Gas chromatography profile of estrogens: Application to pregnancy urine

A method for the simultaneous quantitation of 7 estrogens in pregnancy urine is described. It involves enzymatic hydrolysis, extraction of free steroids, ion-exchange column chromatography and quantitation of the trimethylsilyl derivatives by gas chromatography on OV 1. Data obtained from normal and twin pregnancies and from women with anencephalic fetus or intra uterine fetal death are analysed. The sensibility of the method is about 40 μg of each estrogen by liter of urine.     

Wnt antagonist SFRP3 inhibits the differentiation of mouse hepatic progenitor cells

Wnt/β‐catenin pathway plays an important role in regulating embryonic development. Hepatocytes differentiate from endoderm during development. Hepatic progenitor cells (HPCs) have been isolated from fetal liver and extrahepatic tissues. Most current studies in liver development and hepatic differentiation have been focused on Wnts, β‐catenin, and their receptors. Here, we sought to determine the role of Wnt antagonists in regulating hepatic differentiation of fetal liver‐derived HPCs. Using mouse liver tissues derived from embryonic day E12.5 to postnatal day (PD) 28, we found that 13 of the 19 Wnt genes and almost all of Wnt receptors/co‐receptors were expressed in most stages. However, Wnt antagonists SFRP2, SFRP3, and Dkk2 were only detected in the early stages. We established and characterized the reversible stable HPCs derived from E14.5 mouse fetal liver (HP14.5). HP14.5 cells were shown to express high levels of early liver progenitor cell markers, but low levels or none of late liver markers. HP14.5 cells were shown to differentiate into mature hepatocytes upon dexamethasone (Dex) stimulation. Dex‐induced late marker expression and albumin promoter activity in HP14.5 cells were inhibited by exogenous expression of SFRP3. Furthermore, Dex‐induced glycogen synthesis of PAS‐positive HP14.5 cells was significantly inhibited by SFRP3. Therefore, our results have demonstrated that the expression of Wnt antagonists decreases as hepatic differentiation progresses, suggesting that a balanced Wnt signaling may be critical during mouse liver development and hepatic differentiation. J. Cell. Biochem. 108: 295–303, 2009. © 2009 Wiley‐Liss, Inc.     

Significance of PGR5-dependent cyclic electron flow for optimizing the rate of ATP synthesis and consumption in Arabidopsis chloroplasts

Photosynthesis Research - The proton motive force (PMF) across the chloroplast thylakoid membrane that is generated by electron transport during photosynthesis is the driving force for ATP...     

Ginsenoside-Rd from Panax notoginseng enhances astrocyte differentiation from neural stem cells

Neural stem cells cultured as neurospheres were used to assess the effects of P. notoginseng on the production of neurons and glia. The crude saponins (PNS) and ginsenoside-Rd promote the differentiation of neurospheres into astrocytes. Ginsenoside-Rd increases the production of astrocytes in a dose-dependent manner. On the other hand, both PNS and ginsenoside-Rd induce a weak but significant effect by decreasing the number of neurons. The other ginsenosides do not induce any differentiation on both neurons and astrocytes.     

Stressful life events and co-occurring depression,substance abuse and suicidality among American Indian and Alaska Native adolescents

Depression, suicidality and substance abuse disorders are examined with special emphasis on the role of stressful life events in predicting severity and patterns of comorbidity among American Indian and Alaska Native adolescents in boarding school environments. Both amount and severity of comorbidity increase with age and specific patterns of comorbidity are associated with gender. Different types and amounts of stressful life events predict specific combinations of comorbidity. These outcomes are interpretable with respect to associated cultural dynamics and the ecology of mental health services delivery for Indian and Native adolescents. Theoretical and methodological issues are discussed in relation to the use of stressful life events in examining cultural factors related to comorbidity among culturally different populations.     

In vitro comparative metabolism of 6,7-3H estrone and 6,7-3H estrone-3-sulfate in maternal and fetal guinea-pig liver]

The metabolism of [6,7-3H] estrone and of [6,7(3)H] estrone-3-sulfate have been comparatively studied in the maternal and fetal guinea-pig livers. The appearance of estradiol-17 beta resulting from the activity of the 17 beta-hydroxysteroid-dehydrogenase is more important in the fetal than in the maternal hepatic tissue. This suggests the direct transformation of estrone-3-sulfate into estradio-3-sulfate in the fetus. After incubation of the [3H] estrone, there is an abundant hepatic conjugation. The glycuroconjugated components are predominant, as well in the maternal as in the fetal hepatic tissue. For the latter-one the sulfoconjugation is inexistant. The sulfatasic activity shown after the incubation of [3H] estrone-3-sulfate is very low in the fetal hepatic tissue; in contrast, this activity is higher in the maternal tissue.     

Viruses Occur Incorporated in Biogenic High-Mg Calcite from Hypersaline Microbial Mats

Using three different microscopy techniques (epifluorescence, electronic and atomic force microscopy), we showed that high-Mg calcite grains in calcifying microbial mats from the hypersaline lake “La Salada de Chiprana”, Spain, contain viruses with a diameter of 50–80 nm. Energy-dispersive X-ray spectrometer analysis revealed that they contain nitrogen and phosphorus in a molar ratio of ~9, which is typical for viruses. Nucleic acid staining revealed that they contain DNA or RNA. As characteristic for hypersaline environments, the concentrations of free and attached viruses were high (>10¹⁰ viruses per g of mat). In addition, we showed that acid treatment (dissolution of calcite) resulted in release of viruses into suspension and estimated that there were ~15 × 10⁹ viruses per g of calcite. We suggest that virus-mineral interactions are one of the possible ways for the formation of nano-sized structures often described as “nanobacteria” and that viruses may play a role in initiating calcification.     

Spatial distribution of Culex mosquito abundance and associated risk factors in Hanoi,Vietnam

Japanese encephalitis (JE) is the major cause of viral encephalitis (VE) in most Asian-Pacific countries. In Vietnam, there is no nationwide surveillance system for JE due to lack of medical facilities and diagnoses. Culex tritaeniorhynchus, Culex vishnui, and Culex quinquefasciatus have been identified as the major JE vectors in Vietnam. The main objective of this study was to forecast a risk map of Culex mosquitoes in Hanoi, which is one of the most densely populated cities in Vietnam. A total of 10,775 female adult Culex mosquitoes were collected from 513 trapping locations. We collected temperature and precipitation information during the study period and its preceding month. In addition, the other predictor variables (e.g., normalized difference vegetation index [NDVI], land use/land cover and human population density), were collected for our analysis. The final model selected for estimating the Culex mosquito abundance included centered rainfall, quadratic term rainfall, rice cover ratio, forest cover ratio, and human population density variables. The estimated spatial distribution of Culex mosquito abundance ranged from 0 to more than 150 mosquitoes per 900m². Our model estimated that 87% of the Hanoi area had an abundance of mosquitoes from 0 to 50, whereas approximately 1.2% of the area showed more than 100 mosquitoes, which was mostly in the rural/peri-urban districts. Our findings provide better insight into understanding the spatial distribution of Culex mosquitoes and its associated environmental risk factors. Such information can assist local clinicians and public health policymakers to identify potential areas of risk for JE virus. Risk maps can be an efficient way of raising public awareness about the virus and further preventive measures need to be considered in order to prevent outbreaks and onwards transmission of JE virus.