METHODS: Using parasite clearance data from 714 patients with knowlesi malaria and enrolled in three trials, the Worldwide Antimalarial Resistance Network (WWARN) Parasite Clearance Estimator (PCE) standard two-stage approach and Bayesian hierarchical modelling were compared. Both methods estimate the parasite clearance rate from a model that incorporates a lag phase, slope, and tail phase for the parasitaemia profiles.
RESULTS: The standard two-stage approach successfully estimated the parasite clearance rate for 678 patients, with 36 (5%) patients excluded due to an insufficient number of available parasitaemia measurements. The Bayesian hierarchical estimation method was applied to the parasitaemia data of all 714 patients. Overall, the Bayesian method estimated a faster population mean parasite clearance (0.36/h, 95% credible interval [0.18, 0.65]) compared to the standard two-stage method (0.26/h, 95% confidence interval [0.11, 0.46]), with better model fits (compared visually). Artemisinin-based combination therapy (ACT) is more effective in treating P. knowlesi than chloroquine, as confirmed by both methods, with a mean estimated parasite clearance half-life of 2.5 and 3.6 h, respectively using the standard two-stage method, and 1.8 and 2.9 h using the Bayesian method.
CONCLUSION: For clinical studies of P. knowlesi with frequent parasite measurements, the standard two-stage approach (WWARN's PCE) is recommended as this method is straightforward to implement. For studies with fewer parasite measurements per patient, the Bayesian approach should be considered. Regardless of method used, ACT is more efficacious than chloroquine, confirming the findings of the original trials.
Methods: Streptomyces strains' growth curves, namely SUK 12 and SUK 48, were measured and P. falciparum 3D7 IC50 values were calculated. Metabolomics analysis was conducted on both strains' mid-exponential and stationary phase extracts.
Results: The most successful antiplasmodial activity of SUK 12 and SUK 48 extracts shown to be at the stationary phase with IC50 values of 0.8168 ng/mL and 0.1963 ng/mL, respectively. In contrast, the IC50 value of chloroquine diphosphate (CQ) for antiplasmodial activity was 0.2812 ng/mL. The univariate analysis revealed that 854 metabolites and 14, 44 and three metabolites showed significant differences in terms of strain, fermentation phase, and their interactions. Orthogonal partial least square-discriminant analysis and S-loading plot putatively identified pavettine, aurantioclavine, and 4-butyldiphenylmethane as significant outliers from the stationary phase of SUK 48. For potential isolation, metabolomics approach may be used as a preliminary approach to rapidly track and identify the presence of antimalarial metabolites before any isolation and purification can be done.
STUDY DESIGN AND SETTING: Scientific databases were systematically searched to identify relevant trials of HCQ/CQ for the treatment of COVID-19 published up to 10 September 2020. The Cochrane risk-of-bias tools for randomized trials and non-randomized trials of interventions were used to assess risk of bias in the included studies. A 10-item Consolidated Standards of Reporting Trials (CONSORT) harm extension was used to assess quality of harm reporting in the included trials.
RESULTS: Sixteen trials, including fourteen randomized trials and two non-randomized trials, met the inclusion criteria. The results from the included trials were conflicting and lacked effect estimates adjusted for baseline disease severity or comorbidities in many cases, and most of the trials recruited a fairly small cohort of patients. None of the clinical trials met the CONSORT criteria in full for reporting harm data in clinical trials. None of the 16 trials had an overall 'low' risk of bias, while four of the trials had a 'high', 'critical', or 'serious' risk of bias. Biases observed in these trials arise from the randomization process, potential deviation from intended interventions, outcome measurements, selective reporting, confounding, participant selection, and/or classification of interventions.
CONCLUSION: In general, the quality of currently available evidence for the effectiveness of CQ/HCQ in patients with COVID-19 is suboptimal. The importance of a properly designed and reported clinical trial cannot be overemphasized amid the COVID-19 pandemic, and its dismissal could lead to poorer clinical and policy decisions, resulting in wastage of already stretched invaluable health care resources.
RESULTS: The pharmacophore modelling mode of 5RE6 displayed two Hydrogen Bond Acceptors (HBA) and one Hydrophobic (HY) interaction. Besides, the pharmacophore model of 5REX showed two HBA and two HY interactions. Finally, the pharmacophore model of 5RFZ showed three HBA and one HY interaction. Based on ligand-based approach, 20 Schiff-based vanillin derivatives, showed strong MPro inhibition activity. This was due to their good alignment and common features to PDB-5RE6. Similarly, monolaurin and tetrodotoxin displayed some significant activity against SARS-CoV-2. From structure-based approach, vanillin derivatives (1) to (12) displayed some potent MPro inhibition against SARS-CoV-2. Favipiravir, chloroquine and hydroxychloroquine also showed some significant MPro inhibition.
Materials and Methods: This study was conducted using the livers of 18 mice fixed in 10% neutral-buffered formalin. A completely randomized design with a unidirectional pattern comprising six treatments was used in this study, with each treatment consisting of three replications. Treatment 0 was the negative control group infected with P. berghei, treatment 1 was the positive control group infected with P. berghei followed by chloroquine administration at a dose of 5 mg/kg BW, and treatments 2, 3, 4, and 5 were groups infected with P. berghei and administered Malacca leaf ethanolic extracts at doses of 100, 300, 600, and 1200 mg/kg BW, respectively. The extracts were administered orally using a gastric tube for 4 consecutive days. Mice were sacrificed on the 7th day and livers were collected for histopathological examination.
Results: Histopathological examination of the livers of mice infected with P. berghei demonstrated the presence of hemosiderin, hydropic degeneration, fat degeneration, necrosis, and megalocytosis. However, all these histopathological changes were reduced in the livers of P. berghei-infected mice treated with various doses of Malacca leaf ethanolic extract. The differences between the treatments were found be statistically significant (p<0.05).
Conclusion: Ethanolic extract of Malacca leaves has the potential to protect against liver damage in mice infected with P. berghei. The dose of 600 mg/kg BW was found to be the most effective compared with the doses of 100, 300, and 1200 mg/kg BW.