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High Potency (high + potency)
Selected AbstractsA Vacuolar ATPase Inhibitor, FR167356, Prevents Bone Resorption in Ovariectomized Rats With High Potency and Specificity: Potential for Clinical Application,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2005Kazuaki Niikura MS Abstract FR167356, a novel inhibitor of vacuolar ATPase, has high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. FR167356 is the first compound of this nature to be tested. It has the potential to be useful for clinical application. Introduction: It has been suggested that the key issue regarding the therapeutic usefulness of V-ATPase inhibitors is their selectivity. Materials and Methods: In in vitro and in vivo studies, we compared FR167356 with other vacuolar ATPase (V-ATPase) inhibitors, bafilomycin A1 and SB242784. H+ transport by various membrane vesicles was assayed by measuring uptake of acridine orange. Inhibitory activity against in vitro bone resorption was examined by measuring the Ca2+ release from cultured calvariae. In vivo, hypercalcemia was induced by retinoic acid in thyroparathyroidectomized-ovariectomized rats, and the effect on serum Ca2+ level was assessed. Ovariectomized rats were treated with FR167356 or SB242784. One week after surgery, free deoxypyridinoline levels in 24-h urine samples, which were collected from 6 h after administration of FR167356, were measured by ELISA. After 4 weeks of treatment, plasma biochemical parameters were analyzed. BMD of the distal femur metaphysis was measured with pQCT. Histomorphometric analysis of the proximal tibias was performed. Blood gases of rats treated with FR167356 were measured with a blood gas analyzer for estimating the effect of FR167356 on in vivo function of renal V-ATPase. Results: FR167356, which is distinctly different from other V-ATPase inhibitors, has a high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. Similarly, FR167356 inhibited bone resorption in vitro when stimulated by PTH, IL-1, and IL-6. FR167356 reduced retinoic acid-induced hypercalcemia in thyroparathyroidectomized-ovariectomized rats in a dose-dependent manner. Moreover, FR167356 was shown to restore BMD of ovariectomized rats caused by the inhibition of bone resorption. Ovariectomized rats treated with FR167356 did not show adverse symptoms, whereas SB242784 caused a decrease in body weight gain and significant changes in two plasma biochemical parameters. Interestingly, FR167356 treatment did not affect blood acid-base balance; however, FR167356 inhibited renal V-ATPase with a similar potency as for osteoclast V-ATPase inhibition. Conclusion: Comparison of FR167356 with SB242784 implies that the characteristics of FR167356 may be more appropriate for clinical application as a V-ATPase inhibitor. [source] Encapsulation of Water-Insoluble Drugs in Polymer Capsules Prepared Using Mesoporous Silica Templates for Intracellular Drug DeliveryADVANCED MATERIALS, Issue 38 2010Yajun Wang Water-insoluble compounds were encapsulated in polymer capsules through mesoporous silica nanoparticle-mediated layer-by-layer assembly. The drug-loaded capsules exhibit excellent colloidal stability and high potency to colorectal cancer cells in vitro with similar cytotoxicity to the free drug dissolved in organic solvent. [source] A potent adjuvant effect of CD40 antibody attached to antigenIMMUNOLOGY, Issue 1 2003Tom A. Barr Summary There is great potential for novel vaccines based on recombinant proteins and synthetic peptides. Unfortunately these antigens often lack the immunogenicity of whole, killed pathogens used in traditional vaccines. Thus there is strong interest in the identification of immunological adjuvants with low reactogenicity, but high potency, to enhance immune responses and realize the potential of these new vaccine strategies. CD40 antibodies have been shown to have adjuvant effects when administered at very high doses. These large doses are impractical and induce a cascade of cytokine release giving rise to septic shock-like symptoms, as well as splenomegaly and polyclonal antibody production. We show here that a very small amount of CD40 antibody can exhibit potent adjuvant effects when attached to soluble antigen. The lack of detectable systemic effects indicates that this method may be a powerful and practical means of enhancing the efficacy of recombinant vaccines. [source] A Vacuolar ATPase Inhibitor, FR167356, Prevents Bone Resorption in Ovariectomized Rats With High Potency and Specificity: Potential for Clinical Application,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2005Kazuaki Niikura MS Abstract FR167356, a novel inhibitor of vacuolar ATPase, has high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. FR167356 is the first compound of this nature to be tested. It has the potential to be useful for clinical application. Introduction: It has been suggested that the key issue regarding the therapeutic usefulness of V-ATPase inhibitors is their selectivity. Materials and Methods: In in vitro and in vivo studies, we compared FR167356 with other vacuolar ATPase (V-ATPase) inhibitors, bafilomycin A1 and SB242784. H+ transport by various membrane vesicles was assayed by measuring uptake of acridine orange. Inhibitory activity against in vitro bone resorption was examined by measuring the Ca2+ release from cultured calvariae. In vivo, hypercalcemia was induced by retinoic acid in thyroparathyroidectomized-ovariectomized rats, and the effect on serum Ca2+ level was assessed. Ovariectomized rats were treated with FR167356 or SB242784. One week after surgery, free deoxypyridinoline levels in 24-h urine samples, which were collected from 6 h after administration of FR167356, were measured by ELISA. After 4 weeks of treatment, plasma biochemical parameters were analyzed. BMD of the distal femur metaphysis was measured with pQCT. Histomorphometric analysis of the proximal tibias was performed. Blood gases of rats treated with FR167356 were measured with a blood gas analyzer for estimating the effect of FR167356 on in vivo function of renal V-ATPase. Results: FR167356, which is distinctly different from other V-ATPase inhibitors, has a high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. Similarly, FR167356 inhibited bone resorption in vitro when stimulated by PTH, IL-1, and IL-6. FR167356 reduced retinoic acid-induced hypercalcemia in thyroparathyroidectomized-ovariectomized rats in a dose-dependent manner. Moreover, FR167356 was shown to restore BMD of ovariectomized rats caused by the inhibition of bone resorption. Ovariectomized rats treated with FR167356 did not show adverse symptoms, whereas SB242784 caused a decrease in body weight gain and significant changes in two plasma biochemical parameters. Interestingly, FR167356 treatment did not affect blood acid-base balance; however, FR167356 inhibited renal V-ATPase with a similar potency as for osteoclast V-ATPase inhibition. Conclusion: Comparison of FR167356 with SB242784 implies that the characteristics of FR167356 may be more appropriate for clinical application as a V-ATPase inhibitor. [source] Highly efficient synthesis of [11C]S12968 and [11C]S12967, for the in vivo imaging of the cardiac calcium channels using PETJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 7 2001Frédéric Dolle Abstract The dihydrophyridines S12968 ((,)-S11568, absolute configuration S) and S12967 ((+)-S11568, absolute configuration R), 3-ethyl 5-methyl (,/+)-2-[(2-(2-aminoethoxy)ethoxy)methyl]-4-(2,3-dichlorophenyl)-6-methyl-1,4-dihydropyridine-3,5-dicarboxylate, have both an in vitro profile of high potency and of high selectivity for the low-voltage-dependent L-type calcium channel. In this paper, the radiosynthesis of both enantiomers, S12968 and S12967, with carbon-11, a positron-emitting isotope (half-life : 20.4 min) was investigated and oriented towards the preparation of multi milliCuries of radiotracer. Typically, 130,250 mCi (4.81,9.25 GBq) of [11C]S12968 and [11C]S12967 were obtained within 30 min of radiosynthesis (HPLC purification included) with specific radioactivities ranging from 500 to 1000 mCi/,mol (18.5,37.0 GBq/,mol) using no-carrier-added [11C]methyl triflate as the alkylating agent and the appropriate, enantiomerically pure carboxylic acid precursor at 100°C for 1 min. Based on preliminary PET experiments, only the levo enantiomer S12968 ((,)-[11C]-1) appears to be suitable for myocardial PET imaging as demonstrated in vivo in beagle dogs: with S12968, 85% of the uptake of [11C]S12968 could be inhibited in pretreatment experiments and up to 70% of [11C]S12968 could be displaced. Further investigations are currently underway in order to provide an absolute quantification of ventricular calcium channels with PET. Copyright © 2001 John Wiley & Sons, Ltd. [source] Pregnenolone sulfate induces NMDA receptor dependent release of dopamine from synaptic terminals in the striatumJOURNAL OF NEUROCHEMISTRY, Issue 2 2008Matthew T. Whittaker Abstract Neuromodulators that alter the balance between lower-frequency glutamate-mediated excitatory and higher-frequency GABA-mediated inhibitory synaptic transmission are likely to participate in core mechanisms for CNS function and may contribute to the pathophysiology of neurological disorders such as schizophrenia and Alzheimer's disease. Pregnenolone sulfate (PS) modulates both ionotropic glutamate and GABAA receptor mediated synaptic transmission. The enzymes necessary for PS synthesis and degradation are found in brain tissue of several species including human and rat, and up to 5 nM PS has been detected in extracts of postmortem human brain. Here, we ask whether PS could modulate transmitter release from nerve terminals located in the striatum. Superfusion of a preparation of striatal nerve terminals comprised of mixed synaptosomes and synaptoneurosomes with brief-duration (2 min) pulses of 25 nM PS demonstrates that PS increases the release of newly accumulated [3H]dopamine ([3H]DA), but not [14C]glutamate or [3H]GABA, whereas pregnenolone is without effect. PS does not affect dopamine transporter (DAT) mediated uptake of [3H]DA, demonstrating that it specifically affects the transmitter release mechanism. The PS-induced [3H]DA release occurs via an NMDA receptor (NMDAR) dependent mechanism as it is blocked by D-2-amino-5-phosphonovaleric acid. PS modulates DA release with very high potency, significantly increasing [3H]DA release at PS concentrations as low as 25 pM. This first report of a selective direct enhancement of synaptosomal dopamine release by PS at picomolar concentrations via an NMDAR dependent mechanism raises the possibility that dopaminergic axon terminals may be a site of action for this neurosteroid. [source] Tetrapeptides, as small-sized peptidic inhibitors; synthesis and their inhibitory activity against BACE1JOURNAL OF PEPTIDE SCIENCE, Issue 6 2010Taeko Kakizawa Abstract ,-Site amyloid precursor protein cleaving enzyme 1 (BACE1) is known to be involved in the production of amyloid ,-peptide in Alzheimer's disease and is a major target for current drug design. We previously reported substrate-based peptidomimetics, KMI-compounds as potent BACE1 inhibitors. In this study, we designed and synthesized tetrapeptides as low molecular-sized inhibitors. These exhibited high potency against recombinant BACE1, with the highest IC50 value of 34.6 nM from KMI-927. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. [source] Inhibitory effects of Hibiscus sabdariffa L extract on low-density lipoprotein oxidation and anti-hyperlipidemia in fructose-fed and cholesterol-fed ratsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2004Chang-Che Chen Abstract Hibiscus sabdariffa L extract (HSE) is an aqueous extract of Hibiscus sabdariffa L flowers that is used as a local soft drink and medical herb in Taiwan. Oxidation of low-density lipoprotein (LDL) has been shown to increase the incidence of atherosclerosis. In this study, we determined the antioxidative activity of HSE on LDL oxidation by examining relative electrophoretic mobilities (REM) and thiobarbituric acid-reactive substances (TBARS). The data revealed an inhibitory effect of HSE on Cu2+ -mediated REM and TBARS. HSE exhibited a remarkable ability to reduce cholesterol degradation and ApoB fragmentation. Overall, HSE showed a high potency to inhibit the production of oxidized LDL induced by copper and, specifically, to reduce serum triglycerides in high-fructose diet (HFD) fed rats and serum cholesterol in high-cholesterol diet (HCD) fed animals. The levels of LDL and the ratio of LDL-cholesterol (LDL-C) to HDL-cholesterol (HDL-C) were reduced by HSE in both hyperlipidaemia models. Based on these findings, we suggest that HSE may be used to inhibit LDL oxidation and to prevent various types of hyperlipidaemia in HFD- or HCD-fed rats. Copyright © 2004 Society of Chemical Industry [source] Review article: current antiviral therapy of chronic hepatitis BALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2008W. S. AYOUB Summary Background, The long-term goals of therapy for chronic hepatitis B are to reduce serum HBV DNA to low or undetectable levels and ultimately reduce or prevent the development of cirrhosis and hepatocellular carcinoma. Aim, To review the current treatment of chronic hepatitis B, with a focus on diagnosis and management of resistance and active management of suboptimal responses. Methods, A systematic review of the literature, with a focus on recent guidelines, was undertaken. Results, Among the six drugs licensed for the treatment of chronic hepatitis B in the US, the preferred agents in 2008 will include entecavir, peginterferon alfa-2a, possibly telbivudine, and tenofovir following licensure. When using an oral agent, a major focus of management is on the selection of a drug with high potency and low rate of resistance, and active on-treatment management to optimize therapy. Preventing the sequelae of antiviral drug resistance and appropriate management when resistance is initially detected are also the major focus of current management. The addition of an antiviral agent that is not cross-resistant is critical to restore suppression of viral replication. Conclusions, Newer agents and modified treatment strategies, especially using combination therapy, hold promise to optimize the management of patients with chronic hepatitis B by achieving the high potency and the lowest rate of resistance. [source] Remifentanil in paediatric anaesthetic practiceANAESTHESIA, Issue 3 2009D. F. Marsh Summary Remifentanil is a synthetic opioid, first introduced into clinical practice in 1996. Its unique pharmacokinetic profile has resulted in a gradual increase in its popularity in paediatric anaesthesia. It is an opioid of high potency and rapid clearance, consequently lacking problems of accumulation. These characteristics give it a high degree of predictability and it has become an attractive choice for a wide variety of anaesthetic challenges, from premature neonates to the elderly. Neonates and infants have a higher clearance than older children and, as a result, remifentanil has additional benefits in this group. Remifentanil can be described as the only consistently predictable opioid in paediatric practice. [source] Either interleukin-12 or interferon-, can correct the dendritic cell defect induced by transforming growth factor ,1 in patients with myelomaBRITISH JOURNAL OF HAEMATOLOGY, Issue 6 2004Ross Brown Summary The poor response to immunotherapy in patients with multiple myeloma (MM) indicates that a better understanding of any defects in the immune response in these patients is required before effective therapeutic strategies can be developed. Recently we reported that high potency (CMRF44+) dendritic cells (DC) in the peripheral blood of patients with MM failed to significantly up-regulate the expression of the B7 co-stimulatory molecules, CD80 and CD86, in response to an appropriate signal from soluble trimeric human CD40 ligand. This defect was caused by transforming growth factor ,1 (TGF,1) and interleukin (IL)-10, produced by malignant plasma cells, and the defect was neutralized in vitro with anti-TGF,1. As this defect could impact on immunotherapeutic strategies and may be a major cause of the failure of recent trials, it was important to identify a more clinically useful agent that could correct the defect in vivo. In this study of 59 MM patients, the relative and absolute numbers of blood DC were only significantly decreased in patients with stage III disease and CD80 up-regulation was reduced in both stage I and stage III. It was demonstrated that both IL-12 and interferon- , neutralized the failure to stimulate CD80 up-regulation by huCD40LT in vitro. IL-12 did not cause a change in the distribution of DC subsets that were predominantly myeloid (CD11c+ and CDw123,) suggesting that there would be a predominantly T-helper cell type response. The addition of IL-12 or interferon- , to future immunotherapy trials involving these patients should be considered. [source] | |||||||||||||