Acute effects of caffeine on several operant behaviors in rhesus monkeys

The acute effects of 1,3-trimethylxanthine (caffeine) were assessed using an operant test battery (OTB) of complex food-reinforced tasks that are thought to depend upon relatively specific brain functions, such as motivation to work for food (progressive ratio, PR), learning (incremental repeated acquisition, IRA), color and position discrimination (conditioned position responding, CPR), time estimation (temporal response differentiation, TRD), and short-term memory and attention (delayed matching-to-sample, DMTS). Endpoints included response rates (RR), accuracies (ACC), and percent task completed (PTC). Caffeine sulfate (0.175-20.0 mg/kg, IV), given 15 min pretesting, produced significant dose-dependent decreases in TRD percent task completed and accuracy at doses > or = 5.6 mg/kg. Caffeine produced no systematic effects on either DMTS or PR responding, but low doses tended to enhance performance in both IRA and CPR tasks. Thus, in monkeys, performance of an operant task designed to model time estimation is more sensitive to the disruptive effects of caffeine than is performance of the other tasks in the OTB.     

Evaluation of pulsed-field gel electrophoresis as a typing system for Candida rugosa: comparison of karyotype and restriction fragment length polymorphisms

Nosocomial infections with Candida species have emerged as an increasingly important cause of morbidity and mortality in intensive care units. Ten Candida rugosa isolates from a previously documented cluster of C. rugosa infections in one hospital (nine burn unit isolates and one isolate from another hospital ward) and eight C. rugosa isolates recovered in a referral fungus testing laboratory (comparison isolates) from distinct geographic areas were investigated by molecular techniques. Isolates were from multiple anatomic sites. Pulsed-field gel electrophoresis (PFGE) of whole-cell DNA was performed with the 18 C. rugosa isolates as a marker of strain identity. The PFGE karyotypes of the C. rugosa isolates were demonstrated from four to seven chromosome bands. Karyotyping revealed the same PFGE pattern for the nine outbreak isolates from the burn unit, confirming clonal strain transmission. The isolate from the other hospital ward had a distinct karyotype. Distinct PFGE karyotype patterns were demonstrated for the eight comparison isolates. Restriction fragment length polymorphisms (RFLP) generated from whole-cell DNA digested with SfiI demonstrated the same RFLP pattern among outbreak isolates. Among comparison isolates, karyotyping distinguished some isolates that were indistinguishable by RFLP patterns. Karyotyping by PFGE appears to be the most useful molecular typing tool for discrimination among strains of C. rugosa and will be a useful marker for evaluating the epidemiology of future C. rugosa infections.     

Appendectomy and the risk of developing ulcerative colitis or Crohn''s disease: results of a large case-control study. South Limburg Inflammatory Bowel Disease Study Group

Copper amine oxidase from lentil seedlings was shown to be able to catalyze the oxidative deamination of the indoleamines tryptamine, 5-hydroxytryptamine, and 5-methoxytryptamine. These compounds showed saturation kinetics with Km values as normal substrates, but their oxidation led to irreversible loss of enzyme activity suggesting a covalent interaction with the enzyme, most probably through its cofactor 6-hydroxydopa (2,4,5-trihydroxyphenylalanine). These indoleamines acted as irreversible inhibitors of the enzyme only in the absence of oxygen but they brought about changes in the electronic spectra of the enzyme both in aerobiosis and in anaerobiosis. This study reports on the mechanism by which these compounds inhibit lentil amine oxidase which involves first the oxidation of indoleamines bound to 6-hydroxydopa followed by the formation of an irreversible covalent derivative. The same inhibitory mechanism could possibly lead to inactivation of mammalian amine oxidases involved in serotonin neurotransmitter metabolism in conditions of ischemia or hypoxia.     

Diagnosis by a waiter and a Mars explorer

This paper shows how state-of-the-art state estimation techniques can be used to provide efficient solutions to the difficult problem of real-time diagnosis in mobile robots. The power of the adopted estimation techniques resides in our ability to combine particle filters with classical algorithms, such as Kalman filters. We demonstrate these techniques in two scenarios: a mobile waiter robot and planetary rovers designed by NASA for Mars exploration.     

A comparison of the predictive values of the Salmonella/microsome mutation and BHK21 cell transformation assays in relation to dyestuffs and similar materials

A group of 22 dye-related compounds were selected for testing in two short-term predictive tests for carcinogenicity. The group of compounds was made up of nine established animal carcinogens and 13 chemicals for which there was substantial evidence of non-carcinogenicity. The materials were coded and used to assess the predictive value of the Salmonella/microsome reverse mutation assay and the BHK21 cell transformation test. The overall predictive value with these compounds obtained for the Salmonella microsome reverse mutation assay was 86% and it is concluded that because of the good predictive value and the relative ease of experimental procedure, the Salmonella mutation assay is a useful first step in any proposed series of toxicological bioassays for the identification of genotoxic agents in the dyestuffs industry.The cell transformation test on the other hand was difficult to conduct and interpret. The interpretation of the coded data as judged by the IRI scientists was that of the 22 'unknown' compounds, eight results were judged to be correct, six were wrong and seven were doubtful. However, when the same data were re-evaluated uncoded by ICI staff, 15 results were judged to be correct and six were wrong. These results serve to exemplify the difficulties encountered with cell transformation assays and it is concluded that the system should not be used as a routine test for dyestuffs and related compounds.     

The A-kinase anchoring domain of type IIalpha cAMP-dependent protein kinase is highly helical

Subcellular localization of the type II cAMP-dependent protein kinase is controlled by interaction of the regulatory subunit with A-Kinase Anchoring Proteins (AKAPs). This contribution examines the solution structure of a 44-residue region that is sufficient for high affinity binding to AKAPs. The N-terminal dimerization domain of the type IIalpha regulatory subunit of cAMP-dependent protein kinase was expressed to high levels on minimal media and uniformly isotopically enriched with 15N and 13C nuclei. Sequence-specific backbone and side chain resonance assignments have been made for greater than 95% of the amino acids in the free dimerization domain using high resolution multidimensional heteronuclear NMR techniques. Contrary to the results from secondary structure prediction algorithms, our analysis indicates that the domain is highly helical with a single 3-5-residue sequence involved in a beta-strand. The assignments and secondary structure analysis provide the basis for analyzing the structure and dynamics of the dimerization domain both free and complexed with specific anchoring proteins.     

New pathway of heparan sulphate degradation. Iduronate sulphatase and N-sulphoglucosamine 6-sulphatase act on the polymer chain prior to depolymerisation by a N-sulpho-glucosaminidase and glycuronidases in the mollusc Tagelus gibbus

In current clinical practice, it is important to be able to evaluate the evidence supporting each of our actions. Physicians can no longer rely on tradition or habit; however, with the increasing number of journals available, it is impossible for the practicing clinician to keep abreast of all the relevant literature. One valuable method of gathering and summarizing the latest information and opinions is the use of round tables and consensus conferences. Published reports of round table and consensus conference findings can be invaluable in guiding the clinician.