Oxidative drug metabolism in liver microsomes from uremic rats

Oxidative drug metabolism in liver microsomes from uremic rats. Uremia was achieved by subtotal nephrectomy in 50 to 70 day old male rats weighing 252.0 ± 20.1 g. Nephrectomized rats and sham-operated controls were sacrificed six days later. After liver microsomes had been isolated, microsomal cytochrome P-450 and cytochrome b5 content as well as microsomal specific activity for N-demethylation of aminopyrine, O-demethylation of p-nitroanisole and p-hydroxylation of acetanilide were measured. Serum urea concentration rose to 370.0 ± 80.0 mg/100 ml. The serum creatinine rose to 4.8 ± 1.2 mg/100 ml. In sham-operated controls serum urea and creatinine concentrations were approximately 50 and 0.6 mg/100 ml, respectively. Uremic rats, in contrast to sham-operated controls, lost about 25 % of their initial body wt. In uremic rats and in sham-operated controls with caloric deficiency there was a significant decrease of total microsomal protein to 51 % of the value measured in sham-operated controls fed ad libitum. Absolute and relative liver wet wt decreased more in caloric deficient controls than in uremic rats, whereas microsomal protein content per g liver was lower in uremic rats. In comparison with sham-operated controls, there was a pronounced decrease in the specific activity of liver microsomes from uremic rats for the demethylation of aminopyrine and p-nitroanisole and for the p-hydroxylation of acetanilide. The microsomal cytochrome P-450 content was also significantly diminished, whereas the microsomal cytochrome b5 content was not influenced, but there was stimulation of the O-demethylation of p-nitroanisole to 125.1% when compared to controls fed ad libitum. Four intraperitoneal injections of 6 mg δ-aminolevulinic acid/kg body given to uremic rats normalized the cytochrome P-450 content and significantly stimulated the specific activity for demethylation of p-nitroanisole, whereas demethylation of aminopyrine, p-hydroxylation of acetanilide and cytochrome b5 content were not altered. In sham-operated controls none of the measured parameters were influenced by δ-aminolevulinic acid pretreatment. It is assumed that the reduction of cytochrome P-450 content in liver microsomes from uremic rats is caused by a deficiency of δ-aminolevulinic acid which leads to disturbances in cytochrome synthesis. The observed decrease in the ability of liver microsomes from uremic rats to metabolize aminopyrine, p-nitroanisole and acetanilide is not merely due to reduced cytochrome P-450 content

Analysis of Na+-D-glucose cotransporter and other renal brush border proteins in human urine

Analysis of Na+-D-glucose cotransporter and other renal brush border proteins in human urine. A sensitive quantitative radioimmunoassay is described by which different antigens in the urine can be assayed simultaneously. Urinary excretion of three proteins from proximal tubules was compared: 1) the Na+-D-glucose cotransporter from brush border membranes and subapical vesicles; 2) a kidney-specific hydrophobic Mr 400,000 polypeptide from intermicroviUar invaginations and subapical vesicles; and 3) villin from microvilli cores. In the normal urine about 50% of the excreted Na+-D-glucose cotransporter and villin, and about 25% of the Mr 400,000 polypeptide was associated with brush border membrane vesicles, whereas trie remaining fractions of the three proteins formed small sedimentable aggregates which contained some cholesterol and fatty acids but no phospholipids. The normal urinary excretion of the Na+-D-glucose cotransporter was correlated with that of villin and the Mr 400,000 polypeptide. The data show that membrane proteins from the proximal tubule are excreted by the shedding of different brush border membrane areas. They suggest that some microvilli are released in total, and that a large fraction of the brush border membrane proteins is excreted without being associated with a phospholipid bilayer. In an attempt to define protein excretion patterns during kidney malfunctions, the excretion of brush border membrane proteins was analyzed after one intravenous injection of the X-ray contrast medium, iopamidol. No change in villin excretion was observed, but a reversible increase in the excretion of brush border membrane proteins was found in patients without diabetes. With diabetes a more pronounced iopamidol effect on the excretion of brush border membrane proteins and a significant increase in the excretion of villin was observed

State Aid in the new EU Member States

In the early phase of transition, which began in the 1990s, Central and Eastern European countries (CEECs) pursued economic restructuring that involved massive injections of state support. With reference to the history of state aid in centrally planned economies, we investigate state aid practices of CEECs since attaining full EU membership. We analyse whether their state aid policies during and after transition challenged European state aid legislation, and whether these fit into the EU strategy of ‘less but better targeted aid’. The data-based analysis is complemented with some indicative insights from state aid in the steel industry as well as the financial service sector to suggest that there is today no significant difference in state aid law application between East and West any more – the new EU members have further caught up by better aligning to the objectives of the State Aid Action Plan

Customized interface biofunctionalization of decellularized extracellular matrix: towards enhanced endothelialization

Interface biofunctionalization strategies try to enhance and control the interaction between implants and host organism. Decellularized extracellular matrix (dECM) is widely used as a platform for bioengineering of medical implants, having shown its suitability in a variety of preclinical as well as clinical models. In this study, specifically designed, custom-made synthetic peptides were used to functionalize dECM with different cell adhesive sequences (RGD, REDV, and YIGSR). Effects on in vitro endothelial cell adhesion and in vivo endothelialization were evaluated in standardized models using decellularized ovine pulmonary heart valve cusps (dPVCs) and decellularized aortic grafts (dAoGs), respectively. Contact angle measurements and fluorescent labeling of custom-made peptides showed successful functionalization of dPVCs and dAoGs. The functionalization of dPVCs with a combination of bioactive sequences significantly increased in vitro human umbilical vein endothelial cell adhesion compared to nonfunctionalized controls. In a functional rodent aortic transplantation model, fluorescent-labeled peptides on dAoGs were persistent up to 10 days in vivo under exposure to systemic circulation. Although there was a trend toward enhanced in vivo endothelialization of functionalized grafts compared to nonfunctionalized controls, there was no statistical significance and a large biological variability in both groups. Despite failing to show a clear biological effect in the used in vivo model system, our initial findings do suggest that endothelialization onto dECM may be modulated by customized interface biofunctionalization using the presented method. Since bioactive sequences within the dECM–synthetic peptide platform are easily interchangeable and combinable, further control of host cell proliferation, function, and differentiation seems to be feasible, possibly paving the way to a new generation of multifunctional dECM scaffolds for regenerative medicinePeer ReviewedPostprint (published version