scholarly journals A Novel Innate Immune-Enhancement Strategy Combined with IVIG Rescues Mice from FatalStaphylococcus aureusSepticemia

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Gowrisankar Rajam ◽  
Gabrielle M. Hammons ◽  
George M. Carlone ◽  
Jacquelyn S. Sampson ◽  
Edwin W. Ades
Keyword(s):  
Immune Therapy ◽  
Innate Immune ◽  
Control Group ◽  
Amino Acid Peptide ◽  
Resistant Strains ◽  
Immune Enhancement ◽  
Opsonophagocytic Killing ◽  
Drug Resistant Strains

Staphylococcus aureus(SA) is a major community-acquired pathogen. The emergence of drug-resistant strains like, methicillin-resistant SA (MRSA), poses stiff challenges to therapeutic intervention. Passive immune-therapy with specific antibodies is being actively examined to treat fulminant infections with limited success. In this study, we demonstrate that P4, a 28-amino acid peptide, derived from pneumococcal surface adhesin A along with pathogen-specific antibody (IVIG; P4 therapy) is successful in enhancing the opsonophagocytic killing (OPK) ofS. aureus in vitro. We questioned if it is possible to expand P4 therapy to treat staphylococcal infectionsin vivo. P4 therapy in combination with IVIG rescued 7/10 morbidly illS. aureus-infected mice while only 2/10 survived in the control group.

scholarly journals Evaluation of a Novel Therapeutic Approach to Treating Severe Pneumococcal Infection Using a Mouse Model

2009 ◽  
Vol 16 (6) ◽  
pp. 806-810 ◽  
Author(s):  
Nikkol Melnick ◽  
Gowrisankar Rajam ◽  
George M. Carlone ◽  
Jacquelyn S. Sampson ◽  
Edwin W. Ades
Keyword(s):  
Single Dose ◽  
Combination Therapy ◽  
Polymorphonuclear Leukocytes ◽  
Low Dose ◽  
Control Level ◽  
Pneumococcal Infection ◽  
Amino Acid Peptide ◽  
Opsonophagocytic Killing

ABSTRACT P4, a 28-amino-acid peptide, is a eukaryotic cellular activator that enhances specific in vitro opsonophagocytic killing of multiple bacterial pathogens. In a previous study, we successfully recreated this phenomenon in mice in vivo by using a two-dose regimen of P4 and pathogen-specific antibodies, which significantly reduced moribundity in mice. For the present study, we hypothesized that the inclusion of a low-dose antibiotic would make it possible to treat the infected mice with a single dose containing a mixture of P4 and a pathogen-specific antibody. A single dose consisting of P4, intravenous immunoglobulin (IVIG), and ceftriaxone effectively reduced moribundity compared to that of untreated controls (n = 10) by 75% (P < 0.05) and rescued all (10 of 10) infected animals (P < 0.05). If rescued animals were reinfected with Streptococcus pneumoniae and treated with a single dose containing P4, IVIG, and ceftriaxone, they could be rerescued. This observation of the repeated successful use of P4 combination therapy demonstrates a low risk of tolerance development. Additionally, we examined the polymorphonuclear leukocytes (PMN) derived from infected mice and observed that P4 enhanced in vitro opsonophagocytic killing (by >80% over the control level; P < 0.05). This finding supports our hypothesis that PMN are activated by P4 during opsonophagocytosis and the recovery of mice from pneumococcal infection. P4 peptide-based combination therapy may offer an alternative and rapid immunotherapy to treat fulminant pneumococcal infection.

scholarly journals In Vitro and In Vivo Antimalarial Activities of a Carbohydrate Antibiotic, Prumycin, against Drug-resistant Strains of Plasmodia

2004 ◽  
Vol 57 (6) ◽  
pp. 400-402 ◽  
Author(s):  
KAZUHIKO OTOGURO ◽  
AKI ISHIYAMA ◽  
MIYUKI KOBAYASHI ◽  
HITOMI SEKIGUCHI ◽  
TAKASHI IZUHARA ◽  
...  
Keyword(s):  
Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

scholarly journals Sontochin as a Guide to the Development of Drugs against Chloroquine-Resistant Malaria

2012 ◽  
Vol 56 (7) ◽  
pp. 3475-3480 ◽  
Author(s):  
Sovitj Pou ◽  
Rolf W. Winter ◽  
Aaron Nilsen ◽  
Jane Xu Kelly ◽  
Yuexin Li ◽  
...  
Keyword(s):  
Multidrug Resistant ◽  
Plasmodium Yoelii ◽  
Significant Activity ◽  
Drug Resistant ◽  
Content Type ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Derivatives Of

ABSTRACTSontochin was the original chloroquine replacement drug, arising from research by Hans Andersag 2 years after chloroquine (known as “resochin” at the time) had been shelved due to the mistaken perception that it was too toxic for human use. We were surprised to find that sontochin, i.e., 3-methyl-chloroquine, retains significant activity against chloroquine-resistant strains ofPlasmodium falciparum in vitro. We prepared derivatives of sontochin, “pharmachins,” with alkyl or aryl substituents at the 3 position and with alterations to the 4-position side chain to enhance activity against drug-resistant strains. Modified with an aryl substituent in the 3 position of the 7-chloro-quinoline ring, Pharmachin 203 (PH-203) exhibits low-nanomolar 50% inhibitory concentrations (IC50s) against drug-sensitive and multidrug-resistant strains andin vivoefficacy against patent infections ofPlasmodium yoeliiin mice that is superior to chloroquine. Our findings suggest that novel 3-position aryl pharmachin derivatives have the potential for use in treating drug resistant malaria.

Synthesis and antimalarial activity of new 4-aminoquinolines active against drug resistant strains

RSC Advances ◽  
2016 ◽  
Vol 6 (107) ◽  
pp. 105676-105689 ◽  
Author(s):  
Srinivasarao Kondaparla ◽  
Awakash Soni ◽  
Ashan Manhas ◽  
Kumkum Srivastava ◽  
Sunil K. Puri ◽  
...  
Keyword(s):  
Antimalarial Activity ◽  
Drug Resistant ◽  
New Class ◽  
Resistant Strains ◽  
Drug Resistant Strains

In the present study we have synthesized a new class of 4-aminoquinoline derivatives and bioevaluated them for antimalarial activity against theP. falciparum in vitro(3D7 & K1) andP. yoelii in vivo(N-67 strain).

scholarly journals The antimalarial efficacy and mechanism of resistance of the novel chemotype DDD01034957

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Celia Miguel-Blanco ◽  
James M. Murithi ◽  
Ernest Diez Benavente ◽  
Fiona Angrisano ◽  
Katarzyna A. Sala ◽  
...  
Keyword(s):  
Resistance Mechanism ◽  
Parasite Burden ◽  
Metabolic Clearance ◽  
The Novel ◽  
Control Programmes ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Fast Acting

AbstractNew antimalarial therapeutics are needed to ensure that malaria cases continue to be driven down, as both emerging parasite resistance to frontline chemotherapies and mosquito resistance to current insecticides threaten control programmes. Plasmodium, the apicomplexan parasite responsible for malaria, causes disease pathology through repeated cycles of invasion and replication within host erythrocytes (the asexual cycle). Antimalarial drugs primarily target this cycle, seeking to reduce parasite burden within the host as fast as possible and to supress recrudescence for as long as possible. Intense phenotypic drug screening efforts have identified a number of promising new antimalarial molecules. Particularly important is the identification of compounds with new modes of action within the parasite to combat existing drug resistance and suitable for formulation of efficacious combination therapies. Here we detail the antimalarial properties of DDD01034957—a novel antimalarial molecule which is fast-acting and potent against drug resistant strains in vitro, shows activity in vivo, and possesses a resistance mechanism linked to the membrane transporter PfABCI3. These data support further medicinal chemistry lead-optimization of DDD01034957 as a novel antimalarial chemical class and provide new insights to further reduce in vivo metabolic clearance.

scholarly journals Multistage antiplasmodial activity of hydroxyethylamine compounds, in vitro and in vivo evaluations

RSC Advances ◽  
2020 ◽  
Vol 10 (58) ◽  
pp. 35516-35530
Author(s):  
Neha Sharma ◽  
Yash Gupta ◽  
Meenakshi Bansal ◽  
Snigdha Singh ◽  
Prateek Pathak ◽  
...  
Keyword(s):  
Human Population ◽  
Antiplasmodial Activity ◽  
Drug Resistant ◽  
Fast Growing ◽  
Resistant Strains ◽  
Global Threat ◽  
Drug Resistant Strains

Malaria, a global threat to the human population, remains a challenge partly due to the fast-growing drug-resistant strains of Plasmodium species.

scholarly journals In Vitro Efficacies, ADME, and Pharmacokinetic Properties of Phenoxazine Derivatives Active against Mycobacterium tuberculosis

2019 ◽  
Vol 63 (11) ◽  
Author(s):  
Lloyd Tanner ◽  
Joanna C. Evans ◽  
Ronnett Seldon ◽  
Audrey Jordaan ◽  
Digby F. Warner ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Infected Animal ◽  
Mechanisms Of Action ◽  
Drug Resistant ◽  
Content Type ◽  
Pharmacokinetic Properties ◽  
Resistant Strains ◽  
Drug Resistant Strains

ABSTRACT Mycobacterium tuberculosis, the causative agent of tuberculosis, remains a leading infectious killer globally, demanding the urgent development of faster-acting drugs with novel mechanisms of action. Riminophenazines such as clofazimine are clinically efficacious against both drug-susceptible and drug-resistant strains of M. tuberculosis. We determined the in vitro anti-M. tuberculosis activities, absorption, distribution, metabolism, and excretion properties, and in vivo mouse pharmacokinetics of a series of structurally related phenoxazines. One of these, PhX1, displayed promising drug-like properties and potent in vitro efficacy, supporting its further investigation in an M. tuberculosis-infected animal model.

scholarly journals Modified Fixed-Ratio Isobologram Method for Studying In Vitro Interactions between Atovaquone and Proguanil or Dihydroartemisinin against Drug-Resistant Strains of Plasmodium falciparum

2004 ◽  
Vol 48 (11) ◽  
pp. 4097-4102 ◽  
Author(s):  
Quinton L. Fivelman ◽  
Ipemida S. Adagu ◽  
David C. Warhurst
Keyword(s):  
Plasmodium Falciparum ◽  
Treatment Failure ◽  
Resistant Strain ◽  
Fixed Ratio ◽  
Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
In Vitro Interactions

ABSTRACT A modified fixed-ratio isobologram method for studying the in vitro interactions between antiplasmodial drugs is described. This method was used to examine the interactions between atovaquone, proguanil, and dihydroartemisinin. The interaction between atovaquone and proguanil was synergistic against atovaquone-sensitive strains K1 and T996; however, there was a loss of synergy against atovaquone-resistant strain NGATV01 isolated after Malarone (the combination of atovaquone and proguanil) treatment failure. While the interaction between atovaquone and dihydroartemisinin was indifferent against isolate NGATV01, the interaction displayed indifference tending toward antagonism against the atovaquone-sensitive strains tested. The relevance of in vitro interactions to in vivo treatment is discussed.

scholarly journals Antimalarial Activity of Phenylthiazolyl-Bearing Hydroxamate-Based Histone Deacetylase Inhibitors

2008 ◽  
Vol 52 (10) ◽  
pp. 3467-3477 ◽  
Author(s):  
Geoffrey S. Dow ◽  
Yufeng Chen ◽  
Katherine T. Andrews ◽  
Diana Caridha ◽  
Lucia Gerena ◽  
...  
Keyword(s):  
Histone Deacetylase ◽  
Half Life ◽  
Histone Deacetylase Inhibitors ◽  
Antimalarial Activity ◽  
Relative Bioavailability ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Oral Doses

ABSTRACT The antimalarial activity and pharmacology of a series of phenylthiazolyl-bearing hydroxamate-based histone deacetylase inhibitors (HDACIs) was evaluated. In in vitro growth inhibition assays approximately 50 analogs were evaluated against four drug resistant strains of Plasmodium falciparum. The range of 50% inhibitory concentrations (IC50s) was 0.0005 to >1 μM. Five analogs exhibited IC50s of <3 nM, and three of these exhibited selectivity indices of >600. The most potent compound, WR301801 (YC-2-88) was shown to cause hyperacetylation of P. falciparum histones, which is a marker for HDAC inhibition in eukaryotic cells. The compound also inhibited malarial and mammalian HDAC activity in functional assays at low nanomolar concentrations. WR301801 did not exhibit cures in P. berghei-infected mice at oral doses as high as 640 mg/kg/day for 3 days or in P. falciparum-infected Aotus lemurinus lemurinus monkeys at oral doses of 32 mg/kg/day for 3 days, despite high relative bioavailability. The failure of monotherapy in mice may be due to a short half-life, since the compound was rapidly hydrolyzed to an inactive acid metabolite by loss of its hydroxamate group in vitro (half-life of 11 min in mouse microsomes) and in vivo (half-life in mice of 3.5 h after a single oral dose of 50 mg/kg). However, WR301801 exhibited cures in P. berghei-infected mice when combined at doses of 52 mg/kg/day orally with subcurative doses of chloroquine. Next-generation HDACIs with greater metabolic stability than WR301801 may be useful as antimalarials if combined appropriately with conventional antimalarial drugs.

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