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PubMed1990

Direct introduction of a formamido group into the 7 alpha (6 alpha)-position of cephalosporins (penicillins).

A novel direct introduction of a formamido group into the 7 alpha (6 alpha)-position of cephalosporins (penicillins) was achieved by treatment of 7 beta (6 beta)-[(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-1- ylidene)methylimino]cephem (penam) esters with N,N-bis(trimethylsilyl)formamide, followed by deblocking with Girard reagent T to give the corresponding 7 alpha (6 alpha)-formamido-7 beta (6 beta)-amino derivatives. Three 7 alpha-formamidocephalosporins were prepared by the conventional N-acylation of 7 alpha-formamidocephem. All of them were resistant to beta-lactamases, showing similar MIC values against both of a pair of a beta-lactamase-producing strain and the corresponding non or low-producing strain of the same species of bacteria, when tested on Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Enterobacter cloacae and Citrobacter freundii.

Bacteria↗
PubMed1976

The interaction of salts, amides, and water.

Infrared and Raman spectra are presented for salt solutions in N-methyl formamide and N,N'-dimethylformamide. Viscosities are reported for many of these solutions. Spectroscopic and viscosity data are also given for amide-salt solutions containing water. The three-component systems exhibit a hydrogen-bonding strength of water proton greater than amide proton, and an acceptor strength of Cl- greater than amide carbonyl oxygen greater than water oxygen. The salt cation is deduced by means of viscosity measurements to interact strongly with the amide carbonyl oxygen, even in the presence of appreciable quantities of water. Association of amides by hydrogen bonding through halide ions is also indicated.

Amides↗
PubMedDate not supplied

[Measurement of N-methylformamide in occupational exposure to N,N-dimethylformamide].

N,N-dimethylformamide (DMF) is a solvent that is widely used in industry. The major occupational sources of exposure results from production of synthetic leather. The main metabolite formed in both man and animals is N-hydroxymethyl-N-methylformamide. Demethylation leads to N-methylformamide (NMF) and formamide and also to a small extent to hydroxy-methylformamide. All the metabolites are excreted in urine, as are very small amounts of the unchanged substance. N-acetyl-S-(N-methyl-carbamoyl)-cysteine can be determined in urine as a further metabolite. We conducted this biomonitoring study with the aim of evaluating the correlation between the excretion of N-methylformamide (mainly from N-hydroxymethylformamide) and levels of exposure to N,N-dimethylformamide among occupationally exposed people. The mean time-weighted average (TWA) exposure was about half (13.5 mg/m3) of the current threshold limit value, the range of the values varying from 0.4 to 75.2 mg/m3. A linear equation existed between urinary NMF concentration and DMF concentration in the environment. The findings show that the urinary NMF concentration can be used as an appropriate biological exposure index. The authors suggest for occupationally exposed subjects, a urinary NMF concentration corresponding to the time-weighted average of the threshold limit value of 39.9 mg/l (37.2 mg/g creatinine) and a 95% lower confidence limit (biological threshold) of 23.4 mg/l (22.2 mg/g creatinine).

Adult↗
PubMed1975

Relaxation complexes of plasmid DNA and protein. I. Strand-specific association of protein and DNA in the relaxed complexes of plasmids ColE1 and ColE2.

The ColE1 and ColE2 relaxation complexes of supercoiled DNA and protein were purified from Escherichia coli cells. Protein remains associated with the open circular DNA of these complexes after induction of relaxation with sodium dodecyl sulfate. The protein is associated specifically with the strand that possesses a site-specific break in the Co1E1 and ColE2 relaxed complexes. This protein remains associated with the DNA after centrifugation of the relaxed complex in a neutral or alkaline (pH 12.5) cesium chloride gradient or treatment with 8 M urea, 2 M NaSCN, 2M LiCl, 0.2 M sodium acetate, pH 4.6, and 70% formamide at 60 degrees.

Acetates↗
PubMed2003

Capillary DNA sequencing: maximizing the sequence output.

Like most other DNA sequencing core facilities, one of our continuing goals is to improve our sequence output without substantially adding to cost. To minimize sample-to-sample variability in template DNA concentration, we implemented the rolling circle amplification (RCA) procedure for preparing our DNA templates. In addition to saving time and reducing the number of steps in template DNA preparation, the RCA method has the potential to normalize the DNA concentration in samples that can be sequenced directly without additional purification. In the present study, we used RCA-generated templates to test a recently reported procedure that increased sequence quality by resuspending the sequenced products in low concentrations of agarose before capillary electrophoresis (CE) on a MegaBACE 1000 platform. Although we did not obtain the expected result using the specified procedure, a modification resulted in up to 60% increase in total sequence yield per sample plate. A combination of agarose and formamide-EDTA in the resuspension solution enabled us to generate long-read and high-quality sequences for more than 38,000 templates with minimal additional cost.

DNA, Bacterial↗
PubMed1979

[Spectrum of amidase activity in a mutant of Brevibacterium].

Brevibacterium R 312 has a fairly non-specific amidase. Following the loss of this enzyme by mutation, the following enzymatic activities could be demonstrated: hydrolysis of urea, formamide, nicotinamide, L-glutamine, glycinamide and L-alpha-amino amids.

Amidohydrolases↗
PubMedDate not supplied

Reversal of delayed vasospasm by TS-011 in the dual hemorrhage dog model of subarachnoid hemorrhage.

PURPOSE: Arachidonic acid is avidly metabolized to a potent vasoconstrictor, 20-hydroxyeicosatetraenoic acid (20-HETE), in the cerebral circulation. 20-HETE has been reported to contribute to the acute fall in cerebral blood flow following subarachnoid hemorrhage (SAH), but its role in the development of delayed vasospasm is unknown. The present study examined whether delayed vasospasm is associated with elevations in 20-HETE in CSF in the dual hemorrhage model of SAH in dogs and if blockade of the synthesis of 20-HETE with N-(3-chloro-4-morpholin-4-yl)phenyl-N'-hydroxyimido formamide (TS-011) can reverse delayed vasospasm in this model. MATERIALS AND METHODS: Delayed vasospasm was induced in 22 adult beagle dogs by dual injection of blood (0.5 mL/kg) into the cisterna magna on days 1 and 4. Sequential samples of CSF were collected before intracisternal injections of blood on days 1 and 4 and after the development of delayed vasospasm on day 7. Sequential angiograms were obtained before and after intracisternal injection of blood on days 1 and 4 and before and 1 hour after administration of TS-011 (1 mg/kg IV) on day 7. RESULTS: The dogs consistently developed delayed vasospasm, and the diameter of the basilar artery fell to 68 +/- 3% (n = 15), 3 days after the second intracisternal injection of blood. The levels of 20-HETE in CSF increased from 4 +/- 2 to 39 +/- 16 pg/mL. In 9 dogs with delayed vasospasm, acute blockade of the synthesis of 20-HETE with TS011 (1 mg/kg IV) significantly increased the diameter of the basilar artery by 39%. Chronic administration of TS-011 (1 mg/kg per day) attenuated the development of delayed vasospasm, and the diameter of the basilar artery fell by 17 +/- 1% versus the 33 +/- 3% decrease in diameter seen in control animals 3 days following the second injection of blood into the cisterna magna. CONCLUSIONS: These results indicate that the development of delayed vasospasm in dogs is associated with an increase in 20-HETE levels in CSF, and acute blockade of the synthesis of 20-HETE with TS-011 reverses delayed vasospasm in this model.

Animals↗
PubMed1986

Activation of dynein 1 adenosine triphosphatase by organic solvents and by Triton X-100.

The presence of low concentrations of methanol or isopropyl alcohol (2-5%, v/v) in the assay medium stabilizes the latency of dynein 1 from sea urchin sperm flagella, with about a 50% decrease in ATPase level compared to that in the absence of solvent. Somewhat higher concentrations (10-20%, v/v) of these solvents in the assay give a 5-10-fold activation of ATPase activity. Dioxane, formamide, and dimethylformamide, on the other hand, always activate the ATPase activity, with a 5-10-fold increase observed at about 15% (v/v). The activation of latent ATPase activity by solvents is reversible for short exposures, especially in the presence of ATP and at low temperature, but the activation becomes irreversible upon more prolonged exposure. The rate constant for irreversible activation by 16% methanol at 21 degrees C is 0.08 min-1, compared to rates of 0.44 and 0.02 min-1 for activation by 0.05% Triton X-100 at 21 and 0 degree C, respectively. The slowness of this reversible activation induced by methanol and by Triton X-100 suggests that it is the result of large-scale conformational changes in the structure of the dynein. However, the activation by methanol occurs without the dissociation of the alpha and beta subunits of dynein that is observed with Triton X-100. The presence of 1 mM MgATP, or of 100 microM MgATP and 10 microM vanadate substantially protects latent dynein from activation by 0.05% Triton X-100.

1-Propanol↗
PubMed1985

Mercapturates in the urine of persons exposed to N,N-dimethylformamide.

N,N-dimethylformamide, a nucleophilic aprotic dipolar solvent, has multipurpose uses, especially in the manufacture of plastics. Its acute toxicity for mammals is low; it is hepatotoxic. Vapors are absorbed by the lungs, in the liquid form it causes cutaneous maceration and is rapidly absorbed through the skin. In the organism it is primarily metabolized to N-monomethylformamide, to a lesser extent to formamide. Urine of individuals exposed to N,N-dimethylformamide was newly found to have higher levels of thioethers, most likely mercapturates, as yet of unknown chemical structure. The correlation between the urinary concentrations of mercapturates (y) and N-monomethylformamide (x) can be expressed by equation y = 4.93 + 0.58 x, with the coefficient of correlation r = 0.90. Part of N,N-dimethylformamide metabolites is likely to react with biopolymers, part of it is excreted as metabolic end products, i.e. carbon dioxide, water and urea. Breakdown to mercapturates may implicate N,N-dimethylformamide as being a potential carcinogen.

Acetylcysteine↗
PubMed1982

Studies on the structure of avian myeloblastosis virus (AMV) RNA. I. Factors affecting electron microscopic visualization of AMV RNA.

Factors affecting the visualization of single-stranded (ss) avian myeloblastosis virus (AMV) RNA by the basic protein film technique under strong denaturation conditions were studied. The basic parameters of the electron microscopic picture of ss RNA, involving the visibility, concentration and contour lengths of molecules, were found to be significantly dependent on the (1) quality of denaturing components used for full extension of AMV RNA molecules and (2) spreading and formation of the surface film. Under the conditions used, the presence of artificial secondary structures of AMV RNA molecules were dependent on batches of formamide and urea in the denaturing mixture. The spreading and formation of the surface film were affected by hydrophilicity of glass spreading ramps, speed of spreading, amount of spreading solution, amount of protein in the hyperphase, type of cytochrome c and the presence of substances influencing surface tension. The optimal conditions and spreading arrangement for visualization of ss AMV RNA are described.

Avian Leukosis Virus↗
PubMedDate not supplied

[Ribosomal RNA degradation in rat skeletal muscle in the process of autolysis].

Comparative histochemical study of RNA content in normal and autolyzed within 72 hrs muscle tissue showed that the nucleic acid well retained during autolysis but the tissue was simultaneously destructed. Polymerization of rRNA in autolyzed tissue proved to depend on temperature of dead animals storage. An increase of temperature from 0 degrees to 21 degrees did not affect the rRNA yield. But amount of latent breaks, which were found in rRNA by methods of formamide and temperature treatment, was increased depending on increase in temperature and on length of animal storage after death. The latent breaks appear to be accumulated in animal tissues during autolysis.

Animals↗
PubMed1978

Stabilizing effect of various organic solvents on protein.

The rate of denaturation of hemaglobin and other proteins by mechanical shaking is strongly affected by organic solvents. A group pf solvents,including alcohols and ketones, was found to stabilize proteins at low concentrations, although these same organic solvents denatured proteins at high concentrations. The stabilizing effect of alcohols increased with increasing chain lenghts. The second group of solvents, including toluene and chloroform, showed only a destabilizing effect, while the third group of solvents such as formamide and pentane had no effect over a wide range of concentrations. Organic solvents may be used to protect or denature a specific protein in solutions containing various proteins.

Alcohols↗
PubMed1982

Studies of the pharmacology of N-methylformamide in mice.

When 400 mg/kg of 14C-methyl-labeled N-methylformamide (NMF) was injected ip into mice, the curve for plasma concentration of radioactivity versus time was superimposable on the curve obtained by measuring unmetabolized NMF with gas-liquid chromatography during the first 24 hrs. Radioactivity in plasma was measurable for 8 days after NMF administration, but NMF was not measurable by gas chromatography beyond 24 hrs after administration. Radioactivity was eliminated from the plasma after 60 hrs, with an apparent half-life of 71.1 hrs. Of the radioactivity injected with NMF, 73.6% was recovered in the urine in 24 hrs; 26.4% of this was unchanged NMF. Three percent of the administered radioactivity was exhaled as 14CO2 in 7 hrs at a constant rate of 0.007% per min. One urinary metablite was a stable precursor of formaldehyde, which decomposed to formaldehyde only after alkaline hydrolysis and may well be N-(hydroxymethyl)-formamide. The areas under the plasma concentration versus time curve were estimated after ip, iv, and oral administration of NMF. The bioavailability of NMF was 1.01 after oral administration and 1.10 after ip administration.

Administration, Oral↗
PubMed1982

Inhibition of the growth of human colon cancer xenografts by polar solvents.

The effects of N,N-dimethylformamide (DMF) and N-methyl-formamide (NMF) on the growth of two human colon cancer cell lines xenografted in nude mice were assessed. Toxicological studies with mice heterozygous for the nu/nu gene showed that with both compounds the limiting organ toxicity was hepatic. The 10% lethal doses for DMF and NMF given i.p. daily for 21 days were 2219 and 374 mg/kg, respectively. Nude mice (10/group) received s.c. transplants of HCT-15 or DLD- 2 human colon cancer cells. Mice were treated i.p. with the approximate 10% lethal doses of either DMF (daily for 21 days) or NMF (daily for 19 days) or with 0.9% NaCl solution when tumors became palpable. With the HCT-15 tumor, a growth inhibition of 65% was obtained using DMF compared to 0.9% NaCl solution-treated controls. Two independent experiments with DLD-2 demonstrated that DMF effected growth inhibitions of 45 and 67%. NMF treatment produced 48 and 75% growth inhibitions of HCT-15 and DLD-2 tumors, respectively. Weight loss of groups of treated mice in all experiments was between 2 and 14%, within the acceptable range for 10% lethal drug doses. Results indicate that some human cancer xenografts respond to the polar solvent DMF and to its metabolite NMF and that DMF may be acting at least in part by its metabolism to NMF. Furthermore, the data should alert clinical investigators to the possibility of hepatotoxicity when polar solvents are tested in Phase I clinical trials.

Animals↗
PubMed1994

Reloading and stability of polyacrylamide slab gels for automated DNA sequencing.

Current automated fluorescent instruments are all based on slab gels that are used once and then discarded. Practitioners of capillary gel electrophoresis often reuse their gels for multiple samples. As slab gels are made thinner to increase speed, the ability to reload new samples after each run will become more desirable. Techniques have previously been developed for reloading and stabilizing capillary gels. The application of these methods to slab gel electrophoresis is reported. Gels are shown to be reusable for at least four consecutive automated runs. The stability of various slab gel formulations and their ability to survive multiple loadings with sequencing samples are compared. Formamide-containing gels are shown to be superior to their urea counterparts. The potential that running buffer additives have for improving automated DNA sequencing is discussed. Residual template DNA in sequencing samples can produce gel instability, reduce resolution and decrease signal. These effects are examined.

Autoanalysis↗
PubMed1993

Isolation of RNA from cells in culture using Catrimox-14 cationic surfactant.

Traditional RNA isolation methods use chaotropic agents and anionic detergents to lyse cells and solubilize nucleic acids. In contrast, the cationic surfactant, Catrimox-14, lyses cells and simultaneously precipitates RNA, thereby protecting it from RNases. We describe and compare four methods for extracting RNA from cultured cells that differ in the technique used to extract the RNA from the precipitate. The first uses a high-salt solution (guanidinium isothiocyanate). In the second, the RNA is extracted with a polar solvent (formamide). The third involves conversion of the RNA to the sodium salt by treatment of the precipitate in situ with sodium acetate in ethanol. The fourth uses 2 M lithium chloride to convert the RNA in the pellet to the lithium salt in situ. We applied these methods to human leukemia cells growing in culture and each method resulted in excellent yields of RNA (typically 23 micrograms/million K562 cells, 13 micrograms/million HL-60 cells) over a wide range of cell concentrations (1 x 10(5) - 3 x 10(7)/ml) and of good to excellent quality as judged by agarose electrophoresis and UV absorbance data (OD260/280 1.90-2.05). The advantages and limitations of each method are discussed.

Acetates↗