PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Nitro Compounds”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1976

Cancer and the consumption of home-produced alcoholic drinks in Zambia: a possible correlation.

Evidence has been obtained which suggests that a significant corrlation exists between the drinking of home-produced grain-based alcoholic beverages and the level of incidence of cancer of the oesophagus in parts of Zambia. A similar correlation has been reported from other parts of the continent of Africa. Large numbers of samples of Zambian beers and spirits were screened to discovered what might be the causative agent of the disease. Two major contaminants were found: (i) high levels of zinc, iron and sometimes of copper; (ii) nitrosamine-like compounds. The former results from the use of old metal drums during production of the drinks, but their carcinogenic effects are doubtful. The latter are highly potent carcinogens whose presence has been shown in a wide range of foodstuffs in recent years. At this stage it is impossible because of analytical problems to assert with absolute certainty which of the nitro-so compounds are present. The investigation is continuing and it is hoped that a reliable and relatively easy analytical procedure will soon be available.

Alcohol Drinking↗
PubMed2003

Identification of biochemical markers linked to neonicotinoid cross resistance in Bemisia tabaci (Hemiptera: Aleyrodidae).

The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is a serious pest in many cropping systems world-wide and occurs in different biotypes. The most widespread one is the B-type, whereas the Q-biotype is nowadays still mostly restricted to Southern Spain. Neonicotinoid cross-resistance is known at a high level in Q-types from Spain and individual samples collected in Italy and Germany. Now we detected for the first time high neonicotinoid cross-resistance in a B-type from Israel. Target site resistance to imidacloprid using [(3)H]imidacloprid in nicotinic acetylcholine receptor (nAChR) binding assays could not be detected in any of these highly resistant strains. The impact of metabolizing enzymes such as esterases, glutathione S-transferases, and cytochrome P450-dependent monooxygenases in neonicotinoid resistance was studied biochemically with artificial substrates. Monooxygenase activity was increased 2-3-fold in moderately resistant strains (RF approximately 30) and even 5-6-fold in highly resistant strains (RF approximately 1,000). Only monooxygenase activity correlated with imidacloprid, thiamethoxam and acetamiprid resistance and, therefore, monooxygenases seem to be the only enzyme system responsible for neonicotinoid resistance in B. tabaci Q- and B-types. The oxidative degradation of imidacloprid in resistant Q-type strains could be confirmed by metabolism studies of [(14)C]imidacloprid in vivo. Five-hydroxy-imidacloprid could be detected as the only main metabolite. The insecticidal activity and binding affinity to nAChR of this compound was 10 times lower than imidacloprid itself in B. tabaci.

Animals↗
PubMed1992

Mutagenicity of nitroxyl compounds: structure-activity relationships.

Three piperidinoxyl radicals were found to be directly mutagenic in Salmonella typhimurium TA 100, one pyrrolidinoxyl compound had weaker activity, and two other pyrrolidinoxyl derivatives did not produce an increase of the spontaneous revertants. The tester strain TA 100 was selected in preliminary tests for its higher sensitivity compared to TA 98 and TA 102. The mutagenic activity of the three active compounds was abolished by partial reduction with ascorbic acid, suggesting that the mutagenicity was linked to the free radical nature of these compounds, and reduced in the presence of a cofactor supplemented rat liver subcellular fraction. The mutagenicity of the tested compounds was correlated to the resistance of the nitroxyl spin labels to reduction: the more reactive radicals were found to possess higher mutagenic activity.

Ascorbic Acid↗
PubMed2006

A simple procedure for calculating condensed phase heat of formation of nitroaromatic energetic materials.

A simple procedure has been introduced for calculating solid and liquid heats of formation of nitroaromatic energetic compounds. This model assumes that the heat of formation of a nitroaromatic compound of composition C(a)H(b)N(c)O(d) can be expressed as a new correlation which depends on elemental composition and various structural and special functional group parameters. Condensed phase heats of formation predicted using the method described herein and complicated quantum mechanical computations [B.M. Rice, J. Hare, Thermochem. Acta 384 (2002) 377] have a root mean square (rms) deviation of 5.9 and 11.1 kcal/mol for 19 well-known organic nitroaromatic compounds. Predicted heats of formation for 29 polycyclic nitroaromatic energetic compounds have a rms deviation from experiment of 10.6 kcal/mol. The results show that the present method gives comparable prediction respect to the other methods such as complex quantum mechanical computation.

Algorithms↗
PubMed2006

Insect nicotinic acetylcholine receptors: neonicotinoid binding site specificity is usually but not always conserved with varied substituents and species.

The diversity of neonicotinoid insecticides acting as insect nicotinic acetylcholine (ACh) receptor (nAChR) agonists is illustrated by imidacloprid (IMI) with chloropyridinylmethyl (CPM) and N-nitroimine substituents, dinotefuran (DIN) with tetrahydrofurylmethyl (TFM) and N-nitroimine moieties, and acetamiprid (ACE) with CPM and N-cyanoimine groups. These three neonicotinoids are used here as radioligands to test the hypothesis that they all bind to the same site in the same way in both fruit flies (Drosophila melanogaster) and a leafhopper pest (Homalodisca coagulata): that is, neonicotinoid binding site specificity is conserved in the insect nAChRs. Multiple approaches show that [3H]IMI and [3H]ACE interact with an identical site in both species. However, although [3H]DIN binds with high affinity in both insects, its pharmacological profile in Homalodisca is surprisingly unique, with high sensitivity to some TFM-containing compounds and ACh. The TFM moiety of DIN may bind in a different orientation compared to the CPM group of IMI and ACE.

Animals↗
PubMed2001

In vivo and in vitro effects of imidacloprid on sheep keds (Melophagus ovinus): a light and electron microscopic study.

The effects of imidacloprid (Advantage) on sheep keds (Melophagus ovinus Linne 1758) were studied in vivo and in vitro by means of direct observation (monitored on video tape) and by light and electron microscopy. It was found that: 1. Imidacloprid acted rapidly on all motile stages of the sheep keds. Within 3-4 min after exposure they became immobile and their legs and the abdomen started tetanic trembling movements for 15-30 min, leading to death. 2. The compound is apparently taken up by the body, since it also acted on those sheep keds that had been exclusively exposed to imidacloprid-contaminated filter papers. 3. The compound is available and active for more than 1 month in the wool of sheep; even rainfall does not reduce its efficacy. Body contact between treated mother sheep and their lambs protects them from infestation with these ectoparasites. 4. The compound initiates an ultimately lethal destruction of the ganglia, nerve chords and related muscle fibers, as can be seen in electron micrographs.

Administration, Topical↗
PubMedDate not supplied

Polycyclic phenols, estrogens and neuroprotection: a proposed mitochondrial mechanism.

Polycyclic phenols, including the estrogens, have been shown to be potent neuroprotectants in a variety of cellular and animal model systems. Although classical estrogen receptor interactions and consequent responses play a role in certain circumstances, the neuroprotective activity of polycyclic phenols that do not interact with estrogen receptors ERalpha or ERbeta is more likely to be through non-genomic mechanism(s). We propose here that such non-feminizing polycyclic phenols exert their protective effects at least in part by stabilizing mitochondria, preventing apoptotic and/or necrotic forms of cell death that are associated with mitochondrial dysfunction. Consistent with this mitochondrial model and the available data, these compounds protect neurons and other cell types from a wide variety of pathologically relevant stressors.

Adenosine Triphosphate↗
PubMed1975

Effects of 4-nitrobenzofurazans and their N-oxides on synthesis of protein and nucleic acid by murine leukemia cells.

A series of benzo-2,1,3-oxadiazoles (benzofurazans) and their N-oxides (benzofuroxans) inhibit incorporation of precursors into nucleic acids and protein by murine leukemia cells. At slighly higher levels, substantial single- and double-strand DNA breakage was observed. At still higher concentrations, inhibition of phosphorylation of uridine and thymidine was found. Structure-activity relationships show that only compounds bearing appropriate substitutions at positions 4 and 7 were effective inhibitors of biosynthetic pathways. Such compounds appear to interact with a wide variety of biological systems and may be useful in elucidating modes of macromolecule synthesis.

Animals↗
PubMed1998

3-Nitropropionic acid's lethal triplet: cooperative pathways of neurodegeneration.

3-Nitropropionic acid (3-NP) is a mitochondrial toxin which interferes with ATP synthesis. Accidental ingestion of 3-NP by humans as well as other mammals results in neuronal degeneration within the basal ganglia and movement dysfunction characterized by dystonia, chorea, and hypokinesia. The selective degeneration of structures of the basal ganglia occurs despite the non-selective impairment of energy metabolism throughout the brain and body. These effects of 3-NP are shared with the genetic disorder Huntington's disease (HD), which is characterized by progressive neurodegeneration of the basal ganglia and choreic motor dysfunction. These similarities have prompted further investigation of 3-NP as an animal model of HD. Metabolic compromise with 3-NP causes neurodegeneration that involves three interacting processes: energy impairment, excitotoxicity, and oxidative stress. This triplet of cooperative pathways of neurodegeneration helps to explain 3-NP's regional selectivity of neurotoxicity to the basal ganglia. This mini-review will focus on the actions of 3-NP and the related compound, malonic acid (MA), in the central nervous system, with an emphasis on the more current findings regarding their mechanisms of action.

Animals↗
PubMed2003

Insecticidal activity and nicotinic acetylcholine receptor binding of dinotefuran and its analogues in the housefly, Musca domestica.

The insecticidal activity of dinotefuran and 23 related compounds against the housefly, Musca domestica (L) was measured by injection with metabolic inhibitors. Dinotefuran was less active than imidacloprid and clothianidin by a factor of 10 in molar concentrations. Their binding activities to the fly-head membrane preparation were measured by using [125I]alpha-bungarotoxin ([125I]alpha-BGTX) and [3H]imidacloprid ([3H]IMI) as radioligands. The activity of some selected compounds measured with [3H]IMI was 10(4)-fold higher than that measured with [125I]alpha-BGTX. With [3H]IMI as a radioligand, dinotefuran was 13-fold less active than imidacloprid. The inhibitory effect of dinotefuran on the binding of [3H]IMI to the membrane preparation was in a competitive manner. Quantitative analysis of the insecticidal activity of the test compounds with the binding activity measured with [3H]IMI showed that the higher the binding activity, the higher was the insecticidal activity.

Animals↗
PubMed2006

Influence of light in acute toxicity bioassays of imidacloprid and zinc pyrithione to zooplankton crustaceans.

The acute toxicity of imidacloprid, a neonicotinoid insecticide, and zinc pyrithione (Zpt), a biocide used in anti-dandruff shampoos and protective antifouling paints, to three species of ostracods and two waterfleas, including Daphnia magna, was determined and compared under light and dark conditions. Under normal laboratory conditions, UV light had no significant influence on the outcome of toxicity bioassays, although in the case of imidacloprid both EC(50) and LC(50) calculated values were twice as high under the light as in the dark. No influence of UV light was observed on bioassays conducted with Zpt, in spite of the fast aqueous photolysis exhibited by this compound. Imidacloprid 48-h LC(50) for cladocerans (65-133mg/L) were two orders of magnitude higher than for ostracods (301-715microg/L); values of EC(50) for cladocerans and ostracods were 2-6mg/L and 3-16microg/L, respectively. Toxicity of Zpt to both ostracod and cladoceran species appears to be similar, with 48-h LC(50) in the range 137-524 and 75-197microg/L for ostracods and cladocerans, respectively, and similar values for EC(50)s. The mortality endpoint (LC(50)), however, is not a reliable predictor of the effects of imidacloprid under field situations (e.g. rice paddies), because the paralysis effect induced by this insecticide takes place at much lower concentrations than those required to cause the death of the animals: regardless of the taxa, differences as large as 100- or 600-fold were observed between the EC(50) and LC(50) for the same exposures. As a consequence, immobilization tests and EC(50) values are recommended for this class of compounds, while caution should be exercised in environmental risk assessments of this and possibly other related neonicotinoid insecticides with similar activity.

Animals↗
PubMed1996

In vitro anticryptosporidial activity of dinitroaniline herbicides.

Despite the evaluation of over 100 antimicrobial drugs, the diarrheal disease cryptosporidiosis has remained refractory to treatment. We report the evaluation of five dinitroaniline herbicides including trifluralin, profluralin, nitralin, pendimethalin, and fluchloralin for anticryptosporidial activity in an in vitro cultivation model of Cryptosporidium parvum. All five compounds exhibited significant anticryptosporidial activities with no corresponding evidence of toxicity. The most active compound was pendimethalin with an IC50 of 0.19 microM while nitralin was the least active with an IC50 of 4.5 microM. These compounds should be evaluated further in an animal model of cryptosporidiosis.

Aniline Compounds↗