Apply MIKE 11 model to study impacts of climate change on water resources and develop adaptation plan in the Mekong Delta, Vietnam: a case of Can Tho city.

Can Tho city in the Mekong Delta is in the top ten areas affected by climate change. Therefore, assessing climate change impacts, social and economic activities require proposed solutions to respond to climate change. This study aims to (i) apply the MIKE 11 model (Hydrodynamic module and Advection-Dispersion module) to simulate the impacts of climate change scenarios on water resources in Can Tho city; (ii) calculate water balance in Can Tho city; and (iii) suggest climate change adaptation plan for sustainable social-economic activities of the city. The results show that when the rainfall changes due to climate change, the flow rate tends to decrease at high tide and increase at low tide. When the sea level rises due to climate change, the flow rate tends to increase at high tide and decrease at low tide. For 2030, the flow will decrease up to 15.6% and 14.3% at the low tide period for RCP 2.6 and RCP 8.5 compared to the present, respectively. The flow will increase up to 63.5% and 58.9% at the high tide period for RCP 2.6 and RCP 8.5 compared to the present, respectively. The water demand evaluation shows that the water resource reserve in Can Tho city meets water demands in current and future scenarios under climate change. While rainwater and groundwater can provide enough water in the rainy season, the city has to use surface water during the dry season due to a lack of rainwater. Of these, agriculture contributes the most water demands (85%). Eight adaptation measures to climate change for Can Tho city are developed from 2021 to 2050.

Effects of chlorpyrifos ethyl on acetylcholinesterase activity in climbing perch cultured in rice fields in the Mekong Delta, Vietnam.

Climbing perch is commonly harvested in rice fields and associated wetlands in the Mekong Delta. Despite its importance in providing food and income to local households, there is little information how this fish species is affected by the high use of pesticides in rice farming. Organophosphate insecticides, such as chlorpyrifos ethyl, which are highly toxic to aquatic organisms, are commonly used in the Mekong Delta. This study shows that the brain acetylcholinesterase (AChE) activity in climbing perch fingerlings cultured in rice fields, was significantly inhibited by a single application of chlorpyrifos ethyl, at doses commonly applied by rice farmers (0.32-0.64 kg/ha). The water concentration of chlorpyrifos ethyl decreased below the detection level within 3 days, but the inhibition of brain AChE activity remained for more than 12 days. In addition, the chlorpyrifos ethyl treatments had a significant impact on the survival and growth rates of climbing perch fingerlings, which were proportional to the exposure levels. The results indicate that the high use of pesticides among rice farmers in the Mekong Delta could have a negative impact on aquatic organisms and fish yields, with implications for the aquatic biodiversity, local people's livelihoods and the aquaculture industry in the Mekong Delta.

Effectiveness and Tolerability of First-Line Afatinib for Advanced EGFR-Mutant Non-Small Cell Lung Cancer in Vietnam.

BACKGROUND: We aimed to evaluate the effectiveness and tolerability of Afatinib as first-line treatment of advanced epidermal growth factor receptor (EGFR) mutant non small cell lung cancer (NSCLC) in a real-world setting. PATIENTS AND METHODS: This is a retrospective study of Vietnamese patients  with advanced EGFR-mutant NSCLC treated with first-line afatinib at the National Cancer Hospital from 1st January 2018 to 31st October 2020. Patients' demographic, clinical and treatment data were captured. Objective response rate (ORR), disease control rate (DCR), time to treatment failure (TTF) and tolerability were evaluated. We used Kaplan-Meier curve and log-rank test for survival, and Cox regression model for multivariate analysis. RESULTS: A total of 44 patients were included. Common EGFR mutations (Del 19/L858R) were detected in 61% patients. Fifty percent of patients with uncommon mutations had compound mutations of G719X, L861Q and S768I. The ORR was 75% while DCR rate was 98%. The median TTF was 12.3 months (95% CI: 7.2-17.3); the mTTFs were 12.3 and 10.8 months for patients with common and uncommon mutations (p = 0.001), respectively, and 14.0 and 7.5 months for patients with Del 19 and L858R mutations (p = 0.067), respectively. Afatinib 30 mg once daily was the most common starting (77%) and maintenance (64%) doses. The mTTFs were 12.3 and 7.5 months for patients with 30 mg starting dose vs 40 mg dose (p = 0.256), respectively. Diarrhea, skin rash, paronychia and fatigue were observed in 32%, 30%, 25% and 9%, respectively. There was no grade 4 toxicity except three patients with grade 3 paronychia. CONCLUSIONS: First-line afatinib is beneficial for Vietnamese patients with advanced EGFR-mutant NSCLC with a good response rate and prolonged TTF with manageable adverse event profile. Baseline brain metastasis status and starting doses do not significantly impact TTF.
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A Case Report of Primary Pulmonary Choriocarcinoma in a Man: Successful Combination of Surgery and Chemotherapy.

Choriocarcinoma is a malignant tumor that typically appears in gonadal organs and primarily occurs in women of reproductive age. Being a primary extragonadal choriocarcinoma, primary pulmonary choriocarcinoma (PPC) is an extremely rare condition. Due to the rarity of PPC, no standardized treatment has been established so far. However, surgery combined with adjuvant chemotherapy appears to be the most optimal treatment. Here, we report a rare case of a man with PPC that was successfully treated with surgery followed by chemotherapy.

Study loading capacties of air pollutant emissions for developing countries: a case of Ho Chi Minh City, Vietnam.

Ho Chi Minh City (HCMC) is one of the cities in developing countries where many concentrations of air pollutants exceeded the Vietnam national technical regulation in ambient air quality including TSP, NOx, Ozone and CO. These high pollutant concentrations have destroyed the human health of people in HCMC. Many zones in HCMC can't receive more air pollutants. The objectives of this research are: (i) Air quality modeling over HCMC by using the TAPM-CTM system model by using a bottom up air emission inventory; and (ii) Study loading capactities of air pollutant emissions over Ho Chi Minh City. Simulations of air pollution were conducted in Ho Chi Minh City (HCMC), the largest city of Vietnam by using the TAPM-CTM model. The model performance was evaluated using observed meteorological data at Tan Son Hoa station and air quality data at the Ho Chi Minh City University of Science. The model is then applied to simulate a retire 1-year period to determine the levels of air pollutants in HCMC in 2017, 2025 and 2030. The results show that the highest concentrations of CO, NO2, and O3 in 2017 exceeded the National technical regulation in ambient air quality (QCVN 05:2013) 1.5, 1.5, and 1.1 times, respectively. These values also will increase in 2025 and 2030 if the local government does not have any plan for the reduction of emissions, especially, SO2 in 2030 also will be 1.02 times higher than that in QCVN 05:2013. The emission zoning was initially studied by calculating and simulating the loading capacities of each pollutant based on the highest concentration and the National technical regulation in ambient air quality. The results show that the center of HCMC could not receive anymore the emission, even needs to reduce half of the emission. Under the easterly prevailing wind in the dry season, the high pollution was more likely to be experienced in the west of Ho Chi Minh. In contrast, the eastern regions were the upwind areas and the pollutants could transport to the downwind sectors. It was recommended that the best strategy for emission control in HCMC is avoiding industrial and urban development in the upwind areas to achieve better air quality for both areas. In the case of necessity to choose one area for development, the downwind sector is preferred. The results show that TAPM-CTM performed well as applied to simulate the air quality in HCMC and is a promising tool to study the emission zoning.

A Rare Colonic Metastasis Case from Hepatocellular Carcinoma.

BACKGROUND: Hepatocellularcarcinoma (HCC) metastasis include intrahepatic and extrahepatic metastasis. Similar to intrahepatic metastasis, extrahepatic metastases are not unusual in cases with HCC. However, colonic metastasis is infrequent. CASE REPORT: We describe a clinical case, he was diagnosed with HCC a year ago, treated with TACE (transarterialchemoembolisation), re-examined with abdominal pain and defecation disorder. The tests such as CT scan, colorectal endoscopy, fine needle aspiration (FNA) revealed secondary metastatic lesion of HCC in sigmoid colon. This is the first gastrointestinal (GI) tract metastatic we have encountered. CONCLUSION: HCC metastases of the colon are rare, especially cases of hematogenous spread. The prognosis of these patients is often very critical. Indications for surgical removal of the lesion may be used if the general situation of patient is acceptable.

Mutations in the gyrA, parC, and mexR genes provide functional insights into the fluoroquinolone-resistant Pseudomonas aeruginosa isolated in Vietnam.

INTRODUCTION: Pseudomonas aeruginosa has many mechanisms of resistance to fluoroquinolones. The main mechanism is to change the effect of two enzymes that open the DNA helix - the enzyme DNA gyrase (gyrA) and the topoisomerase IV (parC). In addition, mutations that render the MexAB-oprM pump (mexR) dysfunctional, leading to its overexpression, also enhance resistance to fluoroquinolones. In this study, we aim to detect point mutations of gyrA, parC, and mexR genes that are predicted to be associated with fluoroquinolone resistance in 141 fluoroquinolone-resistant clinical isolates of P. aeruginosa isolated in Vietnam during 2013-2016. METHODS: We tested minimum inhibitory concentrations (MICs) of fluoroquinolone antibiotics in 141 clinical isolates of P. aeruginosa using the VITEK 2 Compact System, followed by PCR assay, to detect and clone the fluoroquinolone resistance-determining region (FRDR) of gyrA, parC, and mexR. Point mutations were analyzed through Sanger sequencing, and the correlation between genetic mutations and phenotypic resistance of 141 clinical isolates was undertaken. RESULTS: Fluoroquinolone-resistant substitution mutations such as Ile for Thr83 and Met for Thr133 in gyrA, Leu for Ser87 in parC, and Val for Glu126 in the repressor of mexR were mainly detected. Comparative analytical data indicated that amino acid alterations within the gyrA and parC genes are highly associated with resistance to ciprofloxacin (CIP) and levofloxacin (LEV) in the isolates, whereas alterations in the efflux regulatory mexR gene are not highly consistent with resistance in these isolates. Moreover, fluoroquinolone-resistant clinical isolates of P. aeruginosa were mainly isolated from pus and sputum specimens. CONCLUSION: In clinical isolates of P. aeruginosa, a high correlation was observed between MICs of CIP and LEV and alterations in gyrA and parC genes. However, mutations occurring in mexR did not highly correlate with the antibiotic resistance of the bacterium.