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  • 1
    Language: English
    In: The Journal of organic chemistry, 21 January 2011, Vol.76(2), pp.512-22
    Description: We report the details of the total synthesis of natural and non-natural jatropha-5,12-dienes. The successful tactic for the assembly of the strained trans-bicyclo[10.3.0]pentadecane scaffold employed a B-alkyl Suzuki-Miyaura cross-coupling for the formation of the C5/C6 double bond and a ring-closing metathesis for the construction of the C12/C13 double bond. The key step of the synthesis of the cyclopentane fragment, an uncatalyzed intramolecular carbonyl-ene reaction, was studied computationally by DFT calculations. The members of the ensemble of synthetic natural and non-natural jatrophanes were subsequently examined as modulators for the ABCB1, ABCG2, and ABCC1 efflux proteins, which are associated with multidrug resistance in cancer chemotherapy.
    Keywords: Antineoplastic Agents -- Chemical Synthesis ; Biological Products -- Chemical Synthesis ; Cross-Linking Reagents -- Chemistry ; Cyclopentanes -- Chemistry ; Diterpenes -- Chemical Synthesis ; Drug Resistance, Multiple -- Drug Effects ; Euphorbia -- Chemistry ; Lung Neoplasms -- Drug Therapy ; Plant Extracts -- Chemical Synthesis
    ISSN: 00223263
    E-ISSN: 1520-6904
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  • 2
    Language: English
    In: Bioorganic & Medicinal Chemistry Letters, 01 November 2012, Vol.22(21), pp.6766-6769
    Description: We investigated several 2-phenylquinazolines with different substitutions at position 4 for their BCRP inhibition. Compounds with phenyl ring attached via an amine-containing linker at position 4 were found to be potent inhibitors of BCRP. In general compounds with substitution of phenyl ring at position 4 were found to have higher inhibitory effect, compound being the most potent and selective towards BCRP.
    Keywords: Bcrp ; Inhibitors ; Multidrug Resistance ; Quinazolines ; Hoechst 33342 ; Medicine ; Chemistry ; Anatomy & Physiology
    ISSN: 0960-894X
    E-ISSN: 1464-3405
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  • 3
    Language: English
    In: Bioorganic & Medicinal Chemistry, 15 December 2013, Vol.21(24), pp.7858-7873
    Description: Chemotherapy is one of the major forms of cancer treatment. Unfortunately, tumors are prone to multidrug resistance leading to failure of treatment. Breast cancer resistance protein (BCRP), the second member of ABC transporter subfamily G, has been found to play a major role in drug efflux and hence multidrug resistance. Until now, very few potent and selective BCRP inhibitors like Ko143 have been identified. In the search for more potent and selective BCRP inhibitors, we synthesized and investigated a series of differently substituted quinazoline compounds. Several variations at positions 2, 4, 6 and 7 of the quinazoline scaffold were carried out to develop a structure–activity-relationship analysis for these compounds. It was found that compounds bearing a phenyl substituent at position 2 of the 4-anilinoquinazoline scaffold were most potent. On the aniline ring at position 4 of the quinazoline moiety substituents like NO , CN, CF led to very high BCRP inhibition potencies. The most potent compounds were further investigated for their intrinsic cytotoxicity and their ability to reverse the multidrug resistance. Compound , an anilinoquinazoline bearing a phenyl ring at position 2 and -nitro substitution on the 4-anilino ring, was found to have the highest therapeutic ratio. The most active compounds from each variation were also investigated for their effect on BCRP expression. It was found that compound has no significant effect on BCRP expression, while compound decreased the surface BCRP expression. The only difference in the two compounds was the presence of a 3,4-dimethoxyphenyl ring in compound instead of phenyl substitution at position 2 of the quinazoline moiety. From the study of all target compounds, compound was the most prominent compound having inhibitory potency even higher than Ko143, the most potent BCRP inhibitor known. Compound was also found to be selective towards BCRP with a very high therapeutic ratio.
    Keywords: ATP Binding Cassette (ABC) Transporter ; Breast Cancer Resistance Protein (Bcrp/Abcg2) ; Multidrug Resistance ; Quinazolines ; Hoechst 33342 Accumulation Assay ; Medicine ; Chemistry ; Anatomy & Physiology
    ISSN: 0968-0896
    E-ISSN: 1464-3391
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  • 4
    Language: English
    In: Bioorganic & Medicinal Chemistry, 01 January 2012, Vol.20(1), pp.346-355
    Description: Breast cancer resistance protein (BCRP/ABCG2) belongs to the ATP binding cassette family of transport proteins. BCRP has been found to confer multidrug resistance in cancer cells. A strategy to overcome resistance due to BCRP overexpression is the investigation of potent and specific BCRP inhibitors. The aim of the current study was to investigate different multi-substituted chalcones for their BCRP inhibition. We synthesized chalcones and benzochalcones with different substituents (viz. OH, OCH , Cl) on ring A and B of the chalcone structure. All synthesized compounds were tested by Hoechst 33342 accumulation assay to determine inhibitory activity in MCF-7 MX and MDCK cells expressing BCRP. The compounds were also screened for their P-glycoprotein (P-gp) and Multidrug resistance-associated protein 1 (MRP1) inhibitory activity in the calcein AM accumulation assay and were found to be selective towards inhibition of BCRP. Substituents at position 2′ and 4′ on chalcone ring A were found to be essential for activity; additionally there was a great influence of substituents on ring B. Presence of 3,4-dimethoxy substitution on ring B was found to be optimal, while presence of 2- and 4-chloro substitution also showed a positive effect on BCRP inhibition.
    Keywords: Chalcones ; Multidrug Resistance ; Breast Cancer Resistance Protein ; Inhibitors ; Hoechst 33342 Assay ; Medicine ; Chemistry ; Anatomy & Physiology
    ISSN: 0968-0896
    E-ISSN: 1464-3391
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  • 5
    In: Journal of the American Geriatrics Society, September 2013, Vol.61(9), pp.1508-1514
    Description: Byline: Emily Reeve, Michael D. Wiese, Ivanka Hendrix, Michael S. Roberts, Sepehr Shakib Keywords: elderly; polypharmacy; deprescribing; potentially inappropriate medications; discontinuation Objectives To capture people's attitudes, beliefs, and experiences regarding the number of medications they are taking and their feelings about stopping medications. Design Administration of a validated questionnaire. Setting Multidisciplinary ambulatory consulting service at the Royal Adelaide Hospital. Participants Participants were individuals aged 18 and older (median 71.5) taking at least one regular prescription medication; 100 participants completed all items of the questionnaire, 65 of whom were aged 65 and older. Measurements Participants were administered the 15-item Patients' Attitudes Towards Deprescribing (PATD) questionnaire. Results Participants were taking an average of 10 different prescription and nonprescription (including complementary), regular and as-needed medications. More than 60% felt that they were taking a "large number" of medications, and 92% stated that they would be willing to stop one or more of their current medications if possible. Number of regular medications, age, and number of medical conditions were not found to be correlated with willingness to stop a medication. The findings were similar in older and younger participants. Conclusion This study has shown that a cohort of mostly older adults were largely accepting of a trial of cessation of medication(s) that their prescriber deemed to be no longer required. Because few factors were associated with willingness to cease medications, all patients should be individually evaluated for deprescribing. CAPTION(S): Figure S1. Distribution of propensity score for Intervention and Control participants. Table S1. List of Exclusionary Comorbidities, ICD-9 Codes, and CPT Codes. Table S2. Control county selection criteria. Table S3. ICD-9-CM diagnosis codes for disease classification of participants. Table S4. Regression specifications. Table S1. Comparison of frailty components for Men in the Cardiovascular Health Study (CHS) and Men in the Osteoporotic Fractures in Men (MrOS) Study.
Table S2. Association between Cystatin C and frailty status among 1,257 Subjects with eGFRCr 〉60 ml/min/1.73 m2. Table S1. Adjusted* odds ratios (95% CI) from logistic regression analyses for cognitive impairment (lowest 10% performance within ethnic group) on individual cognitive tests per 10 mmHg increment in each listed blood pressure measurement.
    Keywords: Elderly ; Polypharmacy ; Deprescribing ; Potentially Inappropriate Medications ; Discontinuation
    ISSN: 0002-8614
    E-ISSN: 1532-5415
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  • 6
    Language: English
    In: Bioorganic & Medicinal Chemistry Letters, 2010, Vol.20(1), pp.180-183
    Description: Compound is a novel lead for the design of new and potent BCRP modulators. From our modulator library an interesting inhibitor of breast cancer resistance protein (BCRP) was identified. Due to its high inhibitory potency, this compound may serve as a promising novel lead for the design of new and potent modulators. This adds a new structural class to the few known highly active BCRP inhibitors.
    Keywords: Abcg2 ; Inhibitors ; Multidrug Resistance ; Bcrp ; Hoechst 33342 ; Pheophorbide A ; Medicine ; Chemistry ; Anatomy & Physiology
    ISSN: 0960-894X
    E-ISSN: 1464-3405
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  • 7
    Language: English
    In: The Journal of organic chemistry, 06 October 2017, Vol.82(19), pp.10504-10522
    Description: The synthesis of the A-B-cis,B-C-trans-annulated cyclohepta[e]hydrindane core of a gagunin E analogue is reported in detail. The tricarbocyclic scaffold was assembled starting from an easily accessible A ring building block by a (4 + 2)-cycloaddition for annulation of the B ring. A ring-closing metathesis served for construction of the seven-membered C ring. The angular methyl groups were attached by electrophilic cyclopropanation-ring opening. A library based on the most active lead compound was made accessible by esterification of the terpenols with commercially available acids. A transannular etherification reaction gave access to tetracyclic derivatives of the synthetic inhibitors. The members of the compound library of non-natural homoverrucosanoid-derived esters were examined as modulators of the membrane transporter proteins ABCB1 (P-gp), ABCG2 (BCRP), and ABCC1 (MRP1), which are involved in the formation of multidrug resistance (MDR) in cancer chemotherapy.
    Keywords: Antineoplastic Agents -- Pharmacology ; Drug Resistance, Multiple -- Drug Effects ; Esters -- Pharmacology ; Polycyclic Compounds -- Pharmacology
    ISSN: 00223263
    E-ISSN: 1520-6904
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  • 8
    Language: English
    In: BBA - Biomembranes, November 2014, Vol.1838(11), pp.2929-2938
    Description: Breast Cancer Resistance Protein (BCRP/ABCG2) belongs to the superfamily of ATP binding cassette (ABC) transporters. Characteristic of some of these transporter proteins is the transport of a variety of structurally unrelated substances against a concentration gradient by using the energy of ATP hydrolysis. ABCG2 has been found to confer multidrug resistance (MDR) in cancer cells. Several anticancer drugs have been identified as ABCG2 substrates including mitoxantrone, etoposide and topotecan. As inhibition of the transporter is one of the strategies to overcome MDR, we have synthesized and tested several 3-methoxy flavones and investigated them for their ABCG2 inhibition. Among these, pentamethyl quercetin (compound ) and pentamethyl morin (compound ) were found to be fluorescent and hence screened for their possible transport by ABCG2 using confocal microscopy. This study showed that pentamethyl quercetin was far less accumulated in ABCG2 overexpressing MDCK BCRP cells as compared to MDCK sensitive cells, suggesting possible efflux of this compound by ABCG2. Pentamethyl morin showed no visible difference in both cell lines. Based on this observation, we studied several other fluorescent 3-methoxy flavones for their accumulation in ABCG2 overexpressing cells. To confirm the substrate or inhibitor nature of the tested compounds, these compounds were further investigated by ATPase assay. If stimulation of the transporter ATPase activity is detected, one can conclude that the compound is probably a transported substrate. All compounds except pentamethyl morin (compound ) and tetramethyl quercetin (compound ) were found to stimulate ATPase activity pointing to possible substrates despite being potent inhibitors of ABCG2.
    Keywords: Abcg2 ; Bcrp ; Flavonoids ; Substrate ; Atpase ; Chemistry
    ISSN: 0005-2736
    E-ISSN: 1879-2642
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  • 9
    In: Medical Journal of Australia, July 2011, Vol.195(2), pp.69-73
    Description: To determine the Australian native ant species associated with ant sting anaphylaxis, geographical distribution of allergic reactions, and feasibility of diagnostic venom‐specific IgE (sIgE) testing. Descriptive clinical, entomological and immunological study of Australians with a history of ant sting anaphylaxis, recruited in 2006–2007 through media exposure and referrals from allergy practices and emergency physicians nationwide. We interviewed participants, collected entomological specimens, prepared reference venom extracts, and conducted serum sIgE testing against ant venom panels relevant to the species found in each geographical region. Reaction causation attributed using a combination of ant identification and sIgE testing. 376 participants reported 735 systemic reactions. Of 299 participants for whom a cause was determined, 265 (89%; 95% CI, 84%–92%) had reacted clinically to species and 34 (11%; 95% CI, 8%–16%) to green‐head ant (). Of those with reactions to species, 176 reacted to jack jumper ant ( species complex), 18 to other jumper ants (15 to , three to ) and 56 to a variety of bulldog ants, with some participants reacting to more than one type of bulldog ant. Variable serological cross‐reactivity between bulldog ant species was observed, and sera from patients with bulldog ant allergy were all positive to one or more venoms extracted from , and . Four main groups of Australian ants cause anaphylaxis. Serum sIgE testing enhances the accuracy of diagnosis and is a prerequisite for administering species‐specific venom immunotherapy.
    Keywords: Emergency Medicine ; Immune System Diseases
    ISSN: 0025-729X
    E-ISSN: 1326-5377
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  • 10
    Language: English
    In: Drugs & Aging, 2012, Vol.29(11), pp.925-926
    Keywords: Female–Prevention & Control ; Humans–Statistics & Numerical Data ; Inappropriate Prescribing–Methods ; Male–Therapeutic Use ; Patient Education As Topic–Therapeutic Use ; Proton Pump Inhibitors–Therapeutic Use ; Proton Pump Inhibitors;
    ISSN: 1170-229X
    E-ISSN: 1179-1969
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