(1) A new type of Escherichia coli mutant which shows increased sensitivity to methyl methane sulfonate but not to UV light or to gamma rays was isolated after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine.
(2) Sec-alpha-halo-nitro compounds are active antibacterial and antifungal agents, and the sec-bromo derivatives are the most active and stable.
(3) A series of 2-styryl-5-nitro-1-vinylimidazoles carrying alkylaminomethyl or amidino functions in the 4 position of the styryl ring was prepared and evaluated for antitrypanosomal activity in mice infected with Trypanosoma rhodesiense.
(4) The effects of Ng-nitro-L-arginine were reversed by L-arginine.
(5) The best compound was trans-alpha-[[(4-bromotetrahydro-2H-pyran-3-yl) amino]methyl]-2-nitro-1H-imidazole-1-ethanol (18), which, due to its activity and log P value, is a candidate for additional in vivo studies.
(6) In addition, cell lines exhibiting increased resistance to N-methyl-N'-nitro-N-nitrosoguanidine have been derived from a cell line expressing the Ada protein methylphosphotriester repair function.
(7) It is likely that nitro substitution at the 6-position of 5-MeC interferes with the structural requirements of the 1,2-diol-3,4-epoxide which are necessary for specific DNA interactions.
(8) After mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine and penicillin selection, two kinds of B(12) transport mutant were isolated from this strain.
(9) AOAA-induced (0.25 mumol-1 mumol) striatal lesions in adult rats displayed excitotoxic characteristics and could be prevented by the N-methyl-D-aspartate (NMDA) receptor antagonists (-)-2-amino-7-phosphono-heptanoate (AP7; 0.25 mumol) or kynurenate (KYNA; 0.5 mumol), but not by the non-NMDA antagonist 2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo(F)quinoxaline (NBQX; 0.25 mumol).
(10) The oxidation of the anion radical intermediate by O2 to the parent nitro compound is proposed to account for the well-known O2 inhibition of microsomal nitroreductase.
(11) The complexes are produced by attachment of a carbon of the butenolide ring to an aromatic carbon of the nitro compound with formation of a charge-delocalized cyclohexadienate anion.
(12) With these compounds, the spin density at the nitro group was greater than with nifurtimox, nitrofurazone and nitrofurantoin.
(13) Amino and nitro groups, introduced at position-4 of estrone 3-methyl ether were particularly carcinostatic, a property not shared by 4-bromoestrone 3-methyl ether.
(14) The labeled egg albumin was hydrolyzed in 6N HCl at 110 degrees C for 24 h. The hydrolysate was lyophilized, derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole, a fluorogenic reagent for amines, and subjected to HPLC.
(15) Nitroreductases must therefore be able to compete successfully with molecular oxygen for the MISO nitro radical-anion in such tissues.
(16) It has been suggested that under aerobic conditions the aziridine ring is primarily responsible for aerobic toxicity, whereas under hypoxic conditions, the aziridine moiety combined with a reduced 2-nitro moiety produces a bifunctional agent (I. J. Stratford et al., Br.
(17) N omega-Nitro-L-arginine methyl ester (NAME) (10(-5) to 5 x 10(-4) M) abolished ijps in both tissues, an effect overcome by 10(-3) M L-arginine but not D-arginine.
(18) The incidence, number, and histological types of gastric cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine and the tissue norepinephrine concentration of the gastric wall were investigated in spontaneously hypertensive rats and in control Wistar Kyoto rats and Wistar rats.
(19) A nitroreductase enzyme has been isolated from Walker 256 rat carcinoma cells which can convert 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB 1954) to a cytotoxic DNA interstrand crosslinking agent by reduction of its 4-nitro group to the corresponding hydroxylamino species (Roberts JJ et al., Biochem Biophys Res Commun 140: 1073-1078, 1986; Knox RJ et al., Biochem Pharmacol 37: 4661-4669, 1988).
(20) In contrast, nordihydroguaiaretic acid, metyrapone, NG-monomethyl-L-arginine, and nitro-L-arginine all attenuated the relaxation to acetylcholine; however, indomethacin had no effect on acetylcholine-induced relaxations.
Unstable
Definition:
(a.) Not stable; not firm, fixed, or constant; subject to change or overthrow.
Example Sentences:
(1) Unstable subcapital fractures and dislocation fractures of the humerus can usually be set by closed reduction.
(2) Measurements of mechanical stability of Hb Santa Ana showed that the oxy-form of this hemoglobin was 10 times more unstable than that of Hb S and 100 times more unstable than that of Hb A.
(3) Although operative mortality was significantly greater for women during most of this review period, mortality was similar during 1983 (2.6% for men versus 2.4% for women), in spite of a significantly higher incidence of unstable angina in the female group (54% for women versus 35% for men).
(4) Similar, but less marked changes were seen in the patients unstable angina.
(5) If a tear is found, remove all unstable meniscal fragments, leaving a rim, if possible, especially adjacent to the popliteus recess, and then proceed to open cystectomy.
(6) After the impact … I lost my balance, making my body unstable and falling on top of my opponent,” he said in his submission to the panel, which met on Wednesday, a day after Uruguay had beaten Italy 1-0 in a decisive group-stage match.
(7) The complex was found to be unstable toward low values of pH and ionic strength, concentrations of urea exceeding 1 M, modifications of the cysteine residues, and fragmention in which the C terminal portions of either H3 or H4 are removed.
(8) Then, the males with super-unstable oc-mutations were crossed with females with attached X chromosomes, supporting P-M hybrid dysgenesis.
(9) Since transcription does not take place during mitosis, the amount of protooncogene products is rapidly decreased (they are extremely unstable).
(10) We describe herein, a new unstable mutant of the vestigial locus, isolated from a French natural population.
(11) The Saudi-led war in Yemen launched in March – against Houthi rebels who the Saudis insist are backed by Iran – has diverted resources and underlined the priority being given to the Gulf’s unstable and impoverished backyard.
(12) The hypothesis that opiate agonism requires an N substituent in the axial position does not appear to be consistent with the increased potency of beta isomers in which axial N substituents are thermodynamically more unstable.
(13) These drugs are beneficial also in prevention of recurrent myocardial infarction, especially among patients with unstable angina.
(14) HPLC is of particular value in providing a means of separating unstable compounds prior to assay by relatively nonspecific quantitation methods.
(15) In a cohort of 417 patients admitted consecutively to the Coronary Care Unit for acute myocardial ischemia (unstable angina pectoris in 121, acute myocardial infarction in 296 patients) 21 cases of non arrhythmogenic sudden death occurred within 24 hours after admission.
(16) The homdr mutation is unstable and probably deleterious to the cell.
(17) It is likely that the light chains assemble normally with the HMM fragment in HMM cells, while in cells lacking myosin heavy chain (mhcA) the light chains are unstable.
(18) These findings emphasize the difficulty of identifying patients at low risk for myocardial infarction or unstable angina in the emergency room without consideration of many factors from the history, the physical examination, and the ECG.
(19) During unstable detrusor contractions, which even in these healthy women are observed during bladder filling and also during inhibited voidings through the urethra, the contraction is weaker.
(20) With these scores we expect to facilitate the diagnostic screening, to indicate the way of therapy and to avoid unnecessary surgery for urinary incontinence in cases of motor-urge-incontinence (detrusor instability, unstable bladder), as long as a urodynamic examination is not feasible on every incontinent women.