Subject(s)
Electronic Nose , Breath Tests , Exhalation , Reproducibility of Results , Volatile Organic CompoundsABSTRACT
Electronic noses (e-noses) are a cheap and easy method for exhaled Volatile Organic Compound (VOC)-analysis which has shown its potential in several diseases. Before obtaining a full validation of these instruments in clinical settings, a number of methodological issues still have to be established. We aimed to investigate a potential influence of circadian variation on VOC-profile analyzed by an e-nose in healthy subjects. We enrolled 22 adults free of any known diseases. A sequence of exhaled breath samplings were performed on all participants at predetermined hours (7am, 12pm, 17pm, 23pm) and analyzed by an e-nose (Cyranose 320). According to Principal Component Analysis, significant circadian variations of the exhaled VOC-profile were shown for Principal Component (PC) 1 and 3. In detail, PC1 and PC3 values were significantly higher in the morning compared to the afternoon and evening (for all parameters p less than 0.05). Successive Linear Discriminant analysis confirmed the findings above. The daily variations in VOCs-profile, with the peak in the morning, could be relevant for future clinical applications, especially in the choice of optimal time for sampling patients.
Subject(s)
Breath Tests , Circadian Rhythm/physiology , Electronic Nose , Exhalation/physiology , Adult , Discriminant Analysis , Humans , Linear Models , Principal Component Analysis , Time Factors , Volatile Organic Compounds/analysisABSTRACT
A method is described for determining 4-hexylresorcinol in crab meat. 4-Hexylresorcinol is used to prevent melanosis in shrimp, and the same use has been proposed for crab meat. Because 4-hexylresorcinol may be added illegally to crab meat as a preservative, consumer protection requires that residues of the compound be monitored in crab meat. 4-Hexylresorcinol is extracted from crab meat with acetonitrile. After dilution with water, the extract is passed through a C18 solid-phase extraction column and 4-hexylresorcinol is eluted from the column with ethanol. The compound is determined by reversed-phase liquid chromatography with diode array detection at 206 nm. Limit of quantitation is 1.0 microgram/g. Mean recovery in the range 1-20 micrograms/g is 89%, with a relative standard deviation of 6.3.
Subject(s)
Brachyura/chemistry , Hexylresorcinol/analysis , Meat/analysis , Animals , Chromatography, Liquid , Indicators and ReagentsABSTRACT
The effect of carcinogens given by a single or multiple injections on the extent of (35S)methionine interaction with hepatic tRNA was studied in normal and partially hepatectomized rats. Either partial hepatectomy or administration of ethionine (100 or 330 mg/kg body weight) and dimethylnitrosamine (120 mg/kg body weight) by multiple i.p. injections inhibited the (35S)methionine-tRNA interaction, while administration of hepatocarcinogenic chemicals plus PH resulted rather in a stimulation. Methylnitrosourea enhanced the extent of interaction when administered in a single dose (100 mg per kg body weight) 18 h after partial hepatectomy.
Subject(s)
Dimethylnitrosamine/pharmacology , Liver Regeneration , Liver/metabolism , Methionine/metabolism , Methylnitrosourea/pharmacology , RNA, Transfer/metabolism , Animals , Ethionine/pharmacology , Hepatectomy , Liver/drug effects , Male , Radioisotope Dilution Technique , Rats , Rats, Inbred Strains , Sulfur RadioisotopesABSTRACT
As part of a study to characterize the methionine role in tumorigenesis, we report that methionine sulfur interacts with rat liver tRNA "in vivo" (35S) radioactivity remained associated to the nucleic acid after a number of treatments, including tRNA deacylation. Similar data were obtained after administration of (methyl-3H) methionine, while no comparable tRNA labelling was detected when the aminoacid labelled in the aliphatic chain was given. Hplc analysis of (35S) tRNA enzymic hydrolysate showed two unidentified UV-absorbing radioactive peaks. NMR spectra of these two peaks did not reveal any thiomethyl group.
Subject(s)
Liver/physiology , Methionine/metabolism , RNA, Transfer/metabolism , Sulfur , Animals , DNA/metabolism , Magnetic Resonance Spectroscopy , Rats , Spectrophotometry, UltravioletABSTRACT
14C-Hexachlorocyclopentadiene (HEX, C56 ) was administered to adult rats and mice as a single oral dose (2.5 and 25 mg/kg) and as a component of the diet (1, 5 and 25 ppm) for a maximum of 30 days. The primary route of excretion was via the feces (-70% of dose) with low elimination in the urine (approximately 15%). Biliary excretion of only 16% with 66% still voided in the feces of bile duct cannulated rats suggested that the majority of orally consumed HEX was not absorbed. However, extensive degradation apparently occurred in the gut since little of the fecal material was of an apolar nature. The kidney, liver, ovaries and fat were the major sites of deposition of 14C-HEX equivalents. In rats, the kidney contained the highest levels of residues, whereas in mice the residues in the liver exceeded those in the kidney. Other than this difference, the fate of HEX in rats and mice, both male and female, was quite similar and in each case the tissue residues reached a plateau after about two weeks on the HEX-containing diets.
