Preliminary study on phytogeography of Dipterocarpaceae Blume family in Vietnam

Biogeographically mapping flora of Vietnam requires the studies on the distribution of some important species groups for identifying the typical species composition of each phytochorion. The Dipterocarpaceae family contains taxa originated in tropical Asia and its subfamily of Dipterocarpoideae is proved to have Southeast Asia origin. In Vietnam, this family includes 43 species in 7 genera. In this study, Dipterocarpaceae species from 645 sites in Vietnam are assessed and compared to those in over the world. In Vietnam, this family distributes in tropical and/or slightly passing to subtropical climate but none of its species is naturally found in the Red River and the Mekong River deltas. In the world, the Dipterocarpaceae species found in Vietnam concentrated distributes in Indochina floristic region, corresponding to the originative area of South Myanmar. Statistically, there are 12 endemic species for the Indochinese floristic region and five of them are endemic for four provinces of this region related to Vietnam, respectively as follows: South China - 1, North Indochina - 1, South Indochina - 2 and Annam - 1. Additionally, some species distribute in East Asia floristic region of Holarctic Kingdom because of expanding the distribution area from the Indochinese floristic region. All genera of this family in Vietnam were originated in the Indochinese floristic region. Moreover, the floristic data and phytogeographical phylogeny diagram, based on analyses of phytogeography and DNA, would be better to use for finding out the distributional source or the forming time of species or genus, then the phylogenetic diagram.ReferencesAngiosperm Phylogeny Group, 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Botanical Journal of the Linnean Society, 161(2), 105-121. Ashton P.S., 1982. Dipterocarpaceae. In: Van Steenis C.G.G.J., 1979-1983, Flora Malesiana. Dipterocarpaceae. Martinus Nijhoff Publisher, The Hague, London, 9(2), 250p. Averyanov L.V., Phan K.L., Nguyen T.H., Harder D.K., 2003. Phytogeographic review of Vietnam and adjacent areas of Eastern Indochina, Komarovia, Saint Petersburg, 3, 1-83. Kress W.J., DeFilipps R.A., Farr E. and Yin D.Y.K., 2003. A checklist of the trees, shrubs, herbs and climbers of Myanmar. National Museum of Nature History, Washington DC, 45, 1-590. Le Tran Chan (Editor), 1999. Some characteristics of the flora of Vietnam. Science and Technique publishing house, Hanoi, 305p (Vietnamese). Li X.W., Li J., Ashton P.S., 2007. Dipterocarpaceae. In: Wu Z.Y., Raven P.H. (Hrsg.). Flora of China. Missouri Botanical Garden Press, St. Louis, 13, 48-54. Nguyen Hoang Nghia, 2005. Dipterocarps of Vietnam. Agriculture Publishing House, Hanoi, 100p. Nguyen Kim Dao, 2003. “Dipterocarpceae Blume, 1825” in Checklist Plant species of Vietnam. Agricultural Publishing House, Hanoi, 2, 328-340 (Vietnamese). Nguyen Nga Phi, 2009. Molecular phylogeny of Southeast-Asian Dipterocarps belonging to tribe Dipterocarpeae (family Dipterocarpaceae) based on non-coding sequence data of chloroplast and nuclear DNA. Department of Forest Genetics and Georest Tree Breeding, Büsgen Institute, Faculty of Forest Science and Forest Ecology, Georg-August University of Göttingen. Göttingen, 142p. Nguyen Nghia Thin, 2004. Methods in Botanical Research. HNU publishing house, Hanoi, 172p (Vietnamese). Pham Hoang Ho, 2001. Illustration Flora of Vietnam, Youth Publishing House. Ho Chi Minh City, 2, 1022p (Vietnamese). Smitinand T., 1969. The distribution of Dipterocarpaceae in Thailand. National History Bull. Siam Soci., 23, 67-75. Smitinand T., J.E. Vidal, P.H. Ho, 1990. Flore du Cambodge, du Laos et du Vietnam, 25, Diptérocarpacées. Muséum National d’Histoire Naturelle, Paris, 123p (French). Takhtajan A. (Translated by Theodore J. Crovello), 1986. Floristic Regions of the World. University of California Press, 544p. Thai Van Trung, 1978. Tropical Forest Ecology systems of Vietnam. Science and Technique publishing house, Hanoi, 314p (Vietnamese). The Plant List (Version 1.1.), 2013. Dipterocarpaceae. http://www.theplantlist.org

High cortisol and cortisone levels are associated with breast milk dioxin concentrations in Vietnamese women

Objective: Dioxin (polychlorinated dibenzodioxins Cpolychlorinated dibenzofurans) is one of the most toxic chemical substances known. Although it is suspected to cause endocrine disruption, very few epidemiological studies have been carried out on its effects on human steroid hormones. The aim of this study was to elucidate the association of dioxin exposure with steroid hormone levels in the saliva and serum of Vietnamese women. Study design : Two areas, namely Phu Cat (hot spot) and Kim Bang (nonexposed area), were selected for the study. The study subjects consisted of 51 and 58 women respectively. Saliva, blood, and breast milk samples were collected from the subjects in both the areas. Methods: Cortisol, cortisone, DHEA, androstenedione, estrone, and estradiol levels in serum and saliva were determined by liquid chromatography-tandem mass spectrometry; dioxin concentrations in breast milk were measured by gas chromatography-mass spectrometry. Results: Dioxin concentrations in the breast milk of women from the dioxin hot spot were three to four times higher than those in the breast milk of women from the nonexposed area. Good correlations were found between the levels of six steroid hormones in saliva and those in serum respectively. Salivary and serum cortisol and cortisone levels in women from the dioxin hot spot were significantly higher than those in women from the nonexposed area (P<0.001) and those in all the subjects were positively associated with dioxin concentrations in Vietnamese women (P<0.01). Conclusion: These results suggest that dioxin influences steroidogenesis in humans. Saliva samples can be used for hormone analysis and are therefore excellent specimens in epidemiological studies. © 2014 European Society of Endocrinology

ベトナムダイオキシン高濃度汚染地域における授乳中の母親の唾液中ホルモン値の検討

【目的】アメリカ軍は１９６１年から１９７１年の間に８０００万リットル以上の枯葉剤を南ベトナムに撒布した。この研究の目的はベトナムの枯葉剤高濃度汚染地域（Binh Dinh省Phu Cat県）と非汚染地域（Ha Nam省Kim Bang県）において枯葉剤（オレンジ剤）の暴露と人体への健康影響との関連を検討することである。【方法】２つの地域において疫学的調査を実施した。対象者は授乳中で生後４週から１６週の乳児を持つ２０－３０歳の母親とし、汚染地域では５８名、非汚染地域では５３名であった。疾患の危険因子等に関する情報は母親への面接調査から得た。母乳をすべての対象者から採取したが、唾液を採取したのは汚染地域４１名、非汚染地域１９名であった。母親と子どもの身体計測を行い２地域間で比較を行った。【結果と考察】汚染地域における乳児の体重と胸囲は有意に非汚染地域よりも小さいが、年齢(週数)も汚染地域の方が有意に低かった。汚染地域における母親とその家族の現病歴は非汚染地域よりも有意に多かった。母親の視力は両眼とも２地域間で有意差は認められなかった。汚染地域と非汚染地域双方の母親の唾液中のコルチゾン値は、母乳中のコルチゾン値と高い相関を示した。汚染地域と非汚染地域間で唾液中のホルモン値には有意差は認められなかった。Objective : Between 1961 and 1971 the US military used over 80 million litres of herbicides in southern Vietnam. This study aims to assess hormone levels in the saliva of lactating Vietnamese mothers and human health effects in a dioxin hot spot (Phu Cat district, Binh Dinh province) and a non-exposed (Kim Bang district, Ha Nam province) area in Vietnam. Materials and Methods : An epidemiological study was carried out in both areas. The subjects were 58 lactating females in the hot spot area and 53 lactating females in the non-exposed area. All were aged between 20 and 30 years with infants aged between 4 and 16 weeks. Information about disease risk factors was obtained through interviews with mothers. Breastmilk samples were taken from all subjects, whereas saliva samples were obtained from 41 mothers in the hot spot area and 19 in the non-exposed area. Body measurements for both mothers and their infants were compared between the two areas. Result and Discussion : The weight and chest circumference of infants in the hot spot area were significantly lower than those in the non-exposed area, whereas age (weeks) is also significantly younger in hot spot area than non-exposed area. Present maternal and family diseases in the hot spot area were significantly higher than those in the non-exposed area. Maternal eyesight in both eyes did not differ significantly between the two areas. The cortisone levels in saliva have been found to be closely related to those in breast milk samples of both mothers in hot spot and non-exposed areas. No significant difference was found between salivary hormone levels of mothers in the hot spot and non-exposed areas

Levels of polychlorinated dibenzodioxins and polychlorinated dibenzofurans in breast milk samples from three dioxin-contaminated hotspots of Vietnam

We determined polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in breast milk of 143 primiparae living around the three most dioxin-contaminated areas of Vietnam. The women sampled lived in the vicinity of former U.S. air bases at Bien Hoa (n. =. 51), Phu Cat (n. =. 23), and Da Nang (n. =. 69), which are known as dioxin hotspots. Breast milk samples from Bien Hoa City, where residents live very close to the air base, showed high levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), with 18% of the samples containing >. 5. pg. TCDD/g lipid. However, Phu Cat residents lived far from the air base and their samples showed lower TCDD levels, with none containing >. 5. pg. TCDD/g lipid. In Da Nang, TCDD levels in mothers from Thanh Khe (close to the air base, n. =. 43) were significantly higher than those in mothers from Son Tra (far from the air base, n. =. 26), but not other PCDD and PCDF (PCDD/F) congeners. Although TCDD levels in Bien Hoa were the highest among these hotspots, levels of other PCDD/F congeners as well as the geometric mean concentration of total PCDD/F level in Bien Hoa (9.3. pg toxic equivalents [TEQ]/g lipid) were significantly lower than the level observed in Phu Cat (14.1. pg. TEQ/g lipid), Thanh Khe (14.3. pg. TEQ/g lipid), and Son Tra (13.9. pg. TEQ/g lipid). Our findings indicated that residents living close to former U.S. air bases were exposed to elevated levels of TCDD, but not of other PCDD/F congeners

Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions

Neurodevelopmental Effects of Perinatal TCDD Exposure Differ from Those of Other PCDD/Fs in Vietnamese Children Living near the Former US Air Base in Da Nang, Vietnam

This study reports that children exposed to 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD), the major toxin in Agent Orange, from the breast milk of mothers residing near the former Da Nang US air base in Vietnam may have specific alterations in higher brain functions, resulting in social and communication deficits, including autism spectrum disorder (ASD). After the age of 8 years, girls with high TCDD showed increased attention deficit hyperactivity disorder (ADHD)-like behaviors and altered mirror neuron activity, which is often observed in children with ASD. However, no significant relationship between autistic traits and toxic equivalency values of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (TEQ-PCDD/Fs) was found in these children. Notably, boys with high levels of TEQ-PCDD/Fs showed poor language and motor development in the first 3 years of life, although boys with high TCDD levels did not. However, at 8 years of age, boys with high TCDD showed reading learning difficulties, a neurodevelopmental disorder. These findings suggest that perinatal TCDD exposure impacts social&ndash;emotional cognitive functions, leading to sex-specific neurodevelopmental disorders&mdash;learning difficulty in boys and ADHD in girls. Future studies with a greater number of children exposed to high levels of TCDD are necessary to estimate the threshold values for neurodevelopmental effects

Dioxin Congener Patterns in Breast Milk Samples from Areas Sprayed with Herbicide during the Vietnam War 40 Years after the War Ended

Large amounts of herbicides containing polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) were sprayed in South Vietnam during the Vietnam War. Levels of PCDD/Fs in the environment of South Vietnam remained high even 40 years later. A total of 861 breast milk samples (597 from three areas sprayed with herbicides, Quang Tri, Da Nang, and Bien Hoa, and 264 from three unsprayed areas in North Vietnam) were collected between 2007 and 2015 and the PCDD/F concentrations in the samples were determined. Levels of TEQ-PCDD/Fs and 17 PCDD/F congeners were higher in the sprayed area samples than the unsprayed area samples. We found particular PCDD/F congener patterns for different areas. High tetrachlorodibenzo-p-dioxin (TCDD) concentrations were found in Bien Hoa, high TCDD and 1,2,3,6,7,8-hexadibenzo-p-dioxin concentrations were found in Da Nang, and high 1,2,3,4,6,7,8-heptadibenzo-p-dioxin concentrations were found in Quan Tri. High 1,2,3,4,7,8-hexadibenzofuran and 1,2,3,4,6,7,8-heptadibenzofuran concentrations were also found in Da Nang and Quang Tri. However, breast feeding may have caused associations between the TCDD and polychlorinated dibenzofuran congener concentrations. Advanced statistical analysis will need to be performed in future to assess the characteristic PCDD/F congener profiles in breast milk samples from areas of Vietnam previously sprayed with herbicides

Effect of Perinatal Dioxin Exposure Originating from Agent Orange on Gaze Behavior in 3-Year-Old Children Living in the Most Dioxin-Contaminated Areas in Vietnam

We investigated the effect of perinatal dioxin exposure indicated by dioxins in breast milk on children’s gaze behavior. We studied 142 children aged 3 years from the 2012 Bien Hoa birth cohort in a hotspot of dioxin contamination in Vietnam. Children’s faces were viewed using the eye-tracking method. Associations between gaze behavior of faces and neurodevelopmental indices and head circumference were analyzed to determine whether poor gaze behavior indicates increased autistic traits in these children. The gaze fixation duration on facial areas when viewing 10 still images of children was calculated as the gaze behavior index. Autistic behavior was assessed using the Autism Spectrum Rating Scale, and language development was evaluated by the Bayley Scales of Infant and Toddler Development, Ver. 3. The face fixation duration (%) significantly decreased as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations increased in a dose–effect manner in girls, which suggested atypical gaze behavior for watching human faces. Furthermore, these girls with atypical gaze behavior showed lower social communication scores and smaller head sizes, suggesting increased autistic traits in girls. In conclusion, our findings show sex-specific effects (girls &gt; boys) of perinatal TCDD exposure on gaze behavior in young children

Alterations in Regional Brain Regional Volume Associated with Dioxin Exposure in Men Living in the Most Dioxin-Contaminated Area in Vietnam: Magnetic Resonance Imaging (MRI) Analysis Using Voxel-Based Morphometry (VBM)

To clarify the influence of dioxin exposure on brain morphometry, the present study investigated associations between dioxin exposure at high levels and brain structural irregularities in 32 Vietnamese men. Two exposure markers were used: blood dioxin levels, as a marker of exposure in adulthood, and perinatal dioxin exposure, estimated by maternal residency in a dioxin-contaminated area during pregnancy. All subjects underwent brain magnetic resonance imaging (MRI) scans. We analyzed correlations between regional gray matter volumes and blood dioxin levels, and compared regional volumes between men with and without perinatal dioxin exposure using the voxel-based morphometry (VBM) tool from Statistical Parametric Mapping 12 (SPM12). Blood 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was associated with low volume of the medial temporal pole and fusiform gyrus. Toxic equivalency (TEQ)-PCDDs were correlated with low medial temporal pole volume. However, 1,2,3,4,7,8-HxCDD was associated with high middle frontal gyrus and cerebellum volume. In men with perinatal dioxin exposure, the left inferior frontal gyrus pars orbitalis volume was significantly lower than in those without perinatal exposure. These results suggest that dioxin exposure during the perinatal period and in adulthood may alter regional brain volume, which might lead to cognitive deficits and unusual social emotional behavior in Vietnamese men living in dioxin-contaminated areas