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PubMed2002

[Determination of dimethylformamide in food additive sucrose esters of fatty acids using solid-phase extraction].

A simple method using Florisil cartridges was developed for the determination of dimethylformamide (DMF) in sucrose esters of fatty acids present in sugar esters (SuE) and sucrose acetate isobutyrate (SAIB) used as food additives. SuE was dissolved in acetone and loaded on a Florisil cartridge. SAIB was dissolved in hexane, loaded on a Florisil cartridge and washed with 10% acetone in hexane. The columns were eluted with acetone and DMF in the eluates was determined by GC with an FID detector. Recoveries of DMF at the level of 0.5-100 micrograms/g were 93.3-102.6%. The determination limit was 0.5 microgram/g.

Chromatography, Gas↗

PubMed1976

Acute toxicity of various solvents in the mouse and rat. LD50 of ethanol, diethylacetamide, dimethylformamide, dimethylsulfoxide, glycerine, N-methylpyrrolidone, polyethylene glycol 400, 1,2-propanediol and Tween 20.

The LD50's of various solvents frequently used in toxicological work to improve the solubility of otherwise poorly soluble compounds were determined in the mouse and rat. The substances investigated were ethanol, dimethylacetamide, dimethylformamide, dimethylsulfoxide, glycerine, N-methylpyrrolidone, polyethylene glycol 400, 1,2-propanediol and Tween 20. The substances were administered under standardized conditions to groups of 10 animals (5 females, 5 males) (mice and rats) at doses that supplied at least 3 values lying between the LD16 and LD84. The median lethal dose and slope were determined with the aid of Finney's programmed probit analysis. The results are tabulated as LD50 ml/kg with 95% confidence limits. It is recommended that when using these solvents for pharmacological and toxicological investigations not more than a quarter of the LD50 should be used because otherwise there will be confusion between the deaths due to the substance being investigated and those due to the solvent.

Acetamides↗

PubMedDate not supplied

Capillary electrophoresis in mixed aqueous-organic solvents: effect of aprotic dipolar N,N-dimethylformamide and N,N-dimethylacetamide on acidity constants of substituted aromatic acids.

The change in the pKa values of substituted benzoic acids in binary mixtures of water with N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA), respectively, was determined up to a concentration of 80% (vol/vol) organic cosolvent. Such solvents are applied as media of the background electrolyte in capillary electrophoresis, with the intention of increasing the analyte solubility and the separation selectivity. The pKa values increase nonlinearly with increasing DMF and DMA concentration, and reach values between 2.5 and 3.7 pK units higher than in water at 80% organic solvent content. This change is discussed based on the concept of the medium effect, taking into account the particular stabilization of the species involved in the protolysis equilibria of the acids: HA, A-, and H+, in the different solvents. The contribution of the medium effect of the individual neutral acid HA on the delta pKa values is determined by solubility measurements. The increase in the delta pKa values, averaged for all five acids investigated, is compared in different mixed aqueous-organic media, consisting of methanol, ethanol, 1-propanol, acetonitrile, DMF, and DMA, respectively. The comparison is based on the third-order polynomial fit of the delta pKa versus organic solvent concentration data. It is found that, in this respect, acetonitrile resembles the lower alcohols, and is dissimilar to the other dipolar, aprotic solvents, DMF and DMA. The similarity of the solvent systems is depicted by cluster analysis.

Acetamides↗

PubMed1975

Electrochemical properties of polycyclic compounds studied by the polarographic method in anhydrous systems. II. Polarographic study of carcinogenic nitrogen compounds in dimethylformamide and comparison of half-wave potentials with quantum-chemical calculations of molecular orbitals.

Reduction of half-wave potentials and the mechanism of reduction of 20 polycyclic nitrogen compounds were studied on a dropping-mercury electrode in anhydrous dimethylformamide using tetrabuthylammonium perchlorate as the supporting electrolyte. The measured values of the reducing half-wave potentials of the polycyclic aza-compounds were compared in view of their carcinogenic activity with parental carcinogenic polycyclic hydrocarbons. Electrochemical measurements have confirmed that the size of the shift in reducing potentials towards the more positive values and the decline of the carcinogenic activity generally depend on the number and position of the nitrogen atoms in the molecule of the polycyclic nitrogen compound under study. At the same time, the experimental electrochemical measurements were matched with the results of the quantum-chemical calculations of the molecular orbitals and this showed a good agreement to exist between the values of reducing half-wave potentials obtained by experimental measurement and by calculation.

Aza Compounds↗

PubMed1976

Acute and protracted changes in the liver of Syrian hamsters induced by a single dose of aflatoxin B1. Observations on pathological effects of the solvent (dimethylformamide).

Male Syrian hamsters, 8-10 weeks of age, were treated with a single intraperitoneal injection of crystalline aflatoxin B1 in solution of N -N -Dimethylformamide (DMF). The concentrations of aflatoxin were adjusted to the smallest controllable amount of solvent in relation to the size of the animal (0-5 or 1-0 ml/kg). Treatment with, respectively, 5-0 or 2-5 mg/kg aflatoxin in 1-0 ml/kg DMF was lethal to most animals within one week. However, reduction of the solvent to 0-5 ml/kg, while not eliminating the mortality entirely during the first week, made possible observation of the survivors up to 28 days. Hamsters appear to be more susceptible to DMF poisoning than other species, like rat, guinea-pig and rabbit in which this solvent was used by investigators on the biological effects of aflatoxin. Either dose given of DMF alone was lethal for several animals during the first week of observation and sufficient to produce histological lesions in the liver which were characteristic and clearly different from those induced by aflatoxin during the same period. DMF alone caused centrilobular necrosis which was accompanied by haemosiderosis of liver structures. With a aflatoxin, in addition, periportal and midzonal necrosis of the liver was present. Aflatoxin B1 and B1 and DMF both induce haemorrhagic tendency probably involvement in the coagulation process of the blood. It cannot be decided, however, at present whether this is the result of an indentical mechanism.

Aflatoxins↗

PubMed2004

Molecular dynamics study of the effect of the gamma-Abu insert on the conformational behavior of the glycopeptide dendrimers based on the oligolysine scaffold in N, N'-dimethylformamide.

Glycodendrimers bearing Tn (alpha-D-GalNAc-(1 --> O)-Ser/Thr), an identified tumor-associated carbohydrate antigen, hold promise in the post-surgery treatment of a variety of tumors such as metastatic breast cancer. We used molecular dynamics (MD) techniques to examine structural differences taking place during synthesis of two classes of tetravalent Multiple Antigen Glycopeptides (MAG) that differ only by the gamma-Abu insert in the structure of the oligolysine core. Each of the selected intermediates of the synthesis was modeled, subjected to the 2 ns run in N,N'-dimethylformamide (DMF) and geometrically characterized. We characterized: a) distances of free, or extended termini from the anchor, b) interatomic distances between free or substituted N termini, c) radius of gyration and d) spatial distribution of molecular density. A detailed conformational analysis of 16 glycodendrimers shows the distinct behavior of the inserted vs. non-inserted constructs already during the first steps of the modeled synthesis. It suggests that the character as well as the length of the insert has a major impact on the spatial characteristics and behavior of the dendritic molecules. The inserts can, in principle, increase a tendency of dendrimers to establish a high-density core, which is similar to the effect of a higher generation.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed2006

[Influencing factors that affect the biological monitoring of workers exposed to N,N-dimethylformamide in textile coating factories].

OBJECTIVES: The objective of this study is to assess the factors influencing biological monitoring of textile coating factory workers exposed to N,N-dimethylformamide (DMF). METHODS: We studied 35 workers who were occupationally exposed to DMF from 9 textile coating factories. The study was carried out in two phases; summer and winter. While air concentration of DMF, temperature and humidity were assessed in order to monitor the atmospheric conditions, biological monitoring was done to determine the internal dose by analyzing the N-methylformamide (NMF) collected from urine at the beginning and end of the shift. Questionnaires and medical surveillance were also obtained during the two phases. RESULTS: Median air concentrations of DMF in winter and summer were 1.85 ppm and 2.78 ppm respectively. Also the difference between the urinary NMF concentration at the beginning and end of the shift (delta NMF) was always significant in each season (P < 0.001). The correlations between log DMF in air, log end-of-shift urinary NMF (r = 0.555, P < 0.001) and log delta NMF (r = 0.444, P < 0.001) was statistically significant in summer. The temperature, humidity, a shift system and different styles of clothing worn were significantly different during the two phases. In a multivariate analysis, temperature and the concentration of DMF in the air were the main factors influencing biological monitoring of textile coating factory workers. CONCLUSIONS: Concerning more comprehensive prevention measures to reduce exposure for those workers occupationally exposed to DMF, dermal exposure conditions such as temperature and humidity together with the air concentration of DMF should be assessed and biological monitoring is necessary to reduce adverse health effects, especially during the summer.

Adult↗

PubMed1991

[The experimental transplacental passage of dimethylformamide and toluene].

The author presents data on the transplacental passage of dimethylformamide (DMFA) and toluene in combined exposure at the level of the maximum allowable concentrations. A new method for measurements of chemicals in animal biomedia is suggested. The permeability index for DMFA has made up 37.1%, that for toluene 90.2%. The results recommend the new method for experimental and clinical measurements of chemicals.

Administration, Inhalation↗

PubMed1991

NIOSH alerts on workplace hazards: falls through skylights and roof openings, deaths of farm workers in manure pits, and exposure to dimethylformamide.

CDC's National Institute for Occupational Safety and Health (NIOSH) periodically issues alerts on workplace hazards that have caused injury, illness, or death to workers. Three alerts are now available about the serious hazards posed by skylights and roof openings, manure pits, and the organic solvent dimethylformamide (DMF). Each alert is summarized briefly below.

Accidental Falls↗

PubMed1990

[Catalytic properties of E. coli tryptophanase in a 50% aqueous solution of methanol and dimethylformamide].

Tryptophanase from E. coli retains its ability to form quinonoid intermediate with L-alanine in water--methanol and water--dimethylformamide (1:1 v/v) solutions. Under these conditions the enzyme catalyzes decomposition of S-o-nitrophenyl-L-cysteine (SOPC) to o-nitrophenylthiol, pyruvate and ammonium ion. The enzyme's affinity for this substrate increases on going from water to water-organic solvents whereas the reaction rate decreases. In 50% methanol tryptophanase catalyzes the formation of L-tryptophan from indole and SOPC; in the mixture of 2H2O and C2H3O2H (1:1) the enzymatic isotope exchange of alpha-proton of L-phenylalanine with complete retention of configuration was observed.

Catalysis↗

PubMed1989

A case-control study of cancer among du pont employees with potential for exposure to dimethylformamide.

This case-control study was undertaken to determine whether the risk of developing cancers of the buccal cavity and pharynx (N = 39), liver (N = 6), prostate (N = 43), testis (N = 11), or malignant melanoma of the skin (N = 39) is related to exposure to dimethylformamide (DMF). Case and control subjects were obtained from four Du Pont plants. DMF is produced at one plant and used at the other three. Cancer cases identified from the company Cancer Registry comprise those reported among active male employees at the study plants during 1956 to 1985. For each case, two control subjects were selected, matched on sex, payroll class (wage or salary), birth year, and plant. To determine whether an employee could have been exposed to DMF during his career at the plant, all jobs with potential for exposure to DMF were identified. Each job was assigned an exposure ranking based on DMF industrial hygiene air monitoring, DMF metabolite (measured as N-methylformamide in urine) monitoring, and knowledge of the evolution of manufacturing processes and workplace exposure controls. Each employee's DMF exposure pattern was then characterized as (a) ever v never having been exposed to DMF and (b) highest DMF exposure experienced. Summary analyses for all plants combined showed no statistically significant association between ever having been exposed to DMF and subsequent development of cancers of the buccal cavity and pharynx, liver, malignant melanoma, prostate, and testis. Examined by plant site, prostate cancer at one plant was significantly elevated, based on three case subjects exposed out of four.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Changes in receptor occupancy and growth factor responsiveness induced by treatment of a transformed mouse embryo cell line with N,N-dimethylformamide.

Treatment of the transformed mouse embryo fibroblast cell line (AKR-MCA) with N,N-dimethylformamide (DMF) results in a reversion to the nontransformed AKR-2B cell line phenotype. AKR-MCA cells grown in the presence of 1% DMF showed a 2-fold increase in the sites for epidermal growth factor (EGF) binding. However, most of these sites were occupied by an endogenous ligand. The EGF receptor was unoccupied in untreated AKR-MCA cells. The increased receptor occupation was paralleled by an increase in the mitogenic response to EGF. Treatment of these cells with 1% DMF resulted in a 6-fold stimulation of mitogenesis by EGF. The ability to respond to nutrient replenishment (a property of growth-arrested AKR-MCA cells) was lost within 24 h of DMF treatment. Upon removal of DMF from the cells, both the mitogenic response to EGF and the occupation of the EGF receptor by endogenous ligands were lost. Treatment of the AKR-2B cell line with DMF had little effect on its growth properties. Therefore, DMF altered the growth control response and growth factor binding of AKR-MCA cells in a reversible, noncytotoxic manner.

Animals↗

PubMed1986

Changes in nucleoside transport of HL-60 human promyelocytic cells during N,N-dimethylformamide induced differentiation.

The rate of nucleoside transport decreased profoundly in human promyelocytic leukemia HL-60 cells after myeloid differentiation was induced by 5-6 days of exposure to 0.8% N,N-dimethylformamide (DMF). The facilitated diffusion of 100 microM radiolabeled adenosine and 2'-deoxyadenosine, measured by rapid transport assays, decreased 10- to 20-fold. The transport of 2 microM coformycin or 2'-deoxycoformycin, which is mediated by the same mechanism and was monitored by the adenosine deaminase titration assay, decreased 29-fold. The reduction in nucleoside transport capacity after DMF treatment was confirmed by a 19-fold decrease in the number of specific binding sites per cell (from 24-30 X 10(4) to 1.2-1.7 X 10(4)) for [3H]-6-p-nitrobenzylthioinosine, a nucleoside transport inhibitor. The binding affinity of 6-p-nitrobenzylthioinosine was not altered significantly and nucleoside transport remained sensitive to the transport inhibitors, 6-p-nitrobenzylthioinosine, dipyridamole, and dilazep after DMF-induced maturation. Time-dependence studies showed that the rate of 100 microM deoxyadenosine transport was unchanged for the first 24 h of exposure to DMF but fell to about 36% of control rates at 24-26 h and then gradually decreased further to about 4-5% of control rates after 5-6 days. In contrast, transport rates of the purine bases were reduced only 2- to 3-fold in HL-60 cells after 5 days of DMF treatment. The rates of adenosine and deoxyadenosine transport were unchanged or reduced by no more than 2-fold after 5-6 days of exposure to 0.8% DMF in the following human tumor cell lines that are not inducible with DMF: ARH-77 (multiple myeloma), KG-1 (acute myelogenous), and K-562 (chronic myelogenous). Thus, changes in nucleoside transport may serve as an early, membrane-associated marker of differentiation of the HL-60 cell line.

Adenosine↗

PubMed1987

Effects of N,N-dimethylformamide and retinoic acid on transforming growth factor-beta induced mitogenesis in AKR-2B mouse embryo fibroblasts.

Transforming growth factor-beta (TGF-beta) is a bifunctional reagent which can exert both stimulatory and inhibitory effects upon the same target cell. Treatment of growth arrested AKR-2B mouse embryo fibroblasts with TGF-beta has been shown to stimulate mitogenesis by an indirect mechanism. Addition of the differentiation agents N,N-dimethylformamide (DMF) or retinoic acid simultaneously with TGF-beta blocked the ability of TGF-beta to induce mitogenesis. These agents partially blocked the mitogenic effects of epidermal growth factor and platelet-derived growth factor. DMF blocked TGF-beta induced mitogenesis when added 9 h, but not 24 h, after TGF-beta addition suggesting that DMF affects an early step in the mitogenic cascade induced by TGF-beta. TGF-beta will induce anchorage independent growth in AKR-2B fibroblasts and this was also inhibited by DMF. When AKR-2B cells were grown in monolayer culture, TGF-beta inhibited their growth. The addition of DMF under these conditions did not alter the cell's sensitivity to TGF-beta and the cells were still inhibited to the same extent by TGF-beta. Therefore, DMF did not affect the inhibitory action of TGF-beta on AKR-2B fibroblasts but did block the stimulatory effects of TGF-beta.

Animals↗

PubMedDate not supplied

Solvent artifacts likely to be induced by dimethylformamide.

Dimethylformamide (DMF) is widely used as a drug solvent. We found DMF to have wide-spread pharmacological effects including depressant effect on CNS evidenced by a decrease in locomotor activity, body and limb tone and rectal temperature, and potentiation of pentobarbitone sleep. A dose-dependent hypotensive effect was seen in cats and rats. In rats, it was partially blocked by atropine and was associated with bradycardia. DMF antagonised the contractions of smooth muscle induced by many agonists. An atropine sensitive spasmogenic effect was observed on rabbit ileum at 20 ml/l and a direct relaxant effect at 50 ml/l. A positive inotropic effect on guinea pig atria was observed with 5 ml/l. The results indicate DMF concentrations that may not perhaps produce 'solvent artifacts' when used as a solvent.

Animals↗

PubMed1986

N,N-dimethylformamide-induced synthesis of an anti-fibronectin reactive protein in cultured human colon carcinoma cells.

The cell surfaces of human colon cancer cells before and after exposure to N,N-dimethylformamide (DMF) were probed using radioiodination and immunofluorescent labeling techniques. Growth of the human colon carcinoma cell line HCT MOSER in DMF-supplemented culture medium resulted in monolayer culture growth and marked cell morphology alterations consisting of cellular flattening and elongation. Accompanying the morphology alterations were distinct changes in the cell surface protein composition as determined by 125I labeling and electrophoresis. The cell surface changes associated with growth of HCT MOSER cells in the presence of DMF were dependent upon time of exposure to DMF and DMF concentration. Furthermore, removal of DMF-treated HCT MOSER cells from DMF-containing growth medium caused reversion of both cell morphology and cell surface composition to a state comparable to that of cells not exposed to DMF. The HCT MOSER cell surface alterations produced by DMF included a reduction of radioiodinated surface proteins with molecular weights of 87,000, 120,000, and 180,000 and an increase of a 125I-labeled surface protein with a molecular weight of 200,000-250,000. Appearance of a surface protein of approximately 200,000 molecular weight and assumption of a fibroblast-like morphology by DMF-treated HCT MOSER cells suggested that this approximately 200,000 molecular weight material might be fibronectin. Immunofluorescent labeling with anti-human fibronectin showed that HCT MOSER cells grown in DMF did manifest an anti-fibronectin immunoreactive material that was only transiently associated with the cell surface before being released. DMF-treated HCT MOSER cultures continued to express surface carcinoembryonic antigen, indicating that the presence of material immunoreactive with anti-human fibronectin was not secondary to proliferation of a contaminating fibroblast population. The response of HCT MOSER cells to DMF paralleled in many ways that previously reported for methylcholanthrene-transformed AKR-2B (AKR-MCA) fibroblasts. However, unlike AKR-MCA cells, HCT MOSER cells did not exhibit an increase in 125I incorporation per microgram DNA as a function of time of exposure to DMF, which suggests that the surface protein with a molecular weight of approximately 200,000 induced by DMF was not retained on the cell surface.

Cell Differentiation↗

PubMed1985

Cell surface features associated with differentiation-induction of methylcholanthrene-transformed AKR-2B fibroblasts by N,N-dimethylformamide.

Methylcholanthrene-transformed AKR-2B mouse embryonal fibroblasts (AKR-MCA cells) were examined for cell surface alterations after growth in culture medium containing N,N-dimethylformamide (DMF) using the lactoperoxidase-glucose oxidase radioiodination procedure with subsequent electrophoresis. DMF has been shown to induce maturational changes in a variety of transformed cells in vitro and has been reported to produce a more normal phenotype when applied to cultured AKR-MCA cells. The electrophoretic profile of 125I-labeled surface proteins from AKR-MCA cells exhibited a prominent peak of labeled material with a molecular weight of approximately 85,000. After growth of AKR-MCA cells in medium containing DMF, the Mr 85,000 peak was substantially reduced, while there was a large increase in Mr 200,000 to 250,000 radioiodinated surface material. This cell surface labeling pattern was virtually identical to that of the nontransformed AKR-2B fibroblasts from which AKR-MCA cells were derived. The cell surface alterations observed upon exposure of AKR-MCA cells to DMF occurred as a function of time of growth in DMF and DMF concentration. Growth of AKR-MCA cells in DMF resulted in a steady increase in cell surface 125I incorporation up to the fourth day of exposure to DMF. At this time, the incorporation level was 22.9-fold greater than that for untreated AKR-MCA cells. Incorporation of radiolabel was decreased after the fifth and sixth days of AKR-MCA exposure to DMF. This trend was also manifested by AKR-2B fibroblasts grown in the presence of DMF. The data suggest that there was increased expression of the Mr 200,000 to 250,000 surface protein on both AKR-2B and AKR-MCA cells when grown in DMF. DMF also inhibited morphological transformation and the cell surface changes associated with transformation of AKR-2B cells by exogenous transforming growth factors.

Animals↗

PubMed1985

Expression of YBB 3/10 antigen in human tumor colon cell lines and its induction by N,N-dimethylformamide.

A monoclonal antibody (YBB 3/10) raised against rat small intestinal brush border membranes defined a high-molecular-weight antigen present on the surface membrane of the epithelial cells in fetal and newborn rat small intestine but appeared specific for the undifferentiated crypt cells in adult rat small intestine. In rat colon and rectum, expression of the YBB 3/10 antigen was limited to a specific period of development, from day 17 to 18 of gestation in the fetus to the first few days after birth. This antigen was detected in 11 of 12 human tumor intestinal cell lines. By immunofluorescent staining, it was found present only in subsets of the cultured tumor cells appearing as colonies of variable size. In contrast, it could not be detected in a large panel of normal rat and human cell lines. Expression of the YBB 3/10 antigen could be induced in the only negative colon tumor cell line (DLD-1 cells) by treatment with N,N-dimethylformamide (CAS: 68-12-2). These results suggested that the YBB 3/10 antigen represented a marker for the differentiated state of human colon tumor cells and that it would be useful to investigate the relationship between the state of cell differentiation and the pattern of development of small and large intestine during fetal and postnatal life.

Animals↗