Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A specific fluorescence is developed in melanocytes, nevus cells, and cells of malignant melanoma by treatment of the tissue with dry formaldehyde gas. The fluorescence is often stronger in melanocytes adjacent to nevi or melanomas than in normal melanocytes. The strongest fluorescence occurs in cells of malignant melanoma. Among the limited number of compounds that condense with formaldehyde to fluorescent derivatives, DOPA [beta(3,4-dihydroxyphenyl)L-alanine] seems the most likely substance to give rise to the fluorescence observed in these lesions.
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PMID:Pigmented Nevi and Malignant Melanomas as Studied with a Specific Fluorescence Method. 1780 14

The anticancer drug Adriamycin is widely used in cancer chemotherapy and is classified as a topoisomerase II inhibitor. However, in the presence of formaldehyde, Adriamycin also forms high levels of DNA adducts. In this study, a new series of butyric acid and formaldehyde-releasing drugs related to AN9 (pivaloyloxymethyl butyrate) was assessed for their ability to facilitate Adriamycin-DNA adduct formation in Adriamycin-sensitive and -resistant cell lines (HL60 and HL60/MX2; MES-SA and MES-SA/Dx5). Drugs that released two molar equivalents of formaldehyde per mole of prodrug were superior in their ability to enhance adduct formation compared to those that released one molar equivalent. Adduct formation (as assessed by binding of radiolabeled Adriamycin to genomic DNA) was always lower in the resistant cell lines compared to the sensitive cell lines. However, in growth inhibition experiments, prodrug combinations were able to overcome Adriamycin resistance to varying degrees, and the combination of Adriamycin with selected prodrugs that release two moles of formaldehyde totally overcame resistance in HL60/MX2 cells. These HL60-derived cells express altered levels of topoisomerase II and also express a mutant form of the enzyme. Combinations of Adriamycin with selected prodrugs that release one or two moles of formaldehyde partially overcame P-glycoprotein-mediated resistance in MES-SA/Dx5 cells. Formaldehyde-releasing prodrugs (as single agents) overcame both forms of resistance in the two resistant cell lines, demonstrating that they were not substrates of these resistance mechanisms. Collectively, these results suggest that changing the mechanism via which Adriamycin exerts its anticancer effect by dramatically increasing adduct levels (requiring coadministration of formaldehyde-releasing prodrugs) may be a useful means of cancer treatment, as well as for overcoming Adriamycin-induced resistance.
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PMID:Formaldehyde-releasing prodrugs in combination with adriamycin can overcome cellular drug resistance. 1782 80

This work provides experimental evidence on how the molecular compositions of fuel-rich low-pressure premixed flames are influenced as the oxygenates dimethyl ether (DME) or ethanol are incrementally blended into the propene fuel. Ten different flames with a carbon-to-oxygen ratio of 0.5, ranging from 100% propene (phi = 1.5) to 100% oxygenated fuel (phi = 2.0), are analyzed with flame-sampling molecular-beam mass spectrometry employing electron- or photoionization. Absolute mole fraction profiles for flame species with masses ranging from m/z = 2 (H2) to m/z = 80 (C6H8) are analyzed with particular emphasis on the formation of harmful emissions. Fuel-specific destruction pathways, likely to be initiated by hydrogen abstraction, appear to lead to benzene from propene combustion and to formaldehyde and acetaldehyde through DME and ethanol combustion, respectively. While the concentration of acetaldehyde increases 10-fold as propene is substituted by ethanol, it decreases as propene is replaced with DME. In contrast, the formaldehyde concentration rises only slightly with ethanol replacement but increases markedly with addition of DME. Allyl and propargyl radicals, the dominant precursors for benzene formation, are likely to be produced directly from propene decomposition or via allene and propyne. Benzene formation through propargyl radicals formed via unsaturated C2 intermediates in the decomposition of DME and ethanol is negligibly small. As a consequence, DME and ethanol addition lead to similar reductions of the benzene concentration.
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PMID:Isomer-specific influences on the composition of reaction intermediates in dimethyl ether/propene and ethanol/propene flame. 1850 42

The alpha-methylserine aldolase gene from Variovorax paradoxus strains AJ110406, NBRC15149, and NBRC15150 was cloned and expressed in Escherichia coli. Formaldehyde release activity from alpha-methyl-L-serine was detected in the cell-free extract of E.coli expressing the gene from three strains. The recombinant enzyme from V. paradoxus NBRC15150 was purified. The Vmax and Km of the enzyme for the formaldehyde release reaction from alpha-methyl-L-serine were 1.89 micromol min(-1) mg(-1) and 1.2 mM respectively. The enzyme was also capable of catalyzing the synthesis of alpha-methyl-L-serine and alpha-ethyl-L-serine from L-alanine and L-2-aminobutyric acid respectively, accompanied by hydroxymethyl transfer from formaldehyde. The purified enzyme also catalyzed alanine racemization. It contained 1 mole of pyridoxal 5'-phosphate per mol of the enzyme subunit, and exhibited a specific spectral peak at 429 nm. With L-alanine and L-2-aminobutyric acid as substrates, the specific peak, assumed to be a result of the formation of a quinonoid intermediate, increased at 498 nm and 500 nm respectively.
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PMID:Gene cloning of alpha-methylserine aldolase from Variovorax paradoxus and purification and characterization of the recombinant enzyme. 1883 14

The stoichiometry of the reaction between lead dioxide suspension and EDTA was studied by derivative polarographic titration and determination of the products. Four moles of Pb(IV) are reduced per mole of EDTA with moderate speed at room temperature in sulphuric acid solutions. Four moles of carbon dioxide and 3 moles of formaldehyde are the products of the oxidation of 1 mole of EDTA. One mole of N-hydroxymethylethylenediamine is also thought to be produced. The overall reaction may be written as 4Pb(IV) + EDTA + 4H(2)O-->4Pb(II) + 4CO(2) + 3HCHO + H(2)NCH(2)CH(2)NHCH(2)OH + 8H(+). Ethylenediamine is also partly produced if a large excess of lead dioxide is used.
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PMID:Study of the oxidation of ethylenediaminetetra-acetic acid with lead dioxide suspension in sulphuric acid. 1896 6

The stoichiometry of the oxidation of IDA or NTA with lead dioxide suspension was studied by polarographic measurement and by derivative polarographic titration. One mole and two moles of Pb(IV) are reduced per mole of IDA and NTA respectively, with moderate speed at room temperature in nitric acid solutions. One mole each of carbon dioxide, formaldehyde and glycine are produced from the oxidation of 1 mole of IDA, and two moles of carbon dioxide, two moles of formaldehyde and one mole of glycine from 1 mole of NTA. The overall reaction in each case may be written as follows: Pb(IV) + IDA + H(2)O --> Pb(II) + CO(2) + HCHO + H(2)NCH(2)COOH + 2H(+) 2Pb(IV) + NTA + 2H(2)O --> 2Pb(II) + 2CO(2) + 2HCHO + H(2)NCH(2)COOH + 4H(+).
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PMID:Studies of the oxidation of iminodiacetic acid (IDA) and nitrilotriacetic acid (NTA) with lead dioxide suspension in nitric acid. 1896 2

Silver(I), copper(II) and nickel(II) can be reduced to the metallic state by formaldehyde at pH 11, chromium(II) in 2.5M sulphuric acid, and borohydride at pH 5.5-6.0, respectively. Reoxidation of these metals with iron(III) in the presence of Ferrozine enables their determination at concentration below 1 mug/ml by measurement of the absorbance of the iron(II)-Ferrozine complex at 562 nm, with a precision better than 3%. The apparent molar absorptivities for silver, copper and nickel are 2.78 x 10(4), 5.56 x 10(4) and 5.58 x 10(4) l.mole(-1).cm(-1), respectively. The average thickness of silver films on glass surfaces can be determined in the way.
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PMID:Chemical reduction and spectrophotometric determination of silver, copper and nickel. 1896 40

A new spectrophotometric method for the determination of micro amounts of formaldehyde in aqueous and methanol solutions is based on the oxidation of formaldehyde by hydrous silver oxide at pH 11-12.5 and oxidation of the metallic silver produced, with iron(III) in the presence of Ferrozine. The absorbance of the resulting iron(II)-Ferrozine complex at 562 nm is proportional to the amount of formaldehyde and corresponds to an apparent molar absorptivity of 5.58 x 10(4) 1.mole(-1).cm(-1).
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PMID:Spectrophotometric determination of formaldehyde. 1896 88

A simple indirect spectrophotometric method for the determination of cyanide, based on the oxidation of the cyanide with chlorine (Cl(2)) is described. The residual chlorine is determined by the color reaction with o-tolidine (3,3'-dimethylbenzidine). The maximum absorbance for Cl(2) is at 437 nm. A linear calibration graph (0-4.0x10(-5) M CN(-)) is obtained under optimal reaction conditions at room temperature and pH 11-12. The stoichiometric mole ratio of chlorine to cyanide is 1:1. The effective molar absorptivity for cyanide is 5.87x10(4) l mol(-1) cm(-1) at pH 1.6. The limit of quantification (LOQ) is 3.6x10(-7) M or 9.4 ppb. Effects of pH, excess reagent, sensitivity, reaction time and tolerance limits of interferent ions are reported. The method was applied to the determination of cyanide in a real sample. The basic interferent usually accompanying CN(-), i.e. thiocyanate, is separated from cyanide by sorption on a melamine-formaldehyde resin at pH 9 while cyanide is not retained. Thiocyanate is eluted with 0.4 M NaOH from the column and determined spectrophotometrically using the acidic FeCl(3) reagent. The initial column effluent containing cyanide was analyzed by both the developed chlorine-o-tolidine method and the conventional barbituric acid-pyridine (Spectroquant 14800) procedure, and the results were statistically compared. The developed method is relatively inexpensive and less laborious than the standard (Spectroquant) procedure, and insensitive to the common interferent, cyanate (CNO(-)).
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PMID:Simultaneous spectrophotometric determination of cyanide and thiocyanate after separation on a melamine-formaldehyde resin. 1896 16

The removal of phenol and formaldehyde from phenolic resin plant effluents has been studied by using a combined process. In the first step, phenol was removed from effluent by solvent extraction. Special attention was paid to the effluent with a low content of phenol, which was treated by non-dispersive solvent extraction in hollow fibres. It was found that a single module of Liqui-Cel 2.5in. x 8in. membrane contactor allowed processing approximately 24 L/h of effluent with 0.4-0.7 g/L phenol and attaining values as low as 0.5 mg/L in the raffinate. Formaldehyde, which was left in phenolic resin plant effluent after the removal of phenol, has been treated with hydrogen peroxide in alkaline medium and also in acidic medium (Fenton process). In alkaline medium, formaldehyde was oxidized with hydrogen peroxide to formate ion, which was recovered by solvent extraction. The oxidation of formaldehyde with Fenton process was also studied under several operating conditions. It was found that a large amount of hydrogen peroxide (i.e. mole ratio H(2)O(2):HCHO>6) was necessary to mineralize more than 90% HCHO in 1-2h, at atmospheric pressure and 25 degrees C. The combination of pressure and high temperature strongly increased the kinetics of the process and allowed achieving a very high overall efficiency of the treatment under moderate H(2)O(2) dosage.
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PMID:A study on a combined process for the treatment of phenolic resin plant effluents. 1940 98


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