous electrokinetic properties of the fixed cells may be eliminated by generating formaldehyde gas from paraformaldehyde by heating the latter to 203-210 degrees C; (d) alternatively, the impurities may be eliminated by addition of disodium ethylenediamine tetraacetate dihydrate to fixative solutions prepared directly from paraformaldehyde.

Adult↗
PubMed1976

Effect of formaldehyde on disinfection of filtered air under positive pressure (FAPP) type house.

Effect of formaldehyde liberated from formalin on disinfection of the surface of a filtered air under positive pressure (FAPP) house and the surface of equipment placed in the house was studied. Escherichia coli, Staphylococcus aureus and avian adenovirus were used in this study as a indicator to evaluate degree of disinfection. Satisfactory degree of disinfection of the house and equipment was obtained when formaldehyde was liberated from 40 ml. of formalin per 1 m.3 capacity. Bacteria and virus used in the experiments, as well as air-borne organisms in the house, were perfectly inactivated by fumigation for 24 hours at the level of formalin mentioned above.

Air Microbiology↗
PubMed1993

Formaldehyde exposure and respiratory cancer--a meta-analysis of the epidemiologic evidence.

A recent meta-analysis by Blair and his co-workers stimulated the undertaking of a reanalysis of the epidemiologic evidence of an association between formaldehyde and respiratory cancer. Emphasis was placed on extracting the maximal amount of relevant data from the source studies. In close agreement with the original analysis, the aggregated evidence did not indicate an excess risk or an exposure-response gradient for lung cancer. An exposure-response gradient was seen for both sinonasal and nasopharyngeal cancers. The risk for substantial exposure was significantly elevated (odds ratio 1.7 for sinonasal and 2.7 for nasopharyngeal cancer). It is suggested that at least substantial levels of occupational exposure to formaldehyde are associated with a risk of these cancers. The excess risk would be of the order of 100% or more over background rates.

Epidemiologic Methods↗
PubMed1998

An evolutionary role of formaldehyde.

The evolution can be divided into three stages: chemical, prebiological and biological evolution. Most of the problems emerge when the development of cellular organization, the so-called prebiological evolution, is investigated. Here the possible evolutionary roles for formaldehyde as well as for the methylglyoxalase pathway are proposed. The theory, on the one hand, ascertaines a pathway serving as an anaplerotic route for the reductive citric acid cycle of surface metabolists and using formaldehyde as raw molecule. On the other hand, an explanation for the glyoxalase enigma is offered hoping that in this way a long lasting mystery of almost nine decades biochemical research can be solved.

Biological Evolution↗
PubMed1998

Formaldehyde in the plant kingdom.

Formaldehyde, at its dimedone adduct, formaldemethone, has been detected by thin-layer and high-performance liquid chromatography in extracts of all species tested of marine algae, macrofungi, lichens, bryophytes, pteridophytes, gymnosperms and angiosperms. The yields of formaldehyde recorded in this study varied from 30 microg/g to 4060 microg/g, fresh weight.

Chromatography, High Pressure Liquid↗
PubMed1998

Determination of endogenous formaldehyde in plants (fruits) bound to L-arginine and its relation to the folate cycle, photosynthesis and apoptosis.

A very powerful nucleophilic reagent, hydralazine(1-hydrazino-phtalazine) proved to be suitable for determination of the endogenous formaldehyde level in biological samples. It was found that in different plants (vegetables, fruits, especially in red beet, cauliflower, kohlrabi, grapes) is a large amount of releasable endogenous formaldehyde (0.5-1.0 mM) bound to L-arginine mainly in the form of N(G)-trihydroxymethyl-L-arginine (TriHMA). N(G)-hydroxymethyl-L-arginines (HMA) were proved to transfer their hydroxymethyl groups to tetrahydrofolic acid producing N5,N10-methylene-tetrahydrofolate, the coenzyme of thymidylate synthase. HMA was found to inhibit the cell proliferation of HT-29 cell culture (human colon adenocarcinoma ATCC HT-B 38) causing apoptosis. Photosynthetic experiments produced confirmatory evidences that 14CH2O could be formed in photosynthesis already after 10 seconds of 14CO2 fixation in the seedlings of Zea mays L. (single cross) and the 14CH2O was immediately trapped by L-arginine mainly as TriHMA.

Adenocarcinoma↗
PubMed1998

Change of biotransformation steps of formaldehyde cycle in water-melon plants after infection with Fusarium oxysporum.

Recent experiments indicate that the measurable formaldehyde (HCHO) level is considerably elevated in the parts of water-melon plants immediately after a nonlethal infection with Fusarium oxysporum f. sp. niveum. At the same time the level of some quaternary ammonium compounds (N(epsilon)-trimethyl-L-lysine, choline) as potential HCHO generators (gene products) is considerably decreased. That is probably due to the fact that the alarm reaction phase of this biotic stress syndrome includes an intensive demethylation process. It has been proved that HCHO may play a role in dynamic methylation-demethylation processes that also may include the methylation of biotic stress proteins. In this paper we report on qualitative and quantitative changes in the biotransformation steps of the formaldehyde cycle in different parts of the water-melon plant after nonlethal infection (biotic stress) with Fusarium. In consequence of the infection identical quantitative changes, but to a different degree, of the compounds examined are observable in both varieties. The connections resulting from the depiction of the time-dependent quantitative changes of the measured methylated compounds due to infection show a picture similar to that of Selye's stress syndrome model.

Biotransformation↗