Search

The accumulation of heavy metals (i.e., As, Cu, Ni, Pb, and Zn) in soils and native plant species near copper, nickel, and pyrite mines in Vietnam was assessed. The highest soil As, Cu, Ni, Pb, and Zn concentrations recorded in mine soils were 42.3, 1570, 9870, 128, and 462 mg/kg, and those in agricultural soils were 11.4, 453, 94.9, 34.4, and 147 mg/kg, respectively. Pollution index (PI) values indicated heavy pollution (PI = 3.99-13.0) for mine soils, and unpolluted to severely polluted (PI = 0.65-2.84) for agricultural soils. Soil enrichment factors had a wide range, from minimal to extreme enrichment of heavy metals (EF = 0.03-91.4). Arsenic minerals may be the main source of high As concentrations in sulfide mines. The As, Cu, Ni, Pb, and Zn concentrations of 20 native plant species near three mines were in the ranges of 0.05-1150, 3.17-123, 0.47-291, 0.08-6.34, and 6.87-168 mg/kg (dry weight, DW), respectively. Based on the recorded hyperaccumulation levels (1150 mg/kg, DW), bioaccumulation factors (BAF = 2.4-90.0), biomass, and rapid growth, Pteris vittata L. is considered a promising plant for phytoextraction of As in soils. Bidens pilosa L. has potential for phytostabilization of sulfide-bearing soils, given its low concentrations of heavy metals in plant shoots, BAF values of <1, high biomass, and wide distribution. Integrated phytoremediation and phytomanagement are applicable to metal-contaminated soils. Phytomining, energy crops, and vegetation cover should be investigated for the phytomanagement of metal-contaminated soils in mining areas., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The present article describes the synthesis and biological activity of various series of novel hydroxamic acids incorporating quinazolin-4(3H)-ones as novel small molecules targeting histone deacetylases. Biological evaluation showed that these hydroxamic acids were potently cytotoxic against three human cancer cell lines (SW620, colon; PC-3, prostate; NCI-H23, lung). Most compounds displayed superior cytotoxicity than SAHA (suberoylanilide hydroxamic acid, Vorinostat) in term of cytotoxicity. Especially, N-hydroxy-7-(7-methyl-4-oxoquinazolin-3(4H)-yl)heptanamide (5b) and N-hydroxy-7-(6-methyl-4-oxoquinazolin-3(4H)-yl)heptanamide (5c) (IC 50 values, 0.10-0.16 μm) were found to be approximately 30-fold more cytotoxic than SAHA (IC 50 values of 3.29-3.67 μm). N-Hydroxy-7-(4-oxoquinazolin-3(4H)-yl)heptanamide (5a; IC 50 values of 0.21-0.38 μm) was approximately 10- to 15-fold more potent than SAHA in cytotoxicity assay. These compounds also showed comparable HDAC inhibition potency with IC 50 values in sub-micromolar ranges. Molecular docking experiments indicated that most compounds, as represented by 5b and 5c, strictly bound to HDAC2 at the active binding site with binding affinities much higher than that of SAHA., (© 2019 Wiley-VHCA AG, Zurich, Switzerland.)

In our search for novel histone deacetylases inhibitors, we have designed and synthesized a series of novel hydroxamic acids and N-hydroxybenzamides incorporating quinazoline heterocycles (4a - 4i, 6a - 6i). Bioevaluation showed that these quinazoline-based hydroxamic acids and N-hydroxybenzamides were potently cytotoxic against three human cancer cell lines (SW620, colon; PC-3, prostate; NCI-H23, lung). In term of cytotoxicity, several compounds, e.g., 4g, 4c, 4g - 4i, 6c, and 6h, displayed from 5- up to 10-fold higher potency than SAHA (suberoylanilidehydroxamic acid, vorinostat). The compounds were also generally comparable to SAHA in inhibiting HDACs with IC 50 values in sub-micromolar range. Some compounds, e.g., 4g, 6c, 6e, and 6h, were even more potent HDAC inhibitors compared to SAHA in HeLa extract assay. Docking studies demonstrated that the compounds tightly bound to HDAC2 at the active binding site with binding affinities higher than that of SAHA. Detailed investigation on the estimation of absorption, distribution, metabolism, excretion, and toxicity (ADMET) suggested that compounds 4g, 6c, and 6g, while showing potent HDAC2 inhibitory activity and cytotoxicity, also potentially displayed ADMET characteristics desirable to be expected as promising anticancer drug candidates., (© 2018 Wiley-VHCA AG, Zurich, Switzerland.)

ZSM-5/SBA-15 composite materials with different acidities and mesoporous system formations were successfully synthesized by three-step method. The catalysts were characterized by XRD, HR-TEM, BET, EDX and TPD-NH3 methods. It showed that the Si/Al molar ratio had effect on the formation and property of materials. Among synthesized catalysts with the different Si/Al molar ratios of 30 (HZSC-30), 50 (HZSC-50), 70 (HZSC-70), HZSC-50 catalyst had better mesoporous system formation and acidity. These properties helped this catalyst to have higher catalytic activity in 1,3,5-triisopropylbenzene cracking reaction than other studied catalysts in term of higher benzene product yield. In comparison to HZSM-5 microporous material that had the similar Si/Al molar ratio of 50, it showed that the formation of mesopore system of HZSC-50 catalyst had a major improvement on the cracking catalytic activity.

In our search for novel small molecules targeting histone deacetylases, we have designed and synthesized several series of novel N-hydroxybenzamides/N-hydroxypropenamides incorporating quinazolin-4(3H)-ones (4a-h, 8a-d, 10a-d). Biological evaluation showed that these hydroxamic acids were generally cytotoxic against three human cancer cell lines (SW620, colon; PC-3, prostate; NCI-H23, lung cancer). It was found that the N-hydroxypropenamides (10a-d) were the most potent, both in term of HDAC inhibition and cytotoxicity. Several compounds, e.g. 4e, 8b-c, and 10a-c, displayed up to 4-fold more potent than SAHA (suberoylanilide hydroxamic acid, vorinostat) in term of cytotoxicity. These compounds also comparably inhibited HDACs with IC 50 values in sub-micromolar range. Docking experiments on HDAC2 isozyme revealed some important features contributing to the inhibitory activity of synthesized compounds, especially for propenamide analogues. Importantly, the free binding energy computed was found to have high quantitative correlation (R 2  ∼ 95%) with experimental results., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objectives: To compare the safety, efficacy and acceptability of quinacrine sterilization (QS), tubectomy and vasectomy in Vietnam., Methods: This study was initiated in January 1998 and completed in February 2000. A sample of 9 districts in 5 provinces, where the prevalence of QS was known to be high, was selected. Every person sterilized in these 9 districts between January 1, 1988 and March 31, 1998 was identified and systematically interviewed by family planning clinicians who had received special training for this project., Results: A total of 15,982 sterilization users were identified and 15,190 were interviewed and examined, including a gynecologic exam, if needed: a follow-up rate of 95%. Of those interviewed, 9,753 used tubectomy, 3,734 used QS and 1,703 used vasectomy. All three methods were found to be safe, although morbidity associated with tubectomy was more serious than with QS or vasectomy. No deaths were reported. After more than 5 years of follow-up, tubectomy had the lowest failure rate: 1.0%, followed by 4.1% with vasectomy. A pregnancy rate of 13.2% was reported with quinacrine, although only a small fraction of these failures were confirmed. A strong preference for QS was found., Conclusion: QS has an important role to play in sterilization services in Vietnam., (© 2003 International Federation of Gynecology and Obstetrics.)

Objectives: To compare the safety, efficacy and acceptability of quinacrine sterilization (QS), tubectomy and vasectomy in Vietnam., Methods: This study was initiated in January 1998 and completed in February 2000. A sample of 9 districts in 5 provinces, where the prevalence of QS was known to be high, was selected. Every person sterilized in these 9 districts between January 1, 1988 and March 31, 1998 was identified and systematically interviewed by family planning clinicians who had received special training for this project., Results: A total of 15,982 sterilization users were identified and 15,190 were interviewed and examined, including a gynecologic exam, if needed: a follow-up rate of 95%. Of those interviewed, 9,753 used tubectomy, 3,734 used QS and 1,703 used vasectomy. All three methods were found to be safe, although morbidity associated with tubectomy was more serious than with QS or vasectomy. No deaths were reported. After more than 5 years of follow-up, tubectomy had the lowest failure rate: 1.0%, followed by 4.1% with vasectomy. A pregnancy rate of 13.2% was reported with quinacrine, although only a small fraction of these failures were confirmed. A strong preference for QS was found., Conclusion: QS has an important role to play in sterilization services in Vietnam.

Objective: To determine the rates of ectopic pregnancy with the use of quinacrine sterilization (QS) compared to other methods and no method (non-users)., Methods: Four provinces were selected for their above average numbers of women who had undergone QS: Nam Dinh, Nam Ha, Hai Duong and Hung Yen. Case histories related to surgical treatment of all ectopic pregnancies in these 4 provinces from 1994 through 1996 were collected from all hospitals by researchers from the Ministry of Health in June 1997. Using a questionnaire designed for this study, 120 physicians interviewed every woman in her home who had had an ectopic pregnancy during this period. If deceased, a family member was consulted. All interviews were completed in September 1998. The numbers of users of each method and nonusers were calculated from service statistics and demographic data., Results: Based on 2,551,355 woman-years of exposure, the rate of ectopic pregnancy among users per 1000 woman-years was calculated to be: 0.26 with QS; 0.42 with surgical sterilization (TL) and IUD; 0.45 with the Pill; 0.50 with condoms; 0.78 relying on withdrawal; and 1.18 among non-users., Conclusion: Ectopic pregnancy rates for QS, TL, IUD and the Pill were similar and much lower than the rate for non-users of contraception.

Objective: To determine the long-term safety of nonsurgical sterilization with quinacrine., Design: Observational cohort study., Setting: Rural provinces in northern Vietnam., Patient(s): Two thousand eight hundred forty women who had had quinacrine insertions and an age-matched comparison group of 1,658 women who had an intrauterine device (IUD) insertion between 1989 and 1993., Method(s): Interviews in 1994, 1995, and 1996 and review of available medical records. This is a planned interim analysis., Main Outcome Measure(s): Ectopic pregnancies and the occurrence of other adverse health events., Result(s): Over 90% of women were interviewed at least once. Despite matching on age, the groups differed on baseline parity. The ectopic pregnancy rates were similar after either one or two insertions and were similar to the rate of ectopic pregnancies after surgical sterilization in the United States. The quinacrine group reported more gynecologic health problems than the IUD group. However, after correcting for information bias, there was no dose-response effect between the one- and two-insertion quinacrine groups, suggesting the possibility of recall bias or differing baseline health status., Conclusion(s): Ectopic pregnancies do not appear to be increased compared with U.S. surgical sterilization rates. The data on other adverse events are more difficult to interpret.

Objective: To determine the long-term efficacy of nonsurgical sterilization with quinacrine., Design: Observational cohort study., Setting: Rural provinces in northern Vietnam., Patient(s): Two thousand seven hundred and nine women who had quinacrine insertions between 1989 and 1993., Intervention(s): Interviews in 1994, 1995, and 1996 and review of available medical records. Pregnancy rates were corrected for problems in detecting and confirming pregnancies., Main Outcome Measure(s): Pregnancy rates., Result(s): Over 90% of women were interviewed at least once. Uncorrected cumulative pregnancy rates were 12.9% at 5 y after two insertions and 27.3% after one insertion. Effectiveness varied by age group: the partially corrected pregnancy rates after two insertions were 6.8% in women 35 or older at the time of insertion and 13.0% in women under 35. A subgroup of women who received oral papaverine at the time of quinacrine insertion had lower pregnancy rates, with a cumulative uncorrected rate of 5.3% at 4 years among women of all ages., Conclusion(s): Efficacy of quinacrine appears reasonable for two insertions of quinacrine in women 35 and older. It may be possible to improve efficacy by the use of papaverine or the Hieu insertion technique.

This report presents the first population-based estimates of maternal mortality in Vietnam. All the deaths of women aged 15-49 in 1994-95 in three provinces of Vietnam were identified and classified by cause. Maternal mortality was the fifth most frequent cause of death. The maternal mortality ratio was 155 deaths per 100,000 live births. This ratio compares with the World Health Organization's estimates of 430 such deaths globally and 390 for Asia. The maternal mortality ratio in the delta regions of these provinces was half that of the mountainous and semimountainous regions. Because a larger proportion of the Vietnamese population live in delta regions than elsewhere, the maternal mortality ratio for Vietnam as a whole may be lower than that of the three provinces studied. Maternal mortality is low in Vietnam primarily because a relatively high proportion of deliveries take place in clinics and hospitals, where few women die in childbirth. Also, few women die of the consequences of induced abortion in Vietnam because the procedure is legal and easily available.

The quinacrine method of non-surgical female sterilisation involves transcervical intrauterine insertion of 252 mg quinacrine as pellets during the proliferative phase of the menstrual cycle; the drug causes inflammation and fibrosis of the proximal fallopian tube. We have carried out a field trial of 31,781 cases in twenty-four provinces of Vietnam from Jan 2, 1989, until October, 1992. There were 818 pregnancies after the procedure, of which 80 were carried to term. Some women received only one dose of quinacrine; the majority received two doses with an interval of one month. Cumulative life-table pregnancy rates per 100 women at 1 year (for studies of at least 50 cases followed for 12 months) were 2.63 (SE 0.17) among 9461 women who received two doses and 5.15 (0.48) among 2225 who received only one dose. Failure rates (pregnancies) were strongly affected by the skill of the doctor or midwife. There were no deaths and only 8 serious complications were reported (0.03%); by contrast, in a similar series of women undergoing surgical sterilisation, 30 deaths and between 540 and 1812 serious complications would be expected. All reported side-effects were minor and of short duration. There were 19 ectopic pregnancies and the incidence was 0.89 per 1000 woman-years of use. There was one birth defect (anencephaly), in a fetus conceived 2.5 months after quinacrine insertions; however, we believe it is not related to the procedure. An estimated 242 maternal deaths will be averted by these 31,781 sterilizations. This method is safe and acceptably effective for female sterilisation.