Comparison of Dihydrofolate Reductase Activities for Folic Acid in Pigs and Rats Using In Vivo and In Vitro Evaluation Techniques.

AbstractIn 2005, the Nigerian Federal Ministry of Health revised the treatment policy for uncomplicated malaria with the introduction of artemisinin-based combination therapies (ACTs). This policy change discouraged the use of Sulphadoxine-pyrimethamine (SP) as the second-line treatment of uncomplicated falciparum malaria. However, SP is used as an intermittent preventive treatment of malaria in pregnancy (IPTp) and seasonal malaria chemoprevention (SMC) in children aged 3–59 months. There have been increasing reports of SP resistance especially in the non-pregnant population in Nigeria, thus, the need to continually monitor the efficacy of SP as IPTp and SMC by estimating polymorphisms in dihydropteroate synthetase (dhps) and dihydrofolate reductase (dhfr) genes associated with SP resistance. The high resolution-melting (HRM) assay was used to investigate polymorphisms in codons 51, 59, 108 and 164 of the dhfr gene and codons 437, 540, 581 and 613 of the dhps gene. DNA was extracted from 271 dried bloodspot filter paper samples obtained from children (< 5 years old) with uncomplicated malaria. The dhfr triple mutant I51R59N108, dhps double mutant G437G581 and quadruple dhfr I51R59N108 + dhps G437 mutant haplotypes were observed in 80.8%, 13.7% and 52.8% parasites, respectively. Although the quintuple dhfr I51R59N108 + dhps G437E540 and sextuple dhfr I51R59N108 + dhps G437E540G581 mutant haplotypes linked with in-vivo and in-vitro SP resistance were not detected, constant surveillance of these haplotypes should be done in the country to detect any change in prevalence.

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A new dual function orodissolvable/dispersible meclizine HCL tablet to challenge patient inconvenience: in vitro evaluation and in vivo assessment in human volunteers

Drug Delivery and Translational Research ◽

10.1007/s13346-020-00889-z ◽

2021 ◽

Author(s):

Alaa Y. Darwesh ◽

Marwa S. El-Dahhan ◽

Mahasen M. Meshali

Keyword(s):

Dual Function ◽

In Vitro Evaluation ◽

Human Volunteers ◽

In Vivo Assessment

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Inhibition of Kirsten-Ras reduces fibrosis and protects against renal dysfunction in a mouse model of chronic folic acid nephropathy

Scientific Reports ◽

10.1038/s41598-019-50422-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Lucy J. Newbury ◽

Jui-Hui Wang ◽

Gene Hung ◽

Bruce M. Hendry ◽

Claire C. Sharpe

Keyword(s):

Folic Acid ◽

Kidney Disease ◽

Mouse Model ◽

Renal Dysfunction ◽

Antisense Oligonucleotides ◽

Underlying Mechanism ◽

Therapeutic Benefit ◽

End Stage

Abstract Chronic Kidney Disease is a growing problem across the world and can lead to end-stage kidney disease and cardiovascular disease. Fibrosis is the underlying mechanism that leads to organ dysfunction, but as yet we have no therapeutics that can influence this process. Ras monomeric GTPases are master regulators that direct many of the cytokines known to drive fibrosis to downstream effector cascades. We have previously shown that K-Ras is a key isoform that drives fibrosis in the kidney. Here we demonstrate that K-Ras expression and activation are increased in rodent models of CKD. By knocking down expression of K-Ras using antisense oligonucleotides in a mouse model of chronic folic acid nephropathy we can reduce fibrosis by 50% and prevent the loss of renal function over 3 months. In addition, we have demonstrated in vitro and in vivo that reduction of K-Ras expression is associated with a reduction in Jag1 expression; we hypothesise this is the mechanism by which targeting K-Ras has therapeutic benefit. In conclusion, targeting K-Ras expression with antisense oligonucleotides in a mouse model of CKD prevents fibrosis and protects against renal dysfunction.

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In situ gels of Metoclopramide Hydrochloride for intranasal delivery: In vitro evaluation and in vivo pharmacokinetic study in rabbits

Drug Delivery ◽

10.3109/10717540903447194 ◽

2009 ◽

Vol 17 (1) ◽

pp. 19-27 ◽

Cited By ~ 35

Author(s):

Hitendra S. Mahajan ◽

Surendra Gattani

Keyword(s):

Pharmacokinetic Study ◽

Intranasal Delivery ◽

In Vitro Evaluation ◽

Metoclopramide Hydrochloride

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Molecular Basis of In Vivo Resistance to Sulfadoxine-Pyrimethamine in African Adult Patients Infected withPlasmodium falciparum Malaria Parasites

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.7.1811 ◽

1998 ◽

Vol 42 (7) ◽

pp. 1811-1814 ◽

Cited By ~ 45

Author(s):

Leonardo K. Basco ◽

Rachida Tahar ◽

Pascal Ringwald

Keyword(s):

Dihydrofolate Reductase ◽

Point Mutations ◽

Gene Mutations ◽

Adult Patients ◽

Wild Type ◽

Dihydropteroate Synthase ◽

Reductase Gene ◽

Parasite Populations

ABSTRACT In vitro sulfadoxine and pyrimethamine resistance has been associated with point mutations in the dihydropteroate synthase and dihydrofolate reductase domains, respectively, but the in vivo relevance of these point mutations has not been well established. To analyze the correlation between genotype and phenotype, 10 Cameroonian adult patients were treated with sulfadoxine-pyrimethamine and followed up for 28 days. After losses to follow-up (n = 1) or elimination of DNA samples due to mixed parasite populations with pyrimethamine-sensitive and pyrimethamine-resistant profiles (n = 3), parasite genomic DNA from day 0 blood samples of six patients were analyzed by DNA sequencing. Three patients who were cured had isolates characterized by a wild-type or mutant dihydrofolate reductase gene (with one or two mutations) and a wild-type dihydropteroate synthase gene. Three other patients who failed to respond to sulfadoxine-pyrimethamine treatment carried isolates with triple dihydrofolate reductase gene mutations and either a wild-type or a mutant dihydropteroate synthase gene. Three dihydrofolate reductase gene codons (51, 59, and 108) may be reliable genetic markers that can accurately predict the clinical outcome of sulfadoxine-pyrimethamine treatment in Africa.

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