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Peptide Concentration (peptide + concentration)
Kinds of Peptide Concentration Selected AbstractsEffects of immersion water temperature on whole-body fluid distribution in humansACTA PHYSIOLOGICA, Issue 1 2004J. M. Stocks Abstract Aim:, In this study, we quantified acute changes in the intracellular and extracellular fluid compartments during upright neutral- and cold-water immersion. We hypothesized that, during short-term cold immersion, fluid shifts would be wholly restricted to the extracellular space. Methods:, Seven males were immersed 30 days apart: control (33.3 ° SD 0.6 °C); and cold (18.1 ° SD 0.3 °C). Posture was controlled for 4 h prior to a 60-min seated immersion. Results:, Significant reductions in terminal oesophageal (36.9 ° ± 0.1 °,36.3 ° ± 0.1 °C) and mean skin temperatures (30.3 ° ± 0.3 °,23.0 ° ± 0.3 °C) were observed during the cold, but not the control immersion. Both immersions elicited a reduction in intracellular fluid [20.17 ± 6.02 mL kg,1 (control) vs. 22.72 ± 9.90 mL kg,1], while total body water (TBW) remained stable. However, significant plasma volume (PV) divergence was apparent between the trials at 60 min [12.5 ± 1.0% (control) vs. 6.1 ± 3.1%; P < 0.05], along with a significant haemodilution in the control state (P < 0.05). Plasma atrial natriuretic peptide concentration increased from 18.0 ± 1.6 to 58.7 ± 15.1 ng L,1 (P < 0.05) during cold immersion, consistent with its role in PV regulation. We observed that, regardless of the direction of the PV change, both upright immersions elicited reductions in intracellular fluid. Conclusion:, These observations have two implications. First, one cannot assume that PV changes reflect those of the entire extracellular compartment. Second, since immersion also increases interstitial fluid pressure, fluid leaving the interstitium must have been rapidly replaced by intracellular water. [source] An automated, sheathless capillary electrophoresis-mass spectrometry platform for discovery of biomarkers in human serumELECTROPHORESIS, Issue 7-8 2005Alexander P. Sassi Abstract A capillary electrophoresis-mass spectrometry (CE-MS) method has been developed to perform routine, automated analysis of low-molecular-weight peptides in human serum. The method incorporates transient isotachophoresis for in-line preconcentration and a sheathless electrospray interface. To evaluate the performance of the method and demonstrate the utility of the approach, an experiment was designed in which peptides were added to sera from individuals at each of two different concentrations, artificially creating two groups of samples. The CE-MS data from the serum samples were divided into separate training and test sets. A pattern-recognition/feature-selection algorithm based on support vector machines was used to select the mass-to-charge (m/z) values from the training set data that distinguished the two groups of samples from each other. The added peptides were identified correctly as the distinguishing features, and pattern recognition based on these peptides was used to assign each sample in the independent test set to its respective group. A twofold difference in peptide concentration could be detected with statistical significance (p -value < 0.0001). The accuracy of the assignment was 95%, demonstrating the utility of this technique for the discovery of patterns of biomarkers in serum. [source] IL-15-induced human DC efficiently prime melanoma-specific naive CD8+ T cells to differentiate into CTLEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2007Peter Dubsky Abstract Monocytes differentiate into dendritic cells (DC) in response to GM-CSF combined with other cytokines including IL-4 and IL-15. Here, we show that IL15-DC are efficient in priming naive CD8+ T cells to differentiate into melanoma antigen-specific cytotoxic T,lymphocytes (CTL). While both melanoma peptide-pulsed IL15-DC and IL4-DC expand high-precursor frequency MART-1-specific CD8+ T cells after two stimulations in vitro, IL15-DC require much lower peptide concentration for priming. IL15-DC are more efficient in expanding gp100-specific CD8+ T cells and can expand CD8+ T cells specific for Tyrosinase and MAGE-3. CTL primed by IL15-DC are superior in their function as demonstrated by (i),higher IFN-, secretion, (ii),higher expression of Granzyme,B and Perforin, and (iii),higher killing of allogeneic melanoma cell lines, most particularly the HLA-A*0201+ Sk-Mel-24 melanoma cells that are resistant to killing by CD8+ T cells primed with IL4-DC. Supernatants of the sonicated cells demonstrate unique expression of IL-1, IL-8 and IL-15. Therefore, membrane-bound IL-15 might contribute to enhanced priming by IL15-DC. Thus, IL-15 induces myeloid DC that are efficient in priming and maturation of melanoma antigen-specific CTL. [source] Qualitative difference between the cytotoxic T,lymphocyte responses to melanocyte antigens in melanoma and vitiligoEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2005Belinda Palermo Abstract Vitiligo is a skin disorder characterized by depigmented macules secondary to melanocyte loss. An unusual facet is its relation to melanoma: Cytotoxic T,lymphocytes directed to melanocyte antigens are found in both conditions and imply a breakdown of tolerance, yet the resulting immune reaction is the opposite. The mechanisms at the basis of these opposite effects are not known. Here, we performed a direct comparison of whole melanocyte-specific T,cell populations in the two diseases. We demonstrate that neither precursor frequencies of Melan-A/MART-1-specific T,lymphocytes nor their status of activation differ significantly. However, by using a tetramer-based T,cell receptor down-regulation assay, we documented a higher affinity of vitiligo T,cells. We calculated that the peptide concentration required for 50% of maximal receptor down-regulation differed by 6.5-fold between the two diseases. Moreover, only vitiligo T,cells were capable of efficient receptor down-regulation and IFN-, production in response to HLA-matched melanoma cells, suggesting that this difference in receptor affinity is physiologically relevant. The differences in receptor affinity and tumor reactivity were confirmed by analyzing Melan-A/MART-1-specific clones established from the two diseases. Our results suggest that the quality, and not the quantity, of the melanocyte-specific cytotoxic responses differs between the two pathologies. [source] Self-Assembling Peptide as a Potential Carrier for Hydrophobic Anticancer Drug Ellipticine: Complexation, Release and In Vitro DeliveryADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Shan Yu Fung Abstract The self-assembling peptide EAK16-II is capable of stabilizing hydrophobic compounds to form microcrystal suspensions in aqueous solution. Here, the ability of this peptide to stabilize the hydrophobic anticancer agent ellipticine is investigated. The formation of peptide-ellipticine suspensions is monitored with time until equilibrium is reached. The equilibration time is found to be dependent on the peptide concentration. When the peptide concentration is close to its critical aggregation concentration, the equilibration time is minimal at 5,h. With different combinations of EAK16-II and ellipticine concentrations, two molecular states (protonated or cyrstalline) of ellipticine could be stabilized. These different states of ellipticine significantly affect the release kinetics of ellipticine from the peptide-ellipticine complex into the egg phosphatidylcholine vesicles, which are used to mimic cell membranes. The transfer rate of protonated ellipticine from the complex to the vesicles is much faster than that of crystalline ellipticine. This observation may also be related to the size of the resulting complexes as revealed from the scanning electron micrographs. In addition, the complexes with protonated ellipticine are found to have a better anticancer activity against two cancer cell lines, A549 and MCF-7. This work forms the basis for studies of the peptide-ellipticine suspensions in vitro and in vivo leading to future development of self-assembling peptide-based delivery of hydrophobic anticancer drugs. [source] The shared tumor associated antigen cyclin-A2 is recognized by high-avidity T-cellsINTERNATIONAL JOURNAL OF CANCER, Issue 10 2009Eisei Kondo Abstract Cyclin-A2, a key cell cycle regulator, has been shown to be overexpressed in various types of malignancies with little expression in normal tissue. Such tumor-associated genes potentially are useful targets for cancer immunotherapy. However, high-avidity cyclin-specific T cells are considered to be thymically deleted. We identified at least one nonameric HLA-A*0201 binding cyclin-A2 epitope by a reverse immunology approach. Using a highly efficient T-cell expansion system that is based on CD40-activated B (CD40-B) cells as sole antigen-presenting cells we successfully generated cyclin-A2 specific CTL from HLA-A*0201+ donors. Interestingly, high-avidity cyclin-A2 specific CTL lines, which recognized peptide-pulsed and antigen expressing target cells, were indeed generated by stimulation with CD40-B cells when pulsed with low concentrations of peptide, whereas CD40-B cells pulsed at saturating concentrations could only induce low-avidity CTL, which recognized peptide-pulsed target cells only. One high-avidity CTL line was subcloned and CTL clones, whose peptide concentration required for half-maximal lysis were less than 1 nM, could lyse cyclin-A2 expressing tumor cells. Taken together, cyclin A2 is an attractive candidate for immune intervention in a significant number of cancer patients and high-avidity T cells can be readily generated using CD40-B cells as antigen-presenting cells. © 2009 UICC [source] Hyper osmolality does not modulate natriuretic peptide concentration in patients after coronary artery surgeryACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2009E. L. HONKONEN Background: The heart secretes natriuretic peptides (NPs) in response to myocardial stretch. Measuring NP concentrations is a helpful tool in guiding treatment. It has been suggested that sodium ion and hyperosmolality could affect NP excretion. If this is true, peri-operative NP measurements could be inconsistent when hypertonic solutions are used. With different osmolalities but equal volumes of hydroxyethyl starch (HES) , and hypertonic saline (HS) , infusions, this double-blinded study tested the hypothesis that osmolality modulates the excretion of NPs. Methods: Fifty coronary surgery patients were randomized to receive within 30 min 4 ml/kg either HS or HES post-operatively. Samples for analysis of atrial NP (ANP), brain NP (BNP), plasma and urine sodium and osmolality and urine oxygen tension were obtained before and 60 min after starting the infusions and on the first post-operative morning. The haemodynamic parameters were measured at the same time points. Results: Plasma osmolality and sodium increased only in the HS group. Changes in plasma BNP and ANP levels did not differ between the groups (P=0.212 and 0.356). There were no correlations between NP levels and osmolality or sodium at any time point. In the HS group, urine volume was higher (3295 vs. 2644 ml; P<0.05) and the need for furosemide treatment was less (0.4 vs. 3.8 mg; P<0.01) than in the HES group. Conclusions: The absence of effects of plasma sodium content or hyperosmolality on NP release validates the value of NPs as a biomarker in peri-operative patients. [source] Preparation, characterization, and binding profile of molecularly imprinted hydrogels for the peptide hepcidinJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2010Vincenzo Abbate Abstract Molecularly imprinted hydrogels for the capture of the peptide hormone hepcidin were prepared by water-in-oil (w/o) suspension polymerization under mild conditions. Spherical and relatively uniformly sized gel beads were routinely obtained after optimization of the synthetic methodology. The polymers were analyzed by Fourier transform infrared spectroscopy, optical microscopy, and scanning electron microscopy. Although the imprinted materials exhibited higher affinity towards the epitope template (hepcidin N -terminus) than their corresponding blank polymers, the full-length target peptide was found strongly bound to all the hydrogels tested. However, by using whole fluorescent hepcidin as the print species, the imprinting effect was more pronounced. Moreover, bovine serum albumin did not bind to the poly N -isopropylacrylamide (PNIPAm)-based polymers. Thus, polymeric "sponges" for biomacromolecules with size-exclusion effect were developed, useful for peptide concentration, immobilization and/or purification from serum samples. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1721,1731, 2010 [source] N-terminal pro B-type natriuretic peptide and left ventricular diameter independently predict mortality in dogs with mitral valve diseaseJOURNAL OF SMALL ANIMAL PRACTICE, Issue 2 2010W. Moonarmart Objectives: To determine whether natriuretic peptide concentrations would predict all cause mortality in dogs with degenerative mitral valve disease. Methods: One hundred dogs with naturally occurring degenerative mitral valve disease were prospectively recruited for this longitudinal study. Analysis of outcome was undertaken for 73 dogs for which the outcome was known. Dogs underwent physical examination, electrocardiography and echocardiography. Natriuretic peptide concentrations were measured by Enzyme-linked immunosorbent assay. The ability of natriuretic peptide concentrations, clinical, electrocardiographic and echocardiographic data, to predict all cause mortality was determined using univariable and multivariable Cox proportional hazards analyses. Results: Thirty dogs died during the period of follow-up. Two variables were independently predictive of all cause mortality; these were the normalised left ventricular end-diastolic diameter and the N-terminal pro B-type natriuretic peptide concentration. An increase of the left ventricular end-diastolic diameter by 0.1 increased the hazard of all cause mortality by 20% (95% confidence interval: 4 to 37%, P=0.01) and a 100 pmol/l increase in N-terminal pro B-type natriuretic peptide increased the hazard by 7% (95 confidence interval: 2 to 11%, P=0.003). Clinical Significance: N-terminal pro B-type natriuretic peptide concentration and left ventricular end-diastolic diameter are significantly and independently predictive of all cause mortality in dogs with degenerative mitral valve disease. [source] Neurohormonal and Circulatory Effects of Short-Term Treatment with Enalapril and Quinapril in Dogs with Asymptomatic Mitral RegurgitationJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2005Sophia Gry Moesgaard The aim of the study was to compare the effect of 2 angiotensin-converting enzyme (ACE) inhibitors on neurohormonal and circulatory variables in Cavalier King Charles Spaniels (CKCSs) with asymptomatic mitral regurgitation (MR). Ten CKCSs with mild to severe untreated MR were treated with 2 ACE inhibitors, quinapril and enalapril (each at 0.5 mg/kg PO q24h for 7 days), in a double-blind, crossover study with a washout period of 7 days between treatments. Blood samples were drawn and echocardiography was performed on days 0, 7, 14, and 21. Both treatments reduced ACE activity (P < .001) and increased renin activity (P < .001) and atrial natriuretic peptide concentration (P < .005). The ACE inhibitors had no effect on the concentrations of nitrate and nitrite (NOx) or asymmetric dimethylarginine (ADMA). On day 0, a lower NOx concentration (P= .02) was found in samples taken in the clinic as compared to samples taken in the homes of the dogs. Quinapril caused a significant reduction in more variables that reflect the severity of MR (eg, jet size and left ventricular end diastolic diameter) than did enalapril. However, in terms of specific variables, no significant difference was identified between the effects of the 2 treatments on MR. These results suggest that ACE inhibitors do not affect NOx and ADMA concentrations in asymptomatic dogs, but exercise, stress, or some combination may influence NOx concentrations in these dogs. [source] In Vitro Toxicity towards Kiwifruit Pollen of the Antimicrobial Peptides Magainins 1 and 2PLANT BIOLOGY, Issue 6 2007A. M. Speranza Abstract: In vitro toxicity of the antimicrobial peptides (AMPs) magainin 1 and 2 to a higher plant organism, i.e., the bicellular male gametophyte of Actinidia deliciosa (kiwifruit), is investigated. Heavy damage to the plasma membrane, the primary cellular target of the peptides, was rapidly induced: in as few as 15 min, from 70 to nearly 100 % of pollen grains were rendered unviable by 20 ,M magainin 1 or 2, respectively. Therefore, kiwifruit pollen sensitivity to natural magainins seemed to be higher if compared to the sensitivity of other pollen species towards magainin 2 amide or synthetic magainin analogues. Strong dose-dependent inhibitory effects on kiwifruit pollen performance were registered: as for magainin 1, the EC50 at 120 min varied from 14.0 (germination) to 15.8 ,M (tube elongation). The inhibitory effect was much greater when administering magainin 1 to elongating tubes rather than to ungerminated pollen grains. The two peptides differentially affected kiwifruit pollen, in line with the previously documented greater activity of magainin 2 in other cell systems. Furthermore, 20 ,M magainin 1-treated pollen grains took on a shrivelled shape within 30 min of incubation, an increasingly widespread effect with higher peptide concentration. At the ultrastructural level, both protoplast shrinkage and striking organelle alterations were evident, including chromatin condensation, swelling and loss of mitochondrial cristae, dilation of rough endoplasmic reticulum cisternae, and vacuolization of cytoplasm. To our knowledge, similar alterations in animal or plant cells treated with AMPs have not been described yet. [source] Rapid and specific high-performance liquid chromatography for the in vitro quantification of d -Lys6,GnRH in a microemulsion-type formulation in the presence of peptide oxidation productsBIOMEDICAL CHROMATOGRAPHY, Issue 2 2010Alexandra P. Kafka Abstract A high-performance liquid chromatography (HPLC) method for assay of d -Lys6,GnRH contained in a microemulsion-type formulation is described. The peptide is extracted from the microemulsion matrix and quantified using a two-step gradient method. Separation from microemulsion compounds and potential peptide oxidation products was achieved on a Jupiter C18 column at 40°C, using a gradient of 10,35% CH3CN for peptide elution. The correlation of peak intensity measured at 220 nm and peptide concentration was linear over the range 2.5,60 µg/mL with a correlation coefficient of 0.9997 and a y -intercept not significantly different from zero (p > 0.05). Intraday and interday variability of the assay was less than 5% for multiple injections of samples containing 7.5, 30 and 60 µg/mL. The lower limit of quantitation was calculated to be 0.38 µg/mL, and the lower limit of detection was 0.13 µg/mL. The assay was applied to samples that were stressed under physiological conditions (37°C, pH 7.4) over 4 days. Three degradation peaks were well resolved from the parent peptide, demonstrating the selectivity of the assay. Off-line MALDI TOF mass spectrometry was applied to identify these degradation species as oxidation products of the peptide. Copyright © 2009 John Wiley & Sons, Ltd. [source] Secondary conformation of short lysine- and leucine-rich peptides assessed by optical spectroscopies: Effect of chain length, concentration, solvent, and timeBIOPOLYMERS, Issue 1 2006Belén Hernández Abstract Solution secondary structures of three synthetic cationic peptides, currently used in antisense oligonucleotide delivery into living cells, have been analyzed by means of circular dichroism (CD) and Raman scattering in different buffers as a function of concentration and time. All three peptides are of minimalist conception, i.e., formed by only two types of amino acids (leucine: L and lysine: K). Two of these peptides contain 15 aminoacids: Nter - KLLKLLLKLLLKLLK (L10K5), Nter -KLKLKLKLKLKLKLK (L7K8), and the third one has only 9 residues: Nter -KLKLKLKLK (L4K5). The conformational behavior of the 15-mers in pure water differs considerably one from another. Although both of them are initially disordered in the 50,350 ,M range, L10K5 gradually undergoes a disordered to , -helix transition for molecular concentrations above 100 ,M. In all other solvents used, L10K5 adopts a stable , -helical conformation. In methanol and methanol/Tris mixture, nonnative , -helices can be induced in both KL-alternating peptides, i.e., L7K8 and L4K5. However, in major cases and with a time delay depending on peptide concentration, , -like structures can be gradually formed in both solutions. In PBS and methanol/PBS mixture, the tendency for L7K8 and L4K5 is to form structures belonging to , -family. A discussion has been undertaken on the effect of counterions as well as their nature in the stabilization of ordered structures in both KL-alternating peptides. © 2005 Wiley Periodicals, Inc. Biopolymers 81: 8,19, 2006 This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Ortho-aminobenzoic acid-labeled bradykinins in interaction with lipid vesicles: Fluorescence studyBIOPOLYMERS, Issue 5 2002R. F. Turchiello Abstract The peptide hormone bradykinin (BK) (Arg1 -Pro2 -Pro3 -Gly4 -Phe5 -Ser6 -Pro7 -Phe8 -Arg9) and its shorter homolog BK1,5 (Arg1 -Pro2 -Pro3 -Gly4 -Phe5) were labeled with the extrinsic fluorescent probe ortho -aminobenzoic acid (Abz) bound to the N-terminal and amidated in the C-terminal carboxyl group (Abz-BK-NH2 and Abz-BK1,5 -NH2). The fragment des-Arg9 -BK was synthesized with the Abz fluorescent probe attached to the 3-amino group of 2,3-amino propionic acid (DAP), which positioned the Abz group at the C-terminal side of BK sequence, constituting the peptide des-Arg9 -BK-DAP(Abz)-NH2. The spectral characteristics of the probe were similar in the three peptides, and their fluorescent properties were monitored to study the interaction of the peptides with anionic vesicles of dimyristoylphosphatidylglycerol (DMPG). Time-resolved fluorescence experiments showed that the fluorescence decay of the peptides was best described by double-exponential kinetics, with mean lifetimes values around 8.0 ns in buffer pH 7.4 that increased about 10% in the presence of DMPG vesicles. About a 10-fold increase, compared with the values in aqueous solution, was observed in the steady-state anisotropy in the presence of vesicles. A similar increase was also observed for the rotational correlation times obtained from time-resolved anisotropy decay profiles, and related to the overall tumbling of the peptides. Equilibrium binding constants for the peptide,lipid interaction were examined monitoring anisotropy values in titration experiments and the electrostatic effects were evaluated through Gouy,Chapman potential calculations. Without corrections for electrostatic effects, the labeled fragment Abz-BK1,5 -NH2 presented the major affinity for DMPG vesicles. Corrections for the changes in peptide concentration due to electrostatic interactions suggested higher affinity of the BK fragments to the hydrophobic phase of the bilayer. © 2002 Wiley Periodicals, Inc. Biopolymers 65: 336,346, 2002 [source] Assessment of CD8 involvement in T,cell clone avidity by direct measurement of HLA-A2/Mage3 complex density using a high-affinity TCR like monoclonal antibodyEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2005Karine Bernardeau Abstract Peptide affinity for MHC molecules determines the number of MHC/peptide complexes stabilized at the cell surface in in vitro tests or in vaccination protocols. We isolated a high affinity monoclonal antibody specific for the HLA-A2/Mage3 complex that enables an equilibrium binding assay to be performed on T2 cell line loaded with a range of Mage3 peptides. Binding of Mage3 to the HLA-A2 molecule can be modeled by a standard receptor-ligand interaction characterized by an affinity constant. This model enables the measurement of the affinity of other immunogenic peptides for HLA-A2 by a competition test and the calculation of the density of complexes stabilized at the T2 cell surface for all peptide concentrations. Quantification of the HLA-A2/Mage3 complexes at target cell surfaces was used to estimate the number of complexes required to reach cytotoxicity ED50 of human T,cell clones sorted from an unprimed repertoire. We confirm with this antibody the direct relationship between clone avidity and TCR affinity, and the moderate contribution of the CD8 co-receptor in the reinforcement of TCR-MHC/peptide contact. Nevertheless, CD8 plays a critical role in the amplification of the specific signal to establish an efficient T,cell response at low specific complex densities found in physiological situations. [source] Comparison of the aggregation properties, secondary structure and apoptotic effects of wild-type, Flemish and Dutch N-terminally truncated amyloid , peptidesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2001N. Demeester Abstract The Dutch (E22Q) and Flemish (A21G) mutations in the ,APP region of the amyloid precursor protein (APP) are associated with familial forms of Alzheimer dementia. However, patients with these mutations express substantially different clinical phenotypes. Therefore, secondary structure and cytotoxic effects of the three A,(12,42) variants [wild-type (WT), Dutch and Flemish] were tested. At a concentration of 5 µm the aggregation of these peptides followed the order: A,(1,42) WT > A,(12,42) WT > A,(12,42) Flemish >,A,(12,42) Dutch. The stability of the secondary structure of these peptides upon decreasing the trifluoroethanol (TFE) concentration in the buffer was followed by circular dichroism measurements. WT peptides progressively lost their ,-helical structure; this change occurred faster for both the Flemish and Dutch peptides, and at higher percentages of TFE in the buffer, and was accompanied by an increase in ,-sheet and random coil content. Apoptosis was induced in neuronal cells by the A,(12,42) WT and Flemish peptides at concentrations as low as 1,5 µm, as evidenced by propidium iodide (PI) staining, DNA laddering and caspase-3 activity measurements. Even when longer incubation times and higher peptide concentrations were applied the N-truncated Dutch peptide did not induce apoptosis. Apoptosis induced by the full length A,(1,42) peptide was weaker than that induced by its N-truncated variant. These data suggest that N-truncation enhanced the cytotoxic effects of A, WT and Flemish peptides, which may play a role in the accelerated progression of dementia. [source] Circulating EM66 is a highly sensitive marker for the diagnosis and follow-up of pheochromocytomaINTERNATIONAL JOURNAL OF CANCER, Issue 8 2006Johann Guillemot Abstract We have previously demonstrated that measurement of tissue concentration of the novel secretogranin II-derived peptide EM66 may help to discriminate between benign and malignant pheochromocytomas. The aim of the present study was to characterize EM66 in plasma and urine of healthy volunteers and pheochromocytoma patients, in order to further evaluate the usefulness of this peptide as a circulating marker for the management of the tumors. HPLC analysis of plasma and urine samples demonstrated that the EM66-immunoreactive material coeluted with the recombinant peptide. In healthy volunteers, plasma and urinary EM66 levels were, respectively, 2.6 (1.9,3.7) ng/ml and 2.9 (1.9,4.6) ng/ml. In patients with pheochromocytoma, plasma EM66 levels were 10-fold higher than those of healthy volunteers (26.9 (7.3,44) ng/ml), and returned to normal values after removal of the tumor. In contrast, urinary EM66 levels were not significantly different from those of healthy volunteers (3.2 (2.2,3.9) ng/ml). Measurement of total or free plasma metanephrines and 24 hr urinary metanephrines in our series of patients revealed that these tests, taken separately, are less sensitive than the EM66 determination. Pheochromocytes in primary culture secreted high levels of EM66, suggesting that the chromaffin tumor was actually responsible for the increased plasma peptide concentrations in the patients. These data indicate that EM66 is secreted in the general circulation and that elevated plasma EM66 levels are correlated with the occurrence of pheochromocytoma. Thus, EM66 is a sensitive plasma marker that should be considered as a complementary tool in the management of pheochromocytoma. © 2005 Wiley-Liss, Inc. [source] N-terminal pro B-type natriuretic peptide and left ventricular diameter independently predict mortality in dogs with mitral valve diseaseJOURNAL OF SMALL ANIMAL PRACTICE, Issue 2 2010W. Moonarmart Objectives: To determine whether natriuretic peptide concentrations would predict all cause mortality in dogs with degenerative mitral valve disease. Methods: One hundred dogs with naturally occurring degenerative mitral valve disease were prospectively recruited for this longitudinal study. Analysis of outcome was undertaken for 73 dogs for which the outcome was known. Dogs underwent physical examination, electrocardiography and echocardiography. Natriuretic peptide concentrations were measured by Enzyme-linked immunosorbent assay. The ability of natriuretic peptide concentrations, clinical, electrocardiographic and echocardiographic data, to predict all cause mortality was determined using univariable and multivariable Cox proportional hazards analyses. Results: Thirty dogs died during the period of follow-up. Two variables were independently predictive of all cause mortality; these were the normalised left ventricular end-diastolic diameter and the N-terminal pro B-type natriuretic peptide concentration. An increase of the left ventricular end-diastolic diameter by 0.1 increased the hazard of all cause mortality by 20% (95% confidence interval: 4 to 37%, P=0.01) and a 100 pmol/l increase in N-terminal pro B-type natriuretic peptide increased the hazard by 7% (95 confidence interval: 2 to 11%, P=0.003). Clinical Significance: N-terminal pro B-type natriuretic peptide concentration and left ventricular end-diastolic diameter are significantly and independently predictive of all cause mortality in dogs with degenerative mitral valve disease. [source] Plasma brain natriuretic peptide concentrations in patients with Kawasaki diseasePEDIATRICS INTERNATIONAL, Issue 3 2000Takashi Kawamura Abstract Background: Brain natriuretic peptide (BNP) is a cardiac hormone and plasma levels of it increase in patients with congestive heart failure and in those with acute myocardial infarction. Kawasaki disease (KD) is a well-known generalized vasculitis and the most prominent features of this disease are the cardiovascular manifestations, which involve the pericardium, myocardium, endocardium and coronary arteries. It was hypothesized that the plasma concentrations of BNP in patients with KD might be increased and that plasma BNP might be a useful biological marker of cardiovascular manifestations in patients with KD. Methods: Blood was obtained to measure and compare plasma BNP concentrations in the acute (n=32) and convalescent (n=35) phases of KD and in the acute phase of the patients with viral infection (n=26), which included adenovirus, influenza, measles and herpes group virus infection. In patients with KD, two-dimensional echocardiography was performed to check for pericardial effusion and coronary arterial lesions and to measure the dimensions of the left ventricle at diastole and the shortening fraction of the left ventricle (LVSF). Results: The mean plasma BNP concentration in patients with KD in the acute phase was 55.0~39.5 pg/mL, but was 6.8~7.3 pg/mL in patients with viral infection. The plasma BNP concentration in patients with KD in the acute phase was significantly higher than in patients with viral infection (P<0.0001). In 31 cases of KD, the plasma BNP concentrations were measured both in the acute and convalescent phases. The mean plasma BNP concentration in the acute phase of KD was 55.3~40.1 pg/mL and in the convalescent phase was 5.9~5.7 pg/mL. The level of plasma BNP decreased significantly in the convalescent phase (P<0.0001). The mean BNP level in patients with KD with pericardial effusion (n=8) in the acute phase was 80.3~43.4 pg/mL and that in patients without pericardial effusion (n=24) was 46.5~35.1 pg/mL. The BNP level in patients with pericardial effusion was significantly higher than that of patients without pericardial effusion (P<0.05). There was no significant correlation between the plasma concentrations of BNP in the acute phase of KD and LVSF (r=, 0.161, P=0.39, n=31). Conclusion: It was shown that the plasma BNP concentration increased in the acute phase of KD and decreased to within normal range in the convalescent phase. Further examinations are needed to clarify the mechanism by which the elevated levels of plasma BNP occur in the acute phase of KD. However, plasma BNP might be a useful biological marker of the cardiovascular manifestations in patients with KD. [source] Comparative LC-MS: A landscape of peaks and valleysPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 4 2008Antoine H. P. America Dr. Abstract Quantitative proteomics approaches using stable isotopes are well-known and used in many labs nowadays. More recently, high resolution quantitative approaches are reported that rely on LC-MS quantitation of peptide concentrations by comparing peak intensities between multiple runs obtained by continuous detection in MS mode. Characteristic of these comparative LC-MS procedures is that they do not rely on the use of stable isotopes; therefore the procedure is often referred to as label-free LC-MS. In order to compare at comprehensive scale peak intensity data in multiple LC-MS datasets, dedicated software is required for detection, matching and alignment of peaks. The high accuracy in quantitative determination of peptide abundancies provides an impressive level of detail. This approach also requires an experimental set-up where quantitative aspects of protein extraction and reproducible separation conditions need to be well controlled. In this paper we will provide insight in the critical parameters that affect the quality of the results and list an overview of the most recent software packages that are available for this procedure. [source] CSF amyloid-, 1-38 and 1-42 in FTD and AD: Biomarker performance critically depends on the detergent accessible fractionPROTEOMICS - CLINICAL APPLICATIONS, Issue 10-11 2008Mirko Bibl Dr. Abstract Cerebrospinal fluid (CSF) A,1-38, A,1-40, and A,1-42 were comparatively analyzed by amyloid-beta SDS-PAGE with Western immunoblot (A,-SDS-PAGE/immunoblot), electrochemiluminescence detection and ELISA (MSD/ELISA) in patients with Alzheimer's disease (AD, n,=,40), frontotemporal dementia (FTD, n,=,30), and other dementias (n,=,50) and nondemented disease controls (n,=,30). CSF A,-peptide concentrations were higher and selective decreases of CSF A,1-38 in FTD and A,1-42 in AD were more evident as measured after SDS-denaturizing of samples by A,-SDS-PAGE/immunoblot. The SDS-accessible pool of CSF A,1-38 and A,1-42, represented by the individual gain of A,-peptide yield using A,-SDS-PAGE/immunoblot, was reduced in both FTD and AD. Accordingly, biomarker accuracies of A,1-38 and A,1-42 for detection of FTD and AD, respectively declined as determined by MSD/ELISA. We conclude that a pool of CSF A,1-38 and A,1-42, which shows disease-specific reductions in FTD and AD, may be bound to carriers and can be released by SDS. Assessing this SDS-accessible A,-peptide pool may crucially enhance the accuracy of CSF biomarker tests. Identifying disease-specific binding properties of affected A, carriers may elucidate pathogenic aspects and open up a novel field for therapeutic approaches. [source] Closely spaced external standard: a universal method of achieving 5 ppm mass accuracy over the entire MALDI plate in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2003Eugene Moskovets Close deposition of the sample and external standard was used in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to achieve mass accuracy equivalent to that obtained with an internal standard across the entire MALDI plate. In this work, the sample and external standard were deposited by continuous deposition in separate traces, each approximately 200,,m wide. The dependence of the mass accuracy on the distance between the sample and standard traces was determined across a MALDI target plate with dimensions of 57.5,mm,×,57.0,mm by varying the gap between the traces from 100,,m to 4,mm. During acquisition, two adjacent traces were alternately irradiated with a 200-Hz laser, such that the peaks in the resulting mass spectra combined the sample and external standard. Ion suppression was not observed even when the peptide concentrations in the two traces differed by more than two orders of magnitude. The five peaks from the external standard trace were used in a four-term mass calibration of the masses of the sample trace. The average accuracy across the whole plate with this method was 5,ppm when peaks of the sample trace had signal-to-noise ratios of at least 30 and the gap between the traces was approximately 100,,m. This approach was applied to determining peptide masses of a reversed-phase liquid chromatographic (LC) separation of a tryptic digest of , -galactosidase deposited as a long serpentine trace across the MALDI plate, with accuracy comparable to that obtainable using internal calibration. In addition, the eluent from reversed-phase LC separation of a strong cation-exchange fraction containing tryptic peptides from a yeast lysate along with the closely placed external standard was deposited on the MALDI plate. The data obtained in the MS and MS/MS modes on a MALDI-TOF/TOF mass spectrometer were combined and used in database searching with MASCOT. Since the significant score is a function of mass accuracy in the MS mode, database searching with high mass accuracy reduced the number of false positives and also added peptides which otherwise would have been eliminated at lower mass accuracy (false negatives). Copyright © 2003 John Wiley & Sons, Ltd. [source] The Influence of Left Ventricle Diastolic Function on Natriuretic Peptides Levels in Patients with Atrial FibrillationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2009DAWID BAKOWSKI M.D., Ph.D. Background:The diagnosis of the impaired left ventricle (LV) diastolic function during atrial fibrillation (AF) using traditional methods is very difficult. Natriuretic peptides seem to be useful for assessment of diastolic function in patients with AF. Aim:To evaluate the influence of LV diastolic dysfunction on natriuretic peptides concentrations and to assess the diagnostic value of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in patients with AF and impaired LV diastolic function. Methods:The study included 42 patients (23 males, 19 females), aged 58.6 ± 8.2 years with nonvalvular persistent AF with preserved LV systolic function who were converted into sinus rhythm by DC cardioversion (CV) and maintained sinus rhythm for at least 30 days. Echocardiography (ECG), ANP, and BNP level measurements were taken at baseline 24 hours before CV and 24 hours and 30 days after CV. On the 30th day following CV in patients with sinus rhythm, Doppler ECG was performed to assess LV diastolic function. Results:Thirty days after CV, normal LV diastolic function in 15 patients and impaired diastolic function in 27 patients was diagnosed: 20 with impaired LV relaxation and seven with impaired LV compliance. During AF and 24 hours, and 30 days after sinus rhythm restoration, significantly higher ANP and BNP levels were observed in patients with LV diastolic dysfunction as compared to the subgroup with normal LV diastolic function. The average values of ANP during AF in patients with normal and impaired diastolic function were 167.3 ± 70.1 pg/mL and 298.7 ± 83.6 pg/mL, respectively (P < 0.001), and the average values of BNP in the above mentioned subgroups were 49.5 ± 14.7 pg/mL and 145.6 ± 49.6 pg/mL respectively (P < 0.001). While comparing the diagnostic value of both natriuretic peptides it was noted that BNP was a more specific and sensitive marker of impaired LV diastolic function. ANP value >220.7 pg/mL measured during AF identified patients with impaired LV diastolic function with 85% sensitivity and 90% specificity. BNP value >74.7 pg/mL proved 95% sensitive and 100% specific in the diagnosing of such a group. Conclusions:The increase of ANP/BNP concentration in patients with AF results not only from the presence of AF, but also reflects the impaired LV diastolic function. Natriuretic peptides, especially BNP, may be useful in diagnosing LV diastolic dysfunction in patients with AF. [source] | |||||||||||||||||||