Noninvasive detection of fetal sex: the laboratory diagnostician's view

Toward the end of the twentieth century it was discovered that cell-free fetal DNA sequences could be detected in maternal blood plasma. Initially, Y-chromosome sequences originating from male fetuses were targeted in cell-free DNA extracted from maternal plasma in order to demonstrate proof of this concept towards the development of noninvasive prenatal diagnosis methods. Clinical application of this approach is now possible. Fetal sex can be detected through a procedure that is noninvasive with respect to the fetus. Specifically, the presence of Y-chromosome sequences in maternal blood plasma indicates that the fetus is male, whereas lack of a signal will indicate that the fetus is female. Fetal sex can be detected very early, from at least the 7th week of pregnancy (and even earlier, according to several studies), about two months before this information is available through ultrasound scanning. Although the controversial issue of fetal sexing is not new, it is expected that with the availability of an accurate noninvasive test, public interest will rise. It is therefore imperative that an authorized committee of experts in each country generates an official policy regarding application of the test. Copyright © 2006 John Wiley & Sons, Ltd.     

Comparing Scales of Environmental Effects from Gasoline and Ethanol Production

Understanding the environmental effects of alternative fuel production is critical to characterizing the sustainability of energy resources to inform policy and regulatory decisions. The magnitudes of these environmental effects vary according to the intensity and scale of fuel production along each step of the supply chain. We compare the spatial extent and temporal duration of ethanol and gasoline production processes and environmental effects based on a literature review and then synthesize the scale differences on space–time diagrams. Comprehensive assessment of any fuel-production system is a moving target, and our analysis shows that decisions regarding the selection of spatial and temporal boundaries of analysis have tremendous influences on the comparisons. Effects that strongly differentiate gasoline and ethanol-supply chains in terms of scale are associated with when and where energy resources are formed and how they are extracted. Although both gasoline and ethanol production may result in negative environmental effects, this study indicates that ethanol production traced through a supply chain may impact less area and result in more easily reversed effects of a shorter duration than gasoline production.     

Astaxanthin and papilioerythrinone in the skin of birds: a chromatic convergence of two metabolic routes with different precursors?

Carotenoids are organic pigments involved in several important physiological functions and may serve as indicators of individual quality in animals. These pigments are only obtained by animals from the diet, but they can be later transformed into other carotenoids by specific enzymatic reactions. The diet of farm-reared and probably wild red-legged partridges (Alectoris rufa) is mainly based on cereals that contain high levels of lutein and zeaxanthin. These two carotenoids are also predominant in internal tissues and blood of red-legged partridges. However, in their integuments, astaxanthin and papilioerythrinone (the last one identified in this work) are mainly present in their free form and esterified with fatty acids. According to available literature about carotenoid metabolism in animals, we propose that astaxanthin (λ _max?=?478 nm) and papilioerythrinone (λ _max?=?452–478 nm) are the result of a chromatic convergence of the transformation of dietary zeaxanthin and lutein, respectively. Moreover, the results obtained in this work provide the first identification by liquid chromatography coupled to accurate mass quadrupole time-of-flight mass spectrometer system of papilioerythrinone (m/z 581.3989 [M?+?H]⁺) in the skin (i.e., not feathers) of a vertebrate. Astaxanthin and papilioerythrinone are very close in terms of chemical structure and coloration, and the combination of these two keto-carotenoids is responsible for the red color of the ornaments in red-legged partridges.     

Correcting serum concentrations of organochlorine compounds by lipids: Alternatives to the organochlorine/total lipids ratio

IntroductionWhen studying the effects of organochlorine compounds (OCs) on human health it is common to correct serum concentrations of OC by total lipids (TL). However, the relationship between serum OCs and serum TL is far from established in many diseases, including several cancers. Our aim was to analyze the relationship between serum OC and TL in patients with pancreatic ductal adenocarcinoma (PDA), and to explore several alternatives to perform the OC lipid correction.MethodsIncident cases of PDA were interviewed and had blood drawn soon around hospital admission (n = 144). Serum concentrations of OCs were analysed by high-resolution gas chromatography with electron-capture detection.ResultsMost patients with high TL had moderate or low concentrations of OCs. By contrast, the variability of OC values among patients with normal TL was large. Correlations were of a similar magnitude between OC and TL and between OC and total cholesterol; while these correlations were weak (all Spearman's ρ < 0.3 and R² < 0.11), no OC were significantly correlated with triglycerides. Although all alternatives to the OC/TL linear ratio were statistically significant for at least one OC, their R² was always below 10%.ConclusionsIn patients with severe diseases as PDA, linear correction of OC by TL as commonly performed in epidemiologic studies may be inappropriate. Results contribute to the scant literature on the rationale to correct serum concentrations of OC by lipids. They suggest that it is unwarranted to routinely correct OC by TL, offer ways to assess such need, and present alternatives as no TL correction, correction by total cholesterol only or use of different statistical models.     

Biodegradable Composite Foams of PLA and PHBV Using Subcritical CO<Subscript>2</Subscript>

One key strategy for increasing the application potential for biodegradable plastics lies in improving the physical and mechanical characteristics, which can be attained by inducing a cellular morphology in the pure polymer with the aid of a blowing agent, as well as by blending two or more polymers with the desirable properties. This paper examines the effect that blending two biodegradable polymers has on the thermal properties and morphology of the resultant foams blown with carbon dioxide (CO₂). Polylactic acid (PLA), polyhydroxybutyrate-co-valerate (PHBV) and blends of both were foamed and characterized in terms of thermal characteristics, relative density, cell size, and foam morphology. The results indicate that although PLA and PHBV are immiscible, the presence of small quantities of PHBV (25 wt%) could lead to low density foams with finer, more uniform cells. Furthermore, the crystallinity of PHBV was found to be unaffected by the presence of PLA in the composite, which supports the immiscibility of PLA and PHBV.     

Urban Air Quality Assessment Model: UAQAM

The Urban Air Quality Assessment Model (UAQAM) calculates urban concentrations caused by city emissions themselves, the so-called city background concentration. Three versions of the model for describing the dispersion were studied: Box, Gifford Hanna (GH) and a combined form of these two (Box–GH model). Regional background emissions contributing to the urban background concentration were accounted for by using measurements and calculations from a dispersion model on the continental scale. The results of the three UAQAM versions for a number of European cities were compared to measurements of SO₂ and NO _X . The Box–GH model shows better results when compared to the Box model and slightly better results in comparison to the GH model. The Box–GH model has been taken as a starting point for the assessment of urban air quality with UAQAM.     

Studies on atmospheric degradation of diazinon in the EUPHORE simulation chamber

The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.2) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 302 ± 10 K and atmospheric pressure. The available evidence indicates that tropospheric degradation of diazinon is mainly controlled by reaction with OH radicals, and that the tropospheric lifetime with respect to the OH reaction is estimated to be around 4 h whereas its lifetime with respect to the photolysis is higher than 1 d under our conditions. Significant aerosol formation was observed following the reaction of diazinon with OH radicals, and the main carbon-containing products detected in the particle phase were hydroxydiazinon, hydroxydiazoxon and 2-isopropyl-6-methyl-pyrimidinyl-4-ol.