Validation of an ultra-high-performance liquid chromatography-mass spectrometry method for the quantification of cysteinylated aldehydes and application to malt and beer samples.

This paper describes the method validation for the simultaneous determination of seven cysteinylated aldehydes, i.e. 2-substituted 1,3-thiazolidines-4-carboxylic acids, using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). Authentic reference compounds were first synthesized for identification and quantification purposes. Moreover, nuclear magnetic resonance (1H NMR and 13C NMR) was applied for verification of their structure, while ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) was applied for estimation of the purity. The method for quantification of cysteinylated aldehydes in model solutions has been validated according to the criteria and procedures described in international standards. The synthesized compounds were successfully identified via UHPLC-MS by comparing retention time and MS spectra with the commercial reference compounds. Method validation revealed good linearity (R2 > 0.995) over the range of 0.4-2.2 µg/L to approximately 1000 µg/L, depending on the analyte. The limits of quantification varied from 0.9 to 4.3 µg/L depending on the nature of the compound. Furthermore, evaluation of the method showed good accuracy and stability of the standard solutions. Reported chromatographic recoveries ranged from 112 to 120%. Consequently, the currently described method was applied on malt and beer samples. For the first time, quantification of cysteinylated aldehydes was obtained in malt. In contrast, in fresh beers unambiguous identification of these compounds was not achieved.

Prevalence and determinants of seborrhoeic dermatitis in a middle-aged and elderly population: the Rotterdam Study.

BACKGROUND: Seborrhoeic dermatitis is a chronic relapsing inflammatory skin disease with unclear pathophysiological mechanisms. OBJECTIVES: To establish which lifestyle and physiological determinants are associated with seborrhoeic dermatitis. METHODS: Seborrhoeic dermatitis was diagnosed by a trained physician during a full-body skin examination within the Rotterdam Study, a prospective population-based cohort study in middle-aged and elderly people. The current design is a comparative cross-sectional study embedded in the Rotterdam Study. Potential factors were identified from the literature and analysed in a multivariable logistic regression, including: age, sex, obesity, skin colour, stress, depression, education level, hypertension, climate, xerosis cutis, alcohol and tobacco use. RESULTS: Of the 5498 participants, 788 participants were diagnosed with seborrhoeic dermatitis (14·3%). We found associations between seborrhoeic dermatitis and male sex [adjusted odds ratio (OR) 2·09, 95% confidence interval (CI) 1·77-2·47], darker skin (adjusted OR 0·39, 95% CI 0·22-0·69), season (summer vs. winter: adjusted OR 0·63, 95% CI 0·48-0·82) and generalized xerosis cutis (adjusted OR 1·41, 95% CI 1·11-1·80). CONCLUSIONS: Seborrhoeic dermatitis is one of the most common inflammatory dermatoses in middle-aged and elderly individuals, especially during winter. Men, and people with a light and dry skin were most likely to have seborrhoeic dermatitis.

Single-cell imaging of inflammatory caspase dimerization reveals differential recruitment to inflammasomes.

The human inflammatory caspases, including caspase-1, -4, -5 and -12, are considered as key regulators of innate immunity protecting from sepsis and numerous inflammatory diseases. Caspase-1 is activated by proximity-induced dimerization following recruitment to inflammasomes but the roles of the remaining inflammatory caspases in inflammasome assembly are unclear. Here, we use caspase bimolecular fluorescence complementation to visualize the assembly of inflammasomes and dimerization of inflammatory caspases in single cells. We observed caspase-1 dimerization induced by the coexpression of a range of inflammasome proteins and by lipospolysaccharide (LPS) treatment in primary macrophages. Caspase-4 and -5 were only dimerized by select inflammasome proteins, whereas caspase-12 dimerization was not detected by any investigated treatment. Strikingly, we determined that certain inflammasome proteins could induce heterodimerization of caspase-1 with caspase-4 or -5. Caspase-5 homodimerization and caspase-1/-5 heterodimerization was also detected in LPS-primed primary macrophages in response to cholera toxin subunit B. The subcellular localization and organization of the inflammasome complexes varied markedly depending on the upstream trigger and on which caspase or combination of caspases were recruited. Three-dimensional imaging of the ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain)/caspase-1 complexes revealed a large spherical complex of ASC with caspase-1 dimerized on the outer surface. In contrast, NALP1 (NACHT leucine-rich repeat protein 1)/caspase-1 complexes formed large filamentous structures. These results argue that caspase-1, -4 or -5 can be recruited to inflammasomes under specific circumstances, often leading to distinctly organized and localized complexes that may impact the functions of these proteases.

Characterizing plant cell wall derived oligosaccharides using hydrophilic interaction chromatography with mass spectrometry detection.

Analysis of complex mixtures of plant cell wall derived oligosaccharides is still challenging and multiple analytical techniques are often required for separation and characterization of these mixtures. In this work it is demonstrated that hydrophilic interaction chromatography coupled with evaporative light scattering and mass spectrometry detection (HILIC-ELSD-MS(n)) is a valuable tool for identification of a wide range of neutral and acidic cell wall derived oligosaccharides. The separation potential for acidic oligosaccharides observed with HILIC is much better compared to other existing techniques, like capillary electrophoresis, reversed phase and porous-graphitized carbon chromatography. Important structural information, such as presence of methyl esters and acetyl groups, is retained during analysis. Separation of acidic oligosaccharides with equal charge yet with different degrees of polymerization can be obtained. The efficient coupling of HILIC with ELSD and MS(n)-detection enables characterization and quantification of many different oligosaccharide structures present in complex mixtures. This makes HILIC-ELSD-MS(n) a versatile and powerful additional technique in plant cell wall analysis.

Performance of copper naphthenate and its analogs as ground contact wood preservatives.

For several years, an extensive research program investigating new preservative systems has been ongoing at Mississippi State University. This paper details our continuing experience with field testing of copper naphthenate and other copper carboxylate preservative systems. Results from field stake tests at an AWPA Zone 4 test site are presented. In general, copper carboxylates made with 'synthetic' acids yielded results equivalent to or only slightly lower than systems with straight naphthenic acids or nap acids amended with synthetic neodecanoic acid bottoms. Oil carrier formulations outperformed those in water or light organic solvents. All systems carried in oil would qualify as ground contact preservatives at the proper retention.

Analytical applications of liquid phase chemiluminescence reactions--a review.

This paper reviews the literature on analytical applications of quantitative liquid phase chemiluminescence (CL) from 1991 to mid-1995. Other relevant reviews in this general area are also cited to provide an historical perspective. The focus is on the two major analytical techniques used in conjunction with flow-through CL detection, namely flow injection (FI) and liquid chromatography (LC). Entries have been tabulated under these two headings and are categorized in terms of the analyte, CL reaction, sample matrix and limits of detection.

Adaptive plasticity in primate spinal stretch reflex: persistence.

Monkeys can gradually change the amplitude of the wholly segmental, largely monosynaptic, spinal stretch reflex (SSR) when confronted by a task requiring such change (15-19). Change develops over months and may reverse and redevelop at similarly slow rates. We investigated the persistence of SSR amplitude change over nonperformance periods of up to 38 days. Eight animals with chronic EMG electrodes learned to maintain elbow angle and a given level of biceps background EMG against constant extension torque. At random times, a brief additional extension torque pulse elicited the biceps SSR. In the control mode, reward always followed. Under the SSR increase or SSR decrease mode, reward occurred only if the absolute value of biceps EMG in the SSR interval was above or below a set value. Animals completed 3,000-6,000 trials/day over data-collection periods of 2-17 mo. Animals worked first under the control mode for up to 60 days and then under the SSR increase or SSR decrease mode for up to 274 days. Mode was switched once or twice more (SSR increase to SSR decrease or vice versa) over subsequent months. Animals responded to each SSR increase or SSR decrease mode exposure with gradual mode-appropriate change in SSR amplitude. Mode exposures were interrupted by gaps in performance of 10-38 days. Gaps produced transient 10- to 15% decreases in SSR amplitude under the control mode. This nonspecific decrease disappeared over the first week of postgap performance. Under the control mode, gaps had no other effects on SSR amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced day-to-day variation accompanies adaptive plasticity in the primate spinal stretch reflex.

Monkeys can change the amplitude of the spinal stretch reflex (SSR), or M1, when reward is made contingent on amplitude. The present study demonstrates that reduced SSR day-to-day variation accompanies such adaptive SSR change. This finding supports the assumption that initial, phase I, SSR change results from contingency-appropriate stabilization of tonic activity in relevant descending spinal cord pathways.

Adaptive plasticity in the spinal stretch reflex.

Monkeys can change the amplitude of the spinal stretch reflex without change in initial alpha motor neuron tone, as measured by EMG, or in initial muscle length. Change is apparent in 5-10 days, continues to develop over weeks, and persists during inactive periods. Spinal stretch reflex change may be a valuable system for studying the neuronal and synaptic bases of an adaptive change in primate CNS function.

Changes in the U.S. Army aviator selection and training program.

The Army's aviator selection program began in the mid 1950's. The first Flight Aptitude Selection Test (FAST) was implemented in 1966 and remained in use until 1980 when changes in personnel, aircraft, and tactics necessitated an improved or revised FAST (RFAST). This paper presents an overview of 1) the composition of the FAST and RFAST; 2) the advantages of the RFAST; and 3) the predictive validity estimates for the FAST and RFAST. Also presented are examples of current research projects which show promise for increasing effectiveness and for broadening the scope of the Army aviator selection program.

A human performance/workload evaluation of the AN/PVS-5 bifocal night vision goggles.

Eight experienced U.S. Army aviators performed various maneuvers in an instrumented helicopter to test the relative usability of two bifocal-configured night vision goggles. Both configurations were statistically better than the unmodified arrangement when looking at a pilot's ability to fly a standard traffic pattern and to hold a precise altitude at night. The subjective data, supported by comparative flight performances with the two bifocals, further suggested that a 24% bifocal version was more desirable than a 14% configuration. The inference is that the reduced inside field of view presented by the 14% bifocal interferes with a pilot's ability to readily locate instruments once he has directed his attention inside the cockpit.

Marijuana and human performance: an annotated bibliography (1970-1975).

A bibliography of 199 annotated references was compiled to aid the reader in determining the impact of marijuana on psychomotor, cognitive, and physiological factors considered pertinent to flight performance. The bibliography contains an index which categorizes the references into the following major areas: (1) reviews or overviews of issues, literature or research; (2) psychological effects of marijuana use; (3) physiological and pharmacological research; (4) medical comments and research critiques; and (5) additional reference sources. The basic period of coverage is 1970 to 1975, although selected studies from earlier years are also included.

Internal-external locus of control and performance on a vigilance task.

Previous studies have demonstrated there are large individual differences in subjects' ability to perform on vigilance or watch-keeping tasks. This study used Rotter's Internal-External (I-E) Locus of Control Scale to resolve some of the variance attributed to individual differences and tested the hypothesis that the internally controlled person is a better monitor on a vigilance task than an externally controlled person. There were 64 subjects who performed a visual watch-keeping task for a 1-hr. period. The results indicated that the external subjects made significantly more incorrect responses and missed significantly more signals during the entire task. The internal-external dimension was effective in differentiating performance on a vigilance task.

Cross-validation study of the personality aspects of involvement in pilot-error accidents.

Pilot-error accidents have dominated accident statistics consistently from the 1940s to the present. Sanders and Hofmann (3) found that three factors from Cattell's Sixteen Personality Factor Questionnaire (16 PF) significant differences (p less than 0.05) between pilot-error accident groups and were used to correctly classify 86% of the aviators tested as to their previous pilot-error accident involvement. There were 66 aviators given the 16 PF in the present study in an attempt to cross-validate the findings reported in the original study. The results indicate that the personality factors did not significantly discriminate between the pilot-error accident groups. The primary personality differences between the present sample and the original sample were due to variations in the pilot-error accident-free groups. The findings indicate that individual differences in personality characterstics of the aviators prevent consistent identification of traits associated with pilot-error groups.

Personality aspects of involvement in pilot-error accidents.

The consistently high frequency of pilot-error accidents in both military and civilian aviation programs does much to support exploratory research which might help alleviate the problem. Cattell's Sixteen Personality Factor Questionnaire (16 PF), Mehrabian Achievement Scale, and a dynamic decision making task (under risk) were given to 51 Army aviators. Accident files were then examined in order to classify the aviators as to their prior pilot-error accident involvement. Stepwise discriminant analyses revealed that the decision-making task scores and the achievement scores were unrelated to the pilot error accident groupings while the 16 PF scores were able to correctly classify 86% of the aviators as to whether or not they had been previously listed as a cause factor in a military aviation accident.

Attenuation of "acute" habituation by scopolamine in the black-tailed prairie dog (Cynomys ludovicianus).

The hypothesis after scopolamine attenuates habituation occurring within a training session as well as that occurring between training sessions was tested and confirmed. Scopolamine injections (.5 mg/kg) reduced spontaneous wheel running in the prairie dog. The same dosage did not affect the threshold for wheen running induced by electrical brain stimulation (EBS). Another experiment demonstrated that EBS-induced running declined during a 10-min. stimulation period and indicated that the decline was habituative since the response was repeatedly dishabituated. In a final experiment .5 mg/kg of scopolamine reduced habituation of EBS-induced wheel running during 10-min. sessions.

Chronic idiopathic intestinal pseudo-obstruction with malabsorption, a scleroderma-like disorder.

A case of intestinal pseudo-obstruction in a 76-year-old man who presented with a six-year history of intermittent vomiting and abdominal pain and a 1(1/2)-year history of diarrhea is described. Investigation demonstrated aperistalsis of the lower esophagus and an unresponsive atonic small intestine. Marked malabsorption was present and appeared due to intestinal bacterial overgrowth consequent to the hypomotility. Autonomic nervous system testing failed to reveal any definite abnormality. Although this disorder is markedly similar to scleroderma involving the gastrointestinal tract, there was only minimal fibrosis of the bowel musculature evident at autopsy and the neural components appeared to be intact. These findings suggest that the basic disorder may be one of smooth muscle dysfunction. Other known causes of pseudo-obstruction could not be demonstrated.