Septic encephalopathy: does inflammation drive the brain crazy?

Sepsis and the multiorgan dysfunction syndrome are among the most common reasons for admission to an intensive care unit, and are a leading cause of death. During sepsis, the central nervous system (CNS) is one of the first organs affected, and this is clinically manifested as sepsis-associated encephalopathy (SAE). It is postulated that the common final pathway that leads to SAE symptoms is the deregulation of neurotransmitters, mainly acetylcholine. Thus, it is supposed that inflammation can affect neurotransmitters, which is associated with SAE development. In this review, we will cover the current evidence (or lack thereof) for the mechanisms by which systemic inflammation interferes with the metabolism of major CNS neurotransmitters, trying to explain how systemic inflammation drives the brain crazy.

New ammonia lyases and amine transaminases: Standardization of production process and preparation of immobilized biocatalysts

Background: New enzymes for biotransformations can be obtained by different approaches including directed mutagenesis and in vitro evolution. These mutants have to be efficiently produced for laboratory research on bioreactions as well as for process development. In the framework of a European ERA-IB project, two different types of enzymes (ammonia lyases and aminotransferases) have been selected as biocatalysts for the synthesis of industrially relevant amines. New mutant enzymes have been obtained: a) aspartases able to recognize β-amino acids; b) ω-transaminases with improved activity. The objectives are to find out a common operational strategy applicable to different mutants expressed in E. coli with the same initial genetic background, the development of an integrated process for production and the preparation of stable useful biocatalysts. Results: Mutant enzymes were expressed in E. coli BL21 under the control of isopropylthiogalactoside (IPTG) inducible promoter. The microorganisms were grown in a formulated defined medium and a high-cell density culture process was set up. Fed-batch operation at constant specific growth rate, employing an exponential addition profile allowed high biomass concentrations. The same operational strategy was applied for different mutants of both aspartase and transaminase enzymes, and the results have shown a common area of satisfactory operation for maximum production at low inducer concentration, around 2 μmol IPTG/g DCW. The operational strategy was validated with new mutants and high-cell density cultures were performed for efficient production. Suitable biocatalysts were prepared after recovery of the enzymes. The obtained aspartase was immobilized by covalent attachment on MANA-agarose, while ω-transaminase biocatalysts were prepared by entrapping whole cells and partially purified enzyme onto Lentikats (polyvinyl alcohol gel lens-shaped particles). Conclusions: The possibility of expressing different mutant enzymes under similar operation conditions has been demonstrated. The process was standardized for production of new aspartases with β-amino acid selectivity and new ω-transaminases with improved substrate acceptance. A whole process including production, cell disruption and partial purification was set up. The partially purified enzymes were immobilized and employed as stable biocatalysts in the synthesis of chiral amines.

Long term tea intake attenuates brain monoamine metabolism in rats

Tea is one of the most popular caffeine containing beverages consumed all over the world for increasing work performance and as a social drink. In the present study effects of long term intake of tea administration are monitored on the activity and brain monoamine levels in rats. Animals taking tea as sole source of liquid exhibited a significant increase in the home cage activity after one week which was normalized after four weeks of treatment. No effect of tea was observed on the activity of rats in an open field. Four weeks of tea intake did not alter plasma tryptophan [TRP] levels but increased plasma glucose levels. The concentration of TRP and 5-hydroxytryptamine [5-HT, serotonin] but not 5-hydroxyindole acetic acid [5-HIAA] decreased in the brain. Brain levels of dopamine [DA], dihydroxyphenyl acetic acid [DOPAC] and homovanillic acid [HVA] were also significantly attenuated in tea-treated rats. The findings are explained in terms of tea increasing activity in a familiar but not novel environment. Decrease in brain monoamine metabolism following long term tea administration may be involved in the lowering of mood observed in the consumers

CYP1A2 activity as a risk factor for bladder cancer

CYP1A2, CYP2D6 and N-acetyltransferase activities were estimated in 100 patients with bladder cancer and 84 control subjects from measurements of theophylline, metoprolol and isoniazid and their metabolites in urine, respectively. The frequency of occurrence of slow acetylators of isoniazid and poor metabolizers of metoprolol were 16.7% and 1.2% in the control group and 16.3% and 2.0% in the cancer patient group. These differences were not significant. The recovery ratio of 1-methyluric acid(1-MU) from theophylline was significantly higher in patients with bladder cancer than in control subjects(0.340 +/- 0.016 versus 0.260 +/- 0.020, p< 0.05). The 1-MU recovery ratio was a significant, independent risk factor among the metabolic capacities tested as shown by logistic regression analysis, controlling for N-acetylation of isoniazid, hydroxylation of metoprolol, age, sex, and smoking. We concluded that the capacity for 3-demethylation of theophylline, as a reflection of CYP1A2 activity, is significantly associated with increased risk of nonoccupational urinary bladder cancer.

Gas liquid chromatography of amines produced by the Enterobacteriaceae

1. Gas liquid chromatography (GLC) was used to test the production of amines by 85 strains of Enterobacteriaceae. 2. The strains tested produced cadaverine, ß-phenylethylamine, putrescine, iso-amylamine, 2-methylbutylamine and iso-butylamine. 3. Although the overlap in amine production between obviouasly different genera sspecies limits the general applicability of this methology in clinical microbiology, the results obtained limits the general applicability of this methodology in clinical microbiology, the results obtained demonstrate the possibility of differentiating Proteus rettgeri from other Proteus species, Escherichia coli from Proteus species and Salmonella species from Shigella species on the basis of their amine composition. 4. In general, members of the Enterobacteriaceae family produce qualitatively similar amine profiles, thought differing quantitatively in the amounts of individual amines produced. GLC proves to be useful for separating amines and for provididng tentative peak identification