Exploring Innovative Solutions for Quality of Life and Care of Bed-Ridden Nursing Home Residents through Codesign Sessions.

Bed-ridden nursing home residents are in need of environments which are homelike and facilitate the provision of care. Design guidance for this group of older people is limited. This study concerned the exploration and generation of innovative environmental enrichment scenarios for bed-ridden residents. This exploration was conducted through a combination of participatory action research with user-centred design involving 56 professional stakeholders in interactive work sessions. This study identified numerous design solutions, both concepts and products that are available on the marketplace and that on a higher level relate to improvements in resident autonomy and the supply of technological items and architectural features. The methodology chosen can be used to explore the creative potential of stakeholders from the domain of healthcare in product innovation.

19F NMR study on the biological Baeyer-Villiger oxidation of acetophenones.

The biological Baeyer-Villiger oxidation of acetophenones was studied by 19F nuclear magnetic resonance (NMR). The 19F NMR method was used to characterise the time-dependent conversion of various fluorinated acetophenones in either whole cells of Pseudomonas fluorescens ACB or in incubations with purified 4'-hydroxyacetophenone monooxygenase (HAPMO). Whole cells of P. fluorescens ACB converted 4'-fluoroacetophenone to 4-fluorophenol and 4'-fluoro-2'-hydroxyacetophenone to 4-fluorocatechol without the accumulation of 4'-fluorophenyl acetates. In contrast to 4-fluorophenol, 4-fluorocatechol was further degraded as evidenced by the formation of stoichiometric amounts of fluoride anion. Purified HAPMO catalysed the strictly NADPH-dependent conversion of fluorinated acetophenones to fluorophenyl acetates. Incubations with HAPMO at pH 6 and 8 showed that the enzymatic Baeyer-Villiger oxidation occurred faster at pH 8 but that the phenyl acetates produced were better stabilised at pH 6. Quantum mechanical characteristics explained why 4'-fluoro-2'-hydroxyphenyl acetate was more sensitive to base-catalysed hydrolysis than 4'-fluorophenyl acetate. All together, 19F NMR proved to be a valid method to evaluate the biological conversion of ring-substituted acetophenones to the corresponding phenyl acetates, which can serve as valuable synthons for further production of industrially relevant chemicals.

19F NMR study on the biological Baeyer-Villiger oxidation of acetophenones.

The biological Baeyer-Villiger oxidation of acetophenones was studied by (19)F nuclear magnetic resonance (NMR). The (19)F NMR method was used to characterise the time-dependent conversion of various fluorinated acetophenones in either whole cells of Pseudomonas fluorescens ACB or in incubations with purified 4'-hydroxyacetophenone monooxygenase (HAPMO). Whole cells of P. fluorescens ACB converted 4'-fluoroacetophenone to 4-fluorophenol and 4'-fluoro-2'-hydroxyacetophenone to 4-fluorocatechol without the accumulation of 4'-fluorophenyl acetates. In contrast to 4-fluorophenol, 4-fluorocatechol was further degraded as evidenced by the formation of stoichiometric amounts of fluoride anion. Purified HAPMO catalysed the strictly NADPH-dependent conversion of fluorinated acetophenones to fluorophenyl acetates. Incubations with HAPMO at pH 6 and 8 showed that the enzymatic Baeyer-Villiger oxidation occurred faster at pH 8 but that the phenyl acetates produced were better stabilised at pH 6. Quantum mechanical characteristics explained why 4'-fluoro-2'-hydroxyphenyl acetate was more sensitive to base-catalysed hydrolysis than 4'-fluorophenyl acetate. All together, (19)F NMR proved to be a valid method to evaluate the biological conversion of ring-substituted acetophenones to the corresponding phenyl acetates, which can serve as valuable synthons for further production of industrially relevant chemicals.

4-Hydroxyacetophenone monooxygenase from Pseudomonas fluorescens ACB. A novel flavoprotein catalyzing Baeyer-Villiger oxidation of aromatic compounds.

A novel flavoprotein that catalyses the NADPH-dependent oxidation of 4-hydroxyacetophenone to 4-hydroxyphenyl acetate, was purified to homogeneity from Pseudomonas fluorescens ACB. Characterization of the purified enzyme showed that 4-hydroxyacetophenone monooxygenase (HAPMO) is a homodimer of approximately 140 kDa with each subunit containing a noncovalently bound FAD molecule. HAPMO displays a tight coupling between NADPH oxidation and substrate oxygenation. Besides 4-hydroxyacetophenone a wide range of other acetophenones are readily converted via a Baeyer-Villiger rearrangement reaction into the corresponding phenyl acetates. The P. fluorescens HAPMO gene (hapE) was characterized. It encoded a 640 amino-acid protein with a deduced mass of 71 884 Da. Except for an N-terminal extension of approximately 135 residues, the sequence of HAPMO shares significant similarity with two known types of Baeyer-Villiger monooxygenases: cyclohexanone monooxygenase (27-33% sequence identity) and steroid monooxygenase (33% sequence identity). The HAPMO sequence contains several sequence motifs indicative for the presence of two Rossman fold domains involved in FAD and NADPH binding. The functional role of a recently identified flavoprotein sequence motif (ATG) was explored by site-directed mutagenesis. Replacement of the strictly conserved glycine (G490) resulted in a dramatic effect on catalysis. From a kinetic analysis of the G490A mutant it is concluded that the observed sequence motif serves a structural function which is of importance for NADPH binding.

In vitro inhibition of thyroid hormone sulfation by hydroxylated metabolites of halogenated aromatic hydrocarbons.

Earlier studies in our laboratory showed that hydroxylated metabolites of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) competitively inhibit thyroxine (T4) binding to transthyretin (TTR) and type I deiodinase (D1) activity. In this study, we investigated the possible inhibitory effects of hydroxylated metabolites of polyhalogenated aromatic hydrocarbons (PHAHs) on iodothyronine sulfotransferase activity. Rat liver cytosol was used as a source of sulfotransferase enzyme in an in vitro assay with 125I-labeled 3,3'-diiodothyronine (T2) as a model substrate. Increasing amounts of hydroxylated PCBs, PCDDs, or PCDFs or extracts from incubation mixtures of PHAHs and induced liver microsomes were added as potential inhibitors of T2 sulfotransferase activity. Hydroxylated metabolites of PCBs, PCDDs, and PCDFs were found to be potent inhibitors of T2 sulfotransferase activity in vitro with IC50 values in the low micromolar range (0.2-3.8 microM). The most potent inhibitor of T2 sulfotransferase activity in our experiments was the PCB metabolite 3-hydroxy-2,3',4, 4',5-pentachlorobiphenyl with an IC50 value of 0.2 microM. A hydroxyl group in the para or meta position appeared to be an important structural requirement for T2 sulfotransferase inhibition by PCB metabolites. Ortho hydroxy PCBs were much less potent, and none of the parent PHAHs was capable of inhibiting T2 sulfotransferase activity. In addition, the formation of T2 sulfotransferase-inhibiting metabolites of individual brominated diphenyl ethers and nitrofen as well as from some commercial PHAH mixtures (e.g., Bromkal, Clophen A50, and Aroclor 1254) was also demonstrated. These results indicate that hydroxylated PHAHs are potent inhibitors of thyroid hormone sulfation. Since thyroid hormone sulfation may play an important role in regulating free hormone levels in the fetus, and PCB metabolites are known to accumulate in fetal tissues after maternal exposure to PCBs, these observations may have implications for fetal thyroid hormone homeostasis and development.

Regioselectivity and quantitative structure-activity relationships for the conjugation of a series of fluoronitrobenzenes by purified glutathione S-transferase enzymes from rat and man.

Quantitative structure-activity relationships (QSAR's) are described for the rate of conjugation of a series of fluoronitrobenzenes with cytosolic as well as with two major alpha and mu class enzymes of rat and human liver, viz., glutathione S-transferases (GST) 1-1, 3-3, A1-1, and M1a-1a. For all purified enzymes studied, the natural logarithm of the rate of conversion of the fluoronitrobenzenes correlates with both the calculated reactivity of the fluoronitrobenzenes for an electrophilic attack (i.e., E(LUMO)) and the calculated relative heat of formation for formation of the respective Meisenheimer complex intermediate (delta delta HF). In addition, the regioselectivity of the reaction was determined and compared. The results obtained strongly support the conclusion that chemical reactivity of the fluoronitrobenzenes is the main factor determining the outcomes of their conversion by all glutathione S-transferase enzymes. The regioselectivities vary only a few percent from one enzyme to another, whereas QSAR lines for all purified enzymes are in the same region and run parallel. This indicates that in the overall reaction the nucleophilic attack of the thiolate anion on the fluoronitrobenzenes, leading to formation of the Meisenheimer complex, is the rate-limiting step in the overall catalysis. The fact that chemical reactivity of the fluoronitrobenzenes is the main factor in setting the outcomes of the overall conversion by the different glutathione S-transferase enzymes implies that extrapolation from rat to results of other species including man, and also from one individual to another, must be feasible. That this is actually the case is clearly demonstrated by the results of the present study.