Comparison of aerobic granulation in SBR and continuous-flow plants.

Up to now, aerobic granulation of activated sludge is only realised in SBRs, where the discontinuous feed and sedimentation allow the formation of dense granules with excellent settling properties. However, aerobic granulation in continuous-flow plants (CFP) is gaining more and more interest in order to exploit the advantages of these excellent sludge properties to construct compact and efficient WWTP. Within the scope of this project, a SBR and CFP were operated in parallel to investigate the aerobic granulation of activated sludge and to compare the biomass in terms of their structure and settling behavior. CFP operation included two experimental phases with different reactor designs. The use of synthetic wastewater during phase I led to a biomass with a SVI of 42 ml g-1, whereby the SVI declined only to 85 ml g-1 in the second phase and the use of municipal sewage. After the start-up period, microscopic images of the biomass from CFP comprised small compact granules with a high flocculent fraction. Particle size distribution for phase II confirm, that 72% of the particles had a size over 200 µm. A strong correlation was observed between the appearance of NOx-N in the first reactor and the SVI. The results illustrate, that the anaerobic conditions during feeding are essential to keep stable granules.

The fungicide Mancozeb induces metacaspase-dependent apoptotic cell death in Saccharomyces cerevisiae BY4741.

Mancozeb (MZ), a mixture of ethylene-bis-dithiocarbamate manganese and zinc salts, is one of the most widely used fungicides in agriculture. Toxicologic studies in mammals and mammalian cells indicate that this fungicide can cause neurological and cytological disorders, putatively associated with pro-oxidant and apoptotic effects. Yeast adaptation to sub-inhibitory concentrations of MZ has been correlated with oxidative response, proteins degradation, and energy metabolism, and its main effect on yeast has been attributed to its high reactivity with thiol groups in proteins. Herein, we show that acute MZ treatments on aerobic exponentially growing yeast of wild type (BY4741) and deletion mutant strains, coupled with multiplex flow cytometry analysis, conclusively demonstrated that MZ displays the typical features of pro-oxidant activity on Saccharomyces, elevating mitochondrial ROS, and causing hyper-polarization of mitochondrial membranes leading to apoptosis. A drastic reduction of cellular viability associated with the maintenance of cell membrane integrity, as well as phosphatidyl serine externalization on yeast cells exposed to MZ, also supports an apoptotic mode of action. Moreover, abrogation of the apoptotic response in yca1 deficient mutants indicates that metacaspase-1 is involved in the programmed cell death mechanism induced by MZ in yeast.

The influence of temperature and SRT on high-solid digestion of municipal sewage sludge.

The influence of temperature and solids retention time (SRT) on high-solid digestion of municipal sewage sludge was investigated in laboratory-scale reactors. Digestion with high-solid concentration reduces the required digestion volume and is advantageous for urban areas. The experimental conditions comprised total suspended solids (TSS) in digested sludge between 4.0 and 4.6%, temperatures in a range of 33 to 41 °C and the SRT between 10 and 25 d. High-solid digestion operates with increased NH4-N concentrations released from organic compounds. The anaerobic process can be limited by high NH4-N concentration and toxic NH3. In this study a stable digestion was observed up to 2,000 mg L(-1) NH4-N and 75 mg L(-1) NH3. Volatile suspended solids (VSS) and chemical oxygen demand removal was 53% and 57% respectively. However, digestion with 10 d SRT led to a declined VSS removal of 49%. The removal at 41 and 37 °C showed minor differences, while reduced NH4-N release and reduced methane production were observed at 33 °C. For economic reasons, high-solid digestion at 41 °C is not recommended, but will not impair VSS removal. The outcomes of this study confirm that digestion with up to 7.8% TSS in the feed is feasible for the tested temperatures and SRT down to 15 d.

Two histone deacetylases, FfHda1 and FfHda2, are important for Fusarium fujikuroi secondary metabolism and virulence.

Histone modifications are crucial for the regulation of secondary metabolism in various filamentous fungi. Here we studied the involvement of histone deacetylases (HDACs) in secondary metabolism in the phytopathogenic fungus Fusarium fujikuroi, a known producer of several secondary metabolites, including phytohormones, pigments, and mycotoxins. Deletion of three Zn(2+)-dependent HDAC-encoding genes, ffhda1, ffhda2, and ffhda4, indicated that FfHda1 and FfHda2 regulate secondary metabolism, whereas FfHda4 is involved in developmental processes but is dispensable for secondary-metabolite production in F. fujikuroi. Single deletions of ffhda1 and ffhda2 resulted not only in an increase or decrease but also in derepression of metabolite biosynthesis under normally repressing conditions. Moreover, double deletion of both the ffhda1 and ffhda2 genes showed additive but also distinct phenotypes with regard to secondary-metabolite biosynthesis, and both genes are required for gibberellic acid (GA)-induced bakanae disease on the preferred host plant rice, as Δffhda1 Δffhda2 mutants resemble the uninfected control plant. Microarray analysis with a Δffhda1 mutant that has lost the major HDAC revealed differential expression of secondary-metabolite gene clusters, which was subsequently verified by a combination of chemical and biological approaches. These results indicate that HDACs are involved not only in gene silencing but also in the activation of some genes. Chromatin immunoprecipitation with the Δffhda1 mutant revealed significant alterations in the acetylation state of secondary-metabolite gene clusters compared to the wild type, thereby providing insights into the regulatory mechanism at the chromatin level. Altogether, manipulation of HDAC-encoding genes constitutes a powerful tool to control secondary metabolism in filamentous fungi.

Insulin and insulin-like growth factor-I enhance human skeletal muscle protein anabolism during hyperaminoacidemia by different mechanisms.

Insulin inhibits proteolysis in human muscle thereby increasing protein anabolism. In contrast, IGF-I promotes muscle protein anabolism principally by stimulating protein synthesis. As increases or decreases of plasma amino acids may affect protein turnover in muscle and also alter the muscle's response to insulin and/or IGF-I, this study was designed to examine the effects of insulin and IGF-I on human muscle protein turnover during hyperaminoacidemia. We measured phenylalanine balance and [3H]-phenylalanine kinetics in both forearms of 22 postabsorptive adults during a continuous [3H] phenylalanine infusion. Measurements were made basally and at 3 and 6 h after beginning a systemic infusion of a balanced amino acid mixture that raised arterial phenylalanine concentration about twofold. Throughout the 6 h, 10 subjects received insulin locally (0.035 mU/min per kg) into one brachial artery while 12 other subjects were given intraaterial IGF-I (100 ng/min per kg) to raise insulin or IGF-I concentrations, respectively, in the infused arm. The contralateral arm in each study served as a simultaneous control for the effects of amino acids (aa) alone. Glucose uptake and lactate release increased in the insulin- and IGF-I-infused forearms (P < 0.01) but did not change in the contralateral (aa alone) forearm in either study. In the aa alone arm in both studies, hyperaminoacidemia reversed the postabsorptive net phenylalanine release by muscle to a net uptake (P < 0.025, for each) due to a stimulation of muscle protein synthesis. In the hormone-infused arms, the addition of either insulin or IGF-I promoted greater positive shifts in phenylalanine balance than the aa alone arm (P < 0.01). With insulin, the enhanced anabolism was due to inhibition of protein degradation (P < 0.02), whereas IGF-I augmented anabolism by a further stimulation of protein synthesis above aa alone (P < 0.02). We conclude that: (a) hyperaminoacidemia specifically stimulates muscle protein synthesis; (b) insulin, even with hyperaminoacidemia, improves muscle protein balance solely by inhibiting proteolysis; and (c) hyperaminoacidemia combined with IGF-I enhances protein synthesis more than either alone.

Physiologic hyperinsulinemia enhances human skeletal muscle perfusion by capillary recruitment.

Despite intensive study, the relation between insulin's action on blood flow and glucose metabolism remains unclear. Insulin-induced changes in microvascular perfusion, independent from effects on total blood flow, could be an important variable contributing to insulin's metabolic action. We hypothesized that modest, physiologic increments in plasma insulin concentration alter microvascular perfusion in human skeletal muscle and that these changes can be assessed using contrast-enhanced ultrasound (CEU), a validated method for quantifying flow by measurement of microvascular blood volume (MBV) and microvascular flow velocity (MFV). In the first protocol, 10 healthy, fasting adults received insulin (0.05 mU. kg(-1). min(-1)) via a brachial artery for 4 h under euglycemic conditions. At baseline and after insulin infusion, MBV and MFV were measured by CEU during continuous intravenous infusion of albumin microbubbles with intermittent harmonic ultrasound imaging of the forearm deep flexor muscles. In the second protocol, 17 healthy, fasting adults received a 4-h infusion of either insulin (0.1 mU. kg(-1). min(-1), n = 9) or saline (n = 8) via a brachial artery. Microvascular volume was assessed in these subjects by an alternate CEU technique using an intra-arterial bolus injection of albumin microbubbles at baseline and after the 4-h infusion. With both protocols, muscle glucose uptake, plasma insulin concentration, and total blood flow to the forearm were measured at each stage. In protocol 2 subjects, tissue extraction of 1-methylxanthine (1-MX) was measured as an index of perfused capillary volume. Caffeine, which produces 1-MX as a metabolite, was administered to these subjects before the study to raise plasma 1-MX levels. In protocol 1 subjects, insulin increased muscle glucose uptake (180%, P < 0.05) and MBV (54%, P < 0.01) and decreased MFV (-42%, P = 0.07) in the absence of significant changes in total forearm blood flow. In protocol 2 subjects, insulin increased glucose uptake (220%, P < 0.01) and microvascular volume (45%, P < 0.05) with an associated moderate increase in total forearm blood flow (P < 0.05). Using forearm 1-MX extraction, we observed a trend, though not significant, toward increasing capillary volume in the insulin-treated subjects. In conclusion, modest physiologic increments in plasma insulin concentration increased microvascular blood volume, indicating altered microvascular perfusion consistent with a mechanism of capillary recruitment. The increases in microvascular (capillary) volume (despite unchanged total blood flow) indicate that the relation between insulin's vascular and metabolic actions cannot be fully understood using measurements of bulk blood flow alone.

Fibrinogen promotes monocyte adhesion via a protein kinase C dependent mechanism.

The accumulation of blood monocytes at sites of predilection of the vessel wall is an early cellular event of atherogenesis. Proteins of the vessel wall may facilitate monocyte adhesion and thus promote their recruitment. It has been shown that the relative content of extracellular fibrinogen increases during lesion development, and this study investigated the contribution of immobilized fibrinogen to monocyte adhesion and the underlying mechanism. Freshly isolated human blood monocytes were cultivated in serum-free RPMI 1640 in tissue culture wells precoated with albumin, fibrinogen, or fibrin. After 16 h the plates were washed and adherent cells enumerated. Immobilized fibrinogen enhanced monocyte adhesion more than 1.9-fold compared to immobilized albumin or fibrin (P < 0.05). Concomitant addition of the protein kinase C (PKC) inhibitors staurosporine or H7 suppressed monocyte adherence to immobilized fibrinogen but exerted no significant effect upon adhesion to any other surface tested. Stimulation of monocytes using phorbol myristate acetate resulted in increased binding of monocytes on fibrinogen but not on bovine serum albumin. When PKC activity was reduced through prolonged incubation with PMA for 16 h, a significant reduction of monocyte adhesion on fibrinogen was observed. Peptides containing RGD sequences, which have been demonstrated to be ligands for certain integrins, did not inhibit monocyte adhesion. The data suggest that fibrinogen promotes monocyte adhesion in vitro by a PKC-dependent mechanism. PKC appears to be important not only for the initial cell adhesion but also for sustained binding of monocytes to fibrinogen.

Low level expression of cytokeratins 8, 18 and 19 in vascular smooth muscle cells of human umbilical cord and in cultured cells derived therefrom, with an analysis of the chromosomal locus containing the cytokeratin 19 gene.

Of the various intermediate filament (IF) proteins certain cytokeratins, usually a hallmark of epithelial differentiation, can also be detected in some non-epithelial cells in low amounts. We have studied a representative case of this atypical expression, the smooth muscle cells of the blood vessel walls of the human umbilical cord, at the protein and nucleic acid level, by light and electron microscopic immunolocalization, gel electrophoresis and immunoblotting of cytoskeletal proteins, and mRNA identification by Northern blotting. For the latter we have used sensitive probes for various cytokeratins, including new probes for cytokeratin 19. We also describe the chromosome 17 locus comprising the genes for cytokeratins 15 and 19, and we emphasize the occurrence of several unusual and evolutionarily stable sequence elements in the introns of the cytokeratin 19 gene. Most, perhaps all smooth muscle cells of these blood vessels, positively identified by the presence of desmin and smooth muscle type alpha-actin, are immunostained by antibodies specific for cytokeratins 8 and 18, and a subpopulation also contains cytokeratin 19. Immunoelectron microscopy indicates that these cytokeratins are arranged in IFs that are distributed differently from the majority of the IFs formed by desmin and vimentin. Gel electrophoresis of cytoskeletal proteins from microdissected vascular wall tissue shows that the amounts of cytokeratins 8 and 18 present in these tissues are very low, representing less than 1% of the total IF protein, and that cytokeratin 19 is present only in trace amounts. Correspondingly, the contents of mRNAs for cytokeratins 8, 18 and 19 in these tissues are much lower than those present in epithelial cells examined in parallel. We have also established cell cultures derived from umbilical cord vascular smooth muscles that have maintained the expression of cytokeratins 8, 18 and 19, together with vimentin and the smooth muscle type alpha-actin, but do not synthesize desmin. In these cell cultures the cytokeratins are present in much higher amounts than in the original tissue and form IFs that, surprisingly, show a similar distribution as the vimentin IFs and, upon treatment of the cells with colcemid, collapse into juxtanuclear aggregates, often even more effectively than the vimentin IFs do. We conclude that in a certain subtype of smooth muscle cells, the genes encoding cytokeratins of the "simple epithelial type", i.e., cytokeratins 8, 18 and 19, are expressed and that the low level expression of these genes is compatible with myogenic differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Physiological hyperinsulinemia stimulates p70(S6k) phosphorylation in human skeletal muscle.

Using tracer methods, insulin stimulates muscle protein synthesis in vitro, an effect not seen in vivo with physiological insulin concentrations in adult animals or humans. To examine the action of physiological hyperinsulinemia on protein synthesis using a tracer-independent method in vivo and identify possible explanations for this discrepancy, we measured the phosphorylation of ribosomal protein S6 kinase (P70(S6k)) and eIF4E-binding protein (eIF4E-BP1), two key proteins that regulate messenger ribonucleic acid translation and protein synthesis. Postabsorptive healthy adults received either a 2-h insulin infusion (1 mU/min.kg; euglycemic insulin clamp; n = 6) or a 2-h saline infusion (n = 5). Vastus lateralis muscle was biopsied at baseline and at the end of the infusion period. Phosphorylation of P70(S6k) and eIF4E-BP1 was quantified on Western blots after SDS-PAGE. Physiological increments in plasma insulin (42 +/- 13 to 366 +/- 36 pmol/L; P: = 0.0002) significantly increased p70(S6k) (P: < 0.01), but did not affect eIF4E-BP1 phosphorylation in muscle. Plasma insulin declined slightly during saline infusion (P: = 0.04), and there was no change in the phosphorylation of either p70(S6k) or eIF4E-BP1. These findings indicate an important role of physiological hyperinsulinemia in the regulation of p70(S6k) in human muscle. This finding is consistent with a potential role for insulin in regulating the synthesis of that subset of proteins involved in ribosomal function. The failure to enhance the phosphorylation of eIF4E-BP1 may in part explain the lack of a stimulatory effect of physiological hyperinsulinemia on bulk protein synthesis in skeletal muscle in vivo.

Branched chain amino acids activate messenger ribonucleic acid translation regulatory proteins in human skeletal muscle, and glucocorticoids blunt this action.

Branched chain amino acids (BCAA) are particularly effective anabolic agents. Recent in vitro studies suggest that amino acids, particularly leucine, activate a signaling pathway that enhances messenger ribonucleic acid translation and protein synthesis. The physiological relevance of these findings to normal human physiology is uncertain. We examined the effects of BCAA on the phosphorylation of eukaryotic initiation factor 4E-binding protein 1 (eIF4E-BP1) and ribosomal protein S6 kinase (p70(S6K)) in skeletal muscle of seven healthy volunteers. We simultaneously examined whether BCAA affect urinary nitrogen excretion and forearm skeletal muscle protein turnover and whether the catabolic action of glucocorticoids could be mediated in part by inhibition of the action of BCAA on the protein synthetic apparatus. BCAA infusion decreased urinary nitrogen excretion (P < 0.02), whole body phenylalanine flux (P < 0.02), plasma phenylalanine concentration (P < 0.001), and improved forearm phenylalanine balance (P = 0.03). BCAA also increased the phosphorylation of both eIF4E-BP1 (P < 0.02) and p70(S6K) (P < 0.03), consistent with an action to activate the protein synthetic apparatus. Dexamethasone increased plasma phenylalanine concentration (P < 0.001), prevented the BCAA-induced anabolic shift in forearm protein balance, and inhibited their action on the phosphorylation of p70(S6K). We conclude that in human skeletal muscle BCAA act directly as nutrient signals to activate messenger ribonucleic acid translation and potentiate protein synthesis. Glucocorticoids interfere with this action, and that may be part of the mechanism by which they promote net protein catabolism in muscle.

Tissue composition affects measures of postabsorptive human skeletal muscle metabolism: comparison across genders.

Despite clear anthropomorphic differences, gender differences in human skeletal muscle protein and carbohydrate metabolism have not been carefully examined. We compared postabsorptive forearm glucose, oxygen, and lactate balances and forearm protein kinetics between 40 male and 36 female subjects. Forearm composition was measured in a subset of 17 subjects (8 males and 9 females) using multislice magnetic resonance imaging. Oxygen uptake, net phenylalanine release, and estimated rates of forearm protein synthesis and degradation were greater in male than in female subjects when expressed as the rate per 100 mL forearm volume (P < 0.05). In males, however, muscle accounted for 58% of forearm volume, compared with 46% in females (P < 0.001). When phenylalanine balance, protein degradation and synthesis, and glucose and oxygen uptake were expressed per 100 mL forearm muscle, there were no significant differences across gender. Likewise, the extraction fractions for oxygen, glucose, phenylalanine, and labeled phenylalanine were comparable in males and females. We conclude that cross-gender comparisons of metabolic variables must accommodate differences in tissue composition. These data indicate that in the postabsorptive state, skeletal muscle metabolism of glucose, protein, and oxygen do not differ by gender in healthy young humans.

Short-term modulation of the androgen milieu alters pulsatile, but not exercise- or growth hormone (GH)-releasing hormone-stimulated GH secretion in healthy men: impact of gonadal steroid and GH secretory changes on metabolic outcomes.

Gonadal steroids are known to alter GH secretion as well as tissue metabolism. The present study was designed to examine the effects of short term (2- to 3-week) alterations in gonadal steroids on basal pulsatile (nonstimulated) and exercise- and GH-releasing hormone-stimulated GH secretion, urinary nitrogen excretion, and basal and exercise-stimulated oxygen consumption. Two protocols were conducted, which reflect a total of 18 separate studies. In the first paradigm, 5 healthy young men were each studied in a double blind, randomized manner during 3 different gonadal hormone manipulations, in which serum testosterone was varied from hypogonadal (induced by leuprolide) to eugonadal (saline injections) to high levels (testosterone enanthate, 3 mg/kg.week, i.m.). There was a washout period of 8 weeks between treatments. In the second protocol, 3 of the original subjects were studied after 2 weeks of treatment with stanozolol (0.1 mg/kg.day). Two to 3 weeks after the desired changes in serum testosterone, each subject was admitted to the General Clinical Research Center for study. The hypogonadal state (serum testosterone, 33 ng/dL) increased urinary nitrogen loss (by 34%; P < 0.005) and decreased basal metabolic rate (by 12%; P < 0.02) compared with the eugonadal state (testosterone, 796 ng/dL). High dose testosterone (1609 ng/dL) further decreased urinary nitrogen loss over the eugonadal state (by 16%; P < 0.05). Stanozolol yielded the lowest urinary nitrogen excretion of all (P < 0.03). Like urinary nitrogen, the basal metabolic rate showed the greatest change between the hypogonadal and eugonadal states (12%; P < 0.02), with a lesser change during high dose testosterone treatment (4%). Analogously, end-exercise oxygen consumption rose by 11% between the hypogonadal and eugonadal states (P < 0.05). Between the hypogonadal and eugonadal states, no significant changes in pulsatile (nonstimulated), exercise-stimulated, or GRF-stimulated GH secretion or serum insulin-like growth factor I concentrations were observed. Raising testosterone to supraphysiological levels increased pulsatile GH secretion by 62% over that with leuprolide and by 22% over that with saline (P < 0.05). High dose testosterone treatment also increased serum insulin-like growth factor I concentrations by 21% and 34% over those during the eugonadal and hypogonadal states, respectively (P < 0.01). Testosterone did not affect either exercise- or GRF-stimulated GH secretion. In protocol 2, stanozolol did not affect any parameter of GH secretion. To examine the interaction between GH secretion and testosterone on urinary nitrogen excretion and basal metabolic rate, a one-way analysis of covariance was undertaken. Statistical examination of GH production as the covariate and testosterone (by tertile) as the interactive factor demonstrated significant relationships between serum testosterone levels and either urinary nitrogen (P < 0.02) or basal metabolic rate (P < 0.01), but not GH secretion (P = NS). In summary, these results demonstrate that short term modulation of the androgen milieu affects metabolic outcome without necessitating changes in GH secretion. These results have significance for both normal physiology and for the treatment of hypogonadal GH-deficient patients.

Chemotaxis of the monocyte cell line U937: dependence on cholesterol and early mevalonate pathway products.

In the present study we investigated the influence of cholesterol depletion and hydroxymethylglutaryl-coenzyme A reductase (HMG-CoA reductase) inhibition on chemotaxis of the human monocytic cell line U937. Chemotaxis was nearly completely depressed after incubation for 24 h in the absence of lipoproteins. This was accompanied by a significant decrease in cellular cholesterol. Addition of 10 micrograms/ml low density lipoprotein (LDL) for 2 h to the cholesterol-depleted cells restored chemotaxis. Free cholesterol had no effect under these conditions. Inhibition of HMG-CoA reductase by pravastatin (0.01-1.0 mM) for 20 or 72 h also reduced chemotaxis. However, this effect was not accompanied by a decrease in cellular cholesterol when cells were grown in the presence of lipoproteins. The effect of pravastatin could be reversed by the addition of mevalonate. Addition of LDL did not change the response to pravastatin. We propose that the availability of cholesterol plays an important role in cellular chemotaxis. Furthermore, it can be suggested that other products of the mevalonate pathway apart from cholesterol may contribute to the regulation of chemotaxis.

Expression of monocyte chemoattractant protein-1 cDNA in vascular smooth muscle cells: induction of the synthetic phenotype: a possible clue to SMC differentiation in the process of atherogenesis.

In the arterial wall, smooth muscle cells (SMC) normally exist in a quiescent, differentiated state, representing the contractile phenotype. During the development of atherosclerosis SMC change towards the synthetic phenotype going along with proliferation, chemotactic response and increased monocyte binding. Expression of monocyte chemoattractant protein-1 (MCP-1), a potent chemoattractant for monocytes, has been shown to be among the earliest events in atherogenesis. We investigated the effect of MCP-1 on differentiated and dedifferentiated SMC. Differentiation of SMC was induced using Matrigel as a matrix for cultivation. MCP-1 was expressed in SMC by means of a recombinant adenovirus. Expression of MCP-1 led to dedifferentiation of SMC as demonstrated by induction of cytokeratin 18, a marker for the synthetic phenotype. Concurrently, migration was only detectable in MCP-1 expressing cells, whereas SMC infected with a control virus, coding for the nuclear-targeted lacZ gene showed no migration. The expression of intercellular adhesion molecule-1 (ICAM-1) could be demonstrated in synthetic SMC and was induced after infection of differentiated cells with recombinant adenovirus, coding for MCP-1 (AdMCP-1). Expression of ICAM-1 was associated with a tenfold higher monocyte binding compared to lacZ infected cells. Our data suggest that MCP-1 plays an important role for SMC in the functional switch from the contractile to the synthetic phenotype in the course of atherogenesis.

Accuracy of the hemocue portable glucose analyzer in a large nonhomogeneous population.

Several studies have reported inconsistent results between HemoCue (HC) whole blood glucose measurements compared to plasma glucose. We selected a large patient population with diverse pathologies and healthy volunteers to evaluate HC. For this comparison, whole blood glucose concentration was measured using HC and referenced to laboratory plasma glucose. The population (n = 512) included healthy volunteers, diabetics, and patients with heart failure, liver failure, renal failure, renal and liver transplant, and other chronic diseases. Patients were on a wide variety of medications, vitamins, and food supplements. Venous blood samples were collected in tubes containing potassium oxalate and sodium fluoride. Comparison of the results was made using the method of Bland and Altman and ANOVA at three selected glucose ranges. The glucose measurement ([HC + laboratory]/2) ranges were 24-75, 76-129, and 130-404 mg/dL. A positive bias for all three glucose ranges was observed: 38 +/- 17 mg/dL for the high glucose group compared to 24 +/- 9 mg/dL and 22 +/- 10 mg/dL for the middle and low groups, respectively. In the high glucose group 90% of the values were within 10% (R = 0.97) of the laboratory reference values compared to 81% and 55% in the normal and low glucose groups, respectively. HC glucose measurements were generally within two SD from the laboratory plasma reference. HC consistently yielded lower whole blood glucose measurements than plasma with the largest differences seen in the low glucose range (29%). HC measured more consistently at the higher glucose concentrations and was 16% lower than plasma, although the mean absolute error was highest for that range. No significant effects in the bias could be attributed to disease while possible effects from instrument modifications by the manufacturer remain uncertain.

[The quality appraisal of copy-milled complete-ceramic crown structures (Celay/In-Ceram)]. / Qualitätsbeurteilung von kopiergefrästen vollkeramischen Kronengerüsten (Celay/In-Ceram).

In the present in vitro-study, the fitting accuracy on In-Ceram crown structures, produced by copy milling under the Celay system, is examined. A total of 32 specimen was produced for four different stump forms (idealized incisor and premolar, each with a shoulder preparation or a 120 degree chamfer preparation) with indirect techniques. The data for the marginal gap ranged between 6 and 274 microns. The shoulder preparation lead to significantly better fitting qualities than the 120 degree chamfer preparation. Median gaps were found at 44 microns (premolar) and 32 microns (incisor). Examinations under the scanning electron microscope showed a homogeneous structure of the sinter with a small variation of grain size and a compact particle packing. As far as the clinical application of In-Ceram crown structures, produced by copy milling, is concerned, a shoulder preparation with a rounded inner edge is recommended.

[Is the determination of the defibrillation threshold in patients with an implantable cardioverter-defibrillator still required?]. / Wird die Bestimmung der Defibrillationsschwelle bei Patienten mit implantierbarem Kardioverter/Defibrillator noch benötigt?

BACKGROUND: Intraoperative testing of implantable cardioverter-defibrillators (ICDs) is time consuming and associated with risks. In the present study, we elucidated whether the initial implantation of an ICD with high energy output makes intraoperative defibrillation threshold testing (DFTT) unnecessary even though antiarrhythmic (AA) therapy is needed in the future. METHODS: A total of 111 patients (94 men, 17 women) receiving an ICD with subsequent AA therapy (mexiletine, amiodarone, sotalol, flecainide) were analyzed retrospectively. DFT was performed during ICD implantation and after AA drug therapy. In a second step, DFT results from the study cohort were analyzed for implantation of virtual ICDs with either low (≤ 30 J, LOD), intermediate (34 J, IOD), or high energy output (36 J, HOD). RESULTS: In the study cohort, all patients reached the safety margin (SM) of 10 J between DFT and maximal shock energy of the ICD. After loading of AA agents, 6 patients (12%) with a LOD, 3 patients (11%) with an IOD, and 3 (13%) patients with a HOD failed the 10 J SM. Using virtual ICDs, 6 (5.5%) patients with a LOD, 1 patient (1%) with an IOD, and no patients with a HOD would have failed the 10 J SM. After loading of AA agents, 18 patients (16%) with a virtual LOD, 12 patients (10.8%) with an IOD, and still 9 patients (8%) with a HOD would have failed the 10 J SM. CONCLUSION: Our results demonstrate that the 10 J SM would have been achieved intraoperatively in all patients with virtual HOD ICDs. Thus, determination of the DFT during implantation does not seem to be obligatory. However, in patients receiving AA agents, DFT testing is still required.

Pathology, natural history and treatment of abdominal aortic aneurysms.

With increasing age of the population and improvement of diagnostic tools, the incidence of abdominal aortic aneurysms (AAA) has been rising steadily. Despite an improvement in operative and interventional treatment options, AAA is the cause of death in 1-3% of men over 65 years of age in industrial countries, mostly due to rupture [1]. Therefore, routine screening for AAA by ultrasonography has been postulated in the past: a 60 year old man with an abdominal aortic diameter of less than 3 cm has a life-time risk of developing AAA close to zero. However, routine screening has not been found to be cost effective. Despite of the results of two well-designed studies, the limits of AAA qualifying the patient for surgery or intervention in contrast to conservative treatment is still a matter of debate. The present review article summarizes the current knowledge of the pathology, incidence, risks, natural course as well as symptoms and current treatment strategies of AAA on the basis of the recent literature.

Expression of nitric oxide related enzymes in coronary heart disease.

Enzymes involved in the metabolism nitric oxide (NO) and reactive oxygen species (ROS) may play a role for the decreased availability of NO in atherosclerosis. We, therefore, hypothesized that the pattern of gene expression of these enzymes is altered in atherosclerosis. Myocardial tissue from patients with coronary heart disease (CHD) or without CHD (control group) was investigated. The level of enzymes related to NO/ROS metabolism was determined both at mRNA level and protein level by rt-PCR, real-time PCR, and western blot. The expression of NOS1-3 (synthesis of NO), arginase1 (reduction of L-arginine), p22phox (active subunit of NADPH oxidase), GTPCH (rate limiting enzyme for tetrahydrobiopterin), SOD1-3 (scavengers of superoxide anions), PRTMT1-3, and DDAH2 (involved in the metabolism of ADMA) was determined. All enzymes were found to be expressed in human myocardium. NOS isoforms were decreased in CHD in protein level, but only the downregulation of NOS3 expression reached statistical significance. The expression of PRMT1 and PRMT3 was increased. In addition, the expression of DDAH2 was reduced, both theoretically leading to an increase of ADMA concentration. SOD3 was downregulated in tissue from patients with CHD. Taken together, in myocardial tissue from patients with atherosclerosis, the expression of genes increasing ADMA levels is enhanced in contrast to a reduced expression of genes promoting NO synthesis. These results may contribute to the explanation of increased oxidative stress in atherosclerosis on the level of gene expression.