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A new heterocycles compound: Liver cancer treatment combined with high intensity focused ultrasound. J INDIAN CHEM SOC 2022. [DOI: 10.1016/j.jics.2022.100484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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2
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Sáez-Peñataro J, Avendaño-Solá C, González-Juanatey J. Clinical considerations on the posology of direct oral anticoagulants. Rev Clin Esp 2016. [DOI: 10.1016/j.rceng.2016.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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3
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Consideraciones clínicas sobre la posología de los anticoagulantes orales de acción directa. Rev Clin Esp 2016; 216:384-392. [DOI: 10.1016/j.rce.2016.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 03/29/2016] [Accepted: 04/11/2016] [Indexed: 11/20/2022]
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Boonyawat K, Wang L, Lazo-Langner A, Kovacs MJ, Yeo E, Schnurr T, Schulman S, Crowther MA. The effect of low-dose oral vitamin K supplementation on INR stability in patients receiving warfarin. A randomised trial. Thromb Haemost 2016; 116:480-5. [PMID: 27346552 DOI: 10.1160/th16-04-0320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 05/19/2016] [Indexed: 11/05/2022]
Abstract
The anticoagulant effect of warfarin is influenced by variations in vitamin K intake. Concomitant use of daily low-dose oral vitamin K (LDVK) and warfarin may improve INR stability. We hypothesise that administration of LDVK improves INR control. To test this hypothesis we performed a multi-centre, placebo-controlled, randomised trial conducted at four university-affiliated hospitals in Canada. Patients on chronic warfarin therapy received oral vitamin K 150 mcg daily or a matching placebo for a total of six months after a one-month run in period. The primary outcome was a comparison of mean time in therapeutic range (TTR) in LDVK and placebo group during a six-month-period. The secondary outcome was number of INR excursions <1.5 or >4.5. There was no significant difference in the final TTR between the two groups (65.1 % vs 66 %, p =0.8). Mean TTR in both LDVK and placebo groups were statistically increased compared with prior to the study. The number of INR excursions were significantly decreased in the LDVK group (9.4 % and 5.4 %, absolute difference [pre- minus post-] = 4 %, 95 % CI, 2 to 6 %, p-value <0.001). We conclude that LDVK administration did not increase mean TTR, but did decrease the number of INR excursions. The observed improvement in mean TTR in both groups suggests that more attentive monitoring of warfarin therapy, rather than LDVK, was responsible for the improvement in TTR observed. The reduced excursions suggest that LDVK did reduce extreme INR variation. The study is registered at www.ClinicalTrial.gov# NCT00990158.
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Affiliation(s)
- Kochawan Boonyawat
- Kochawan Boonyawat, Department of Medicine, Ramathibodi Hospital, 270 Rama 6th Rd, Rachathewi, Bangkok, Thailand 10400, E-mail:
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Lopopolo G, de Candia M, Panza L, Romano MR, Lograno MD, Campagna F, Altomare C. β-D-Glucosyl Conjugates of Highly Potent Inhibitors of Blood Coagulation Factor Xa Bearing 2-Chorothiophene as a P1 Motif. ChemMedChem 2012; 7:1669-77. [DOI: 10.1002/cmdc.201200224] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/11/2012] [Indexed: 11/08/2022]
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Peng HT, Blostein MD, Shek PN. Characterization of In Vitro Hemostatic Peptide Effects by Thromboelastography. Clin Appl Thromb Hemost 2011; 18:27-34. [DOI: 10.1177/1076029611412371] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In this study, we validated a thromboelastography (TEG) method to evaluate the hemostatic effects of 3 peptides. The first peptide is an ideal amphipathic peptide composed of 22 leucine and lysine in a ratio of 2:1. At a very low concentration, the peptide had a procoagulant effect shown by decreases in reaction time (R) and coagulation time (K) but was impaired by a decrease in maximum amplitude (MA). At higher concentrations, the peptide had an anticoagulant effect. The α angle was minimally affected by the peptide. The second peptide is melittin derived from bee venom. Melittin showed procoagulant effects reflected by a decrease in clotting time but led to lower MA. The third peptide derived from fibrinogen γ chain promoted hemostasis only at an optimal concentration and became anticoagulant at a higher concentration. The hemostatic mechanisms of each peptide were discussed. Our study would facilitate further development of peptides for either hemorrhage control or thrombosis treatment.
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Affiliation(s)
- Henry T. Peng
- Defence Research and Development Canada, Toronto, Ontario, Canada
| | - Mark D. Blostein
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | - Pang N. Shek
- Defence Research and Development Canada, Toronto, Ontario, Canada
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Li J, Lu CH, Yao QH, Zhang XL, Liu JJ, Yang HH, Chen GN. A graphene oxide platform for energy transfer-based detection of protease activity. Biosens Bioelectron 2011; 26:3894-9. [PMID: 21458253 DOI: 10.1016/j.bios.2011.03.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/25/2011] [Accepted: 03/02/2011] [Indexed: 12/12/2022]
Abstract
In this article, we report the first graphene oxide (GO)-based platform to detect protease activity in a homogeneous real-time format. In designing such GO-based biosensing platform, we put a protease substrate peptide as the linker between the energy transfer donor (QDs) and the energy transfer acceptor (GO) to fabricate the GO-peptide-QDs nanoprobes. In the nanoprobes, the photoluminescence (PL) of donor QDs was strongly quenched due to the presence of GO in close proximity. The protease activity caused modulation in the efficiency of the energy transfer between the acceptor and donor, thus enabling the protease assay. The proposed GO-based platform is easy to assemble and has little background interference, yet still give superior sensitivity and rapid response. Furthermore, this GO-QDs architecture can serve as a universal platform by simply changing the types of peptide sequences for the different proteases. In this work, GO-based platform has been successfully applied in the sensitive detection of matrix metalloproteinase (MMP) and thrombin activity. Meanwhile, we also utilized this platform to monitor the protease inhibitor. The proposed GO-based platform is anticipated to find applications in the diagnosis of protease-related diseases and screening of potential drugs with high sensitivity in a high-throughput way.
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Affiliation(s)
- Juan Li
- The Key Lab of Analysis and Detection Technology for Food Safety of the MOE, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350002, PR China
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8
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Abstract
BACKGROUND The activation of coagulation mechanisms plays a central role in the pathogenesis of acute coronary syndromes (ACS). Administration of unfractionated heparin (UFH) and low molecular weight heparins (LMWH), agents preventing the progression of thrombus formation, is a crucial therapeutic strategy. However, some limitations related to their use have recently stimulated the development of new synthetic agents. OBJECTIVES To evaluate the clinical efficacy and safety of factor Xa inhibitors for treatment of ACS compared to UFH or LMWH. SEARCH STRATEGY We searched the Cochrane Central Register of Controlled Trials (CENTRAL) of the Cochrane Library (Issue 1, 2008), PubMed, EMBASE and LILACS as well as the publications from International Congresses and the reference lists of the selected studies in December 2008. SELECTION CRITERIA We used randomized controlled trials (RCTs) comparing factor Xa inhibitors to UFH or LMWH during the course of ACS. Outcome measures included all-cause mortality, myocardial infarction, re-infarction, ischemia recurrence, and adverse events. DATA COLLECTION AND ANALYSIS The selection, quality assessment and data extraction of the included trials were done independently by two authors and disagreements were resolved by consensus. Data were analysed by the use of risk ratio (RR) with 95% confidence interval (CI), and the numbers needed to treat (NNT) were reported as needed. MAIN RESULTS A total of four RCTs involving 27,976 subjects were included. Fondaparinux was the only factor Xa inhibitor identified in our included RCTs. Fondaparinux appeared to be related to a lower risk in all-cause mortality at 90 to 180 days (RR 0.89; 95% CI 0.81 to 0.97), especially in the group where enoxaparin (a LMWH) was the control drug. Fondaparinux was also associated with a lower risk in major and minor bleeding at 30 days compared to enoxaparin (RR 0.63, 95% CI 0.55 to 0.73; RR 0.34, 95% CI 0.28 to 0.43, respectively), but not when compared to UFHs (RR 1.41; 95% CI 0.49 to 4.10; RR 0.70, 95% CI 0.14 to 3.39 respectively). AUTHORS' CONCLUSIONS The therapeutic efficacy of factor Xa inhibitors in ACS seemed to be related to a reduced risk in all-cause mortality at 90 to 180 days, with a better safety profile than enoxaparin in terms of reduce incidence of major and minor bleeding.
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Affiliation(s)
- Viviana Brito
- Coronary Care Unit, Hospital de Clinicas, Universidad de Buenos Aires, Avenida Cordoba 2351 Piso Sala 1, Ciudad Autonoma Buenos Aires, Capital Federal, Argentina
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Emerging Anticoagulants and Heparin-Induced Thrombocytopenia: Indirect and Direct Factor Xa Inhibitors and Oral Thrombin Inhibitors. ACTA ACUST UNITED AC 2010. [DOI: 10.3109/9781420045093.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Gresham C, Levine M, Ruha AM. Case files of the Medical Toxicology Fellowship at Banner Good Samaritan Medical Center in Phoenix, AZ: a non-warfarin anticoagulant overdose. J Med Toxicol 2010; 5:242-9. [PMID: 19876861 DOI: 10.1007/bf03178275] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
A 50-year-old man presented to the emergency department (ED) following an overdose of his "blood thinners." The patient had become increasingly depressed over financial concerns, prompting a suicide attempt. He declined to provide any details regarding his current medications or his past medical history. A review of the computerized medical record, however, revealed he had a Factor V Leiden mutation with multiple venothromboembolic events. He previously had an inferior vena cava filter placed, and had received tissue plasminogen activator (tPA) for a cerebrovascular accident. A toxicology consult was obtained in the ED.
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Affiliation(s)
- Chip Gresham
- Department of Medical Toxicology, Banner Good Samaritan Medical Center, Banner Poison Control Center, Phoenix, AZ 85006, USA
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de Candia M, Lopopolo G, Altomare C. Novel factor Xa inhibitors: a patent review. Expert Opin Ther Pat 2010; 19:1535-80. [PMID: 19743898 DOI: 10.1517/13543770903270532] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD New oral anticoagulants with favorable safety profiles and fixed doses are required for the management of thromboembolism and stroke prevention in patients with atrial fibrillation. Among them, fXa inhibitors (the so-called xabans) are attractive options that can overcome limitations (e.g., bleeding) of the current oral antithrombotic therapy. The rational design of small-molecule direct fXa inhibitors, whose importance is testified by the growing number of publications and patents recently registered, has been fully supported by the X-ray crystallography of enzyme-ligand complexes. AREAS COVERED IN THIS REVIEW Pubmed, SciFinder Scholar, ISI web of knowledge(SM), http://ep.espacenet.com/ and Google websites were used as the main sources for literature retrieving, and > 100 patents filed between 2006 and April 2009, reviewed and discussed herein, highlight the variety among the P1 and P4 moieties on suitable scaffolds. WHAT THE READER WILL GAIN The replacement of the benzamidine P1 moiety, which characterizes the first generation, with less basic bioisosteric or nonpolar neutral P1 groups led to the disclosure of numerous fXa inhibitors with high potency, selectivity and oral bioavailability. Novel selective fXa inhibitors with stable pharmacokinetics, better therapeutic windows and ease-of-use than the existing anticoagulants are currently under advanced stage clinical trials. TAKE-HOME MESSAGE Available data from Phase II and Phase III studies reflect the drive towards fXa inhibitors as potentially more effective and safer antithrombotic drugs. Their development is expected to address two major needs for anticoagulation, namely safety and ease-of-use, and to significantly affect the anticoagulant market.
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Affiliation(s)
- Modesto de Candia
- University of Bari, Dipartimento Farmaco-Chimico, Via E. Orabona 4, I-70125 Bari, Italy
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Nimjee SM, Oney S, Volovyk Z, Bompiani KM, Long SB, Hoffman M, Sullenger BA. Synergistic effect of aptamers that inhibit exosites 1 and 2 on thrombin. RNA (NEW YORK, N.Y.) 2009; 15:2105-2111. [PMID: 19846574 PMCID: PMC2779679 DOI: 10.1261/rna.1240109] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 08/13/2009] [Indexed: 05/28/2023]
Abstract
Thrombin is a multifunctional protease that plays a key role in hemostasis, thrombosis, and inflammation. Most thrombin inhibitors currently used as antithrombotic agents target thrombin's active site and inhibit all of its myriad of activities. Exosites 1 and 2 are distinct regions on the surface of thrombin that provide specificity to its proteolytic activity by mediating binding to substrates, receptors, and cofactors. Exosite 1 mediates binding and cleavage of fibrinogen, proteolytically activated receptors, and some coagulation factors, while exosite 2 mediates binding to heparin and to platelet receptor GPIb-IX-V. The crystal structures of two nucleic acid ligands bound to thrombin have been solved. Previously Padmanabhan and colleagues solved the structure of a DNA aptamer bound to exosite 1 and we reported the structure of an RNA aptamer bound to exosite 2 on thrombin. Based upon these structural studies we speculated that the two aptamers would not compete for binding to thrombin. We observe that simultaneously blocking both exosites with the aptamers leads to synergistic inhibition of thrombin-dependent platelet activation and procoagulant activity. This combination of exosite 1 and exosite 2 inhibitors may provide a particularly effective antithrombotic approach.
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Affiliation(s)
- Shahid M Nimjee
- Department of Surgery, Division of Surgical Sciences, Duke University Medical Center, Durham, North Carolina 27710, USA
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15
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de Candia M, Liantonio F, Carotti A, De Cristofaro R, Altomare C. Fluorinated Benzyloxyphenyl Piperidine-4-carboxamides with Dual Function against Thrombosis: Inhibitors of Factor Xa and Platelet Aggregation. J Med Chem 2009; 52:1018-28. [DOI: 10.1021/jm801141f] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Modesto de Candia
- Dipartimento Farmaco-chimico, University of Bari, Via Orabona 4, I-70125, Bari, Italy, Hemostasis Research Centre, Institute of Internal Medicine and Geriatrics, Catholic University School of Medicine, Largo F. Vito 1, I-00168 Rome, Italy
| | - Francesco Liantonio
- Dipartimento Farmaco-chimico, University of Bari, Via Orabona 4, I-70125, Bari, Italy, Hemostasis Research Centre, Institute of Internal Medicine and Geriatrics, Catholic University School of Medicine, Largo F. Vito 1, I-00168 Rome, Italy
| | - Andrea Carotti
- Dipartimento Farmaco-chimico, University of Bari, Via Orabona 4, I-70125, Bari, Italy, Hemostasis Research Centre, Institute of Internal Medicine and Geriatrics, Catholic University School of Medicine, Largo F. Vito 1, I-00168 Rome, Italy
| | - Raimondo De Cristofaro
- Dipartimento Farmaco-chimico, University of Bari, Via Orabona 4, I-70125, Bari, Italy, Hemostasis Research Centre, Institute of Internal Medicine and Geriatrics, Catholic University School of Medicine, Largo F. Vito 1, I-00168 Rome, Italy
| | - Cosimo Altomare
- Dipartimento Farmaco-chimico, University of Bari, Via Orabona 4, I-70125, Bari, Italy, Hemostasis Research Centre, Institute of Internal Medicine and Geriatrics, Catholic University School of Medicine, Largo F. Vito 1, I-00168 Rome, Italy
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Abstract
In contrast to older anticoagulant agents vitamin K antagonists and heparins, the new ones are directed towards a single target in general. The main characteristics of the new agents are: their site of action in the coagulation cascade and their mechanism of action which is indirect, antithrombin dependent, most often such as Fondaparinux and Idraparinux or direct such as Dabigatran, Rivaroxaban; the specificity of the new molecules, since they must not interact with other enzymes: trypsin, kallikrein, t-PA, etc...; their mode of administration parenteral and/or oral; their pharmacokinetics and their clearance frequently by the kidney (Hirudin, fondaparinux) or through hepatic metabolism (argatroban); tolerance including for all compounds the bleeding risk or an unexpected hepatic intolerance for Ximelagatran; the availability of a specific antidote and the cost of the drug; one compound is registered in France Arixtra Fondaparinux in major orthopedic surgery and in the treatment of venous thromboembolism and in prophylactic treatment in medical patients. However, the main indications of interest for these new drugs is atrial fibrillation. There is a real need in this indication and the number of patients to treat is growing with the longer life expectancy.
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Affiliation(s)
- M-M Samama
- Service d'hématologie Biologique, Hôtel-Dieu, place du Parvis Notre-Dame, F 75181 Paris Cedex 04.
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Medintz IL, Clapp AR, Brunel FM, Tiefenbrunn T, Uyeda HT, Chang EL, Deschamps JR, Dawson PE, Mattoussi H. Proteolytic activity monitored by fluorescence resonance energy transfer through quantum-dot-peptide conjugates. NATURE MATERIALS 2006; 5:581-9. [PMID: 16799548 DOI: 10.1038/nmat1676] [Citation(s) in RCA: 363] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Accepted: 05/15/2006] [Indexed: 05/10/2023]
Abstract
Proteases are enzymes that catalyse the breaking of specific peptide bonds in proteins and polypeptides. They are heavily involved in many normal biological processes as well as in diseases, including cancer, stroke and infection. In fact, proteolytic activity is sometimes used as a marker for some cancer types. Here we present luminescent quantum dot (QD) bioconjugates designed to detect proteolytic activity by fluorescence resonance energy transfer. To achieve this, we developed a modular peptide structure which allowed us to attach dye-labelled substrates for the proteases caspase-1, thrombin, collagenase and chymotrypsin to the QD surface. The fluorescence resonance energy transfer efficiency within these nanoassemblies is easily controlled, and proteolytic assays were carried out under both excess enzyme and excess substrate conditions. These assays provide quantitative data including enzymatic velocity, Michaelis-Menten kinetic parameters, and mechanisms of enzymatic inhibition. We also screened a number of inhibitory compounds against the QD-thrombin conjugate. This technology is not limited to sensing proteases, but may be amenable to monitoring other enzymatic modifications.
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Affiliation(s)
- Igor L Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900, US Naval Research Laboratory, Washington, DC 20375, USA.
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Wen PY, Schiff D, Kesari S, Drappatz J, Gigas DC, Doherty L. Medical management of patients with brain tumors. J Neurooncol 2006; 80:313-32. [PMID: 16807780 DOI: 10.1007/s11060-006-9193-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 05/03/2006] [Indexed: 10/24/2022]
Abstract
The most common medical problems in brain tumor patients include the management of seizures, peritumoral edema, medication side effects, venous thromboembolism (VTE), fatigue and cognitive dysfunction. Despite their importance, there are relatively few studies specifically addressing these issues. There is increasing evidence that brain tumor patients who have not had a seizure do not benefit from prophylactic antiepileptic medications. Patients on corticosteroids are at greater risk of Pneumocystis jerovecii pneumonia and may benefit from prophylactic therapy. There is also growing evidence suggesting that anticoagulation may be more effective than inferior vena cava IVC) filtration devices for treating VTE in brain tumor patients and the risk of hemorrhage with anticoagulation is relatively small. Low-molecular weight heparin may be more effective than coumadin. Medications such as modafinil and methylphenidate have assumed an increasing role in the treatment of fatigue, while donepezil and memantine may be helpful with memory loss.
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Affiliation(s)
- Patrick Y Wen
- Division of Neuro-Oncology, Department of Neurology, Brigham and Women's Hospital and Center for Neuro-Oncology, Dana-Farber Brigham and Women's Cancer Center, SW430D, 44 Binney Street, Boston, MA 02115, USA.
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Motlekar NA, Youan BBC. The quest for non-invasive delivery of bioactive macromolecules: a focus on heparins. J Control Release 2006; 113:91-101. [PMID: 16777255 PMCID: PMC1539865 DOI: 10.1016/j.jconrel.2006.04.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Accepted: 04/06/2006] [Indexed: 11/24/2022]
Abstract
The development of a non-invasive drug delivery system for unfractionated heparin (UFH) and low molecular weight heparins (LMWHs) has been the elusive goal of several research groups since the initial discovery of this glycosaminogylcan by McLean in 1916. After a brief update on current parenteral formulations of UFH and LMWHs, this review revisits past and current strategies intended to identify alternative routes of administration (e.g. oral, sublingual, rectal, nasal, pulmonary and transdermal). The following strategies have been used to improve the bioavailability of this bioactive macromolecule by various routes: (i) enhancement in cell-membrane permeabilization, (ii) modification of the tight-junctions, (iii) increase in lipophilicity and (iv) protection against acidic pH of the stomach. Regardless of the route of administration, a simplified unifying principle for successful non-invasive macromolecular drug delivery may be: "to reversibly overcome the biological, biophysical and biochemical barriers and to safely and efficiently improve the in vivo spatial and temporal control of the drug in order to achieve a clinically acceptable therapeutic advantage". Future macromolecular drug delivery research should embrace a more systemic approach taking into account recent advances in genomics/proteomics and nanotechnology.
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Affiliation(s)
- Nusrat A. Motlekar
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 Coulter Drive, Amarillo, TX 79106, USA
| | - Bi-Botti C. Youan
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 Coulter Drive, Amarillo, TX 79106, USA
- * Corresponding author. Tel.: +1 806 356 4015x236; fax: +1 806 354 4034. E-mail address: (B.-B.C. Youan)
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Waters EK, Morrissey JH. Restoring full biological activity to the isolated ectodomain of an integral membrane protein. Biochemistry 2006; 45:3769-74. [PMID: 16533060 PMCID: PMC2525505 DOI: 10.1021/bi052600m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Integral membrane proteins, which include many cellular effector proteins and drug targets, can be difficult to produce, purify, and manipulate. Although the isolated ectodomains of many membrane proteins can be expressed as water soluble proteins, biological activity is frequently lost when these proteins are released from the membrane surface. An example is tissue factor, the integral membrane protein that triggers the blood clotting cascade and for which membrane anchoring is essential. Its isolated ectodomain (soluble tissue factor) can be expressed with high yield in bacteria but is orders of magnitude less active than the intact, membrane-anchored protein. We now report full restoration of biological activity to the isolated tissue factor ectodomain via the engineering of a hexahistidine tag onto its C-terminus and its use in combination with membrane bilayers containing nickel-chelating lipids. When soluble tissue factor was tethered to the membrane surface via such metal-chelating lipids, it bound factor VIIa with the same high affinity as wild-type tissue factor, and the resulting factor VIIa-tissue factor complexes supported factor X activation and factor VII autoactivation with essentially wild-type enzyme kinetic constants. Furthermore, when such bilayers were immobilized onto solid supports, they efficiently captured histidine-tagged soluble tissue factor directly from crude culture supernatants, with full biological activity, obviating the need for purification or laborious membrane reconstitution procedures. This strategy is rapid, efficient, scalable, and automatable and should be applicable to other integral membrane proteins, especially those with a single transmembrane domain. Applications include high-throughput screening of mutants or drugs, flow reactors, clinical assays, and point-of-care instrumentation.
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Affiliation(s)
- Emily K Waters
- Department of Biochemistry, College of Medicine, University of Illinois, Urbana, Illinois 61801, USA
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Affiliation(s)
- Robina Matyal
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
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