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PubMed2001

C-H activation with elemental sulfur: synthesis of cyclic thioureas from formaldehyde aminals and S8.

The C-H activation of cyclic formaldehyde aminals LCH2 (L = RN-CH2CH2CH2-NR and RNCH2CH2-NR, R = Me, Et, iPr, tBu, or Ph) with S8 proceeds at unusually low temperatures (T< 160 degrees C) and results in the formation of the respective thioureas LC=S and H2S. The reaction constitutes a new, solvent-free method for the synthesis of thioureas that eliminates the toxic and highly flammable CS2. For R = tBu, the ionic carbenium thiocyanates [LCH]+ SCN- dominate the product spectrum and the respective thioureas are obtained in low yield. The reactivity of the analogous sulfur and oxygen ring systems towards S8 was investigated. 1,3-Dithiolane is cleanly converted into 1,3-dithiolane-2-thione (S8, 14 d, 190 degrees C) and resembles the cyclic formaldehyde aminals in this respect. 1,3-Dioxolane (L = OCH2CH2O) is completely inert towards sulfur even under forceful reaction conditions (190 degrees C, 14 d). The formation of thioureas from aminals was investigated at the CBS-4 and B3LYP/6-31G(d) levels of theory.

Formaldehyde↗

PubMed1984

Cancer mortality among workers exposed to formaldehyde.

Proportionate mortality among workers exposed to formaldehyde was analyzed among employees of a large chemical plant in Western Massachusetts. Twenty-four such decedents, all males, were identified through union records, reports of former co-workers, and a systematic review of obituaries in local newspaper. Work histories were obtained from seniority lists. Race-age-sex-adjusted proportionate mortality ratios ( PMRs ) were significantly elevated for cancer of the colon based on United States, county, and county cancer mortality proportions (PMR = 702, 424, 333, p less than or equal to .05), as were PMRs for the category buccal and pharyngeal cancer (PMR = 870, 952, 833, p less than .05). This study provides evidence of formaldehyde's carcinogenicity. These findings are at variance with a previous report of the mortality experience of workers at the same plant from an earlier period.

Aged↗

PubMed1985

Proportionate mortality study of workers in the garment industry exposed to formaldehyde.

In order to evaluate the human carcinogenicity of formaldehyde, we conducted a proportionate mortality study of garment workers engaged in the production of shirts from formaldehyde-treated cloth. This study included three plants, and was based upon 256 deaths identified from a death-benefit insurance fund. No deaths due to nasal cancer were observed, and the mortality from respiratory cancer (11 cases, PMR = 95) was slightly less than expected. Statistically significant (p less than .05) elevations in proportionate mortality were observed for malignant neoplasms of the "buccal cavity" (three cases, PMR = 750), for "biliary passages and liver" (four cases, PMR = 313) and for "other lymphatic and hematopoietic sites" (four cases, PMR = 400). A proportionate cancer mortality (PCMR) analysis also was conducted, and cancer of the "buccal cavity" (three cases, PCMR = 682), and other "lymphatic and hematopoietic sites" (four cases, PCMR = 342) were still significantly elevated. The observed excesses in cancer mortality were primarily experienced by white females, who made up the major portion of the workforce, and workers with more than 10 years of latency and duration of exposure, a criterion for inclusion for most workers in the study group. The neoplasms observed were not equally distributed among the three facilities included in the study. Because of the small number of deaths involved and the lack of consistency with other studies, we believe that these findings should be viewed cautiously, pending the outcome of more definitive studies.

Adolescent↗

PubMedDate not supplied

Simple determination of formaldehyde in dimedone adduct form in biological samples by high performance liquid chromatography.

A high performance liquid chromatographic method for the determination of endogenous formaldehyde in dimedone adduct form in biological samples is described. The simple procedure involves extraction of the formaldehyde of different binding force in biological samples with methanol containing dimedone as the capture molecule and separation on a C18 reversed phase column with methanol as eluent.

Animals↗

PubMed2002

Nitric oxide synthase histochemistry in insect nervous systems: Methanol/formalin fixation reveals the neuroarchitecture of formaldehyde-sensitive NADPH diaphorase in the cockroach Periplaneta americana.

Formaldehyde-insensitive NADPH diaphorase (NADPHd) activity is used widely as a histochemical marker for neuronal nitric oxide synthase (NOS). However, in several insects including the cockroach Periplaneta americana, NOS is apparently formaldehyde-sensitive; NADPHd fails to reveal neuron morphology and results in faint generalized staining. Here we have used a novel fixative, methanol/ formalin (MF), to reveal for the first time the neuroarchitecture of NADPHd in the cockroach, with intense selective staining occurring in neurons throughout the brain and thoracic ganglia. Immunocytochemical and histochemical analysis of cockroach and locust nervous systems indicated that neuronal NADPHd after MF fixation can be attributed to NOS. However, NADPHd in locust glial and perineurial cells was histochemically different from that in neurons and may thus be due to enzymes other than NOS. Histochemical implications of species-specific enzyme properties and of the transcriptional complexity of the NOS gene are discussed. The present findings suggest that MF fixation is a valuable new tool for the comparative analysis of the neuroarchitecture of NO signaling in insects. The Golgi-like definition of the staining enabled analysis of the NADPHd architecture in the cockroach and comparison with that in the locust. NADPHd in the tactile neuropils of the thoracic ganglia showed a similar organization in the two species. The olfactory glomeruli of the antennal lobes were in both species densely innervated by NADPHd-positive local interneurons that correlated in number with the number of glomeruli. Thus, the NADPHd architectures appear highly conserved in primary sensory neuropils. In the cockroach mushroom bodies, particularly dense staining in the gamma-layer of the lobes was apparently derived from Kenyon cells, whereas extrinsic arborizations were organized in domains across the lobes, an architecture that contrasts with the previously described tubular compartmentalization of locust mushroom bodies. These divergent architectures may result in different spatiotemporal dynamics of NO diffusion and suggest species differences in the role of NO in the mushroom bodies.

Animals↗

PubMed1986

Flow cytometric discrimination of mitotic cells: resolution of M, as well as G1, S, and G2 phase nuclei with mithramycin, propidium iodide, and ethidium bromide after fixation with formaldehyde.

Cells in mitosis can be flow cytometrically discriminated from G1, S, and G2 cells by analysis of a nuclear suspension prepared with nonionic detergent, fixed with formaldehyde, and stained with mithramycin, propidium iodide, or ethidium bromide. With these DNA-fluorochromes, the fluorescence is quenched by formaldehyde less in mitotic nuclei than in interphase nuclei. Mitotic nuclei have a 20-40% increased mithramycin fluorescence and 30-60% decreased light scatter in comparison to those of G2 nuclei. There is a high correlation (r = 0.95; P less than 0.001) between microscope counts of mitotic figures in smear preparations of the initial cell suspension and the flow cytometrically estimated fraction of nuclei with increased mithramycin fluorescence. Flow sorting (FACS) demonstrates that the mitotic nuclei are confined to the peak of increased mithramycin fluorescence and decreased light scatter. The method has been applied to cultures of Yoshida ascites tumor cells, JB-1 reticulosarcoma cells, and PHA-stimulated human lymphocytes, incubated in the presence or absence of vinblastine for mitotic arrest. In a heteroploid mixture of fixed Yoshida (near-diploid) and JB-1 (hypotetraploid) nuclei, the mitotic fractions of the two cell lines could be estimated separately when analyzed with mithramycin fluorescence versus light scatter or with mithramycin fluorescence versus propidium iodide fluorescence.

Animals↗

PubMed1999

Chronic ethanol consumption impairs receptor-mediated endocytosis of formaldehyde-treated albumin by isolated rat liver endothelial cells.

Receptor-mediated endocytosis (RME) by a scavenger receptor on sinusoidal liver endothelial cells (LECs) for formaldehyde-treated bovine serum albumin (f-Alb) has previously been shown to be impaired following chronic ethanol consumption. These studies were initially performed by in situ perfusion, making it difficult to determine the point in the process at which RME is affected. Therefore, it was the purpose of this study to use isolated LECs to begin elucidating at what point in the process chronic ethanol consumption affects RME. Initial studies showed that degradation at the single-cell level were similarly decreased at levels that had been observed for in situ studies, suggesting that the ethanol effects can be repeated using isolated LECs, making them useful for in vitro studies. Binding studies with 125I-formaldehyde-treated bovine serum albumin (125I-f-Alb) demonstrated there was a slight, but significantly different, decrease in binding by LECs from ethanol-fed rats when compared with pair-fed or chow-fed rats. However, the affinity of these receptors was not different between these groups. In contrast, a defect in the initial stages of receptor-ligand internalization was indicated as less surface-bound ligand was internalized and subsequently degraded in cells from the ethanol-treated animals as compared with controls. Additionally, once the data were adjusted for the amount of ligand internalized, the degradation of the internalized ligand was only slightly impaired. These results indicate that chronic ethanol feeding impairs the process of RME by the liver; the major cause of this impairment appears to be caused by a decreased ability of these cells to internalize all of the surface-bound ligand, with a minimal defect in postinternalization events.

Alcohol Drinking↗

PubMedDate not supplied

Cell proliferation in the respiratory tract of the rat after acute inhalation of formaldehyde or acrolein.

Male Sprague Dawley rats were exposed by inhalation for 6 h per day on one or three successive days to 0, 2, 6 or 20 ppm formaldehyde or 0, 0.2 or 0.6 ppm acrolein. Nasal and tracheal epithelial and free lung cells were then analyzed for proliferative responses. The proliferative response was expressed as the proportion of DNA synthesizing cells determined by the 5-bromodeoxyuridine (BrdU) labeling technique. Single exposure to both irritants increased the DNA synthesizing (proliferating) cells by a factor of 3. After three exposures the increase was distinctly lower. All sites analyzed showed approximately the same concentration/response pattern. Significant changes in cell proliferation could be detected at 2 ppm formaldehyde and 0.2 ppm acrolein.

Acrolein↗

PubMed2005

Theoretical studies on nonlinear optical properties of formaldehyde oligomers by ab initio and density functional theory methods.

The first and second hyperpolarizability beta and gamma are obtained for formaldehyde oligomers (H2CO)n (n = 1-7) using computational methods. We have used the finite field (FF) approach and hyperpolarizability density analysis (HDA) to predict the microscopic first and second nonlinear hyperpolarizability of the formaldehyde oligomers. The spatial contributions of electrons to the hyperpolarizability by using plots of HDA are presented. It has been found from the numerical stability checking of the hyperpolarizability calculations that the calculated values by FF method are more stable than those by HDA approach. The values of beta are zero when n is even as the molecule possesses centrosymmetry, and when n is odd, the differences among beta values are not clear. The gamma values are increased with increase in n.

Computer Simulation↗

PubMed1981

Urinary excretion of methenamine and formaldehyde: evaluation of 10 methenamine products in humans.

The urinary excretion of both methenamine and formaldehyde was measured for 48 hr after the oral administration of 10 different methenamine products to 10 human subjects in a crossover study. The following dosage forms were evaluated: a tablet of methenamine base, a methenamine hippurate tablet, and eight products containing methenamine mandelate, including six enteric-coated tablets, a suspension, and a granule dosage form. The nonenteric-coated dosage forms were absorbed more rapidly, based on maximum excretion rates that occurred within 3 hr after dosing. The enteric-coated tablets, which were designed not to release methenamine until reaching the intestinal tract, exhibited maximum excretion rates that did not occur until 7-17 hr after dosing. There were no significant differences (p greater than 0.05) among products in terms of total excretion of free formaldehyde in the urine. However, large differences (p less than 0.05) were noted among products for urinary recovery of total methenamine, with the amount of administered dose recovered ranging from 16 to 83%.

Adult↗

PubMed1988

Antigen preservation in microwave-irradiated tissues: a comparison with formaldehyde fixation.

A wide range of immunoreactive antigens commonly investigated in diagnostic pathology were evaluated in tissues subjected to fixation by microwave irradiation in normal saline to 63 degrees C. All of the 23 antigens studied were well preserved and compared with corresponding tissues conventionally fixed by formaldehyde for periods of 16 and 18 h, respectively, immunostaining in microwave-irradiated tissues was clearly superior, being more intense and also more extensive. Proteolytic digestion was not necessary for irradiated tissues except for the staining of cytokeratins and desmin. It was also possible to stain for Leu-14 (CD22) and Leu-1 (CD5), whereas these lymphocyte antigens were lost during formaldehyde fixation. Cytomorphological details were well preserved in the rapidly-fixed irradiated tissues.

Antigens↗

PubMed1995

The first solvation shell of magnesium ion in a model protein environment with formate, water, and X-NH3, H2S, imidazole, formaldehyde, and chloride as ligands: an Ab initio study.

The first coordination shell of an Mg(II) ion in a model protein environment is studied. Complexes containing a model carboxylate, an Mg(II) ion, various ligands (NH3, H2S, imidazole, and formaldehyde) and water of hydration about the divalent metal ion were geometry optimized. We find that for complexes with the same coordination number, the unidentate carboxylate-Mg(II) ion is greater than 10 kcal mol-1 more stable than the bidentate orientation. Imidazole was found to be the most stable ligand, followed in order by NH3, formaldehyde, H2O, and H2S.

Cations↗

PubMed1980

Influence of formaldehyde and Sonacide (potentiated acid glutaraldehyde) on embryo and fetal development in mice.

Pregnant outbred albino mice were given formaldehyde or Sonacide (potentiated acid glutaraldehyde) by gavage on days 6--15 of gestation. The mice were killed on day 18, the general health and reproductive status of the dam evaluated, and the fetuses examined and processed in order to characterize external, visceral, and skeletal malformations. Although formaldehyde (stock solution containing 12--15% methanol as a preservative) was lethal to 22 of 34 dams treated with 185 mg/kg/day, and one of 35 dams treated with 148 mg/kg/day, these doses did not produce statistically significant (two-sided p < 0.05 versus controls) teratogenic effects in the fetuses of the surviving dams. Sonacide was also judged not to be teratogenic to the mice employed in this study, in spite of the fact that relatively high doses were employed. The highest doses of Sonacide studied (5.0 ml/kg/day, which is equivalent to 100 mg/kg/day of glutaraldehyde) killed 19 of 35 dams and caused a significant reduction in the mean weight gain of the surviving mothers. In addition, this dose produced a significant increase in the number of stunted fetuses.

Abnormalities, Drug-Induced↗

PubMed1999

Quantification of bacterial lipopolysaccharides by the purpald assay: measuring formaldehyde generated from 2-keto-3-deoxyoctonate and heptose at the inner core by periodate oxidation.

We have adapted the purpald assay (M. S. Quesenberry and Y. C. Lee, Anal. Biochem. 234, 50-55, 1996) to quantify lipopolysaccharide (LPS) content in solution in 96-well microtiter plates at room temperature. This method employs the oxidation of unsubstituted terminal vicinal glycol groups in 2-keto-3-deoxyoctonate (Kdo) and l-(or d-)glycero-d-manno-heptose of LPS molecules by periodate to release formaldehyde. The formaldehyde is quantified at 550 nm (or 530-570 nm) by reacting with purpald reagent followed by oxidation with NaIO4. The sensitivity of the purpald assay is comparable to that of the Kdo assay for LPS determination. However, the purpald assay is superior to the Kdo assay because: (i) No acid hydrolysis of the samples and no boiling in the assay process are required; thus, it can be directly carried out with microtiter plates for a large number of samples at room temperature. (ii) The purpald assay can detect many types of LPS from various bacteria since LPS contains Kdo and heptose which possess unsubstituted terminal vicinal glycol in its structure, while the Kdo assay cannot detect LPS from certain bacteria (e.g., Haemophilus influenzae, Bordetella pertussis, and Vibrio cholerae) due to substitution at the C-4 and C-5 positions of Kdo.

Bordetella pertussis↗

PubMed1993

Time-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on serum and urine levels of malondialdehyde, formaldehyde, acetaldehyde, and acetone in rats.

The ability of TCDD to produce lipid mobilization and alter lipid metabolism is well known. Previous studies have indicated that TCDD induces an oxidative stress and enhances lipid peroxidation. However, the products resulting from altered lipid metabolism in response to TCDD have not been studied. We have examined the time-dependent changes in serum and urine levels of malondialdehyde, formaldehyde, acetaldehyde, and acetone in response to a single oral 50 micrograms/kg dose of TCDD in rats. The changes in these four metabolic products were quantitated by high-pressure liquid chromatography (HPLC). The effects of TCDD were compared in ad libitum-fed control animals and pair-fed animals. Serum and urine levels of the four metabolites were assayed on Days 0, 3, 6, 9, and 12. Following TCDD administration, significant increases in the four metabolites present in serum and urine were observed at all time points. For example, on Day 6 post-treatment malondialdehyde, formaldehyde, acetaldehyde, and acetone increased approximately 1.8-, 1.4-, 2.0-, and 3.0-fold in serum, respectively, and 1.3-, 1.4-, 1.6-, and 2.0-fold in urine, respectively, relative to pair-fed control animals. Increases in the serum and urine levels of the four metabolites were significantly greater for TCDD animals than for pair-fed control animals at most time points. When the serum levels of malondialdehyde as determined by HPLC were compared with the results obtained by the thiobarbituric acid (TBA) colorimetric method, similar time courses were observed although higher results were obtained for the less specific TBA method. The results clearly demonstrate that TCDD causes markedly elevated serum and urine levels of four specific products associated with lipid metabolism.

Acetaldehyde↗

PubMed1999

Pharmacodynamics of formaldehyde: applications of a model for the arrest of DNA replication by DNA-protein cross-links.

A variety of evidence suggests that formaldehyde (HCHO)-induced DNA-protein cross-links (DPX) are genotoxic as a result of their ability to arrest DNA replication. Although DPX can be removed and the DNA can be repaired, failure to remove the blockage prior to cell division or excision followed by incomplete repair could cause cell death or a mutation. To characterize the concentration and time dependence of this mechanism, a biologically based model for DNA replication in the presence of DPX was developed based on the assumptions that (1) DPX are formed randomly in the DNA and (2) a replication fork can advance up to but not past a DPX. Using a combination of Poisson and binomial statistics, a quantitative relationship between the amount of newly synthesized DNA and the concentration of DPX was derived, which predicts that the rate of DNA replication should decrease nonlinearly with increasing concentrations of DPX. Because the latter is a nonlinear function of the airborne concentration of HCHO, an inverse sigmoidal relationship is predicted between the rate of DNA replication and the concentration of inhaled formaldehyde. The model was parameterized using data derived from a study of the incorporation of [methyl-(14)C]thymidine monophosphate into the DNA of the nasal respiratory mucosa of Fischer-344 rats exposed to (3)HCHO and H(14)CHO (6 ppm, 6 h). The model was then applied to measurements of DNA replication in the nasal mucosa of experimental animals exposed to wide ranges of H(14)CHO (rats: 0.7, 2, 6, or 15 ppm, 3 h; rhesus monkeys: 0.7, 2, or 6 ppm, 6 h). The results indicate that, at airborne concentrations above 6 ppm in rats, there is a marked decrease (ca. 62% at 15 ppm) in the amount of newly synthesized DNA due to DPX formation during a single 6-h exposure to HCHO. The arrest of DNA replication at high HCHO concentrations could result in cytolethality or genotoxicity, both of which are critical factors in the induction of rat nasal cancer by HCHO. However, at concentrations below 2 ppm in monkeys or 1 ppm in rats, the decrease in the rate of DNA replication is predicted to be <1% after a 6-h exposure. This small decrease is probably undetectable using currently available techniques. The parameterized model suggests that the arrest of DNA replication by DPX is mainly a high-dose phenomenon and that at ambient exposure concentrations it is unlikely to be a major risk factor.

Animals↗

PubMed1977

Cross-linking of amino acids by formaldehyde. Preparation and 13C NMR spectra of model compounds.

Model cross-linked systems have been prepared by reacting amino acids or alkylamines with formaldehyde and various amino acid model compounds such as 2,4-dimethylphenol (tyrosine), 3-methylindole (tryptophan) and alkylamides (glutamine, asparagine. 13C NMR spectra of the products show the resonances of the formaldehyde-derived methylene carbons in the region 45-60 ppm. Interferences occur from resonances of the alpha-amino acid methine carbons. From the data for these products and other model compounds it has been possible to predict the shifts of the residual methylene carbons in a variety of cross-linked systems. This NMR technique shows promise as a rapid non-degradative method for identification of cross-linking sites.

Amino Acids↗

PubMed1982

The peripheral innervation of the gill of the marine mollusc demonstrated by the aluminium-formaldehyde (ALFA) histofluorescence method.

The aluminium-formaldehyde (ALFA) histofluorescence method was used to study the innervation of the gill of the marine bivalve mollusc Mytilus edulis and the results were contrasted with those obtained with the standard formaldehyde-induced-fluorescence (FIF) method. The ALFA method produced more fluorescing structures than the FIF method, thus revealing fine branches of the branchial nerve running beneath the gill epithelium which previously remained undetected. This study of marine invertebrates.

Aluminum↗