VOC Profiles of Saliva in Assessment of Halitosis and Submandibular Abscesses Using HS-SPME-GC/MS Technique.

Halitosis and submandibular abscesses are examples of mouth-related diseases with the possible bacterial origin. Salivary volatile organic compounds (VOCs) are potential biomarkers of them, once they can be addressed as metabolites of bacterial activity. Healthy patients (n = 15), subjects with submandibular abscesses located in fascial deep space (n = 10), and subjects with halitosis (n = 5) were enrolled in the study. Saliva samples were subjected to headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to mass spectrometry (GC/MS) analysis. A total number of 164 VOCs was detected by the developed methodology, 23 specific for halitosis and 41 for abscess. Halitosis' profiles were characterized by a larger number of sulfur compounds, while for abscess they had a higher variety of alcohols, aldehydes, and hydrocarbons-biomarkers of inflammatory processes. Principal components analysis allowed visualization of clusters formed according to the evaluated conditions. Kruskal-Wallis test indicated that 39 VOCs presented differentiated responses between the studied groups, with statistical relevance (p < 0.05). Random forest was applied, and a prediction model based on eight VOCs (2-butanone, methyl thioacetate, 2-methylbutanoic acid, S-methyl pentanethioate, dimethyl tetrasulfide, indolizine, pentadecane, and octadecanal) provided 100% of sensitivity, 82% of specificity, and 91% of balanced accuracy, indicating the specific presence of submandibular abscess.

Desinfectantes químicos de uso clínico: Aldehídos / No disponible

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Identification of 2-alkenals, 4-hydroxy-2-alkenals, and 4-hydroxy-2,6-alkadienals in exhaled breath condensate by UHPLC-HRMS and in breath by real-time HRMS.

In recent years, breath analysis in real time has become a noninvasive alternative for the diagnosis of diseases and for molecular fingerprinting of exhaled breath. However, the techniques used lack the capabilities for proper identification of the compounds found in the exhalome. Here, we report the use of UHPLC-HRMS as a tool for the identification of several aldehydes (2-alkenals, 4-hydroxy-2-alkenals, and 4-hydroxy-2,6-alkadienals), biomarkers of lipid peroxidation, in exhaled breath condensate of three healthy subjects (N = 3). Some of the aldehydes studied have never been identified before. Their robust identification is based on retention times, on the generation of fragmentation trees from tandem mass spectra, and on the comparison of these parameters with standards. We also show that the identified compounds can be analyzed and confirmed by MS/MS in breath in real time and, therefore, they could be used as biomarkers for the rapid and noninvasive diagnosis of related diseases.

Simple derivatization of aldehydes with D-cysteine and their determination in beverages by liquid chromatography-tandem mass spectrometry.

We describe a simple derivatization method to determine aldehydes. This method is based on derivatization with D-cysteine and consecutive liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimum derivatization conditions of aldehydes with D-cysteine were 10 min at 50°C and pH 7.0. The formed alkyl thiazolidine-4-carboxylic acid derivatives were directly injected in LC-MS/MS. In the established condition, the method was used to detect eight aldehydes in beverages. The limit of detection (LOD) and limit of quantification (LOQ) of the aldehydes were 0.2-1.9 µg L(-1) and 0.7-6.0 µg L(-1) and the relative standard deviation was less than 2.0% at concentrations of 0.1 mg L(-1) and 1.0 mg L(-1) with the exception of octanal. All the beverage samples had detectable levels of methanal (0.033-0.145 mg L(-1)), ethanal (0.085-2.12 mg L(-1)), propanal (ND to 0.250 mg L(-1)), butanal (ND to 0.003 mg L(-1)), pentanal (ND to 0.471 mg L(-1)), hexanal (ND to 0.805 mg L(-1)), heptanal (0.019-3.91 mg L(-1)) and octanal (0.029-0.118 mg L(-1)).

Headspace volatile composition of the flowers of Caralluma europaea N.E.Br. (Apocynaceae).

The volatile constituents of the flowers of Caralluma europaea (Guss.) N.E.Br (Apocynaceae) from Lampedusa Island were analyzed by a headspace GC method. The analyses allowed the identification and quantification of 41 compounds. The main components were, among the monoterpenoids, terpinolene (23.3%), alpha-terpinene (19.1%) and linalool (18.4%), whereas, among the carbonylic compounds the major constituents were heptanal (2.0%), octanoic acid (2.4%) and hexanoic acid (1.7%). The presence of a nitrogen containing compound, indole (0.8%) and of a sulphur containing compound, dimethylsulphide (t), noteworthy. The compounds found in the flowers of C. europaea have been compared with data available in the literature as regard to their odor, presence in other sapromyiophilous taxa, possible role as semiochemicals, and presence in decaying organic matter. 89.3% of total constituents have been described in other sapromyiophilous taxa. Some of the compounds are present in several types of decaying organic matter (excrements, decomposing bodies, and spoiled fish, etc). Several volatiles found in C. europaea flowers are used as semiochemicals by Hymenoptera, Coleoptera, Diptera, Lepidoptera and other insects. Sixteen volatiles, accounting for 32.4% of the total constituents, are described as attractants of some Diptera families, with a biology linked to decaying organic matter. Our data thus confirm that C. europaea floral bouquet falls within the sapromyiophilous pollination syndrome.

Formation of categories from structure-activity relationships to allow read-across for risk assessment: toxicity of alpha,beta-unsaturated carbonyl compounds.

alpha,beta-Unsaturated carbonyl compounds are common environmental pollutants that are able to interact with proteins, enzymes, and DNA through various mechanisms. As such, they are able to stimulate a range of environmental toxicities and adverse health effects. In this study, a "category" of alpha,beta-unsaturated carbonyl compounds (aldehydes and ketones), assumed to act by a common mechanism of action (Michael type addition), was formed. This toxicologically and mechanistically important category was formed on the premise of structure-activity relationships. The acute aquatic toxicities to Tetrahymena pyriformis of compounds within the category were obtained in an effort to develop approaches for (qualitative) read-across. In addition, Salmonella typhimurium (strain TA100) mutagenicity data were analyzed to establish the structural differences between mutagenic and nonmutagenic compounds. These structural differences were compared with the structural characteristics of molecules associated with acute aquatic toxicity in excess of narcosis as well as other end points, for example, skin sensitization. The results indicate that a category can be formed that allows structural information and boundaries to be elucidated. This knowledge will guide future toxicity prediction within this category and assist in the development of category formation.

Structural basis for the potent antisickling effect of a novel class of five-membered heterocyclic aldehydic compounds.

Naturally occurring five-membered heterocyclic aldehydes, including 5-hydroxymethyl-2-furfural, increase the oxygen affinity of hemoglobin (Hb) and strongly inhibit the sickling of homozygous sickle red blood (SS) cells. X-ray studies of Hb complexed with these compounds indicate that they form Schiff base adducts in a symmetrical fashion with the N-terminal alphaVal1 nitrogens of Hb. Interestingly, two cocrystal types were isolated during crystallization experiments with deoxygenated Hb (deoxyHb): one crystal type was composed of the low-affinity or tense (T) state Hb quaternary structure; the other crystal type was composed of high-affinity or relaxed state Hb (with a R2 quaternary structure). The R2 crystal appears to be formed as a result of the aldehydes binding to fully or partially ligated Hb in the deoxyHb solution. Repeated attempts to crystallize the compounds with liganded Hb failed, except on rare occasions when very few R state crystals were obtained. Oxygen equilibrium, high performance liquid chromatography (HPLC), antisickling, and X-ray studies suggest that the examined heterocyclic aldehydes may be acting to prevent polymerization of sickle hemoglobin (HbS) by binding to and stabilizing liganded Hb in the form of R2 and/or various relaxed state Hbs, as well as binding to and destabilizing unliganded T state Hb. The proposed mechanism may provide a general model for the antisickling effects of aldehyde containing small molecules that bind to N-terminal alphaVal1 nitrogens of Hb. The examined compounds also represent a new class of potentially therapeutic agents for treating sickle cell disease (SCD).

Olfactory sensitivity for aliphatic aldehydes in squirrel monkeys and pigtail macaques.

Using a conditioning paradigm, the olfactory sensitivity of three squirrel monkeys and three pigtail macaques for a homologous series of aliphatic aldehydes ( n-butanal to n-nonanal) was assessed. With only few exceptions, the animals of both species significantly discriminated concentrations below 1 ppm from the odorless solvent, and with n-butanal and n-hexanal individual pigtail macaques even demonstrated thresholds below 1 ppb. The results showed (1). both primate species to have a well-developed olfactory sensitivity for aliphatic aldehydes, (2). pigtail macaques to generally perform better than squirrel monkeys in detecting members of this class of odorants, and (3). no significant correlation between perceptibility in terms of olfactory detection thresholds and carbon chain length of the aliphatic aldehydes in both species tested. These findings lend further support to the growing body of evidence suggesting that between-species comparisons of the number of functional olfactory receptor genes or of neuroanatomical features are poor predictors of olfactory performance. Further, our findings suggest that olfaction may play an important and hitherto underestimated role in the regulation of behavior in the species tested.

On robust partial discriminant analysis as a decision-making tool with clinical and analytical chemical data.

Classification is one of the fundamental goals of science and is basic to the diagnosis of disease. Unfortunately, classifying objects (e.g., patients) on the basis of clinical and/or laboratory experimental observations into various groups can be difficult when the groups overlap or contain outlying points. Recently, Broffitt, Randles, and co-workers proposed a procedure, robust partial discriminant analysis (RPDA) for dealing with such problems, but testing of the procedure was limited to Monte Carlo simulation. In this study, RPDA was applied to real data, in order to compare its effectiveness with ordinary discriminant analysis, as well as to determine if RPDA was a suitable procedure to use to classify chemical compounds on the basis of experimental observations and as a tool in the diagnosis of disease (in particular, multiple sclerosis and thyrotoxicosis), with data based on experimental and clinical observations. The resulting RPDA classifications were an improvement over those obtained from ordinary discriminant analysis.