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At least 19 recordsLinked to original sources
PubMed1975

Quenching of excited chlorophyll A in vivo by nitrobenzene.

Nitrobenzene exerts a dual effect on the excitation of chlorophyll a(Chl a) in vivo. (a) A 3(3,4-dichlorophenyl)-1,1-dimethylurea-inhibited quenching that manifests as a partial inhibition of variable chloroplast fluorescence and of 2,6-dichlorophenol indophenol (DCPIP) photoreduction and saturates at ca. 5-10 muM. Since nitrobenzene is not a Hill oxidant, this effect is attributed to a catalyzed back flow of electrons from intersystem intermediates to pre-photosystem II oxidants. (b) A direct quenching of the excited Chl a in vivo. This effect has a threshold of ca. 100 muM nitrobenzene; at higher concentrations it leads to almost complete suppression of chloroplast fluorescence and DCPIP photoreduction. Tris-washed chloroplast enriched in the photosystem II reaction center species Z+Q- and ZQ- are nearly four times more sensitive to nitrobenzene quenching than those enriched in Z+Q. On the other hand, normal chloroplasts are about 10 to the fourth times more sensitive. Hence, it is argued that the extreme sensitivity of normal chloroplast fluorescence is not due to a preferential association of nitrobenzene with a particular redox species of the reaction center.

Chlorophyll↗
PubMed1975

Effect of repeated exposure to aniline, nitrobenzene, and benzene on liver microsomal metabolism in the rat.

Exposure of rats to aniline at daily doses of 50 mg/kg of body weight over a month stimulated the microsomal metabolism as manifested by (1) acceleration of p-hydroxylation of anilin and N-demethylation of aminopyrine in 9-000 times g postmitochondrial supernatant of the liver, (2) shortening the sleeping time after hexobarbital, and (3) reduction of the antipyretic effect of phenacetin. In the rats exposed to nitrobenzene in a similar manner to aniline, nitroreduction of nitrobenzene and p-hydroxylation of aniline remained unaffected; the antipyretic effect of phenacetin was decreased, whereas hexobarbital sleeping time remained unchanged. Exposure of rats to benzene (50 mg/kg of body weight daily for a month) had no effect on the rate of hydroxylation of benzene and N-demethylation of aminopyrine. In benzene-exposed rats hexobarbital sleeping time was prolonged whereas the antipyretic effect of phenacetin was unaffected. Microsomal metabolism of aniline, nitrobenzene, and benzene was stimulated and inhibited when the rats were pretreated with phenobarbital and SKF 525-A, respectively.

Aminopyrine N-Demethylase↗
PubMed1978

Methemoglobinemia: nitrobenzene ingestion.

In an unusually severe case of multiple toxin ingestion, a 48-year-old man ingested approximately 300 cc of Hoppe's Gunpower Solvent #9, which contains kerosene, denatured ethyl alcohol, oil and nitrobenzene. The major manifestation was nitrobenzene-induced methemoglobinemia of rapid onset. Treatment involves the judicious use of 1% methylene blue plus, in severe cases, hemodynamic and ventilatory support. The patient recovered after 48 hours and was transferred to the psychiatric service with continued follow-up for a mild poison-induced hemolytic anemia.

Anemia, Hemolytic↗
PubMed1992

Thermal desorption-gas chromatography for the determination of benzene, aniline, nitrobenzene and chlorobenzene in workplace air.

Sampling on Tenax TA of different mesh sizes followed by thermal desorption and gas chromatography was evaluated as a simple method for the determination of benzene, aniline, nitrobenzene and chlorobenzene in the workplace air. An alternative sampling technique in place of pump sampling was developed. Quantitative recoveries were obtained in the mass range 0.04-10 micrograms. It was found that air humidity had no effect on recovery. The charged tubes can be stored at room temperature for 5 days with no change in recovery. The particle size of Tenax TA has no significant effect on adsorption and desorption.

Air Pollutants, Occupational↗
PubMedDate not supplied

A case of multiple sensitization to three halogeno-substituted mono-nitrobenzenes.

A case of occupational contact dermatitis in a female chemical pharmaceutical laboratory researcher is described. The allergological investigation revealed a state of sensitization to three mono-nitrobenzenes with halogen substitutions in the nucleus or a side chain. Problems related to sensitization to these substances and to possible cross-allergy with DNCB are discussed.

Adult↗
PubMed1975

[Chemotherapeutic effects of nitro compounds. 1. Nitroanilines].

More than 200 nitro compounds, most of them nitroaniline derivatives substituted with one or more radicals having a basic reaction, were prepared and investigated as to their therapeutic activity against bacteria, fungi, protozoa, helminths, viruses and tumors. Several mono-nitrobenzenes with a radical having a basic reaction showed weak in-vitro activity against gram-positive bacteria and against Crocker's sarcoma 180; they also showed systemic activity against nematodes (Aspiculuris tetraptera) and viruses. The majority of therapeutically active compounds with pronounced in-vivo activity against Trichomonas fetus, Entamoeba histolytica, Schistosoma mansoni, cestodes, nematodes (Ancylostoma caninum), viruses (influenza, MHV, SAV and EMC) and various types of carcinoma (Ehrlich's carcinoma, leukemia 1210, Crocker's sarcoma 180) were dinitrobenzene derivatives with one radical having a basic reaction and electropositive groups or unreactive or reactive chlorine atom, and di-nitrobenzene with two equal or two different radicals having a basic reaction. Compound No. 70 revealed a marked in-vitro activity against fungi (Trichophyton; Microsporum, Candida albicans). Other nitro compounds such as bis-mono- and bis-dinitrobenzene derivatives likewise showed a systemic action against E. histolytica, viruses and, in particular, carcinoma (Crocker's sarcoma 180, Ridgway's osteosarcoma). Oxygen and sulfur analogue compounds as well as compounds produced by reduction also possessed a distinct activity against E. histolytica and viruses. On the basis of the present results particularly the dinitrobenzenes substituted with two radicals having a basic reaction include a number which have in common that a structure/activity relationship is recognizable in respect of E. histolytica, Schistosoma mansoni and different types of viruses. The activity against viruses in this class of compounds is probably due to an increased interferon production in the host animal. Whether the mechanism of action is the same against E. histolytica or Schistosoma mansoni has not been determined so far. A tumorigenic effect was observed mainly in those di-nitrobenzenes which are classed as alkylating compounds. Because of the small chemotherapeutic index the trials were not continued with the most effective compounds mentioned.

Aniline Compounds↗
PubMed1979

Iodosylbenzene derivatives as oxygen donors in cytochrome P-450 catalyzed steroid hydroxylations.

The mechanism of cytochrome P-450 catalyzed steroid hydroxylations in rat liver microsomes has been investigated by employing derivatives of iodosylbenzene as oxygen donors. The model steroid substrate androstenedione which was hydroxylated in positions 7 alpha, 6 beta, and 16 alpha was used in reactions supported by NADPH, iodosylbenzene, and iodosylbenzene derivatives. Evidence for cytochrome P-450 involvement in iodosylbenzene-sustained androstenedione hydroxylation included inhibition by substrates and modifiers of cytochrome P-450. The most efficient oxygen donors were (diacetoxyiodo)-2-nitrobenzene greater than (diacetoxyiodo)-2-chlorobenzene greater than 2-nitroiodosylbenzene greater than (dinitratoiodo)-2-nitrobenzene greater than (diacetoxyiodo)benzene greater than (diacetoxyiodo)-2-methoxybenzene greater than 4-(diacetoxyiodo)toluene greater than iodosylbenzene. The capacity of the oxidation agents to serve as oxygen donors in cytochrome P-450 dependent steroid hydroxylation is probably dependent upon several factors such as the tendency of iodosyl compounds to associate, which decreases coordination with the heme iron, the presence of bulky substituents in the 2 position (decreases association), and the presence of electron-withdrawing substituents (tends to decrease coordination with the heme iron). The rates of 7 alpha, 6 beta, and i6 alpha hydroxylation of androstenedione catalyzed by (diacetoxyiodo)-2-nitrobenzene were 108-, 130-, and 167-fold higher, respectively, than the rates of the NADPH-supported reactions. These results strongly suggest that the rate-limiting step in NADPH-sustained cytochrome P-450 catalyzed reactions is the rate of reduction of cytochrome P-450.

Androstenedione↗
PubMed1975

Analysis for aqueous nitrates and nitrites and gaseous oxides of nitrogen by electron capture gas chromatography.

A highly sensitive gas chromatographic method is presented for the determination of aqueous nitrates. By suitable chemical pretreatment, this method is also applicable to the analysis of aqueous nitrites and gaseous oxides of nitrogen. The method has been applied to the analysis of drinking water, urine, and nitric acid. The technique involves the conversion of the nitrate ion to nitrobenzene with subsequent analysis by electron capture gas chromatography. The detection limit for nitrobenzene is ca. 10(-12) g, making possible the analysis of environmentally significant concentrations of aqueous nitrates and nitrites and gaseous oxides of nitrogen.

Chromatography, Gas↗