65 patients with uncomplicated Pl.falciparum malaria were monitored during 28 days after 5 -day -course use of artemisinine (year 1998) and 69 patients after 7 day course (year 2001). The mean fever cut time lengthened for 1,5 days in 1998 and 1,8 days in 2001.The mean parasite cut time had lengthened for 1,8 days in1998 and 2,3 days in 2001. The rate of reappearance of parasite accounted for 36,9% within 28 days follow up with 5 -day -course procedure and 7,3 % with 7 days procedure. The rate of repeated infestion was remarkable: 10/21 patients (year1998) and 3/5 (year 2001) had got recurrence. No change of EC50 was reported between the years 1998 and 2001, but an increase by 2 and 4 folds of EC90 and EC99 was reported.EC50,90 and 99% of chloroquine, mefloquine and quinine in the year 2001 decreased by 2 folds vs 1998
malaria ; malaria, falciparum ; Artemisinins ;

Background: In many years, National Institute of Malariology, Parasitology and Entomology conducted collection, storage and preservation of malaria parasites species \r\n', u'Objective: to evaluate some results of malaria parasite species collected from Daknong province and analysis of drug resistance in P.Palciparum by the polymerase chain reaction.\r\n', u'Subject and method: Malaria parasite species collected from Daknong province in 2006. Thirty-five isolates were confirmed to be resistant with chloroquin by in vitro test. Polymerase chain reaction-restriction fragment leng polymorphism were used. \r\n', u'Results: 55 Plasmodium jalciparum. 7 Plasmodium vivax. 4 Plasmodium malariae. 1 Plasmodium ovale samples were collected from the malaria patients. A preliminary analysis of drug-resistant mutations in the Plasmodium jalciparum chloroquine resistance transpory (pfcrt) and P Jalciparummulti-drug resistant genes showed that the change of the order of amino-acid of Plasmodium jalciparum was closely correlated to chloroquine resistance in 35 isolates at the mutant allele 76 of pfcrt gene of chloroquine resistant Plasmodiuntjalciparum isolates. \r\n', u'Conclusion: These results contributed to supplement malaria parasite species that were stored in National Institute of Malariology, Parasitology ad Entomology.\r\n', u'
Malaria parasite species ; polymerase chain reaction ; P.Palciparum ; drug resistance

Background: WHO recommends that malaria drug should be used with essential elements which are derivatives of artemisinin (ART) for treatment phase and limit the development of parasite (MIC). Objective: To assess in vitro effect of artemisinin powder and 10 alpha- trifluoro methyl hydroartemisinin (TEMHA) in powder and tablet form to P.falciparum. Subject and Method: 48h in vitro test of Phuc Nguyen Dinh was applied to this study. Results and Conclusions: The results showed that: for T996, IC50 values of ART, 10 alpha- TEMHA powder and 10 alpha- TEMHA pill were as follows: 37.8; 16.4 and 17.6 nM/L, respectively. For K1, IC50 values of ART, 10 alpha- TEMHA powder and 10 alpha- TEMHA pill were: 22.8; 11.4 and 12.2 nM/L, respectively. MIC values of artemisinin powder, 10 alpha- TEMHA powder and pill for T996 were as follows: 100; 40 and 40nM/L, respectively. For K1, MIC values of ART, 10 alpha- TEMHA powder and pill are: 76; 24; 32 nM/L, respectively.
10 a- trifluoro methyl hydroartemisinin ; P.falciparum

Objective: To evaluate the anti-arthritic effects of Polygonatum kingianum rhizome extract using both in vitro and in vivo models.Methods: Lipopolysaccharide-induced RAW 264.7 macrophages were treated with an ethanol extract of Polygonatum kingianum rhizomes at different concentrations to determine nitric oxide and prostaglandin E2 (PGE2) production. For in vivo study, Polygonatum kingianum ethanol extract was further investigated for its anti-inflammatory effect in a mouse model with collagen antibody-induced arthritis. Phytochemical study of Polygonatum kingianum ethanol extract was also performed. Results: Saponins (142 mg/g total yield) was the main component in the Polygonatum kingianum ethanol extract. 5α,8α-ergosterol peroxide, (E,E)-9-oxooctadeca-10,12-dienoic acid and 3-(2?-hydroxy-4?-methoxy-benzyl)-5,7-dihydroxy-8-methyl-chroman-4-one were isolated from the extract. Polygonatum kingianum ethanol extract exhibited potential anti-inflammatory effects by inhibiting nitric oxide and PGE2 production in RAW 264.7 cells in a dose-dependent manner. The level of arthritis in mice with collagen antibody-induced arthritis was significantly reduced (P<0.01) after treatment with Polygonatum kingianum ethanol extract, particularly at a dose of 1?000 mg/kg body weight. Besides, the extract demonstrated the regulatory effects on serum tumor necrosis factor-alpha, interleukin-6, and interleukin-10 in treated mice. Conclusions: Polygonatum kingianum ethanol extract has beneficial effects on inflammatory cytokine regulation and PGE2 inhibition in an experimental mouse model with collagen antibody-induced arthritis. The phytochemical screening reveals that the saponin, as the main component, and sterols (daucosterol and 5α,8α-ergosterol peroxide) from Polygonatum kingianum ethanol extract may contribute to its promising in vitro and in vivo anti-inflammatory activities.

A new crinane-type alkaloid, 6-epihydroxypowelline (1), together with six known alkaloids, lycorine (2), 2-O-acetyllycorine (3), deacetylbowdensine (4), 1-epideacetylbowdensine (5), 8-demethyl-3-oxomaritidine (6), and (-)-marithamine (7) were isolated from the whole parts of the Crinum latifolium L. in Vietnam. The structure identification of all compounds was determined by 1D, 2D-NMR as well as HR-ESI-MS spectroscopic techniques. The absolute configuration of these compounds was established by the ECD data. In addition, in vitro inhibition of acetylcholinesterase (AChE) activities was assessed for all isolated alkaloids. All alkaloids had AChE inhibitory effects, with IC50 values ranging from 32.65 ± 2.72 to 212.76 ± 8.30 µM and compound 3 displayed the strongest inhibition of AChE, with IC50 values of 32.65 ± 2.72 µM (in comparison to the reference drug, galanthamine, which had an IC50 of 2.40 ± 0.45 µM).

A new crinane-type alkaloid, 6-epihydroxypowelline (1), together with six known alkaloids, lycorine (2), 2-O-acetyllycorine (3), deacetylbowdensine (4), 1-epideacetylbowdensine (5), 8-demethyl-3-oxomaritidine (6), and (-)-marithamine (7) were isolated from the whole parts of the Crinum latifolium L. in Vietnam. The structure identification of all compounds was determined by 1D, 2D-NMR as well as HR-ESI-MS spectroscopic techniques. The absolute configuration of these compounds was established by the ECD data. In addition, in vitro inhibition of acetylcholinesterase (AChE) activities was assessed for all isolated alkaloids. All alkaloids had AChE inhibitory effects, with IC50 values ranging from 32.65 ± 2.72 to 212.76 ± 8.30 µM and compound 3 displayed the strongest inhibition of AChE, with IC50 values of 32.65 ± 2.72 µM (in comparison to the reference drug, galanthamine, which had an IC50 of 2.40 ± 0.45 µM).

A new crinane-type alkaloid, 6-epihydroxypowelline (1), together with six known alkaloids, lycorine (2), 2-O-acetyllycorine (3), deacetylbowdensine (4), 1-epideacetylbowdensine (5), 8-demethyl-3-oxomaritidine (6), and (-)-marithamine (7) were isolated from the whole parts of the Crinum latifolium L. in Vietnam. The structure identification of all compounds was determined by 1D, 2D-NMR as well as HR-ESI-MS spectroscopic techniques. The absolute configuration of these compounds was established by the ECD data. In addition, in vitro inhibition of acetylcholinesterase (AChE) activities was assessed for all isolated alkaloids. All alkaloids had AChE inhibitory effects, with IC50 values ranging from 32.65 ± 2.72 to 212.76 ± 8.30 µM and compound 3 displayed the strongest inhibition of AChE, with IC50 values of 32.65 ± 2.72 µM (in comparison to the reference drug, galanthamine, which had an IC50 of 2.40 ± 0.45 µM).

A new crinane-type alkaloid, 6-epihydroxypowelline (1), together with six known alkaloids, lycorine (2), 2-O-acetyllycorine (3), deacetylbowdensine (4), 1-epideacetylbowdensine (5), 8-demethyl-3-oxomaritidine (6), and (-)-marithamine (7) were isolated from the whole parts of the Crinum latifolium L. in Vietnam. The structure identification of all compounds was determined by 1D, 2D-NMR as well as HR-ESI-MS spectroscopic techniques. The absolute configuration of these compounds was established by the ECD data. In addition, in vitro inhibition of acetylcholinesterase (AChE) activities was assessed for all isolated alkaloids. All alkaloids had AChE inhibitory effects, with IC50 values ranging from 32.65 ± 2.72 to 212.76 ± 8.30 µM and compound 3 displayed the strongest inhibition of AChE, with IC50 values of 32.65 ± 2.72 µM (in comparison to the reference drug, galanthamine, which had an IC50 of 2.40 ± 0.45 µM).

A new crinane-type alkaloid, 6-epihydroxypowelline (1), together with six known alkaloids, lycorine (2), 2-O-acetyllycorine (3), deacetylbowdensine (4), 1-epideacetylbowdensine (5), 8-demethyl-3-oxomaritidine (6), and (-)-marithamine (7) were isolated from the whole parts of the Crinum latifolium L. in Vietnam. The structure identification of all compounds was determined by 1D, 2D-NMR as well as HR-ESI-MS spectroscopic techniques. The absolute configuration of these compounds was established by the ECD data. In addition, in vitro inhibition of acetylcholinesterase (AChE) activities was assessed for all isolated alkaloids. All alkaloids had AChE inhibitory effects, with IC50 values ranging from 32.65 ± 2.72 to 212.76 ± 8.30 µM and compound 3 displayed the strongest inhibition of AChE, with IC50 values of 32.65 ± 2.72 µM (in comparison to the reference drug, galanthamine, which had an IC50 of 2.40 ± 0.45 µM).

Objective: The risk of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from schoolchildren to their household and the protective effects of vaccination in these settings remain poorly understood. We assessed the transmission dynamics of schoolchildren with SARS-CoV-2 within their households and the protective effects of coronavirus disease (COVID-19) vaccination among household members in Viet Nam. Methods: We estimated the attack rate, vaccine effectiveness and adjusted risk ratio (aRR) of factors associated with SARS-CoV-2 transmission to household contacts of children confirmed to have COVID-19 who attended three schools in Ha Nam, Phu Tho and Thanh Hoa provinces between September and December 2021 using multivariable regression with household-level random effects. Results: This retrospective cohort study included 157 children infected with SARS-CoV-2 and their 540 household contacts. The attack rate among household contacts was 24.6% (133/540). Overall, vaccine effectiveness among household contacts was 39% (95% confidence interval [CI]: -1 to -63), higher among males than females and higher in adults aged >40 years. COVID-19 transmission was greater among female household contacts compared with males (aRR: 1.35, 95% CI: 0.94 to 1.95), although not statistically significant, and highest among those aged 19–39 years (aRR: 2.51, 95% CI: 1.50 to 4.21). Fully vaccinated household contacts had significantly lower infection risk (aRR: 0.46, 95% CI: 0.26 to 0.84). Discussion: We found substantial onward transmission of SARS-CoV-2 from schoolchildren to household members, and older people were more likely to be protected by vaccination. We recommend that schoolchildren and all household members living with schoolchildren receive at least two doses of a COVID-19 vaccine. Recognizing the role of schoolchildren in the onward transmission of COVID-19 is an important lesson learned by Viet Nam that can help not only in managing other outbreaks but also in protecting schoolchildren by predicting the progress of the outbreak and preparing for a timely response.