[Papillomatosis in a bile duct cyst in an adult].
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Ampulla of Vater↗
Biomedical subjects
H Lill
Publications and source records attributed to H Lill.
Complementation of Escherichia coli unc mutant strains by chloroplast and cyanobacterial F1-ATPase subunits.
The genes encoding the five subunits of the F1 portion of the ATPases from both spinach chloroplasts and the cyanobacterium Synechocystis sp. PCC 6803 were cloned into expression vectors and expressed in Escherichia coli. The recombinant subunits formed inclusion bodies within the cells. Each particular subunit was expressed in the respective unc mutant, each unable to grow on non-fermentable carbon sources. The following subunits restored growth under conditions of oxidative phosphorylation: alpha (both sources, cyanobacterial subunit more than spinach subunit), beta (cyanobacterial subunit only), delta (both spinach and Synechocystis), and epsilon (both sources), whereas no growth was achieved with the gamma subunits from both sources. Despite a high degree of sequence homology the large subunits alpha and beta of spinach and cyanobacterial F1 were not as effective in the substitution of their E. coli counterparts. On the other hand, the two smallest subunits of the E. coli ATPase could be more effectively replaced by their cyanobacterial or chloroplast counterparts, although the sequence identity or even similarity is very low. We attribute these findings to the different roles of these subunits in F1: The large alpha and beta subunits contribute to the catalytic centers of the enzyme, a function rendering them very sensitive to even minor changes. For the smaller delta and epsilon subunits it was sufficient to maintain a certain tertiary structure during evolution, with little emphasis on the conservation of particular amino acids.
Amino Acid Sequence↗
The atp2 operon of the green bacterium Chlorobium limicola.
The operon (atp2) encoding the beta and epsilon subunits of F-ATPase from Chlorobium limicola was cloned and sequenced. In contrast with purple bacteria these genes are arranged in a separate operon similar to the cyanobacteria. The operon terminates with a pronounced stem-loop structure. About 0.8 kb upstream of the beta subunit a gene encoding the enzyme phospho enol pyruvate carboxykinase was identified. This gene is transcribed in the opposite direction of the atp2 operon and also ends with a stem-loop structure. These genes of green bacteria are among the first to be sequenced, and therefore the genetic distance between these genes and corresponding genes from other bacteria and eukaryotes was studied. Even though the operon structure resembles that of cyanobacteria, the evolutionary tree compiled from these data places the chlorobium gene close to purple bacteria. Chlorobium limicola beta and epsilon subunits complemented Escherichia coli mutants defective in the corresponding subunits, indicating that the hybrid enzyme formed from subunits of the two bacteria is active in ATP synthesis.
Amino Acid Sequence↗
The effect of different exercise intensities on the fibrinolytic system.
The effects of moderate 30-min cycle ergometer exercise (aerobic metabolism) followed by short-term exercise at maximal capacity (anaerobic metabolism) on fibrinolytic activity were investigated in ten female and ten male healthy, untrained subjects. The following parameters of fibrinolytic activity were measured initially (t0), at the end of the aerobic phase (t1), at the end of the anaerobic phase (t2) and after a 30-min recovery period (t3): tissue plasminogen activator (PAt) activity, PAt concentration, plasminogen activator (PAt) activity, PAt concentration, plasminogen activator inhibitor (PAi) activity, and D-Dimer concentration. Moderate long-term exercise caused a slight but significant increase in PAt concentration and PAt activity (t1; P < 0.01), whereas short-term exercise at maximal capacity (t2) produced a substantial elevation in both these parameters (P < 0.01). This would suggest that PAt was not inhibited totally by PAi which would itself seem to be consumed during exercise. In addition, a slight exercise intensity-dependent increase in D-Dimer concentration was measured--circumstancial evidence not only for elevated fibrinolytic potential, but also for an actual increase in fibrin degradation (t2: P < 0.01). After t3 both PAt activity and D-Dimer concentration were still slightly but significantly increased. The results obtained in the tests of fibrinolytic activity showed no significant difference between the men and the women. It would seem that the release of PAt is more markedly stimulated by short-term intense physical exercise than by long-term moderate exercise and actually causes increased fibrin degradation.
Adult↗
Sensitive detection of the activation state of blood coagulation in porcine DIC models by a new fibrin immunoassay.
Elevated levels of soluble fibrin in plasma indicate that thrombin converts fibrinogen to fibrin without sufficient inhibitory control. Therefore, measurement of soluble fibrin (SF) in plasma may be considered as a laboratory test for intravascular coagulation. We have demonstrated that a new immunoassay for detection of SF in human plasma (Lill et al., Blood Coag Fibrinol 1993; 4: 97-102), based on a fibrin specific monoclonal antibody, also detects porcine SF with high sensitivity. Thrombin-dependent generation of SF in porcine plasma in vitro resulted in increased reactivity of the assay system, which was time and dose dependent. Dextran sulphate (DXS) and bacterial lipopolysaccharide (LPS) were used as stimuli in in vivo experiments in pigs. Plasma levels of SF increased steadily after intravenous administration of DXS (5 mg/kg for 1 h) to 38 +/- 7.8 micrograms/ml (mean +/- SEM) at 2 h, whereas LPS (2 micrograms/kg/h for 6 h) markedly increased plasma SF levels to over 120 micrograms/ml (at 6 h) after a lag phase of 2 h. In conclusion, this new immunoassay for human fibrin allows specific and sensitive detection of soluble fibrin in porcine plasma.
Animals↗
Binding of a new monoclonal antibody against N-terminal heptapeptide of fibrin alpha-chain to fibrin polymerization site 'A': effects of fibrinogen and fibrinogen derivatives, and pretreatment of samples with NaSCN.
A novel murine monoclonal antibody against the fibrin alpha-chain N-terminus is presented, which reacts with desAA- and desAABB-fibrin. In immunoblot procedures, the antibody reacted with fibrin degradation products X and Y of non-crosslinked fibrin, and fragment E. No binding was observed to the fibrin fragment D-dimer, and fibrinogen fragments D and E. Minor binding to fibrinogen fragments X, and Y, and desBB-fibrin were presumably due to minor contamination with (desAA)-fibrin. A prerequisite for binding was release of fibrinopeptides A (FpA), the binding site being a fibrin-specific neo-epitope. No binding was observed to fibrinogen or to thrombin-treated dysfibrinogen MANNHEIM III (A alpha 16 Arg-->Cys) molecules, which do not release FpA. The antibody bound to abnormal fibrin molecules prepared from dysfibrinogen MANNHEIM I (A alpha 19 Arg-->Gly), albeit to a lesser extent than to normal fibrin. Binding of the antibody to the fibrin epitope was greatly enhanced by denaturation, e.g. by heat, or by treatment with chaotropic ions. Soluble fibrin in clinical samples is generally found as a complex with fibrinogen, since polymerization sites 'A' exposed by release of FpA react with complementary binding sites 'a' on the D-domains of other fibrin and fibrinogen molecules. Treatment of samples with NaSCN caused dissociation of fibrin monomer complexes. Reassociation was prevented by denaturation of both polymerization sites 'A' and 'a'. The antibody in combination with NaSCN-treatment of samples was useful for specific detection of fibrin monomer in plasma samples. Measurement was not influenced by fibrinogen degradation products, whereas fibrin degradation products at very high concentration caused some underestimation of fibrin monomer concentration.
Animals↗
A new immunoassay for soluble fibrin enables a more sensitive detection of the activation state of blood coagulation in vivo.
A novel sandwich immunoassay for measurement of soluble fibrin in plasma has been developed. For immunization we used the synthetic heptapeptide Gly-Pro-Arg-Val-Val-Glu-Arg representing the amino terminus of the alpha-chain of human fibrin. A monoclonal IgG1 antibody was obtained by conventional hybridoma technology. To increase convenience, the sandwich immunoassay was developed for the Enzymun-Test systems which are based on streptavidin pre-coated tubes. The new assay was designed with the same fibrin specific antibody both in biotinylated and in peroxidase-labelled form. Fibrin in native plasma samples could only be detected after pre-incubation of the plasma with chaotropic ions. Test results were calculated using a standard curve comprising six fibrin standards (0-50 micrograms/ml). Precision of the method was satisfactory; intra-assay CVs using plasma samples ranged between 5.0% (23.7 micrograms/ml) and 12.4% (0.2 microgram/ml). CVs of interassay precision measurements using standards as samples range between 7.3% (25.0 micrograms/ml) and 11.4% (1.0 micrograms/ml). The lower detection limit was 0.12 microgram/ml. Investigations of normal range in 70 age-matched healthy individuals resulted in a mean of 1.12 micrograms/ml. Linearity was excellent; recovery of high fibrin plasma after dilution with normal plasma was always between 100 and 107%. Fibrin specificity was due to the monoclonal antibody 2B5 used and no cross reactivity with fibrinogen, fibrinogen split products or fibrin D-dimer was observed. Fibrin fragment E1 (studied by Dempfle CE, et al. Blood Coag Fibrinol 1993; 4: 79-86) and fragments X and Y showed moderate cross reactivity in the assay and caused some overestimation of fibrin at high fibrin split product concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗
Biochemical properties of the kringle 2 and protease domains are maintained in the refolded t-PA deletion variant BM 06.022.
BM 06.022 is a t-PA deletion variant which comprises the kringle 2 and the protease domain. Production of BM 06.022 in Escherichia coli leads to the formation of inactive inclusion bodies, which have to be refolded by an in vitro refolding process to achieve activity and proper structure of the domains. We analysed the biochemical properties of BM 06.022 to obtain some information about the structure of kringle 2 and the protease as compared with the structure of these domains in the intact t-PA molecule. The kinetic analysis of the amidolytic activity of BM 06.022 and CHO-t-PA yielded similar values for kcat (13.9 s-1 and 11.4 s-1 for the single chain forms and 33.9 s-1 and 27.1 s-1 for the two chain forms of BM 06.022 and CHO-t-PA, respectively) and for Km (2.5 mM and 2.1 mM for the single chains forms and 0.5 mM and 0.3 mM for the two chain forms of BM 06.022 and CHO-t-PA, respectively). BM 06.022 and CHO-t-PA have the same plasminogenolytic activity in the absence of CNBr fragments of fibrinogen. However, BM 06.022 has a lower plasminogenolytic activity in the presence of CNBr fragments of fibrinogen and a lower affinity to fibrin as compared with CHO-t-PA. The affinity of BM 06.022 for fibrin is completely suppressed by 0.3 mM epsilon-aminocaproic acid, while the intact t-PA has a residual affinity of approximately 30%. The dissociation constants for the interaction with the lysine analogue epsilon-aminocaproic acid are 0.10 mM and 0.09 mM for BM 06.022 and the intact t-PA, respectively. Furthermore, BM 06.022 and CHO-t-PA are inhibited by PAI-1 in a similar manner.
Amidohydrolases↗
[Individual laboratory control of anticoagulant therapy].
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Anticoagulants↗
[What is the cost of laparoscopic cholecystectomy?].
After laparoscopic cholecystectomy (LC) has replaced open cholecystectomy (OC) to a large extent as standard method in the operative treatment of cholecystolithiasis the question of costs and economics raises. To evaluate this question the data of 50 patients who underwent elective LC were analysed in a retrospective study and compared with the data of 50 patients who were cholecystectomized using the open technique. The median of in-hospital stay was 6 (3-15) days for LC and 10 (3-33) days for OC. The median of time of working-disability was 14 (2-35) days for LC and 21 (2-56) days for OC. Total cost (median) of 3788 (2637-8101) DM for LC compared to 4509 (2041-15218) DM for OC. The median of hospital income was 2790 (1395-6975) DM for the LC-group and 4650 (1395-15346) DM for the OC-group. Due to the shorter in-hospital stay of LC-patients this method causes a microeconomical loss for the hospital compared to OC. Macroeconomically LC represents a benefit because of shorter working-disability.
Adult↗
The atp1 and atp2 operons of the cyanobacterium Synechocystis sp. PCC 6803.
The two operons atp1 and atp2, encoding the subunits of the F0F1 ATP-synthase, have been cloned and sequenced from the cyanobacterium Synechocystis sp. PCC 6803. The organization of the different genes in the operons have been found to resemble that of the cyanobacteria Synechococcus sp. PCC 6301 and Anabaena sp. PCC 7120. The Synechocystis F0F1 ATP-synthase has nine subunits. A tenth open reading frame with unknown function was detected at the 5' end of atp1, coding for a putative gene product similar to uncI in Escherichia coli. A promoter structure was inferred for the Synechocystis atp operons and compared to other known promoters of cyanobacteria. Even though the operon structure of atp1 and atp2 in Synechocystis resembles the corresponding operons of Synechococcus, the amino acid sequences of individual gene products show marked differences. Genetic distances between cyanobacterial genes and genes for ATP-synthase subunits from other species have been calculated and compiled into evolutionary trees.
Amino Acid Sequence↗
Development of a chromogenic substrate assay for the determination of hirudin in plasma.
Hirudin is a potent and specific thrombin inhibitor. Since recombinant hirudin is being considered for anticoagulant and antithrombotic therapy we developed a fast and sensitive chromogenic substrate assay for its determination in plasma. The plasma samples (20 microliters) were incubated with 1 ml reagent mixture (0.2 M Tris buffer, 0.025 M NaCl, pH 8.1, containing 0.833 M urea, 0.7 trypsin inhibitor U/ml aprotinin, 100 ng/ml Polybrene and 0.31 NIH U/ml bovine thrombin) for 1 min. Thereafter 100 microliters Chromozym TH (Tos-Gly-Pro-Arg-pNA, 1.9 mM) was added. The change in absorbance/min (delta A/min) was recorded at 405 nm. delta A/min was linear for at least 3 min. The calibration curve was linear at least up to 800 ng hirudin/ml plasma. Intra-assay and inter-assay coefficients of variation were 2.8-3.1% and 5.3-5.8% respectively. The influence of progressive thrombin inhibitors can be neglected because of the short incubation time. Plasma samples can be assayed directly if aprotinin, polybrene and urea are added to the reagent mixture.
Calibration↗
A fast photometric assay for the determination of hirudin.
Recombinant hirudin, a potent and specific thrombin inhibitor, is considered for anticoagulant therapy. Therefore we developed a fast and sensitive chromogenic assay for its determination in plasma. Samples can be assayed directly if aprotinin, Polybrene and urea are added to the reagent mixture. The influence of progressive inhibitors is excluded by a short incubation time. The samples (20 microliters) are diluted with 1 ml reagent mixture (0.2 M Tris, 0.025 M NaCl, pH 8.1, containing 0.833 M urea, 0.7 trypsin inhibitory units/ml aprotinin, 100 ng/ml Polybrene and 0.31 NIH units/ml bovine thrombin). After an incubation time of 1 min, 100 microliters Chromoyzm TH (Tos-Gly-Pro-Arg-pNA, 1.9 mM) is added. delta absorbance/min is linear at least up to 3 min. The calibration curve is linear up to at least 800 ng hirudin/ml plasma. The inter- and intraassay coefficient of variation in hirudin spiked normal plasma is below 5%. The detection limit is at 25 ng hirudin/ml. In plasma samples obtained from healthy subjects under hirudin therapy, a good correlation was found to the activated partial thromboplastin time (r = 0.89). In conclusion, we describe a fast and simple chromogenic substrate test to assay hirudin in plasma. Under assay conditions, the influence of endogenous thrombin inhibitors can be neglected.
Amino Acid Sequence↗
Effect of prolonged physical exercise on the fibrinolytic system.
The effect of a test marathon race on plasma fibrinolytic activity (FA) was studied in 16 endurance athletes before, immediately after, 3 h, and 31 h after the run. Tissue plasminogen activator (t-PA) activity increased about 31-fold immediately after the run. Similar increases were found in t-PA antigen concentration. Plasminogen activator inhibitor (PAI) was not detectable immediately after the race and was significantly decreased 3 h (P less than 0.05) and 31 h (P less than 0.01) later. B beta 15-42 peptide increased by 0.63 pmol.ml-1 (P less than 0.001), D-dimer by 68.3 ng.ml-1 (P less than 0.05). Euglobulin lysis time (ELT) was reduced from 109 to 18 min (P less than 0.001). The increased t-PA activity and t-PA antigen concentration disappeared in the course of the first 3 h after exertion. ELT also reached its pre-exercise levels at this time. Thirty-one hours after the race ELT and t-PA antigen levels were slightly but significantly reduced (P less than 0.05), whereas B beta 15-42 peptide remained increased (P less than 0.05). t-PA activity was unchanged compared with pre-exercise values. It seems that the exercise-induced FA is mainly caused by the marked increase of t-PA antigen and t-PA activity.
Adult↗
Properties of a novel plasminogen activator (BM 06.022) produced in Escherichia coli.
Since currently available thrombolytics still show disadvantages, such as administration by infusion, occurrence of intracranial hemorrhage, major hemorrhagic complications, allergic reactions, and high price, a novel tissue plasminogen activator has been developed. BM 06.022 is a t-PA mutant produced in Escherichia coli by DNA technology. It has no oligosaccharide side-chains and comprises the kringle 2- and protease domains of t-PA. Like t-PA, the enzymatic activity of BM 06.022 can be stimulated by fibrin. However, BM 06.022 binds to neither endothelial cells nor fibrin. Despite this, BM 06.022 demonstrates the same fibrin selectivity in vivo as t-PA. Investigation of the pharmacokinetic properties in rats, rabbits, dogs, and primates reveals, depending on species, a 4.5- - 10.4-fold longer dominant half-life and 3- - 8.4-fold slower plasma clearance than t-PA (alteplase). In spite of its lower specific activity in vitro, BM 06.022 has a thrombolytic potency which is 4.6 - 11.5 times higher in vivo than that of alteplase in the rabbit model of venous thrombosis and the canine model of coronary artery thrombosis. BM 06.022 achieves reperfusion significantly more rapid than long-acting anistreplase. Therefore, because of its improved pharmacokinetic properties, BM 06.022 might be administered to infarct patients by i.v. injection in the pre-hospital phase to achieve rapid lysis. Due to its lack of fibrin- and endothelial-cell-binding, combined with retained fibrin selectivity, BM 06.022 further promises to induce fewer hemorrhagic complications than either t-PA or streptokinase.
Animals↗
CF0, the proton channel of chloroplast ATP synthase. After removal of CF1 it appears in two forms with highly different proton conductance.
The discharge of the flash-induced transmembrane voltage through the exposed proton channel, CF0, of the chloroplast ATP synthase, CF0CF1 was investigated. EDTA treatment of thylakoid membranes exposed approximately 50% of total CF0 by removal of the CF1 counterparts. This greatly accelerated the decay of the transmembrane voltage, as was apparent from electrochromic-absorption changes of intrinsic pigments and by pH-indicating-absorption changes of added dyes. Two decay processes were discernible, one rapid with a typical half-decay time of 2 ms, and a slower one with a half-decay time variable between 20-100 ms. Both were sensitive to CF0 inhibitors, but only the rapid decay process was also inhibited by added CF1. CF1 was effective in surprisingly small amounts, which were significantly lower than those previously removed by EDTA treatment. This finding corroborated our previous conclusion that the rapid decay of the transmembrane voltage was attributable to only a few high-conductance channels among many CF0 molecules, typically in the order of one channel/CF1-depleted EDTA vesicle. Inhibition of photophosphorylation in control thylakoids was measured as function of the concentration of CF0 inhibitors. It was compared with the inhibition of proton conduction through exposed CF0 in EDTA vesicles. Photophosphorylation and proton conduction by the high-conductance form of CF0 were inhibited by the same low inhibitor concentrations. This suggested that the high-conducting form of CF0 with a time-averaged single-channel conductance of 1 pS [Lill, H., Althoff, G. & Junge, W. (1987) J. Membrane Biol. 98, 69-78] represented the proton channel in the integral enzyme, which acted as a low-impedance access from the thylakoid lumen to the coupling site in CF0CF1. The slow decay process was attributed to a majority of low-conductance CF0 channels, i.e. about 50 molecules/vesicle. The conductance of these channels was more than 100-fold lower and they did not compete with the very few highly conducting channels for rebinding of added CF1. The low proton conduction of the majority of exposed CF0 molecules, possibly due to a structural rearrangement, may be protecting the thylakoid membrane against rapid energy dissipation caused by accidental loss of CF1. It may also explain the low single-channel conductance of bacterial F0 reported in the literature.
Binding Sites↗
Delta subunit of chloroplast coupling factor 1 inhibits proton leakage through coupling factor O.
The ATP synthase of chloroplasts consists of a proton-conducting portion, CF0, and a catalytic portion, CF1. The smaller subunits of CF1, in particular delta, may play a key role in the coupling of proton transport to ATP synthesis. Purified subunit delta, when added to partially CF1-depleted thylakoid membranes, can restore photophosphorylation (Engelbrecht, S., and Junge, W. (1987) Eur. J. Biochem. 172, 213-218). We report here that it does so by blocking proton conduction through CF0. Thylakoids were CF1-depleted by incubation in hypoosmolar NaCl/EDTA solutions. Variation of the NaCl concentrations and of the incubation times not only changed the overall degree of CF1 depletion but also the subunit composition of solubilized CF1, namely CF1 containing delta and CF1(-delta). This was quantified by immunoelectrophoresis and by fast protein liquid chromatography. Proton conduction was measured by flash spectrophotometry by using standard electrochromic and pH-indicating absorption changes. The removal of integral CF1 was correlated with high electric conductance of thylakoid membranes, an increased extent of rapid proton leakage, and loss of ATP synthesis activity, which exceeded the percentual loss of CF1. The removal of predominantly CF1(-delta) resulted in comparatively lesser effects on the loss of ATP synthesis and on the extent and velocity of proton leakage. On the same line, addition of integral CF1 and of purified delta diminished the electric leak in CF1-depleted thylakoids. Both approaches, the controlled removal of CF1 and CF1(-delta), respectively, and addition of delta and CF1 showed that delta can act as a "stopcock" to the exposed proton channel CF0.
Adenosine Triphosphate↗
Beta-adrenergic receptor mediated release of tissue plasminogen activator in anaesthetized dogs.
Drugs like epinephrine or isoproterenol can enhance fibrinolytic activity of blood. It is still a matter of debate whether this effect can be totally or only partially blocked by beta-receptor blockers. We have developed a dog model for ex vivo measurement of the fibrinolytic activity using a spectrophotometric assay employing human plasminogen, chromogenic plasmin substrate and human fibrinogen-BrCN digests for the stimulation of t-PA. After i.v. administration of isoproterenol the fibrinolytic activity increased, but this could be seen only in the presence of fibrinogen-BrCN digest in the test system. This suggests that isoproterenol caused higher levels of dog t-PA. Pretreatment with the beta-blocker propranolol completely blocked the increase in t-PA.
Anesthesia↗