Pancreatic ductal adenocarcinoma and chronic pancreatitis may be diagnosed by exhaled-breath profiles: a multicenter pilot study.

BACKGROUND: The diagnosis of pancreatic adenocarcinoma and chronic pancreatitis often rely on expensive and invasive diagnostic approaches, which are not always discriminative since patients with chronic pancreatitis and pancreatic adenocarcinoma may present with similar symptoms. Volatile organic compounds (VOCs) in expired breath, could be used as a non-invasive diagnostic biological marker for detection of pancreatic pathology. Detection and discrimination of pancreatic pathology with an electronic nose has not yet been reported. PURPOSE: The objective of this pilot study was to determine the diagnostic potential of an electronic nose to identify pancreatic adenocarcinoma and chronic pancreatitis by analyzing volatile organic compoundg (VOC) profiles in exhaled air. PATIENTS AND METHODS: In a multicenter study, the exhaled air of 56 chronic pancreatitis patients, 29 pancreatic adenocarcinoma patients, and 74 disease controls were analyzed using an electronic nose based on 3 metal oxide sensors (MOS). The measurements were evaluated utilizing an artificial neural network. RESULTS: VOC profiles of chronic pancreatitis patients could be discriminated from disease controls with an accuracy of 0.87 (AUC 0.95, sensitivity 80%, specificity 92%). Also, VOC profiles of patients with pancreatic adenocarcinoma differed from disease controls with an accuracy of 0.83 (AUC 0.87, sensitivity 83%, specificity 82%). Discrimination between chronic pancreatitis and pancreatic adenocarcinoma showed an accuracy of 0.75 (AUC 0.83, sensitivity 83%, specificity 71%). CONCLUSION: An electronic nose may be a valuable diagnostic tool in diagnosis of pancreatic adenocarcinoma and chronic pancreatitis. The current study shows the potential of an electronic nose for discriminating between chronic pancreatitis, pancreatic adenocarcinoma and healthy controls. The results from this proof-of-concept study warrant external validation in larger cohorts.

A Bloembergen-Purcell-Pound 13C NMR relaxation study of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate.

The molecular structure and rotational motion of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) were studied over a wide temperature range using the Bloembergen-Purcell-Pound 13C NMR spin-lattice relaxation method and NOE factors. Examination of the spin-lattice relaxation times (T1) and the rates (R1 = 1/T1) of the 1-butyl-3-methylimidazolium cation reveals the relative motions of each carbon in the imidazolium cation. The rotational characteristics of the [BMIM] cation are supported by ab-initio molecular structures of [BMIM][PF6] using density functional theory (DFT) and Hartree-Fock (HF) methods. The ab-initio gas phase structures of [BMIM][PF6] indicate that the 1-butyl-3-methylimidazolium C2 hydrogen, the ring methyl group, and the butyl side-chain hydrogen atoms form hydrogen bonds with the hexafluorophosphate anion.

Metabolism of D- and L-[(13)C]alanine in rat liver detected by (1)H and (13)C NMR spectroscopy in vivo and in vitro.

Alanine is the major amino acid utilized by the liver for gluconeogenesis under normal conditions. The metabolism of alanine in rat liver was investigated by means of (1)H and (13)C NMR spectroscopic studies in vivo and in vitro after infusion of L- and D-alanine labelled with (13)C at the carboxyl and methyl group into normal, fasted rats. Valuable information about different metabolic pathways of alanine in rat liver and their regulation under the conditions of gluconeogenesis were obtained. The enrichment of the alanine pool by the infusate was estimated to be 11% for L-alanine and 70% for D-alanine. After infusion of labelled D-alanines, the metabolic pathway via D-amino acid oxidase was observed. The labelled alanines entered the tricarboxylic acid cycle mainly via pyruvate carboxylase; the ratio of pyruvate dehydrogenase activity to that of pyruvate carboxylase is about 28%. The ratio of flux from phosphoenolpyruvate (PEP) through phosphoenolpyruvate kinase as compared with the flux from PEP to glucose was approximately 42%. From the labelling pattern of glucose it was concluded that the pentose phosphate cycle was active under the experimental conditions.

N-2-(azol-1(2)-yl)ethyliminodiacetic acids: a novel series of Gd(III) chelators as T2 relaxation agents for magnetic resonance imaging.

The synthesis, physicochemical properties, and toxicological implications of a novel series of N-2-(azol-1(2)-yl)ethyliminodiacetic acids, useful as contrast agents for magnetic resonance imaging are reported. Compounds were prepared by alkylation of methyl iminodiacetate with N-2-bromoethylazoles and subsequent hydrolysis. Stability constants of the corresponding Gd(III) complexes and T1 and T2 relaxivities were determined and interpreted in terms of optimized geometries obtained by semiempirical PM3 calculations. Compounds show increased T2 relaxivity and decreased toxicity in vitro as compared to EDTA-Gd(III) complexes.

A new method for the determination of the dynamic isotope effect and the deuterium quadrupole coupling constant in liquids

Using a self-consistent NMR method, it is now possible to determine both the deuterium quadrupole coupling constant as well as the rotational dynamic isotope effect in liquids. We successfully tested the method on benzene for temperatures between 280 K and 293 K. The average value of 185(3) kHz for the coupling constant is compared with measurements in solid state and gas phase. As might be expected for liquids without hydrogen bonds, no difference can be detected. A rotational dynamic isotope effect of 6(3)% is observed. This value is significantly smaller than 20(5)%, the only other result reported in the literature. The results are corrected for the influence of vibrational motion. Copyright 1998 Academic Press.

Characterization of the chloride conductance in porcine renal brush-border membrane vesicles.

The chloride conductance in brush-border membrane vesicles prepared from pig kidney cortex was investigated using a light-scattering assay, anion-diffusion-potential-dependent Na+-D-glucose cotransport and 36Cl- influx. K+-diffusion-potential-driven salt exit from, or entry into, the vesicles was slow in the presence of gluconate, SO42- and F-, intermediate with Cl- and Br-, and fast with I-, NO3-, and SCN-. Stimulation of Na+-D-glucose uptake followed a similar anion sequence. Conductive Cl- flux had a low activation energy and was inhibited by suphhydryl reagents, the stilbene disulphonates 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonate (SITS) and 4, 4'-diisothiocyanato-2,2'-disulphonate (DIDS), and the arylaminobenzoates diphenylamine-2-carboxylic acid (DPC) and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB). Intravesicular Ca2+ and extravesicular nucleotides were without effect on conductive Cl- flux. These characteristics tentatively exclude some known Cl- channels and leave members of the ClC family as possible candidates responsible for the Cl- conductance in brush-border membranes.

Ketone body metabolism in the Carp Cyprinus carpio: biochemical and 1H NMR spectroscopical analysis.

In fed and starved carp, Cyprinus carpio, ketone body metabolism and those metabolic and endocrine factors that are known to induce ketogenesis in starving mammals were investigated. Acetoacetate was detected in plasma and liver of both fed and starved carp. We could not detect 3-hydroxybutyrate, neither by 1H-NMR spectroscopy nor by spectrophotometric assay, in spite of low activities of hepatic 3-hydroxybutyrate dehydrogenase. Starvation of carp did not create metabolic conditions that would favor ketone body synthesis: Mobilization and hepatic catabolism of fatty acids were only moderately enhanced, the rate of gluconeogenesis was not elevated, and glucagon levels as well as the glucagon/insulin-ratio remained stable or declined. Therefore, the discrepancy in the effect of food deprivation on mammalian and teleostean ketogenesis appears to be caused not by the absence of the ketogenic pathway from teleosts but by major differences between mammals and fish in their metabolic response to starvation.

The attachments of chromatin loops to the nucleoskeleton.

It is widely assumed by cell biologists that chromatin is looped by attachment to some nuclear skeleton. 'Structural' attachments might be mediated through specific sequences; these would be attached in most cells in an organism, underlying the basic structure of the mitotic chromosome and persisting throughout interphase. 'Functional' attachments might also exist, perhaps if active polymerases are attached to the skeleton and replication and transcription occur as DNA is reeled through them. Cells of different tissues--and even cells of the same tissue--would have different attachments of this type. Problems associated with demonstrating these two kinds of attachment are discussed. We find little good evidence for 'structural' attachments and explore the idea that 'functional' attachments are the only kind that exist: 'functional' attachments involving active transcription units might be stable enough to organize chromatin during both interphase and mitosis, but 'dynamic' enough to allow duplication of attached sequences without disrupting loops.

Genomic footprinting of proteins interacting with the chicken lysozyme promoter.

The functions of the promoter of the chicken-lysozyme-encoding gene (Lsz) are complex, since, on the one hand, the promoter serves to mediate the effects of five upstream regulatory elements and, on the other, it contains itself important regulatory sequences. To analyze this interplay we first monitored protein-DNA interactions at the Lsz promoter in hormonally regulated oviducts and in constitutively expressing HD11 cells by in vivo genomic footprinting. Two regions of strong protein-DNA interactions shared by both HD11 and oviduct cells were localized between nucleotides (nt) -105 and -119 and between nt -61 and -74, respectively. A third region of protein-DNA contacts was found selectively in HD11 cells from nt -199 to -204; this region corresponds in position with a previously identified HD11 cell-specific enhancer element. Furthermore, we determined the sites hypersensitive to an endogenous endonuclease in isolated nuclei using the genomic sequencing protocol. These sites fall into two regions: one encompasses the in vivo localized protein-DNA contacts between nt -105 and -119 and between nt -61 and -74; the other was found in a sequence largely devoid of in vivo protein-DNA interactions. We hypothesize that hypersensitive cleavage sites are generated by protein-induced changes in the DNA conformation.

Non-random spontaneous chain breakages occur in DNA methylated with dimethyl sulfate.

The method of in vivo footprinting uses partial methylation of the DNA in living cells with dimethyl sulfate (DMS), cleavage of the DNA chains at modified guanosines with piperidine, and mapping of the site of cleavage by the genomic sequencing technique of Church and Gilbert. Here we report on a spontaneous breakage reaction of DMS-methylated DNA at guanosines as well as adenosines, which is highly non-random with respect to the DNA sequence. In our in vivo genomic footprinting studies at the chicken lysozyme promoter this reaction gave rise to additional adenosine-derived bands in the guanosine sequence ladder.

In situ metabolism of 1,omega medium chain dicarboxylic acids in the liver of intact rats as detected by 13C and 1H NMR.

The hepatic metabolism of 1,omega-dodecanedioic acid, a physiologically relevant representative of the medium-chain dicarboxylic acid family, has been studied by a combination of in vivo and in vitro 13C and 1H NMR spectroscopic techniques. Rats in different nutritional or hormonal situations were infused with [1,12-13C2]- or [1,2,11,12-13C4]dodecanedioic acid, and the kinetics of 13C label appearance as well as the final relative concentrations of metabolic products were measured noninvasively in the liver of the intact rat by 13C NMR spectroscopy. Perchloric acid and chloroform/methanol extracts of liver biopsies obtained at the end of the infusion period were further analyzed by high resolution 13C NMR and one-dimensional and two-dimensional COSY and J-resolved 1H NMR. [1-13C]- and [1,2-13C2]adipic acids were the main end products of the in vivo metabolism of [1,12-13C2]- or [1,2,11,12-13C4]dodecanedioic acids, respectively, indicating that the beta-oxidation pathway of medium-chain dicarboxylic acids proceeds in situ monodirectionally. [1-13C]Adipic acid, the main product of peroxisomal beta-oxidation, could also be detected in situ. This finding, together with the in vivo and in vitro absence of signals characteristic of intramitochondrial oxidation of [1-13C]acetyl-coenzyme A, provide a strong evidence supporting a predominant contribution of the peroxisomal beta-oxidation system to the overall oxidation of these compounds in vivo. Homonuclear two-dimensional COSY 1H NMR spectra of acid extracts from rat liver provided a convenient method of analyzing the metabolic repercussions of dicarboxylic acid accumulation, revealing a decrease in the hepatic concentration of beta-hydroxybutyrate and an accumulation of adipic acid and the amino acid L-lysine.

Chromatin structure of the chicken lysozyme gene domain as determined by chromatin fractionation and micrococcal nuclease digestion.

The chromatin structure encompassing the lysozyme gene domain in hen oviduct nuclei was studied by measuring the partitioning of coding and flanking sequences during chromatin fractionation and by analyzing the nucleosome repeat in response to micrococcal nuclease digestion. Following micrococcal nuclease digestion, nuclei were sedimented to obtain a chromatin fraction released during digestion (S1) and then lysed in tris(hydroxymethyl)aminomethane-(ethylenedinitrilo)tetraacetic acid-[ethylenebis(oxyethylenenitrilo)]tetraacetic acid and centrifuged again to yield a second solubilized chromatin fraction (S2) and a pelleted fraction (P2). By dot-blot hybridization with 14 specific probes, it is found that the fractionation procedure defines three classes of sequences within the lysozyme gene domain. The coding sequences, which partition with fraction P2, are flanked by class I flanking sequences, which partition with fractions S1 and P2 and which extend over 11 kilobases (kb) on the 5'side and probably over about 4 kb on the 3' side. The partitioning of class II flanking sequences, which are located distal of class I flanking sequences, is different from that of class I flanking sequences. Coding sequences lack a canonical nucleosome repeat, class I flanking sequences possess a disturbed nucleosome repeat, and class II flanking sequences generate an extended nucleosomal ladder. Coding and class I flanking sequences are more readily digested by micrococcal nuclease than class II flanking sequences and the inactive beta A-globin gene. In hen liver, where the lysozyme gene is inactive, coding and class I flanking sequences fractionate into fractions S2 and P2.(ABSTRACT TRUNCATED AT 250 WORDS)

Aggressive behaviour of an epigean population of Astyanax mexicanus (Characidae, Pisces) and some observations of three subterranean populations.

The different populations have been tested for aggressive behaviour in groups of four to eight animals of both sexes in tanks ranging from 251 to 9501. In darkness less aggressive behaviour has been observed with the help of an infrared video-camera in the epigean fish and the eyed Micos cave fish. The strongest degree of reduction in aggressive behaviour is shown by the totally blind populations. The aggressiveness increases in the epigean fish as soon as space and food supply diminish.