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Intraindividual Comparison of 18F-PSMA-1007 with Renally Excreted PSMA Ligands for PSMA PET Imaging in Patients with Relapsed Prostate Cancer.
Dietlein, F, Kobe, C, Hohberg, M, Zlatopolskiy, BD, Krapf, P, Endepols, H, Täger, P, Hammes, J, Heidenreich, A, Persigehl, T, et al
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2020;(5):729-734
Abstract
18F-prostate-specific membrane antigen (PSMA)-1007 is excreted mainly through the liver. We benchmarked the performance of 18F-PSMA-1007 against 3 renally excreted PSMA tracers. Methods: Among 668 patients, we selected 27 in whom PET/CT results obtained with 68Ga-PSMA-11, 18F-DCFPyL (2-(3-(1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid), or 18F-JK-PSMA-7 (JK, Juelich-Koeln) were interpreted as equivocal or negative or as oligometastatic disease (PET-1). Within 3 wk, a second PET scan with 18F-PSMA-1007 was performed (PET-2). The confidence in the interpretation of PSMA-positive locoregional findings was scored on a 5-point scale, first in routine diagnostics (reader 1) and then by an independent second evaluation (reader 2). Discordant PSMA-positive skeletal findings were examined by contrast-enhanced MRI. Results: For both readers, 18F-PSMA-1007 facilitated the interpretability of 27 locoregional lesions. In PET-2, the clinical readout led to a significantly lower number of equivocal locoregional lesions (P = 0.024), and reader 2 reported a significantly higher rate of suspected lesions that were falsely interpreted as probably benign in PET-1 (P = 0.023). Exclusively in PET-2, we observed a total of 15 PSMA-positive spots in the bone marrow of 6 patients (22%). None of the 15 discordant spots had a morphologic correlate on the corresponding CT scan or on the subsequent MRI scan. Thus, 18F-PSMA-1007 exhibits a significantly higher rate of unspecific medullary spots (P = 0.0006). Conclusion:18F-PSMA-1007 may increase confidence in interpreting small locoregional lesions adjacent to the urinary tract but may decrease the interpretability of skeletal lesions.
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Effect of His6-tag Position on the Expression and Properties of Phenylacetone Monooxygenase from Thermobifida fusca.
Parshin, PD, Pometun, AA, Martysuk, UA, Kleymenov, SY, Atroshenko, DL, Pometun, EV, Savin, SS, Tishkov, VI
Biochemistry. Biokhimiia. 2020;(5):575-582
Abstract
Phenylacetone monooxygenase (EC 1.14.13.92, PAMО) catalyzes oxidation of ketones with molecular oxygen and NADPH with the formation of esters. PAMО is a promising enzyme for biotechnological processes. In this work, we generated genetic constructs coding for PAMO from Thermobifida fusca, containing N- or C-terminal His6-tags (PAMO N and PAMO C, respectively), as well as PAMO L with the His6-tag attached to the enzyme C-terminus via a 19-a.a. spacer. All PAMO variants were expressed as catalytically active proteins in Escherichia coli BL21(DE3) cells; however, the expression level of PAMO N was 3 to 5 times higher than for the other two enzymes. The catalytic constants (kcat) of PAMO C and PAMO L were similar to that published for PAMO L produced in a different expression system; the catalytic constant for PAMO N was slightly lower (by 15%). The values of Michaelis constants with NADPH for all PAMО variants were in agreement within the published data for PAMO L (within the experimental error); however, the KM for benzylacetone was several times higher. Thermal inactivation studies and differential scanning calorimetry demonstrated that the thermal stability of PAMO N was 3 to 4 times higher compared to that of the enzymes with the C-terminal His6-tag.
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Charges' interaction in polyelectrolyte (nano)complexing of His6-OPH with peptides: Unpredictable results due to imperfect or useless concept?
Aslanli, A, Lyagin, I, Efremenko, E
International journal of biological macromolecules. 2019;:368-376
Abstract
Quorum Quenching (QQ) enzymes can be used to prevent bacterial antibiotic resistance by degradation of Quorum Sensing (QS) signaling molecules, for example N-acyl homoserine lactones (AHLs). This paper is aimed at the in silico investigation of the possible combinations of hexahistidine-tagged organophosphorus hydrolase (His6-OPH) with antimicrobial peptides (AMPs) to improve the enzyme activity and, promisingly, stability. This shall help creating a nanosized QQ preparation capable to hydrolyze different AHLs and possessing an antimicrobial activity. To achieve this, binding of AMPs and His6-OPH was simulated by molecular docking, and various interaction parameters (affinity, charge, contact area, etc.) of the generated models were studied. Both anionic and cationic polypeptides were shown to bind to His6-OPH with negligible effect of their charge, that significantly deviates from the charge-to-charge interaction concept. The (nano)complexes of His6-OPH with Indolicidin and Temporin A appear to have the most balanced characteristics which were issued experimentally also.
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Stimuli-Responsive, Pentapeptide, Nanofiber Hydrogel for Tissue Engineering.
Tang, JD, Mura, C, Lampe, KJ
Journal of the American Chemical Society. 2019;(12):4886-4899
Abstract
Short peptides are uniquely versatile building blocks for self-assembly. Supramolecular peptide assemblies can be used to construct functional hydrogel biomaterials-an attractive approach for neural tissue engineering. Here, we report a new class of short, five-residue peptides that form hydrogels with nanofiber structures. Using rheology and spectroscopy, we describe how sequence variations, pH, and peptide concentration alter the mechanical properties of our pentapeptide hydrogels. We find that this class of seven unmodified peptides forms robust hydrogels from 0.2-20 kPa at low weight percent (less than 3 wt %) in cell culture media and undergoes shear-thinning and rapid self-healing. The peptides self-assemble into long fibrils with sequence-dependent fibrillar morphologies. These fibrils exhibit a unique twisted ribbon shape, as visualized by transmission electron microscopy (TEM) and Cryo-EM imaging, with diameters in the low tens of nanometers and periodicities similar to amyloid fibrils. Experimental gelation behavior corroborates our molecular dynamics simulations, which demonstrate peptide assembly behavior, an increase in β-sheet content, and patterns of variation in solvent accessibility. Our rapidly assembling pentapeptides for injectable delivery (RAPID) hydrogels are syringe-injectable and support cytocompatible encapsulation of oligodendrocyte progenitor cells (OPCs), as well as their proliferation and three-dimensional process extension. Furthermore, RAPID gels protect OPCs from mechanical membrane disruption and acute loss of viability when ejected from a syringe needle, highlighting the protective capability of the hydrogel as potential cell carriers for transplantation therapies. The tunable mechanical and structural properties of these supramolecular assemblies are shown to be permissive to cell expansion and remodeling, making this hydrogel system suitable as an injectable material for cell delivery and tissue engineering applications.
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5.
Advances in primary mitochondrial myopathies.
de Barcelos, IP, Emmanuele, V, Hirano, M
Current opinion in neurology. 2019;(5):715-721
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Abstract
PURPOSE OF REVIEW Although mitochondrial diseases impose a significant functional limitation in the lives of patients, treatment of these conditions has been limited to dietary supplements, exercise, and physical therapy. In the past few years, however, translational medicine has identified potential therapies for these patients. RECENT FINDINGS For patients with primary mitochondrial myopathies, preliminary phase I and II multicenter clinical trials of elamipretide indicate safety and suggest improvement in 6-min walk test (6MWT) performance and fatigue scales. In addition, for thymidine kinase 2-deficient (TK2d) myopathy, compassionate-use oral administration of pyrimidine deoxynucleosides have shown preliminary evidence of safety and efficacy in survival of early onset patients and motor functions relative to historical TK2d controls. SUMMARY The prospects of effective therapies that improve the quality of life for patients with mitochondrial myopathy underscore the necessity for definitive diagnoses natural history studies for better understanding of the diseases.
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Chelating Surfaces for Oriented Human Serum Albumin Molecules.
Tuccitto, N, Messina, GML, Li-Destri, G, Wietecka, A, Marletta, G
Langmuir : the ACS journal of surfaces and colloids. 2019;(9):3354-3362
Abstract
Protein immobilization in a specific conformation or orientation at an interface is influenced by specific interactions with the outer layer of the surface. A strategy to build-up a complex construct which is able to orient protein molecules, based on metal-cation chelation processes, is reported. The proposed methodology implies the formation of a mercaptoundecanoic acid monolayer on a gold surface that is activated to attach covalently the tripeptide glycyl-l-histidyl-l-lysine (GHK) on the surface, whose sites are then employed to chelate copper ions, providing a selective platform for the orientation of human serum albumin (HSA) molecules. The protein adsorption process on GHK and GHK-Cu(II)-complex surfaces was monitored by the in situ quartz crystal microbalance with dissipation monitoring (QCM-D) and force spectroscopy technique. The changes in frequency and dissipation factor as well as the D- f plots from QCM-D measurements help to characterize the changes in the protein conformation and are confirmed by force curve spectroscopy results. An improved kinetic model, based on random sequential adsorption with variable protein footprints, has been developed to predict and simulate the experimentally found HSA average surface coverage onto the GHK and GHK-Cu(II)-complex surfaces.
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Control of AtaA-mediated bacterial immobilization by casein hydrolysates.
Ohara, Y, Yoshimoto, S, Hori, K
Journal of bioscience and bioengineering. 2019;(5):544-550
Abstract
Acinetobacter sp. Tol 5 exhibits an autoagglutinating nature and high adhesiveness to various abiotic surfaces through its bacterionanofiber protein AtaA. We have developed new bacterial immobilization methods utilizing the high adhesiveness of AtaA. We previously reported that salt is essential for the adhesiveness of AtaA. In the current study, we unexpectedly found that Tol 5 cells were not immobilized onto polyurethane foam support during growth in LB medium although AtaA was properly expressed and displayed onto the cell surface. The adhesion of Tol 5 resting cells was not affected by sugars but drastically inhibited by yeast extract and casein hydrolysates such as tryptone and casamino acids technical grade (CA-T). Some amino acids, which are major components of CA-T, partially inhibited the adhesion of Tol 5 cells. Experimental results suggested that oligopeptides might effectively inhibit the cell adhesion. Immobilized cells onto the support through AtaA were detached in CA-T solution. Also, the detached cells could be re-immobilized onto the support without impairing of their adhesiveness by replacing CA-T solution to a basal salt medium. Microscopic observation revealed that breaking of AtaA-mediated cell-cell interaction is important for the detachment of Tol 5 cells from the support. CA-T also inhibited AtaA-mediated autoagglutination and dispersed cell clumps through AtaA. This is the first report on adhesion inhibitors against AtaA and suggests that casein hydrolysates like CA-T would be a powerful tool for controlling AtaA-mediated bacterial immobilization.
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Arginine Biosynthesis Modulates Pyoverdine Production and Release in Pseudomonas putida as Part of the Mechanism of Adaptation to Oxidative Stress.
Barrientos-Moreno, L, Molina-Henares, MA, Pastor-García, M, Ramos-González, MI, Espinosa-Urgel, M
Journal of bacteriology. 2019;(22)
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Abstract
Iron is essential for most life forms. Under iron-limiting conditions, many bacteria produce and release siderophores-molecules with high affinity for iron-which are then transported into the cell in their iron-bound form, allowing incorporation of the metal into a wide range of cellular processes. However, free iron can also be a source of reactive oxygen species that cause DNA, protein, and lipid damage. Not surprisingly, iron capture is finely regulated and linked to oxidative-stress responses. Here, we provide evidence indicating that in the plant-beneficial bacterium Pseudomonas putida KT2440, the amino acid l-arginine is a metabolic connector between iron capture and oxidative stress. Mutants defective in arginine biosynthesis show reduced production and release of the siderophore pyoverdine and altered expression of certain pyoverdine-related genes, resulting in higher sensitivity to iron limitation. Although the amino acid is not part of the siderophore side chain, addition of exogenous l-arginine restores pyoverdine release in the mutants, and increased pyoverdine production is observed in the presence of polyamines (agmatine and spermidine), of which arginine is a precursor. Spermidine also has a protective role against hydrogen peroxide in P. putida, whereas defects in arginine and pyoverdine synthesis result in increased production of reactive oxygen species.IMPORTANCE The results of this study show a previously unidentified connection between arginine metabolism, siderophore turnover, and oxidative stress in Pseudomonas putida Although the precise molecular mechanisms involved have yet to be characterized in full detail, our data are consistent with a model in which arginine biosynthesis and the derived pathway leading to polyamine production function as a homeostasis mechanism that helps maintain the balance between iron uptake and oxidative-stress response systems.
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Pretreatment PET/CT imaging of angiogenesis based on 18F-RGD tracer uptake may predict antiangiogenic response.
Li, L, Ma, L, Shang, D, Liu, Z, Yu, Q, Wang, S, Teng, X, Zhang, Q, Hu, X, Zhao, W, et al
European journal of nuclear medicine and molecular imaging. 2019;(4):940-947
Abstract
PURPOSE To explore the relationship between metabolic uptake of the 18F-ALF-NOTA-PRGD2 (18F-RGD) tracer on positron emission tomography/computerized tomography (PET/CT) and the antiangiogenic effect of apatinib in patients with solid malignancies. MATERIALS AND PATIENTS Patients with measurable lesions scheduled for second- or third-line single-agent therapy with apatinib were eligible for this prospective clinical trial. All patients underwent 18F-RGD PET/CT examination before the start of treatment. Standardized uptake values (SUVs) of contoured tumor lesions were computed and compared using independent sample t-tests or the Mann-Whitney U test. Receiver-operating characteristic (ROC) curve analysis was used to determine accuracy in predicting response. Survival curves were compared using the Kaplan-Meier method. RESULTS Of 38 patients who consented to study participation, 25 patients with 42 measurable lesions met the criteria for inclusion in this response assessment analysis. The median follow-up time was 3 months (range, 1-10 months), and the median progression-free survival (PFS) was 3 months (95% confidence interval, 1.04-4.96). The SUVpeak and SUVmean were significantly higher in responding tumors than in non-responding tumors (4.98 ± 2.34 vs 3.59 ± 1.44, p = 0.048; 3.71 ± 1.15 vs 2.95 ± 0.49, P = 0.036). SUVmax did not differ between responding tumors and non-responding tumors (6.58 ± 3.33 vs 4.74 ± 1.83, P = 0.078). An exploratory ROC curve analysis indicated that SUVmean [area under the ROC curve (AUC) = 0.700] was a better parameter than SUVpeak (AUC = 0.689) for predicting response. Using a threshold value of 3.82, high SUVmean at baseline was associated with improved PFS (5.0 vs. 3.4 months, log-rank P = 0.036). CONCLUSION 18F-RGD uptake on PET/CT imaging pretreatment may predict the response to antiangiogenic therapy, with higher 18F-RGD uptake in tumors predicting a better response to apatinib therapy.
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Sex steroids mediate discrete effects on HDL cholesterol efflux capacity and particle concentration in healthy men.
Rubinow, KB, Vaisar, T, Chao, JH, Heinecke, JW, Page, ST
Journal of clinical lipidology. 2018;(4):1072-1082
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Abstract
BACKGROUND Exogenous testosterone decreases serum concentrations of high-density lipoprotein cholesterol (HDL-C) in men, but whether this alters cardiovascular risk is uncertain. OBJECTIVE To investigate the effects of testosterone and estradiol on HDL particle concentration (HDL-Pima) and metrics of HDL function. METHODS We enrolled 53 healthy men, 19 to 55 years of age, in a double-blinded, placebo-controlled, randomized trial. Subjects were rendered medically castrate using the GnRH receptor antagonist acyline and administered either (1) placebo gel, (2) low-dose transdermal testosterone gel (1.62%, 1.25 g), (3) full replacement dose testosterone gel (1.62%, 5 g) or (4) full replacement dose testosterone gel together with an aromatase inhibitor for 4 weeks. At baseline and end of treatment, serum HDL total macrophage and ABCA1-specific cholesterol efflux capacity (CEC), HDL-Pima and size, and HDL protein composition were determined. RESULTS Significant differences in serum HDL-C were observed with treatment across groups (P = .01 in overall repeated measures ANOVA), with increases in HDL-C seen after both complete and partial testosterone deprivation. Medical castration increased total HDL-Pima (median [interquartile range] 19.1 [1.8] nmol/L at baseline vs 21.3 [3.1] nmol/L at week 4, P = .006). However, corresponding changes in total macrophage CEC and ABCA1-specific CEC were not observed. Change in serum 17β-estradiol concentration correlated with change in total macrophage CEC (β = 0.33 per 10 pg/mL change in serum 17β-estradiol, P = .03). CONCLUSIONS Testosterone deprivation in healthy men leads to a dissociation between changes in serum HDL-C and HDL CEC. Changes in serum HDL-C specifically due to testosterone exposure may not reflect changes in HDL function.