Large-aperture coatings for fusion-class laser systems.

Optical coatings for fusion-class laser systems pose unique challenges, given the large substrate sizes, the high intensities incident on the coatings, and the system-focusing requirements, necessitating a well-controlled optical wavefront. Significant advancements have taken place in the past 30 years to achieve the coating capabilities necessary to build laser systems such as the National Ignition Facility, Laser Mégajoule, OMEGA EP, and OMEGA. This work summarizes the coating efforts and advancements to support such system construction and maintenance.

Extracellular ATP attenuates ischemia-induced caspase-3 cleavage in human endothelial cells.

BACKGROUND: Apoptotic death of endothelial cells (EC) plays a crucial role for the development of ischemic injury. In the present study we investigated the impact of extracellular Adenosine-5'-triphosphate (ATP), either released from cells or exogenously added, on ischemia-induced apoptosis of human EC. METHODS AND RESULTS: To simulate ischemic conditions, cultured human umbilical vein endothelial cells (HUVEC) were exposed to 2 h of hypoxia (Po(2)<4mm Hg) in serum-free medium. Ischemia led to a 1.7-fold (+/-0.4; P<0.05) increase in EC apoptosis compared to normoxic controls as assessed by immunoblotting and immunocytochemistry of cleaved caspase-3. Ischemia-induced apoptosis was accompanied by a 2.3-fold (+/-0.5; P<0.05) increase of extracellular ATP detected by using a luciferin/luciferase assay. Addition of the soluble ecto-ATPase apyrase, enhancing ATP degradation, increased ischemia-induced caspase-3 cleavage. Correspondingly, inhibition of ATP breakdown by addition of the selective ecto-ATPase inhibitor ARL67156 significantly reduced ischemia-induced apoptosis. Extracellular ATP acts on membrane-bound P2Y- and P2X-receptors to induce intracellular signaling. Both, ATP and the P2Y-receptor agonist UTP significantly reduced ischemia-induced apoptosis in an equipotent manner, whereas the P2X-receptor agonist αß-me-ATP did not alter caspase-3 cleavage. The anti-apoptotic effects of ARL67156 and UTP were abrogated when P2-receptors were blocked by Suramin or PPADS. Furthermore, extracellular ATP led to an activation of MEK/ERK- and PI3K/Akt-signaling pathways. Accordingly, inhibition of MEK/ERK-signaling by UO126 or inhibition of PI3K/Akt-signaling by LY294002 abolished the anti-apoptotic effects of ATP. CONCLUSION: The data of the present study indicate that extracellular ATP counteracts ischemia-induced apoptosis of human EC by activating a P2Y-receptor-mediated signaling reducing caspase-3 cleavage.

Effects of high passage cultivation on CHO cells: a global analysis.

Cell lines for industrial pharmaceutical protein production processes need to be robust, fast-growing, and high-producing. In order to find such cells, we performed a high passage cultivation of monoclonal antibody producing Chinese hamster ovary (CHO) cells in shaking flasks for more than 420 days. Examinations of cell growth, productivity, intracellular protein, and metabolite characteristics as well as product transcript and genomic integrate levels revealed substantial differences between subpopulations that were cryopreserved from long-term cultivation at different time points. Detected growth performance as well as intracellular adenylate energy charge increased during high passage cultivation. In addition, proteome analysis indicated an augmented utilization of glycolysis with higher passage number and an enhanced robustness based on anti-stress proteins. Interestingly, the product formation increased at first but decreased dramatically during the later subcultivations, although selection pressure was applied. Utilizing flow cytometry and quantitative real-time polymerase chain reaction, we further examined the translational, transcriptional, and genomic basis for the observed phenotypes. The detected reduction of antibody expression, in particular of the heavy chain, was ascribed to a decrease of antibody transcript, caused by loss of gene copy number and assumably a malfunctioning splicing mechanism of the dicistronic mRNA. To our knowledge, this is the first systematic approach using process analytics and targeted omic techniques to elucidate the effects of long-term cultivation of CHO cells expressing a therapeutic protein.

Transient hypoxia induces ERK-dependent anti-apoptotic cell survival in endothelial cells.

Ischemia-induced apoptosis of endothelial cells may contribute to tissue injury, organ failure, and transplantation rejection. However, little is known about survival mechanisms capable to counteract endothelial apoptosis. This study investigated the potential role of an endogenous anti-apoptotic response elicited by transient hypoxia, capable to avert ongoing apoptosis in endothelial cells. Experiments were carried out in three different types of cultured endothelial cells (human umbilical vein, pig aorta, and from rat coronary microvasculature). As a pro-apoptotic challenge endothelial cells were cultured in serum-free medium and subjected to hypoxia for 2 h. We found that transient hypoxia reduced caspase 3 activation within 1 h of hypoxia. Accordingly, the number of apoptotic cells was reduced after 24 h of reoxygenation. This was true for all three cell types analyzed. Analysis of Akt and mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathways revealed that hypoxia induced a transient activation of ERK 2 but not of Akt. ERK 2 phosphorylation preceded the phosphorylation of pro-apoptotic molecule Bad at Ser112, an inhibitory phosphorylation site specific for ERK. The protective effects of hypoxia regarding Bad phosphorylation, caspase 3 activation, and apoptosis were abolished by MEK 1/2 inhibitors, PD98059 or UO126, as well as by antisense oligonucleotides directed against ERK 1/2. Furthermore, inhibition of this pathway inhibited hypoxia-induced increase in mitochondrial membrane potential. The present study demonstrates that transient hypoxia induces a novel survival mechanism that protects endothelial cells against apoptosis. This endogenous process involves MEK/ERK-mediated inhibition of the pro-apoptotic molecule Bad and caspase 3.

Effect of factor XIII on endothelial barrier function.

The effect of factor XIII on endothelial barrier function was studied in a model of cultured monolayers of porcine aortic endothelial cells and saline-perfused rat hearts. The thrombin-activated plasma factor XIII (1 U/ml) reduced albumin permeability of endothelial monolayers within 20 min by 30 +/- 7% (basal value of 5.9 +/- 0.4 x 10(-6) cm/s), whereas the nonactivated plasma factor XIII had no effect. Reduction of permeability to the same extent, i.e., by 34 +/- 9% could be obtained with the thrombin-activated A subunit of factor XIII (1 U/ml), whereas the iodoacetamide-inactivated A subunit as well as the B subunit had no effect on permeability. Endothelial monolayers exposed to the activated factor XIII A exhibited immunoreactive deposition of itself at interfaces of adjacent cells; however, these were not found on exposure to nonactivated factor XIII A or factor XIII B. Hyperpermeability induced by metabolic inhibition (1 mM potassium cyanide plus 1 mM 2-deoxy-D-glucose) was prevented in the presence of the activated factor XIII A. Likewise, the increase in myocardial water content in ischemic-reperfused rat hearts was prevented in its presence. This study shows that activated factor XIII reduces endothelial permeability. It can prevent the loss of endothelial barrier function under conditions of energy depletion. Its effect seems related to a modification of the paracellular passageways in endothelial monolayers.

Wegener's granulomatosis: anti-proteinase 3 antibodies are potent inductors of human endothelial cell signaling and leakage response.

Anti-neutrophil cytoplasmic antibodies (ANCAs) targeting proteinase 3 (PR3) have a high specifity for Wegener's granulomatosis (WG), and their role in activating leukocytes is well appreciated. In this study, we investigated the influence of PR3-ANCA and murine monoclonal antibodies on human umbilical vascular endothelial cells (HUVECs). Priming of HUVECs with tumor necrosis factor alpha induced endothelial upregulation of PR3 message and surface expression of this antigen, as measured by Cyto-ELISA, with a maximum occurrence after 2 h. Primed cells responded to low concentrations of both antibodies (25 ng-2.5 microg/ml), but not to control immunoglobulins, with pronounced, dose-dependent phosphoinositide hydrolysis, as assessed by accumulation of inositol phosphates. The signaling response peaked after 20 min, in parallel with the appearance of marked prostacyclin and platelet-activating factor synthesis. The F(ab)2 fragment of ANCA was equally potent as ANCA itself. Disrupture of the endothelial F-actin content by botulinum C2 toxin to avoid antigen-antibody internalization did not affect the response. In addition to the metabolic events, anti-PR3 challenge, in the absence of plasma components, provoked delayed, dose-dependent increase in transendothelial protein leakage. We conclude that anti-PR3 antibodies are potent inductors of the preformed phosphoinositide hydrolysis-related signal tranduction pathway in human endothelial cells. Associated metabolic events and the loss of endothelial barrier properties suggest that anti-PR3-induced activation of endothelial cells may contribute to the pathogenetic sequelae of autoimmune vasculitis characterizing WG.

Spatio-temporal coherence of free electron laser pulses in the soft x-ray regime.

The temporal coherence properties of soft x-ray free electron laser pulses at FLASH are measured at 23.9 nm by interfering two time-delayed partial beams directly on a CCD camera. The partial beams are obtained by wave front beam splitting in an autocorrelator operating at photon energies from h nu = 30 to 200 eV. At zero delay a visibility of (0.63+/- 0.04) is measured. The delay of one partial beam reveals a coherence time of 6 fs at 23.9 nm. The visibility further displays a non-monotonic decay, which can be rationalized by the presence of multiple pulse structure.

Extracellular ATP induces assembly and activation of the myosin light chain phosphatase complex in endothelial cells.

OBJECTIVES: Extracellular ATP stabilizes the endothelial barrier and inactivates the contractile machinery of endothelial cells. This inactivation relies on dephosphorylation of the regulatory myosin light chain (MLC) due to an activation of the MLC phosphatase (MLCP). To date, activation and function of MLCP in endothelial cells are only partially understood. METHODS: Here, the mechanism of extracellular ATP-mediated activation of MLCP was analyzed in human endothelial cells from umbilical veins. Cells were transfected with the endogenous protein phosphatase 1 (PP1)-specific inhibitor-2 (I-2). RESULTS: Overexpression of I-2 led to inhibition of PP1 activity and abrogation of the ATP-induced dephosphorylation of MLC. This indicates that the PP1 catalytic subunit is the principal phosphatase catalyzing the MLC dephosphorylation induced by extracellular ATP. As demonstrated by immunoprecipitation analysis, extracellular ATP recruits the PP1delta catalytic subunit and the myosin phosphatase targeting subunit (MYPT1) to form a complex. ATP stimulated dephosphorylation of MYPT1 at the inhibitory phosphorylation sites threonine 850 and 696. However, extracellular ATP failed to stimulate MYPT1 dephosphorylation in I-2-overexpressing cells. CONCLUSIONS: The present study shows for the first time that, in endothelial cells, extracellular ATP causes activation of MLCP through recruitment of PP1delta and MYPT1 into a MLCP holoenzyme complex and PP1-mediated reduction of the inhibitory phosphorylation of MYPT1.

[Point-of-care ultrasonography of the abdomen in emergency and intensive care medicine]. / Point-of-care-Sonographie des Abdomens in der Notfall- und Intensivmedizin.

Point-of-care ultrasound is a fundamental part of diagnostic and therapeutic management in emergency and intensive care medicine. The availability of high-resolution mobile ultrasound systems allows high-quality imaging at the bedside of the patient. Point-of-care ultrasound is not a comprehensive differential diagnostic abdominal ultrasound examination. Rather, the aim of the method is to integrate easily detectable sonographic findings into the clinical context. From this, the necessary diagnostic or therapeutic procedures are derived. This article shows opportunities and limitations of this method. The structure of the article is given by the leading clinical symptoms. The focus is on the ultrasound examination and the characteristic sonographic findings with illustrative ultrasound images. This is followed by a short differential diagnostic interpretation. Further diagnostic or therapeutic management is also briefly addressed.

Development of a hard X-ray split-and-delay line and performance simulations for two-color pump-probe experiments at the European XFEL.

A hard X-ray Split-and-Delay Line (SDL) under construction for the Materials Imaging and Dynamics station at the European X-Ray Free-Electron Laser (XFEL) is presented. This device aims at providing pairs of X-ray pulses with a variable time delay ranging from -10 ps to 800 ps in a photon energy range from 5 to 10 keV for photon correlation and X-ray pump-probe experiments. A custom designed mechanical motion system including active feedback control ensures that the high demands for stability and accuracy can be met and the design goals achieved. Using special radiation configurations of the European XFEL's SASE-2 undulator (SASE: Self-Amplified Spontaneous Emission), two-color hard x-ray pump-probe schemes with varying photon energy separations have been proposed. Simulations indicate that more than 109 photons on the sample per pulse-pair and up to about 10% photon energy separation can be achieved in the hard X-ray region using the SDL.

Label-free protein quantification of sodium butyrate treated CHO cells by ESI-UHR-TOF-MS.

Effects of butyrate on CHO producer cells are contradictory, promoting productivity and at the same time repressing proliferation. Though in previous omics studies the background of butyrate impact on producer cells has been investigated, the knowledge about the mechanism is still very limited. As previous proteomic results on this field are mainly based on 2DE-gels, we conducted a label-free MS quantification, based on fast high resolution ESI-MS and a straight forward software solution, to gain insight in shifted cellular processes of CHO cells 25h after butyrate treatment. 118 proteins or subunits with significantly altered abundances were identified suggesting changes in carbohydrate, protein metabolic and cell cycle processes. Effects of butyrate on the nucleosome assembly as a known direct epigenetic influence on HDAC activity turned out to be unexpectedly fast and persistent, as confirmed by Western blots of histone-H4 acetylation. Contradictory to increased cell specific productivity, most elements of protein metabolism exhibited decreased levels after butyrate treatment. In comparison to published results some overlap of our label free MS data could be observed but also apparently diverging findings, showing the need for complementary omics techniques for a holistic view on cellular processes such as response to butyrate.

The critical steady-state hypoxic conditions in carbon tetrachloride-induced lipid peroxidation in rat liver microsomes.

Defined steady-state oxygen partial pressures (PO2) were maintained constant with an oxystat system to study carbon tetrachloride (CCl4)-induced lipid peroxidation and oxygen uptake in rat liver microsomes. The initial rates of oxygen uptake and malondialdehyde formation indicated drastically increasing lipid peroxidation by decreasing PO2, attaining a maximum between 1-10 mmHg (0.1-1.3 kPa). Under these conditions, at the hypoxic end of the physiological PO2 in liver, CCl4 caused a 5-fold increase in the oxygen uptake rate and a 20-fold increase in the malondialdehyde formation rate while, at 80 mmHg (10.7 kPa) the haloalkane caused only an increase of 2- and 4-fold, respectively; in comparison, there was only a slight increase in NADPH-induced lipid peroxidation with increasing PO2. These data clearly demonstrate the critical role of low steady-state PO2 in CCl4-induced lipid peroxidation and support lipid peroxidation as a key factor in CCl4 hepatotoxicity.

Loss of latent activity of liver microsomal membrane enzymes evoked by lipid peroxidation. Studies of nucleoside diphosphatase, glucose-6-phosphatase, and UDP glucuronyltransferase.

The effects of lipid peroxidation on latent microsomal enzyme activities were examined in NADPH-reduced microsomes from phenobarbital-pretreated male rats. Lipid peroxidation, stimulated by iron or carbon tetrachloride, was assayed as malondialdehyde formation. Independent of the stimulating agent of lipid peroxidation, latency of microsomal nucleoside diphosphatase activity remained unaffected up to microsomal peroxidation equivalent to the formation of about 12 nmol malondialdehyde/mg microsomal protein. However, above this threshold a close correlation was found between lipid peroxidation and loss of latent enzyme activity. The loss of latency evoked by lipid peroxidation was comparable to the loss of latency attainable by disrupting the microsomal membrane by detergent. Loss of latent enzyme activity produced by lipid peroxidation was also observed for microsomal glucose-6-phosphatase and UDPglucuronyltransferase. In contrast to nucleoside diphosphatase, however, both enzymes were inactivated by lipid peroxidation, as indicated by pronounced decreases of their activities in detergent-treated microsomes. According to the respective optimal oxygen partial pressure (po2) for lipid peroxidation, the iron-mediated effects on enzyme activities were maximal at a po2 of 80 mmHg and the one mediated by carbon tetrachloride at a po2 of 5 mmHg. Under anaerobic conditions no alterations of enzyme activities were detected. These results demonstrate that loss of microsomal latency only occurs when peroxidation of the microsomal membrane has reached a certain extent, and that beyond this threshold lipid peroxidation leads to severe disintegration of the microsomal membrane resulting in a loss of its selective permeability, a damage which should be of pathological consequences for the liver cell. Because of its resistance against lipid peroxidation nucleoside diphosphatase is a well-suited intrinsic microsomal parameter to estimate this effect of lipid peroxidation on the microsomal membrane.

Alterations of the microsomal glucose-6-phosphatase system evoked by ferrous iron- and haloalkane free-radical-mediated lipid peroxidation.

Alterations of catalytic activities of the microsomal glucose-6-phosphatase system were examined following either ferrous iron- or halothane (CF3CHBrCl) and carbon tetrachloride (CCl4) free-radical-mediated peroxidation of the microsomal membrane. Enzyme assays were performed in native and solubilized microsomes using either glucose 6-phosphate or mannose 6-phosphate as substrate. Lipid peroxidation was assessed by the amounts of malondialdehyde equivalents formed. Regardless of whether the experiments were performed in the presence of NADPH/Fe3+, NADPH/CF3CHBrCl, or NADPH/CCl4, with the onset of lipid peroxidation, mannose-6-phosphatase activity of the native microsomes increased immediately, while further alterations in catalytic activities were only detectable when lipid peroxidation had passed characteristic threshold values: above 2 nmol malondialdehyde/mg microsomal protein, glucose-6-phosphatase activity of the native microsomes was lost, and at 10 nmol malondialdehyde/mg microsomal protein, glucose-6-phosphatase and mannose-6-phosphatase activity of the solubilized microsomes started to decline. It is concluded that the latter alterations are due to an irreversible damage of the phosphohydrolase active site of the glucose-6-phosphatase system, while the changes observed at earlier stages of microsomal lipid peroxidation may also reflect alterations of the transporter components of the glucose-6-phosphatase system. Virtually no changes in the catalytic activities of the glucose-6-phosphatase system occurred under anaerobic conditions, indicating that CF3CHCl and CCl3 radicals are without direct damaging effect on the glucose-6-phosphatase system. Further, maximum effects of carbon tetrachloride and halothane on lipid peroxidation and enzyme activities were observed at an oxygen partial pressure (PO2) of 2 mmHg, providing additional evidence for the crucial role of low PO2 in the hepatotoxicity of both haloalkanes.

Plasma transglutaminase factor XIII induces microvessel ingrowth into biodegradable hydroxyapatite implants in rats.

Coagulation factor XIII is a member of the transglutaminase-family. Transgluaminases cross-link either fibrin monomers in blood coagulation or extracellular proteins in extracellular matrix formation. In early stages of bone healing migration and proliferation of endothelial cells lead to formation of new vessels. The aim of this study was to investigate the angiogenetic activity of plasma factor XIII in bone defects filled with nanoparticulate hydroxyapatite paste. A critical size defect was created in the tibial head of rats which was not filled in group I. In group II the defect was filled with hydroxyapatite paste, and in group III with hydroxyapatite paste enriched with factor XIII. Ten days after surgery angiogenesis in the defects was assessed using immunohistochemistry and confocal laser scanning microscopy. Ac16 antibody was used to detect activation of factor XIII into factor XIIIA. In defects without biomaterial (group I) vessel-rich connective tissue and diffuse distribution of capillaries was observed. In defects filled with pure hydroxyapatite (group II) formation of capillaries was limited to the host bone-hydroxyapatite interface. In contrast, addition of plasma factor XIII to hydroxyapatite (group III) stimulated formation of vessels within the biomaterial. The current study reveals that factor XIII can improve angiogenesis in hydroxyapatite.

Mechanism of Ca(2+) overload in endothelial cells exposed to simulated ischemia.

OBJECTIVE: Several studies have shown that myocardial ischemia leads to functional failure of endothelial cells (EC) whereby disturbance of Ca(2+) homeostasis may play an important role. The mechanisms leading to Ca(2+) disbalance in ischemic EC are not fully understood. The aim of this study was to test effects of different components of simulated ischemia (glucose deprivation, anoxia, low extracellular pH (pH(o)) and lactate) on Ca(2+) homeostasis in EC. METHODS: Cytosolic Ca(2+) (Ca(i)), cytosolic pH (pH(i)) and ATP content were measured in cultured rat coronary EC. RESULTS: In normoxic cells 60 min glucose deprivation at pH(o) 7.4 had no effect on pH(i). It only slightly increased Ca(i) and decreased ATP content. Reduction of pH(o) to 6.5 under these conditions led to marked cytosolic acidosis and Ca(i) overload, but had no effect on ATP content. Anoxia at pH(o) 6.5 had no additional effect on Ca(i) overload, but significantly reduced cellular ATP. Addition of 20 mmol/l lactate to anoxia at pH(o) 6.5 accelerated Ca(i) overload due to faster cytosolic acidification. Acidosis-induced Ca(i) overload was prevented by inhibition of Ca(2+) release channels of endoplasmic reticulum (ER) with 3 micromol/l ryanodine or by pre-emptying the ER with thapsigargin. Re-normalisation of pH(o) for 30 min led to recovery of pH(i), but not of Ca(i). CONCLUSION: The ischemic factors leading to cytosolic acidosis (low pH(o) and lactate) cause Ca(i) overload in endothelial cells, while anoxia and glucose deprivation play only a minor role. The ER is the main source for this Ca(i) rise. Ca(i) overload is not readily reversible.

Histone H1 expression varies during the Leishmania major life cycle.

The deduced amino acid sequence of Leishmania major sw3 cDNA reveals the presence of characteristic histone H1 amino acid motifs. However, the open reading frame is of an unusually small size for histone H1 (105 amino acids) because it lacks the coding potential for the central hydrophobic globular domain of linker histones present in other eukaryotes. Here, we provide biochemical evidence that the SW3 protein is indeed a L. major nuclear histone H1, and that it is differentially expressed during the life cycle of the parasite. Due to its high lysine content, the SW3 protein can be purified to a high degree from L. major nuclear lysates with 5% perchloric acid, a histone H1 preparative method. Using an anti-SW3 antibody, this protein is detected as a 17 kDa or as a 17/19 kDa doublet in the nuclear subfraction in different L. major strains. The nuclear localization of the SW3 protein is further supported by immunofluorescence studies. During in vitro promastigote growth, both the sw3 cytoplasmic mRNA and its protein progressively accumulate within parasites from early log phase to stationary phase. Within amastigotes, the high level of H1 expression is maintained but decreases when amastigotes differentiate into promastigotes. Together, these observations suggest that the different levels of this histone H1 protein could influence the varying degrees of chromatin condensation during the life-cycle of the parasite, and provide us with tools to study this mechanism.

A cell-culture reactor for the on-line evaluation of radiopharmaceuticals: evaluation of the lumped constant of FDG in human glioma cells.

UNLABELLED: A fluidized-bed cell-culture reactor with on-line radioactivity detection was developed for the in vitro evaluation of radiopharmaceuticals. The technique was applied to measure the dependency of the lumped constant (LC) of FDG on the glucose concentration in the culture medium in a human glioma cell line. METHODS: Human glioblastoma cells (86HG39) immobilized in open porous microcarriers were cultivated in a continuously operating fluidized-bed bioreactor. At different glucose concentrations in the culture medium, step inputs (0.1 MBq/mL) of FDG were performed and the cellular uptake of FDG was measured on-line and compared with analyzed samples. From these results, the LC of FDG and its dependency on the glucose concentration were calculated. RESULTS: This fluidized-bed technique enabled precise and reproducible adjustment of all relevant experimental parameters, including radiotracer time-concentration course, medium composition, pH, dissolved oxygen and temperature under steady-state conditions, and an on-line determination of the intracellular radiotracer uptake. The immobilized glioma cells formed stable, 3-dimensional, tumor-like spheroids and were continuously proliferating, as proven by an S-phase portion of 25%-40%. For further examination of the cells, an enzymatic method for detachment from the carriers without cellular destruction was introduced. In the FDG experiments, a significant dependency of the LC on the glucose level was found. For normoglycemic glucose concentrations, the LC was determined to be in the range of 0.7+/-0.1, whereas in hypoglycemia LC increased progressively up to a value of 1.22+/-0.01 at a glucose concentration of 3 mmol/L. CONCLUSION: The bioreactor represents an improved in vitro model for the on-line evaluation of radiotracers and combines a wide range of experimental setups and 3-dimensional, tissue-like cell cultivation with a technique for on-line radioactivity detection.

beta-agonistic bronchodilators: comparison of dose/response in working rat hearts.

STUDY OBJECTIVES: Different beta-agonists are compared with regard to their cardiodepressive side effects. DESIGN: The metaphenolic bronchodilators reproterol, salbutamol, fenoterol, and terbutaline were introduced at a dosage of 0.0005 micromol to a maximum of 10 micromol per gram of heart tissue into the isolated working rat heart under hypoxic conditions, and the response was observed during subsequent reoxygenation. As an index of external heart work, aortic flow was measured. Heart rate, coronary flow, and developed pressure were recorded. At the end of heart perfusion, mitochondria were isolated and analyzed for adenosine triphosphatase activity, adenosine triphosphate (ATP) synthesis, and membrane fluidity. Moreover, intact mitochondria and lipid peroxidation were investigated using a model system. MEASUREMENTS AND RESULTS: Compared to controls, reproterol gave the most favorable results, with an increase of 25 to 30% of aortic flow during reoxygenation at a concentration of 10 micromol/g heart tissue. In contrast, both fenoterol and salbutamol at a concentration of 1 micromol/g heart tissue decreased aortic flow during reoxygenation, whereas terbutaline had a negative influence on aortic flow at 0.01 to 0.1 micromol/g heart tissue. Mitochondria of these hearts were isolated at the end of the experiment. Mitochondrial ATP synthesis was increased above controls at nearly all concentrations of reproterol. ATP synthesis was decreased at 1 micromol and 10 micromol fenoterol. As little as 0.0005 micromol terbutaline decreased ATP synthesis by 50%. In intact mitochondria, adenosine diphosphate (ADP) to oxygen ratios were found to be increased with terbutaline and fenoterol, indicating ADP consumption by myokinase activation. Lipid peroxidation was increased in a model system between concentrations of 0.002 micromol/mg and 0.04 micromol/mg phosphatidylcholine by fenoterol and terbutaline, whereas a decrease was noted with reproterol. Membrane fluidity was found increased after addition of reproterol, which supports the evidence of efficient ATP synthesis by this compound. CONCLUSIONS: Cardiodepressive side effects and greater toxicity of fenoterol and terbutaline were found under the conditions of our experiment. Salbutamol and, in particular, reproterol appear much better tolerated. In addition to partial beta-adrenergic agonism, reproterol may exert an inhibitory influence on adenosine receptor sites and phosphodiesterase, which could result in membrane stabilization by saving cyclic adenosine monophosphate or ATP.

Factor XIII prevents development of myocardial edema in children undergoing surgery for congenital heart disease.

In a prospective investigation of perioperative cardiac edema formation requiring a delayed sternal closure, we identified thrombin increase combined with a simultaneous decrease of factor XIII as a probable cause. After experimental studies additionally revealed that factor XIII could protect endothelial barrier function, we did another prospective randomized trial in which factor XIII or placebo was preoperatively substituted. The substitution finally showed distinct effects minimizing the incidence of myocardial swelling. Therefore, the clinical application of factor XIII may have a valuable therapeutic benefit in cases of leakage syndrome during extracorporeal circulation in congenital heart surgery.