Synthesis and biological evaluation of shikimic acid derivatives

From shikimic acid, new series of oseltamivir analogues containing either ether sulfur or ether oxygen at C-3 position were prepared and evaluated for their biological activities. This is the first report on synthesis of oseltamivir analogues with ether sulfur at C-3. Except for compounds 4d, 4f, 7c and 7d, the remaining compounds were found to be active against MCF-7, LU-1 and KB cell lines. As oseltamivir had no cytotoxicity against different cell lines such as MCF-7, LU-1, KB, MDCK, MRC-5, VERO, MK and 293, the modification of alkyl groups at C-3 of the oseltamivir ring framework could significantly increase the cytotoxicity for this class of compounds. Loss of neuraminidase inhibition activity of these synthetic oseltamivir analogues suggested that the alkyl ether groups at C-3 should be critical for their anti-neuraminidase activity

Screening of endophytes from rubber trees (hevea brasiliensis) for biological control of Corticium salmonicolor

28 leaves and living-tissue samples of rubber tree (Hevea brasiliensis) were collected from Ho Chi Minh City, Binh Phuoc province and Binh Duong province (Viet Nam). We isolated and screened endophytes that have potential application as agents for biocontrol of Corticium salmonicolor, the agent of Pink Disease in rubber trees. As a result, 21 strains of endophytic bacteria and 14 strains of endophytic fungi were isolated. Antagonistic activity of the endophytes towards C. salmonicolor was checked by using a dual culture. Testing results showed that: T9, T15 and T16 strains have inhibited C. salmonicolor. T9 and T16 strains showed result that 100% of inhibiting C. salmonicolor at the concentration of 1:1. In the test of ability to kill C. salmonicolor, T9 and T16 strains showed that they could kill C. salmonicolor after 3 sprays of bacterial filtrate. T9 and T6 strains, which were identified by biochemical methods, have similar characteristics to Bacillus thuringiensis

KHẢ NĂNG LƯU TRỮ CACBON CỦA THẢM CỎ BIỂN TẠI ĐẦM LĂNG CÔ, TỈNH THỪA THIÊN HUẾ

Seagrass beds play an essential role in mitigating climate change by absorbing CO2 from the atmosphere and converting carbon into biomass through photosynthesis. We used remote sensing and GIS technology with field survey data to establish the distribution and above-ground dry biomass maps of seagrass beds in 2021. A Landsat 8 OLI satellite image was used in the interpretation process. An above-ground dry biomass map was established by building the regression function between the above-ground dry biomass and the reflectance spectrum of the image bands. The overall accuracy and the Kappa coefficient of the classification process were 95.5% and 0.94. At Lang Co Lagoon, the seagrass bed area in 2021 was about 36.18 ha, distributed primarily in the area between Lang Co Town and the north of the lagoon; and scattered in the north of the lagoon, Hoi Can, Hoi Dua, and Hoi Mit. In addition, the total carbon stock of seagrasses in Lang Co Lagoon was estimated at 5.54 tons, equivalent to 20.32 tons of CO2, in which the contribution of Halodule uninervis accounted for 61% of the total carbon stock.Thảm cỏ biển đóng vai trò quan trọng trong việc giảm thiểu biến đổi khí hậu thông qua việc hấp thụ CO2 từ khí quyển và chuyển cacbon thành sinh khối nhờ quá trình quang hợp. Chúng tôi đã sử dụng công nghệ viễn thám và GIS, kết hợp với dữ liệu khảo sát thực địa, để thành lập bản đồ phân bố và sinh khối khô trên mặt đất của hệ sinh thái thảm cỏ biển tại Đầm Lăng Cô vào năm 2021. Một ảnh vệ tinh Landsat 8 OLI đã được sử dụng trong quá trình giải đoán. Một bản đồ sinh khối khô trên mặt đất được thành lập thông qua việc xây dựng hàm hồi quy giữa sinh khối khô trên mặt đất và phổ phản xạ của các kênh ảnh Landsat. Độ chính xác tổng thể và hệ số Kappa là 95,5% và 0,94. Tại Đầm Lăng Cô, diện tích thảm cỏ biển năm 2021 chiếm khoảng 36,18 ha, phân bố chủ yếu ở các khu vực giao giữa Thị trấn Lăng Cô và phía Bắc của đầm; rải rác tại phía Bắc của đầm, Hói Cạn, Hói Dừa và Hói Mít. Ngoài ra, tổng trữ lượng cacbon của cỏ biển ở Đầm Lăng Cô là 5,54 tấn cacbon, tương đương với 20,32 tấn CO2; trong đó, sự đóng góp của loài Halodule uninervis chiếm 61% tổng trữ lượng cacbon

Two Probable Cases of Infection with Treponema pallidum during the Neolithic Period in Northern Vietnam (~2000-1500B.C.)

We would like to thank Dr. Ngo Anh Son, Mr. Bui Van Khanh, and Ms. Nellissa Ling for their assistance with the radiographs, and Dr. Anne Marie E. Snoddy for in-put on the application of a standardized approach to treponemal disease. We thank the associate editor of Bioarchaeology International and three anonymous reviewers for their comments and advice in revising the manuscript. Funding: This research was supported by a National Geographic Early Career Grant (EC-54332R-18), Royal Society of New Zealand Skinner Fund Grant and a University of Otago Doctoral Scholarship.Peer reviewedPostprin

Two probable cases of infection with Treponema pallidum during the Neolithic period in Northern Vietnam (~2000- 1500B.C.)

Skeletal evidence of two probable cases of treponematosis, caused by infection with the bacterium Treponema pallidum, from the northern Vietnamese early Neolithic site of Man Bac (1906–1523 cal B.C.) is described. The presence of nodes of subperiosteal new bone directly associated with superfcial focal cavitations in a young adult male and a seven- year- old child are strongly diagnostic for treponemal disease. Climatic and epidemiological contexts suggest yaws (Treponema pallidum pertenue) as the most likely causative treponeme. This evidence is the oldest discovered in the Asia- Pacific region and is the first well- established pre-Columbian example in this region in terms of diagnosis and secure dating. The coastal ecology, sedentary settlement, and high fertility at the site of Man Bac all provided a biosocial context conducive to the spread of treponemal disease among inhabitants of the site. Co- morbidity with scurvy in both individuals demonstrates that malnutrition during the agricultural transition may have exacerbated the expression of treponematosis in this community. Man Bac is a site of great regional importance owing to its role during the Neolithic transition of Mainland Southeast Asia. During this transition, approximately 4,000 years ago, farmers migrating from southern China into Southeast Asia influenced a number of changes in subsistence and demography and potentially introduced new infectious diseases such as treponematosis to indigenous forager communities. The findings presented here may encourage reevaluation of existing Southeast Asian skeletal samples and demonstrate the importance of using weighted diagnostic criteria for future reporting of treponematosis cases

Forager and farmer evolutionary adaptations to malaria evidenced by 7000 years of thalassemia in Southeast Asia

Acknowledgements We would like to thank Dr. Ngo Anh Son, Mr. Bui Van Khanh and Ms. Nellissa Ling for their assistance with the radiographs. We are grateful to Dr. Dr. Nguyen Gia Doi for permission to extract histological samples. This work was supported by a National Geographic Early Career Grant (EC-54332R-18);Royal Society of New Zealand Skinner Fund Grant; University of Otago Doctoral Scholarship; Australian Research Council DP110101097 and FT120100299. Histologicalprocessing was funded by the Australian Research Council (DE190100068).Peer reviewedPublisher PD

Scurvy in the Tropics: Evidence for increasing non-adult micronutrient deficiency with the transition to agriculture in northern Vietnam

Objective: Scurvy in non-adults was assessed at the Pre-Neolithic site of Con Co Ngua and the Neolithic site of Man Bac in northern Vietnam to investigate nutritional stress during the agricultural transition in Mainland Southeast Asia (MSEA). Materials: One hundred and four human skeletons under the age of 20 years old were assessed. Methods: Lesions were recorded macroscopically and radiographically. Differential diagnosis using prior established paleopathological diagnostic criteria for scurvy was conducted. Results: There was no clear evidence for scurvy at Con Co Ngua and a high burden of scurvy was present at Man Bac (>79% diagnosed with probable scurvy). Scurvy levels were high across all non-adult ages at Man Bac indicating significant burden throughout childhood and adolescence. Conclusions: No scurvy at Con Co Ngua is consistent with widely available food sources at the peak of the Holocene thermal maximum. High levels of scurvy at Man Bac corresponds with decreased dietary diversity, high pathogen load, and increased population stress with the transition to agriculture around the time of the 4.2 ka desertification event. Significance: This is the first systematic population-level non-adult investigation of specific nutritional disease in MSEA and demonstrates an increase in nutritional stress during the Neolithic transition in northern Vietnam. Limitations: Subperiosteal new bone deposits can be due to normal growth in infants and young children, therefore, identification of scurvy in children under the age of 4 years needs to be considered critically. Suggestions for Further Research: Further work in diagnosing specific nutritional disease in other non-adult cohorts throughout MSEA is required

Megastigmans and other compounds from Antidesma hainanensis Merr.

Four megastigmans 7-megastigmene-3-ol-9-one 3-O-[α-L-arabinofuranosyl-(1→6)-β-D-glucopyranoside]  (1),  alangionoside L (2),  alangioside (3), ampelopsisionoside (4), and other constituents as N–trans-feruloyloctopamide (5), trans-linalool-3,6-oxide-β-D-glucopyranoside (6),  5α,8α-dipioxiergosta-6,22-diene-3β-ol (7), and (Z)-2-hexenyl β-D-glucopyranoside (8) were isolated from the methanol extract of the Antidesma hainanensis leaves. Their chemical structures were successfully determined using NMR and ESI-MS analysis as well as in comparison with the reported data. This is the first report of these compounds from Euphorbiaceae family

The Effectiveness of Narrow Band Uvb (Nb-Uvb) In the Treatment of Pityriasis Lichenoides Chronica (PLC) In Vietnam

AIM: This prospective clinical study presents the experiences with NB-UVB monotherapy in the treatment of PLC on Vietnamese patients. METHODS: We enrolled at National Hospital of Dermatology and Venereology (NHDV), Vietnam, 29 PLC patients with generalised disease involving at least 60% of the total body surface (based on Nine’s Rule) and/or failed to respond to other modalities of treatment. Patients were treated with NB-UVB followed the guideline of the psoriatic treatment of AAD-2010, three times weekly. RESULTS: A complete response (CR) was seen in 24 out of 29 PLC patients (82.8%) with a mean cumulative dose of 9760.5 mJ/cm2 after a mean treatment period of 4.6 weeks (13.8 ± 7.4 exposures). Mild side effects were observed: 69% erythema minimum, 55.2% irritation related to dry skin. No severe side effects were seen during the study. No relapses occurred in 24 CR patients within a mean period of 3 months after the last treatment. CONCLUSION: NB-UVB therapy is an effective and safe option for the treatment and management of PLC

Using Patch Testing to Improve Therapeutic Outcome in the Treatment of Hand Eczema in Vietnamese Patients

BACKGROUND: Hand eczema is a common chronic and relapsing skin disease with various clinical features. Hand eczema aetiology can be allergic contact dermatitis (ACD), irritant contact dermatitis (ICD), atopic dermatitis (AD) and unknown or combination causes. If the causative agents are not detected treatment of hand eczema will be a failure. A patch test can be useful to detect causative agents in suspected allergic contact hand eczema. Then patients will avoid contacting them. This results in the improvement of hand eczema. In Vietnam, patch test has not been used before, so we conduct this study. AIM: To identify causative allergens by using patch test with 28 standard allergens in consecutive patients. METHODS: A group of 300 HE patients from the National Hospital of Dermatology and Venereology (NHDV) in Vietnam were enrolled in this study. They were divided into 4 groups-ACD, ICD, AD and unknown aetiology. The patient was patch tested with 28 standard allergens to identify the causative agents. RESULTS: Among the 300 HE enrolled patients, ACD accounted for 72.7%, AD and ICD had the same rate of 12.7%. 39.3% of the patients had a positive patch test. Reaction to nickel sulfate was the most common (10.3%), followed by potassium dichromate (9.7%), cobalt (4%) and fragrance mix (3.1%). About one-third of the cases had relevant clinical reactions correlated with the contact agents and clinical history. Males reacted to cement, thiuram mix and formaldehyde more than females, while females reacted to a nickel more than males. CONCLUSIONS: Hand eczema has variable clinical features and diverse aetiology. ACD is an important cause of hand eczema that can be managed with a patch test to detect causative allergens. Nearly 40% of HE cases had positive patch test. Relevant patch test reactions were seen in one-third of the patients. We propose using patch test detect causative agents in suspected allergic contact hand eczema. Then patients will avoid contacting them. This results in the improvement of hand eczema