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Ramirez DM, Dhiman S, Mukherjee A, Wimalasekara R, Schweizer F. Application of tobramycin benzyl ether as an antibiotic adjuvant capable of sensitizing multidrug-resistant Gram-negative bacteria to rifampicin. RSC Med Chem 2024; 15:1055-1065. [PMID: 38516601 PMCID: PMC10953491 DOI: 10.1039/d3md00602f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 02/13/2024] [Indexed: 03/23/2024] Open
Abstract
The emergence of aminoglycoside resistance has prompted the development of amphiphilic aminoglycoside derivatives which target bacterial membranes. Tobramycin and nebramine ether derivatives initially designed for this purpose were optimized and screened for their potential application as outer membrane (OM) permeabilizing adjuvants. Structure-activity relationship (SAR) studies revealed that the tobramycin benzyl ether was the most optimal OM permeabilizer, capable of potentiating rifampicin, novobiocin, vancomycin, minocycline, and doxycycline against Gram-negative bacteria. The innovative use of this compound as an adjuvant is highlighted by its ability to sensitize multidrug-resistant (MDR) Gram-negative bacteria to rifampicin and restore the susceptibility of MDR Escherichia coli to minocycline.
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Affiliation(s)
| | - Shiv Dhiman
- Department of Chemistry, University of Manitoba Winnipeg MB R3T 2N2 Canada
| | - Ayan Mukherjee
- Department of Chemistry, University of Manitoba Winnipeg MB R3T 2N2 Canada
| | - Ruwani Wimalasekara
- Department of Microbiology, University of Manitoba Winnipeg MB R3T 2N2 Canada
| | - Frank Schweizer
- Department of Chemistry, University of Manitoba Winnipeg MB R3T 2N2 Canada
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Ramirez DM, Ramirez D, Dhiman S, Arora R, Lozeau C, Arthur G, Zhanel G, Schweizer F. Guanidinylated Amphiphilic Tobramycin Derivatives Synergize with β-Lactam/β-Lactamase Inhibitor Combinations against Pseudomonas aeruginosa. ACS Infect Dis 2023; 9:1754-1768. [PMID: 37603592 DOI: 10.1021/acsinfecdis.3c00217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Carbapenem-resistant Pseudomonas aeruginosa (P. aeruginosa) was designated as a critical priority pathogen by the World Health Organization for which new therapeutic solutions are required. With the rapid dissemination of β-lactamases in P. aeruginosa, β-lactam (BL) antibiotics are used in conjunction with β-lactamase inhibitors (BLI). The effectiveness of the BL/BLI combination could be further enhanced with the inclusion of an outer membrane (OM) permeabilizer, such as aminoglycosides and aminoglycoside-based adjuvants. Thus, the development of seven tobramycin derivatives reported herein focused on improving OM permeabilizing capabilities and reducing associated toxicity. The structure-activity relationship studies emphasized the effects of the nature of the cationic group; the number of polar head groups and positive charges; and flexibility, length, and steric bulk of the hydrophobic moiety. The optimized guanidinylated tobramycin-biphenyl derivative was noncytotoxic and demonstrated the ability to potentiate ceftazidime and aztreonam monotherapy and in dual combinations with avibactam against multidrug-resistant (MDR) and β-lactamase harboring isolates of P. aeruginosa. The triple combination of ceftazidime/avibactam plus guanidinylated tobramycin-biphenyl resulted in rapid bactericidal activity within 4-8 h of treatment, demonstrating the potential application of these guanidinylated amphiphilic tobramycin derivatives in augmenting BL/BLI combinations.
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Affiliation(s)
| | - Danyel Ramirez
- Department of Chemistry, University of Manitoba, Winnipeg, MBR3T 2N2, Canada
| | - Shiv Dhiman
- Department of Chemistry, University of Manitoba, Winnipeg, MBR3T 2N2, Canada
| | - Rajat Arora
- Department of Chemistry, University of Manitoba, Winnipeg, MBR3T 2N2, Canada
| | - Christian Lozeau
- Department of Chemistry, University of Manitoba, Winnipeg, MBR3T 2N2, Canada
| | - Gilbert Arthur
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MBR3E 0W2, Canada
| | - George Zhanel
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MBR3E 0J9, Canada
| | - Frank Schweizer
- Department of Chemistry, University of Manitoba, Winnipeg, MBR3T 2N2, Canada
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MBR3E 0J9, Canada
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Dhiman S, Ramirez D, Arora R, Gandhi K, Wimalasekara R, Arthur G, Kumar A, Schweizer F. Trimeric Tobramycin/Nebramine Synergizes β-Lactam Antibiotics against Pseudomonas aeruginosa. ACS Omega 2023; 8:29359-29373. [PMID: 37599980 PMCID: PMC10433466 DOI: 10.1021/acsomega.3c02810] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/13/2023] [Indexed: 08/22/2023]
Abstract
β-Lactam antibiotics remain one of the most effective therapeutics to treat infections caused by Gram-negative bacteria (GNB). However, since ancient times, bacteria have developed multiple resistance mechanisms toward this class of antibiotics including overexpression of β-lactamases, suppression of porins, outer membrane impermeability, overexpression of efflux pumps, and target modifications. To cope with these challenges and to extend the lifetime of existing β-lactam antibiotics, β-lactamase inhibitors are combined with β-lactam antibiotics to prevent antibiotic inactivation by β-lactamases. The combination therapy of an outer membrane permeabilizer with β-lactam antibiotics is an alternative approach to overcoming bacterial resistance of β-lactams in GNB. This approach is of particular interest for pathogens with highly impermeable outer membranes like Pseudomonas aeruginosa. Previous studies have shown that outer membrane permeabilizers can be designed by linking tobramycin and nebramine units together in the form of dimers or chimeras. In this study, we developed trimeric tobramycin and nebramine-based outer membrane permeabilizers presented on a central 1,3,5-triazine framework. The resultant trimers are capable of potentiating outer membrane-impermeable antibiotics but also β-lactams and β-lactam/β-lactamase inhibitor combinations against resistant P. aeruginosa isolates. Furthermore, the microbiological susceptibility breakpoints of ceftazidime, aztreonam, and imipenem were reached by a triple combination consisting of an outer-membrane permeabilizer/β-lactam/β-lactamase inhibitor in β-lactam-resistant P. aeruginosa isolates. Overall, our results indicate that trimeric tobramycins/nebramines can rescue clinically approved β-lactams and β-lactam/β-lactamase inhibitor combinations from resistance.
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Affiliation(s)
- Shiv Dhiman
- Department
of Chemistry, Faculty of Science, University
of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Danyel Ramirez
- Department
of Chemistry, Faculty of Science, University
of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Rajat Arora
- Department
of Chemistry, Faculty of Science, University
of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Karan Gandhi
- Department
of Chemistry, Faculty of Science, University
of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Ruwani Wimalasekara
- Department
of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Gilbert Arthur
- Department
of Biochemistry and Medical Genetics, University
of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Ayush Kumar
- Department
of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Frank Schweizer
- Department
of Chemistry, Faculty of Science, University
of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
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Gandhi K, Dhiman S, Arora R, Ramirez DM, Ramirez D, Arthur G, Schweizer F. Exploring Antibiotic-Potentiating Effects of Tobramycin-Deferiprone Conjugates in Pseudomonas aeruginosa. Antibiotics (Basel) 2023; 12:1261. [PMID: 37627681 PMCID: PMC10451322 DOI: 10.3390/antibiotics12081261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/27/2023] Open
Abstract
Metal ions, including Fe3+, affect the target site binding of some antibiotics and control the porin- and siderophore-mediated uptake of antibiotics. Amphiphilic tobramycins are an emerging class of antibiotic potentiators capable of synergizing with multiple classes of antibiotics against Gram-negative bacteria, including Pseudomonas aeruginosa. To study how the antibiotic-potentiating effect of amphiphilic tobramycins is affected by the presence of intermolecular iron chelators, we conjugated the FDA-approved iron chelator deferiprone (DEF) to tobramycin (TOB). Three TOB-DEF conjugates differing in the length of the carbon tether were prepared and tested for antibacterial activity and synergistic relationships with a panel of antibiotics against clinical isolates of P. aeruginosa. While all TOB-DEF conjugates were inactive against P. aeruginosa, the TOB-DEF conjugates strongly synergized with outer-membrane-impermeable antibiotics, such as novobiocin and rifampicin. Among the three TOB-DEF conjugates, 1c containing a C12 tether showed a remarkable and selective potentiating effect to improve the susceptibility of multidrug-resistant P. aeruginosa isolates to tetracyclines when compared with other antibiotics. However, the antibacterial activity and antibiotic-potentiating effect of the optimized conjugate was not enhanced under iron-depleted conditions, indicating that the function of the antibiotic potentiator is not affected by the Fe3+ concentration.
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Affiliation(s)
- Karan Gandhi
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; (K.G.); (S.D.); (R.A.); (D.M.R.); (D.R.)
| | - Shiv Dhiman
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; (K.G.); (S.D.); (R.A.); (D.M.R.); (D.R.)
| | - Rajat Arora
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; (K.G.); (S.D.); (R.A.); (D.M.R.); (D.R.)
| | - Danzel Marie Ramirez
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; (K.G.); (S.D.); (R.A.); (D.M.R.); (D.R.)
| | - Danyel Ramirez
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; (K.G.); (S.D.); (R.A.); (D.M.R.); (D.R.)
| | - Gilbert Arthur
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
| | - Frank Schweizer
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; (K.G.); (S.D.); (R.A.); (D.M.R.); (D.R.)
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3R 0J9, Canada
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5
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Dhiman S, Ramirez D, Li Y, Kumar A, Arthur G, Schweizer F. Chimeric Tobramycin-Based Adjuvant TOB-TOB-CIP Potentiates Fluoroquinolone and β-Lactam Antibiotics against Multidrug-Resistant Pseudomonas aeruginosa. ACS Infect Dis 2023; 9:864-885. [PMID: 36917096 DOI: 10.1021/acsinfecdis.2c00549] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
According to the World Health Organization, antibiotic resistance is a global health threat. Of particular importance are infections caused by multidrug-resistant Gram-negative bacteria including Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa for which limited treatment options exist. Multiple and simultaneously occurring resistance mechanisms including outer membrane impermeability, overexpression of efflux pumps, antibiotic-modifying enzymes, and modification of genes and antibiotic targets have made antibiotic drug development more difficult against these pathogens. One strategy to cope with these challenges is the use of outer membrane permeabilizers that increase the intracellular concentration of antibiotics when used in combination. In some circumstances, this approach can rescue antibiotics from resistance or repurpose currently marketed antibiotics. Tobramycin-based hybrid antibiotic adjuvants that combine two outer membrane-active components have been previously shown to potentiate antibiotics by facilitating transit through the outer membrane, resulting in increased antibiotic accumulation within the cell. Herein, we extended the concept of tobramycin-based hybrid antibiotic adjuvants to tobramycin-based chimeras by engineering up to three different membrane-active antibiotic warheads such as tobramycin, 1-(1-naphthylmethyl)-piperazine, ciprofloxacin, and cyclam into a central 1,3,5-triazine scaffold. Chimera 4 (TOB-TOB-CIP) consistently synergized with ciprofloxacin, levofloxacin, and moxifloxacin against wild-type and fluoroquinolone-resistant P. aeruginosa. Moreover, the susceptibility breakpoints of ceftazidime, aztreonam, and imipenem were reached using the triple combination of chimera 4 with ceftazidime/avibactam, aztreonam/avibactam, and imipenem/relebactam, respectively, against β-lactamase-harboring P. aeruginosa. Our findings demonstrate that tobramycin-based chimeras form a novel class of antibiotic potentiators capable of restoring the activity of antibiotics against P. aeruginosa.
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Affiliation(s)
- Shiv Dhiman
- Department of Chemistry, University of Manitoba, Winnipeg R3T 2N2, Manitoba, Canada
| | - Danyel Ramirez
- Department of Chemistry, University of Manitoba, Winnipeg R3T 2N2, Manitoba, Canada
| | - Yanqi Li
- Department of Microbiology, University of Manitoba, Winnipeg R3T 2N2, Manitoba, Canada
| | - Ayush Kumar
- Department of Microbiology, University of Manitoba, Winnipeg R3T 2N2, Manitoba, Canada
| | - Gilbert Arthur
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg R3E 0J9, Manitoba, Canada
| | - Frank Schweizer
- Department of Chemistry, University of Manitoba, Winnipeg R3T 2N2, Manitoba, Canada
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Chowdhuri SP, Dhiman S, Das SK, Meena N, Das S, Kumar A, Das BB. Novel Pyrido[2',1':2,3]imidazo[4,5- c]quinoline Derivative Selectively Poisons Leishmania donovani Bisubunit Topoisomerase 1 to Inhibit the Antimony-Resistant Leishmania Infection in Vivo. J Med Chem 2023; 66:3411-3430. [PMID: 36823782 DOI: 10.1021/acs.jmedchem.2c01932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The unique bisubunit structure of Leishmania donovani topoisomerase 1B (LdTop1) is a potential drug target in the parasites unlike the monomeric Top1 from its human host counterpart. Here, we report the design, synthesis, and validation of a chimeric pyrido[2',1':2,3]imidazo[4,5-c]quinoline derivative (C17) as a novel antileishmanial agent that poisons topoisomerase 1-DNA covalent complexes (LdTop1cc) inside the parasites and inhibits Top1 religation activity both in the drug sensitive and antimony-resistant L. donovani clinical isolates. Importantly, the human Top1 is not sensitive to C17. Further, C17 overcomes the chemical instability of camptothecin (CPT) by generating persistent LdTop1cc-induced DNA breaks inside the parasites even after 12 h of drug removal. Intraperitoneal administration of C17 results in marked reduction of the Leishmania amastigotes from the infected spleen and liver of BALB/c mice. C17 confers a host protective immune-response up-regulating the Th1 cytokines facilitating parasite clearance which can be exploited for treating drug-resistant leishmaniasis.
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Affiliation(s)
- Srijita Paul Chowdhuri
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Shiv Dhiman
- Department of Chemistry, Birla Institute of Technology and Science, Pilani 333 031 Rajasthan, India
| | - Subhendu K Das
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Neha Meena
- Department of Chemistry, Birla Institute of Technology and Science, Pilani 333 031 Rajasthan, India
| | - Sonali Das
- Infectious Diseases & Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700 032, India
| | - Anil Kumar
- Department of Chemistry, Birla Institute of Technology and Science, Pilani 333 031 Rajasthan, India
| | - Benu Brata Das
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
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7
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Dhiman S, Rai B, Vamsi K, Gowda S, Anand D, Miriyala R, Arora M, Jain V, Ghoshal S. Hypofractionated Two Week Short-Course Radiotherapy vs. Monthly Single Fraction Palliative Pelvic Radiation in Advanced Gynecologic Cancers. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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8
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Meena N, Dhiman S, Rangan K, Kumar A. Cobalt-catalyzed tandem one-pot synthesis of polysubstituted imidazo[1,5- a]pyridines and imidazo[1,5- a]isoquinolines. Org Biomol Chem 2022; 20:4215-4223. [PMID: 35546113 DOI: 10.1039/d2ob00526c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient cobalt-catalyzed tandem one-pot method has been developed for the synthesis of polysubstituted imidazo[1,5-a]-N-heteroaromatics. The method involves Knoevenagel condensation followed by cobalt-catalyzed direct alkenylation to give the desired polysubstituted imidazo[1,5-a]pyridines and imidazo[1,5-a]isoquinolines in a one-pot manner. This method exhibits a broad substrate scope, provides moderate to good (39-74%) yields and is amenable to scale-up to the gram scale.
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Affiliation(s)
- Neha Meena
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India.
| | - Shiv Dhiman
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India.
| | - Krishnan Rangan
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Telangana, 500078, India
| | - Anil Kumar
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India.
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9
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Pattani S, Irshad S, Sewo L, Dacquel M, Narayan V, Dhiman S. Case Study: Superficial Ulnar Artery and its Clinical Significance. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.l8045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Zamani S, Meawad S, Van Der Horn T, Dhiman S. Gross Anatomy of Bifid Xiphoid Process. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.l7880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Sara Meawad
- Philadelphia College of Osteopathic MedicineMoultrieGA
| | | | - Shiv Dhiman
- Philadelphia College of Osteopathic MedicineMoultrieGA
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11
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Nachtigal MW, Musaphir P, Dhiman S, Altman AD, Schweizer F, Arthur G. Cytotoxic capacity of a novel glycosylated antitumor ether lipid in chemotherapy-resistant high grade serous ovarian cancer in vitro and in vivo. Transl Oncol 2021; 14:101203. [PMID: 34416424 PMCID: PMC8379490 DOI: 10.1016/j.tranon.2021.101203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 01/04/2023] Open
Abstract
L-Rham induces apoptosis-independent cell death in high grade serous ovarian cancer (HGSOC) cells. L-Rham-induced cell death is dose and time dependent in HGSOC cells grown as 2D or 3D cultures. L-Rham is as effective as paclitaxel to reduce tumor burden and metastasis in a CAM model. L-Rham significantly reduces tumor formation in a low tumor burden model. L-Rham blocks ascites formation.
Chemotherapy resistant high grade serous ovarian cancer remains a clinically intractable disease with a high rate of mortality. We tested a novel glycosylated antitumor ether lipid called l-Rham to assess the in vitro and in vivo efficacy on high grade serous ovarian cancer cell lines and patient samples. l-Rham effectively kills high grade serous ovarian cancer cells grown as 2D or 3D cultures in a dose and time dependent manner. l-Rham efficacy was tested in vivo in a chicken allantoic membrane/COV362 xenograft model, where l-Rham activity was as effective as paclitaxel in reducing tumor weight and metastasis. The efficacy of l-Rham to reduce OVCAR3 tumor xenografts in NRG mice was assessed in low and high tumor burden models. l-Rham effectively reduced tumor formation in the low tumor burden group, and blocked ascites formation in low and high tumor burden animals. l-Rham demonstrates efficacy against OVCAR3 tumor and ascites formation in vivo in NRG mice, laying the foundation for further development of this drug class for the treatment of high grade serous ovarian cancer patients.
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Affiliation(s)
- Mark W Nachtigal
- Department of Biochemistry and Medical Genetics, University of Manitoba, 301 BMSB-745 Bannatyne Avenu, Winnipeg, Manitoba R3E 0J9, Canada; Department of Obstetrics, Gynecology and Reproductive Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada; CancerCare Manitoba Research Institute, Winnipeg, Manitoba R2H 2A6, Canada.
| | - Paris Musaphir
- Department of Biochemistry and Medical Genetics, University of Manitoba, 301 BMSB-745 Bannatyne Avenu, Winnipeg, Manitoba R3E 0J9, Canada
| | - Shiv Dhiman
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Alon D Altman
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Frank Schweizer
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Gilbert Arthur
- Department of Biochemistry and Medical Genetics, University of Manitoba, 301 BMSB-745 Bannatyne Avenu, Winnipeg, Manitoba R3E 0J9, Canada
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Nandwana NK, Dhiman S, Shinde VN, Beifuss U, Kumar A. Synthesis of π-Expanded Azole-Fused Imidazo[1,2-a
]pyridine Derivatives and their Photophysical Properties. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000236] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nitesh Kumar Nandwana
- Department of Chemistry; Birla Institute of Technology and Science Pilani; 333031 Rajasthan Pilani India
| | - Shiv Dhiman
- Department of Chemistry; Birla Institute of Technology and Science Pilani; 333031 Rajasthan Pilani India
| | - Vikki N. Shinde
- Department of Chemistry; Birla Institute of Technology and Science Pilani; 333031 Rajasthan Pilani India
| | - Uwe Beifuss
- Institute of Chemistry; University of Hohenheim; Garbenstr. 30 70599 Stuttgart Germany
| | - Anil Kumar
- Department of Chemistry; Birla Institute of Technology and Science Pilani; 333031 Rajasthan Pilani India
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13
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Saini HK, Dhiman S, Nandwana NK, Krishnan R, Kumar A. Copper and palladium-catalyzed sequential reactions: one-pot synthesis of isoindolo[2,1-b]isoquinolin-7(5H)-ones. Org Biomol Chem 2019; 17:4281-4290. [PMID: 30969295 DOI: 10.1039/c9ob00440h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A highly efficient protocol has been developed for the synthesis of diversely substituted isoindolo[2,1-b]isoquinolin-7(5H)-ones through sequential Cu(ii)-catalyzed Sonogashira coupling, intramolecular hydroamidation followed by palladium-catalyzed ligand-free Heck reaction. Good to excellent yields (41-94%) were observed with excellent substrate scope and functional group tolerance. The developed method represents a practical strategy for the construction of bioactive isoindolo[2,1-b]isoquinolin-7(5H)-ones.
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Affiliation(s)
- Hitesh Kumar Saini
- Department of Chemistry, BITS Pilani, Pilani Campus, Pilani, Rajasthan 333031, India.
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14
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Shinde VN, Dhiman S, Krishnan R, Kumar D, Kumar A. Synthesis of imidazopyridine-fused indoles via one-pot sequential Knoevenagel condensation and cross dehydrogenative coupling. Org Biomol Chem 2019; 16:6123-6132. [PMID: 30094426 DOI: 10.1039/c8ob01449c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A simple and efficient strategy for the synthesis of imidazopyridine-fused indoles has been developed that involves one-pot sequential Knoevenagel condensation of readily available active methylene azoles with N-substituted-1H-indole-3-carboxaldehydes or N-substituted-1H-indole-2-carboxaldehydes followed by palladium-catalyzed intramolecular cross dehydrogenative coupling reaction. A series of 36 derivatives was prepared by using this strategy. The products were obtained in moderate to excellent (32-94%) yields and showed broad substrate scope with tolerance of various functional groups and was amiable for gram scale preparation without problems.
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Affiliation(s)
- Vikki N Shinde
- Department of Chemistry, BITS Pilani, Pilani Campus, Pilani 333031, India.
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15
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Patel OPS, Dhiman S, Khan S, Shinde VN, Jaspal S, Srivathsa MR, Jha PN, Kumar A. A straightforward TBHP-mediated synthesis of 2-amidobenzoic acids from 2-arylindoles and their antimicrobial activity. Org Biomol Chem 2019; 17:5962-5970. [DOI: 10.1039/c9ob00797k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesis of 2-amidobenzoic acids has been achieved through TBHP-mediated oxidative ring opening of 2-arylindoles. The synthesized compounds have been evaluated for their antimicrobial activity.
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Affiliation(s)
| | - Shiv Dhiman
- Department of Chemistry
- BITS Pilani
- Pilani Campus
- India
| | - Shahid Khan
- Department of Biological Sciences
- BITS Pilani
- Pilani Campus
- India
| | | | - Sonam Jaspal
- Department of Chemistry
- BITS Pilani
- Pilani Campus
- India
| | | | - Prabhat N. Jha
- Department of Biological Sciences
- BITS Pilani
- Pilani Campus
- India
| | - Anil Kumar
- Department of Chemistry
- BITS Pilani
- Pilani Campus
- India
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16
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Nandwana N, Singh RP, Patel OPS, Dhiman S, Saini HK, Jha PN, Kumar A. Design and Synthesis of Imidazo/Benzimidazo[1,2- c]quinazoline Derivatives and Evaluation of Their Antimicrobial Activity. ACS Omega 2018; 3:16338-16346. [PMID: 31458269 PMCID: PMC6643530 DOI: 10.1021/acsomega.8b01592] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/19/2018] [Indexed: 05/26/2023]
Abstract
A new class of fused quinazolines has been designed and synthesized via copper-catalyzed Ullmann type C-N coupling followed by intramolecular cross-dehydrogenative coupling reaction in moderate to good yields. The synthesized compounds were tested for in vitro antibacterial activity against three Gram negative (Escherichia coli, Pseudomonas putida, and Salmonella typhi) and two Gram positive (Bacillus subtilis, and Staphylococcus aureus) bacteria. Among all tested compounds, 8ga, 8gc, and 8gd exhibited promising minimum inhibitory concentration (MIC) values (4-8 μg/mL) for all bacterial strains tested as compared to the positive control ciprofloxacin. The synthesized compounds were also evaluated for their in vitro antifungal activity against Aspergillus niger and Candida albicans and compounds 8ga, 8gc, and 8gd having potential antibacterial activity also showed pronounced antifungal activity (MIC values 8-16 μg/mL) against both strains. The bactericidal assay by propidium iodide and live-dead bacterial cell screening using a mixture of acridine orange/ethidium bromide (AO/Et·Br) showed considerable changes in the bacterial cell membrane, which might be the cause or consequence of cell death. Moreover, the hemolytic activity for most potent compounds (8ga, 8gc, and 8gd) showed their safety profile toward human blood cells.
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Affiliation(s)
- Nitesh
Kumar Nandwana
- Department
of Chemistry and Department of Biological Sciences, Birla
Institute of Technology and Science, Pilani 333031, Rajasthan, India
| | - Rajnish Prakash Singh
- Department
of Chemistry and Department of Biological Sciences, Birla
Institute of Technology and Science, Pilani 333031, Rajasthan, India
| | - Om P. S. Patel
- Department
of Chemistry and Department of Biological Sciences, Birla
Institute of Technology and Science, Pilani 333031, Rajasthan, India
| | - Shiv Dhiman
- Department
of Chemistry and Department of Biological Sciences, Birla
Institute of Technology and Science, Pilani 333031, Rajasthan, India
| | - Hitesh Kumar Saini
- Department
of Chemistry and Department of Biological Sciences, Birla
Institute of Technology and Science, Pilani 333031, Rajasthan, India
| | - Prabhat N. Jha
- Department
of Chemistry and Department of Biological Sciences, Birla
Institute of Technology and Science, Pilani 333031, Rajasthan, India
| | - Anil Kumar
- Department
of Chemistry and Department of Biological Sciences, Birla
Institute of Technology and Science, Pilani 333031, Rajasthan, India
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17
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Dhiman S, Jayaprakash KS, Iqbal R, Sen AK. Self-Transport and Manipulation of Aqueous Droplets on Oil-Submerged Diverging Groove. Langmuir 2018; 34:12359-12368. [PMID: 30226788 DOI: 10.1021/acs.langmuir.8b01889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report experimental study of self-transport of aqueous droplets along an oil-submerged diverging groove structure. The migration phenomenon is illustrated, and the effect of various parameters such as droplet size d, oil layer thickness h, groove angle 2θ, and groove thickness δ on the droplet transport behavior (i.e., migration velocity and length) is investigated. Our study reveals that complete engulfment of aqueous droplets in the oil layer, that is attributed to a positive spreading parameter ( S > 0), is a prerequisite for the droplet transport. The results show that only droplets of diameter larger than the oil layer thickness (i.e., d ≥ h) get transported owing to a differential Laplace pressure between the leading and trailing faces of a droplet because of the diverging groove. Using experimental data, the variation of droplet migration velocity with distance along the diverging groove is correlated as U( x) = ψ x-0.9, where ψ = d0.32θ-2.2 h-1.5δ0.7. The submerged groove structure was used to demonstrate simultaneous and sequential coalescence and transport of multiple droplets. Finally, the submerged groove structure was employed for extraction of aqueous droplets from oil. The proposed technique opens up a new avenue for evaporation and contamination free transport and coalescence of droplets for chemical and biological applications.
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Affiliation(s)
- S Dhiman
- Department of Mechanical Engineering , Indian Institute of Technology Madras , Chennai 600036 , India
| | - K S Jayaprakash
- Department of Mechanical Engineering , Indian Institute of Technology Madras , Chennai 600036 , India
| | - R Iqbal
- Department of Mechanical Engineering , Indian Institute of Technology Madras , Chennai 600036 , India
| | - A K Sen
- Department of Mechanical Engineering , Indian Institute of Technology Madras , Chennai 600036 , India
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18
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Gujjarappa R, Maity SK, Hazra CK, Vodnala N, Dhiman S, Kumar A, Beifuss U, Malakar CC. Divergent Synthesis of Quinazolines Using Organocatalytic Domino Strategies under Aerobic Conditions. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800746] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Raghuram Gujjarappa
- Department of Chemistry; National Institute of Technology Manipur; 795004 Langol, Imphal Manipur India
| | - Suvik K. Maity
- Department of Chemistry; National Institute of Technology Manipur; 795004 Langol, Imphal Manipur India
| | - Chinmoy K. Hazra
- Department of Chemistry; Korea Advanced Institute of Science & Technology (KAIST); 34141 Daejeon 305 - 701 South Korea
| | - Nagaraju Vodnala
- Department of Chemistry; National Institute of Technology Manipur; 795004 Langol, Imphal Manipur India
| | - Shiv Dhiman
- Department of Chemistry; BITS Pilani; Pilani Campus 333031 Pilani Rajasthan India
| | - Anil Kumar
- Department of Chemistry; BITS Pilani; Pilani Campus 333031 Pilani Rajasthan India
| | - Uwe Beifuss
- Institut für Chemie; Universität Hohenheim; Garbenstr. 30 70599 Stuttgart Germany
| | - Chandi C. Malakar
- Department of Chemistry; National Institute of Technology Manipur; 795004 Langol, Imphal Manipur India
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19
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Dhiman S, Nandwana NK, Saini HK, Kumar D, Rangan K, Robertson KN, Jha M, Kumar A. Nickel-Catalyzed Tandem Knoevenagel Condensation and Intramolecular Direct Arylation: Synthesis of Pyrazolo[5,1-a]-isoquinoline Derivatives. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201701519] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Shiv Dhiman
- Department of Chemistry; BITS Pilani; Pilani Campus Pilani 333031 Rajasthan, India
| | | | - Hitesh Kumar Saini
- Department of Chemistry; BITS Pilani; Pilani Campus Pilani 333031 Rajasthan, India
| | - Dalip Kumar
- Department of Chemistry; BITS Pilani; Pilani Campus Pilani 333031 Rajasthan, India
| | - Krishnan Rangan
- Department of Chemistry; BITS Pilani; Hyderabad Campus; Secunderabad 500078 Telangana India
| | | | - Mukund Jha
- Department of Biology and Chemistry; Nipissing University; North Bay, ON P1B 8L7 Canada
| | - Anil Kumar
- Department of Chemistry; BITS Pilani; Pilani Campus Pilani 333031 Rajasthan, India
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20
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Saini HK, Nandwana NK, Dhiman S, Rangan K, Kumar A. Sequential Copper-Catalyzed Sonogashira Coupling, Hydroamination and Palladium-Catalyzed Intramolecular Direct Arylation: Synthesis of Azepino-Fused Isoindolinones. European J Org Chem 2017. [DOI: 10.1002/ejoc.201701379] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hitesh Kumar Saini
- Department of Chemistry; BITS Pilani; Pilani Campus 333031 Pilani Rajasthan India
| | | | - Shiv Dhiman
- Department of Chemistry; BITS Pilani; Pilani Campus 333031 Pilani Rajasthan India
| | - Krishnan Rangan
- Department of Chemistry; BITS Pilani; Hyderabad Campus 500078 Secunderabad Telangana India
| | - Anil Kumar
- Department of Chemistry; BITS Pilani; Pilani Campus 333031 Pilani Rajasthan India
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21
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Stachowiak EK, Benson CA, Narla ST, Dimitri A, Chuye LEB, Dhiman S, Harikrishnan K, Elahi S, Freedman D, Brennand KJ, Sarder P, Stachowiak MK. Cerebral organoids reveal early cortical maldevelopment in schizophrenia-computational anatomy and genomics, role of FGFR1. Transl Psychiatry 2017; 7:6. [PMID: 30446636 PMCID: PMC5802550 DOI: 10.1038/s41398-017-0054-x] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/17/2017] [Accepted: 09/23/2017] [Indexed: 12/15/2022] Open
Abstract
Studies of induced pluripotent stem cells (iPSCs) from schizophrenia patients and control individuals revealed that the disorder is programmed at the preneuronal stage, involves a common dysregulated mRNA transcriptome, and identified Integrative Nuclear FGFR1 Signaling a common dysregulated mechanism. We used human embryonic stem cell (hESC) and iPSC-derived cerebral organoids from four controls and three schizophrenia patients to model the first trimester of in utero brain development. The schizophrenia organoids revealed an abnormal scattering of proliferating Ki67+ neural progenitor cells (NPCs) from the ventricular zone (VZ), throughout the intermediate (IZ) and cortical (CZ) zones. TBR1 pioneer neurons and reelin, which guides cortico-petal migration, were restricted from the schizophrenia cortex. The maturing neurons were abundantly developed in the subcortical regions, but were depleted from the schizophrenia cortex. The decreased intracortical connectivity was denoted by changes in the orientation and morphology of calretinin interneurons. In schizophrenia organoids, nuclear (n)FGFR1 was abundantly expressed by developing subcortical cells, but was depleted from the neuronal committed cells (NCCs) of the CZ. Transfection of dominant negative and constitutively active nFGFR1 caused widespread disruption of the neuro-ontogenic gene networks in hESC-derived NPCs and NCCs. The fgfr1 gene was the most prominent FGFR gene expressed in NPCs and NCCs, and blocking with PD173074 reproduced both the loss of nFGFR1 and cortical neuronal maturation in hESC cerebral organoids. We report for the first time, progression of the cortical malformation in schizophrenia and link it to altered FGFR1 signaling. Targeting INFS may offer a preventive treatment of schizophrenia.
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Affiliation(s)
- E. K. Stachowiak
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA
| | - C. A. Benson
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA
| | - S. T. Narla
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA
| | - A. Dimitri
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA ,0000 0004 0388 0154grid.264268.cDepartment of Biology, State University of New York at Fredonia, Fredonia, NY USA
| | - L. E. Bayona Chuye
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA
| | - S. Dhiman
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA ,0000 0004 1936 9887grid.273335.3Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY USA
| | - K. Harikrishnan
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA ,0000 0004 1936 9887grid.273335.3Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY USA
| | - S. Elahi
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA
| | - D. Freedman
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA
| | - K. J. Brennand
- Icahn School of Medicine at Mount Sinai, Departments of Psychiatry and Neuroscience, New York, NY USA
| | - P. Sarder
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA ,0000 0004 1936 9887grid.273335.3Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY USA
| | - M. K. Stachowiak
- 0000 0004 1936 9887grid.273335.3Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, NY USA ,0000 0004 1936 9887grid.273335.3Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY USA
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22
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Dhiman S, Rhodes S, Kumar D, Kumar A, Jha M. Copper-Catalyzed Tandem Imine Formation, Sonogashira Coupling and Intramolecular Hydroamination: A Facile Synthesis of 3-Aryl-γ−carbolines. ChemistrySelect 2017. [DOI: 10.1002/slct.201702025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Shiv Dhiman
- Department of Biology and Chemistry; Nipissing University; North Bay, ON P1B 8 L7 Canada, Fax: +1-705-4741947, Tel: +1-705-4743450 ex 4814
- Department of Chemistry; Birla Institute of Technology and Science, Pilani; Pilani 333031 India, Tel: +91-1596-515663, Fax: +91-1596-244183
| | - Steven Rhodes
- Department of Biology and Chemistry; Nipissing University; North Bay, ON P1B 8 L7 Canada, Fax: +1-705-4741947, Tel: +1-705-4743450 ex 4814
| | - Dalip Kumar
- Department of Chemistry; Birla Institute of Technology and Science, Pilani; Pilani 333031 India, Tel: +91-1596-515663, Fax: +91-1596-244183
| | - Anil Kumar
- Department of Chemistry; Birla Institute of Technology and Science, Pilani; Pilani 333031 India, Tel: +91-1596-515663, Fax: +91-1596-244183
| | - Mukund Jha
- Department of Biology and Chemistry; Nipissing University; North Bay, ON P1B 8 L7 Canada, Fax: +1-705-4741947, Tel: +1-705-4743450 ex 4814
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23
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Dhiman S, Nandwana NK, Dhayal S, Saini HK, Kumar D, Kumar A. A Facile Synthesis of Quinazolin-4(3H
)-ones via Copper-Catalyzed One-Pot, Three-Component Tandem Reaction. ChemistrySelect 2017. [DOI: 10.1002/slct.201701778] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Shiv Dhiman
- Department of Chemistry; Birla Institute of Technology and Science; Pilani, Pilani; 333031 Rajasthan India
| | - Nitesh K. Nandwana
- Department of Chemistry; Birla Institute of Technology and Science; Pilani, Pilani; 333031 Rajasthan India
| | - Shreemala Dhayal
- Department of Chemistry; Birla Institute of Technology and Science; Pilani, Pilani; 333031 Rajasthan India
| | - Hitesh K. Saini
- Department of Chemistry; Birla Institute of Technology and Science; Pilani, Pilani; 333031 Rajasthan India
| | - Dalip Kumar
- Department of Chemistry; Birla Institute of Technology and Science; Pilani, Pilani; 333031 Rajasthan India
| | - Anil Kumar
- Department of Chemistry; Birla Institute of Technology and Science; Pilani, Pilani; 333031 Rajasthan India
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24
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Iqbal R, Dhiman S, Sen AK, Shen AQ. Dynamics of a Water Droplet over a Sessile Oil Droplet: Compound Droplets Satisfying a Neumann Condition. Langmuir 2017; 33:5713-5723. [PMID: 28499091 DOI: 10.1021/acs.langmuir.6b04621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the dynamics of compound droplets with a denser liquid (water) droplet over a less dense sessile droplet (mineral oil) that satisfies the Neumann condition. For a fixed size of an oil droplet, depending on the size of the water droplet, either it attains the axisymmetric position or tends to migrate toward the edge of the oil droplet. For a water droplet-to-oil droplet at volume ratio Vw/Vo ≥ 0.05, stable axisymmetric configuration is achieved; for Vw/Vo < 0.05, migration of water droplet is observed. The stability and migration of water droplets of size above and below critical size, respectively, are explained using the force balance at the three-phase contact line and film tension. The larger and smaller droplets that initially attain the axisymmetric position or some radial position, respectively, evaporate continuously and thus migrate toward the edge of the oil droplet. The radial location and migration of the water droplets of different initial sizes with respect to time are studied. Experiments with water droplets on a flat oil-air interface did not show migration, which signified the role of the curved oil-air interface for droplet migration. Finally, coalescence of water droplets of size above the critical size at the axisymmetric position is demonstrated. Our compound droplet studies could be beneficial for applications involving droplet transport where contamination due to direct contact and pinning of droplets on solid surfaces is of concern. Migration and coalescence of water droplets on curved oil-air interfaces could open new frontiers in chemical and biological applications including multiphase processing and biological interaction of cells and atmospheric chemistry.
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Affiliation(s)
- R Iqbal
- Department of Mechanical Engineering, Indian Institute of Technology Madras , Chennai 600036, India
| | - S Dhiman
- Department of Mechanical Engineering, Indian Institute of Technology Madras , Chennai 600036, India
| | - A K Sen
- Department of Mechanical Engineering, Indian Institute of Technology Madras , Chennai 600036, India
| | - Amy Q Shen
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University , Okinawa 904-0495, Japan
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25
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Jha M, Dhiman S, Cameron TS, Kumar D, Kumar A. Au-Catalyzed Synthesis of Thiopyrano[2,3-b]indoles Featuring Tandem Rearrangement and Hydroarylation. Org Lett 2017; 19:2038-2041. [PMID: 28378595 DOI: 10.1021/acs.orglett.7b00617] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Gold(III)-catalyzed synthesis of 14-π electron heteroaromatic thiopyrano[2,3-b]indole is reported using conjugated enyne tethered indole sulfides, featuring skeletal rearrangement conjoined with intramolecular hydroarylation (via C3-H functionalization of the indole core) and oxidative aromatization. Subsequent Pd-catalyzed C-C coupling resulted in a 16-π electron heteroaromatic isothiochromeno[1,8,7-bcd]indole.
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Affiliation(s)
- Mukund Jha
- Department of Biology and Chemistry, Nipissing University , North Bay, ON P1B 8L7, Canada
| | - Shiv Dhiman
- Department of Biology and Chemistry, Nipissing University , North Bay, ON P1B 8L7, Canada.,Department of Chemistry, Birla Institute of Technology and Science , Pilani, Pilani 333031, India
| | - T Stanley Cameron
- Department of Chemistry, Dalhousie University , Halifax, NS B3H 4J3, Canada
| | - Dalip Kumar
- Department of Chemistry, Birla Institute of Technology and Science , Pilani, Pilani 333031, India
| | - Anil Kumar
- Department of Chemistry, Birla Institute of Technology and Science , Pilani, Pilani 333031, India
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26
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Nandwana NK, Dhiman S, Saini HK, Kumar I, Kumar A. Synthesis of Quinazolinones, Imidazo[1,2-c
]quinazolines and Imidazo[4,5-c
]quinolines through Tandem Reductive Amination of Aryl Halides and Oxidative Amination of C(sp3
)-H Bonds. European J Org Chem 2016. [DOI: 10.1002/ejoc.201601329] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Nitesh Kumar Nandwana
- Department of Chemistry; Birla Institute of Technology and Science; Pilani Campus 330331 Pilani, Rajasthan India
| | - Shiv Dhiman
- Department of Chemistry; Birla Institute of Technology and Science; Pilani Campus 330331 Pilani, Rajasthan India
| | - Hitesh Kumar Saini
- Department of Chemistry; Birla Institute of Technology and Science; Pilani Campus 330331 Pilani, Rajasthan India
| | - Indresh Kumar
- Department of Chemistry; Birla Institute of Technology and Science; Pilani Campus 330331 Pilani, Rajasthan India
| | - Anil Kumar
- Department of Chemistry; Birla Institute of Technology and Science; Pilani Campus 330331 Pilani, Rajasthan India
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27
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Garg R, Singh S, Dhiman S, Agrawal P, Prakash P. Novel Bio-Markers for Prediction of Preeclampsia. Nepal j obstet gynaecol 2016. [DOI: 10.3126/njog.v11i1.16237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pre-eclampsia (PE) is a pregnancy related disorder. It is an important cause of maternal and perinatal morbidity and mortality worldwide. Two to eight percent of pregnancies were affected by PE. It is characterized by de novo hypertension and proteinuria after 20 weeks of gestation. The etiology and pathogenesis of the disease is unknown, but recent studies have revealed that placenta is the place of origin of this disorder and widespread maternal endothelial dysfunction is the characteristic feature of the disease. Some biochemical molecules are identified recently which are involved in the pathogenesis of the disease, which may help in early identification of patients at risk and help in providing proper prenatal care. Several promising biomarkers have been proposed, alone or in combination. Maternal serum concentrations of these biomarkers either increase or decrease in PE during gestation. This review focuses on the various biomarkers available and their utility in prediction and diagnosis of pre-eclampsia.
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28
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Nandwana NK, Dhiman S, Shelke GM, Kumar A. Copper-catalyzed tandem Ullmann type C-N coupling and dehydrative cyclization: synthesis of imidazo[1,2-c]quinazolines. Org Biomol Chem 2016; 14:1736-41. [PMID: 26732527 DOI: 10.1039/c5ob02469b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A simple and efficient one-pot protocol has been demonstrated for the synthesis of imidazo[1,2-c]quinazoline derivatives through a copper catalyzed tandem reaction between substituted 2-(2-bromophenyl)-1H-imidazoles and formamide. The synthetic protocol involves initial Ullmann-type C-N coupling followed by intramolecular dehydrative cyclization. The method uses readily available 2-(2-bromophenyl)-1H-imidazoles as the starting materials to afford imidazo[1,2-c]quinazolines in moderate to good yields and provided 610 mg (71%) yield of 3a from a gram scale reaction.
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Affiliation(s)
- Nitesh K Nandwana
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India.
| | - Shiv Dhiman
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India.
| | - Ganesh M Shelke
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India.
| | - Anil Kumar
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India.
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29
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Kumar D, Dhiman S, Rabha B, Goswami D, Yadav K, Deka M, Veer V, Baruah I. Typing of Plasmodium falciparum DNA from 2 years old Giemsa-stained dried blood spots using nested polymerase chain reaction assay. Indian J Med Microbiol 2016; 34:210-2. [PMID: 27080775 DOI: 10.4103/0255-0857.176841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A panel of 129 Giemsa-stained thick blood spots (TBS) confirmed for Plasmodium falciparum infection having different levels of parasite density were collected from a malaria endemic area. DNA was extracted and nested polymerase chain reaction (PCR) assay was performed to amplify P. falciparum DNA. Nested PCR assay successfully amplified P. falciparum DNA at a very low parasitaemia of ~10 parasites/μl of blood. Current PCR assay is very simple and can be used retrospectively to monitor the invasion and prevalence of different Plasmodium species in endemic areas.
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Affiliation(s)
| | - S Dhiman
- Medical Entomology Division, Defence Research Laboratory, Tezpur, Assam, India
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Dhiman S, Saini HK, Nandwana NK, Kumar D, Kumar A. Copper-catalyzed synthesis of quinoline derivatives via tandem Knoevenagel condensation, amination and cyclization. RSC Adv 2016. [DOI: 10.1039/c6ra03798d] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A novel regioselective synthesis of 2-aminoquinolines and 2-arylquinoline-3-carbonitriles is described via copper-mediated tandem reaction.
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Affiliation(s)
- Shiv Dhiman
- Department of Chemistry
- Birla Institute of Technology and Science
- Pilani
- India
| | - Hitesh Kumar Saini
- Department of Chemistry
- Birla Institute of Technology and Science
- Pilani
- India
| | | | - Dalip Kumar
- Department of Chemistry
- Birla Institute of Technology and Science
- Pilani
- India
| | - Anil Kumar
- Department of Chemistry
- Birla Institute of Technology and Science
- Pilani
- India
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Kumar A, Saini H, Dhiman S, Pericherla K. Synthesis of Imidazo[1,2-f]phenanthridines through Palladium-Catalyzed Intramolecular C–C Bond Formation. SYNTHESIS-STUTTGART 2015. [DOI: 10.1055/s-0035-1560177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Dhiman S, Pericherla K, Nandwana NK, Kumar D, Kumar A. Synthesis of Aza-Fused Isoquinolines through Domino Cross-Aldol Condensation and Palladium-Catalyzed Intramolecular Direct Arylation. J Org Chem 2014; 79:7399-404. [DOI: 10.1021/jo501119f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Shiv Dhiman
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India
| | | | - Nitesh K. Nandwana
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India
| | - Dalip Kumar
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India
| | - Anil Kumar
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, 333031 Rajasthan, India
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Nath MJ, Bora AK, Yadav K, Talukdar PK, Dhiman S, Baruah I, Singh L. Prioritizing areas for malaria control using geographical information system in Sonitpur district, Assam, India. Public Health 2013; 127:572-8. [PMID: 23701814 DOI: 10.1016/j.puhe.2013.02.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 01/09/2013] [Accepted: 02/15/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To identify the malaria hot spots at health subcentre level in an endemic district using a geographical information system (GIS). The results will be useful for rapid retrieval of malaria information, and to prioritize malaria control efforts in identified hot spots. STUDY DESIGN Extraction, analysis and synthesis of relevant data. METHODS Malaria epidemiological data from 2006 to 2009 were analysed to determine the annual parasitic index, slide positivity rate, annual blood examination rate and Plasmodium falciparum percentage for each health subcentre in the district. Maps were produced using GIS, and integrated to identify the malaria hotspots. RESULTS Out of 288 health subcentres, GIS identified 10 hot spots at extremely high risk of malaria and 14 hot spots at high risk of malaria. Malaria may flare up in these hot spots whenever favourable transmission conditions arise. Health authorities have been advised to establish control measures in these selected hot spots for timely prevention. CONCLUSION There is a need for adequate monitoring and allocation of available resources for better interventions in the malaria hotspots. The GIS model used in this study can be used, even at village or cluster level, to pin point the malaria hot spots, and information can be updated and retrieved easily.
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Affiliation(s)
- M J Nath
- Defence Research Laboratory, Tezpur, Sonitpur, Assam, India
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Dhiman S, Yadav K, Goswami D, Das NG, Baruah I, Singh L. Epidemiology and Risk Analysis of Malaria among Pregnant Women. Iran J Public Health 2012; 41:1-8. [PMID: 23113116 PMCID: PMC3481657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Accepted: 11/22/2011] [Indexed: 11/04/2022]
Abstract
Malaria remains a complex problem during the pregnancy, which threatens > 35 millions pregnant women every year. Malaria pathogenesis in pregnancy results in accumulation of infected RBCs in the intervillous spaces causing severe alterations leading to the reduced materno-foetal exchanges. In this article we have revisited the current evidences of clinical implications and overall burden of malaria in pregnancy. Many adverse aftermaths including, low birth weight, intrauterine growth retardation, preterm delivery, stillbirth and anemia were found associated with malaria in pregnant women. Despite of worldwide comprehensive control programmes for malaria in pregnancy, the disease control has been a daunting task everywhere. Socio cultural, economical, lack of awareness and various logistic problems compound the disease in developing countries. Thorough evidence based information and estimates, education and awareness and strengthening of prevention programmes are needed urgently to achieve success in malaria control in pregnancy.
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Affiliation(s)
- S Dhiman
- Corresponding Author: Tel: +91 3712 258538/ 34, E-mail address: Sunil Dhiman –
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