Molecular genetic prenatal diagnosis for a case of autosomal recessive spondylocostal dysostosis

Autosomal recessive spondylocostal dysostosis type 1 (ARSCD1) is a member of the heterogeneous group of disorders termed the spondylocostal dysostoses that are characterized by multiple vertebral segmentation defects and rib anomalies. In these patients, the entire vertebral column is malformed and is replaced by multiple hemivertebrae giving rise to truncal shortening, abdominal protrusion and non-progressive spinal curvature. Genetic studies have shown that some cases of ARSCD are due to mutations in the somitogenesis gene, Delta-like 3 (DLL3), that encodes a ligand for the Notch signalling pathway—ARSCD type 1. To date, 17 different DLL3 gene mutations have been reported. A consanguineous family of Turkish origin with ARSCD type 1 due to a homozygous DLL3 mutation requested genetic prenatal diagnosis. Using DNA from a chorionic villus sample, both linkage analysis of the DLL3/19q region and direct sequencing for the familial mutation demonstrated that the unborn fetus was an unaffected carrier. This is the first case of molecular genetic prenatal diagnosis in any form of SCD. Copyright © 2003 John Wiley & Sons, Ltd.     

人口迁徙、汇款、生活轨迹及社会应变能力

我们认为,人口变化的方方面面,包括迁徙,都影响个人和团体的社会应变能力以及基本资源基础的可持续性.社会应变能力是应对和适应通过适当的制度调节的环境和社会变化的能力.我们调查了当今越南沿海地区人口变化、社会应变能力以及可持续发展之间关系的一个侧面:迁徙和汇款对依赖于资源的人口源区居民群的影响.利用有关生活来源的纵向运动数据,我们发现移民出境和汇款对一个逐渐形成的社会和政治范围内的应变能力有抵消作用.移民出境是与不可持续的沿海养殖业的发展同时并存的,而不是起推动作用.日益增加的经济不平等削弱了社会应变能力.同时,多种经营和收入水平的不断提高有助于应变能力的增强.     

High resolution proton NMR spectroscopy of human amniotic fluid

Human amniotic fluid (HAF) is a dynamic system whose characteristics depend on continuous interchanges between fetal and maternal circulations. HAF reflects not only the environment of the fetus but may also provide information about fetal development or pathology. The concentration of HAF constituents varies with gestational age and pathological states. The number of the compounds currently implicated in fetal developmental pathology are relatively few. Currently used assay methods are not adequate to totally explain or predict the complex biochemistry of the fetus. The purpose of this work was to investigate HAF with NMR spectroscopy. In the present study HAF was obtained from 47 women undergoing routine amniocentesis. Cells were separated for karyological analysis and the supernatant was acid-extracted, lyophilized and re-suspended in D₂0 resulting in a concentration increase over native fluid. ¹H NMR spectra were obtained at 360 MHz and 60 MHz. Eighteen compounds including several amino acids, were identified using parallel reference and standard addition protocols. NMR spectroscopy detected compounds of known clinical importance including glucose, leucine, isoleucine, lactate and creatinine. In conclusion, we have demonstrated that a number of physiologically relevant compounds are readily observable in HAF using ¹H NMR spectroscopy. This technique can currently provide valuable information regarding HAF composition and has the potential of being used in vivo in the future.     

Stable chlorine intramolecular kinetic isotope effects from the abiotic dehydrochlorination of DDT

INTENTION, GOAL, SCOPE, BACKGROUND: Identifying different sources and following reaction pathways of chlorinated organic contaminants in the environment can be challenging, especially when only their concentrations are available. Compound-specific stable chlorine measurements of some contaminants have recently been shown to provide additional information and an increased understanding of their biogeochemistry. These studies, however, have been generally limited to volatile molecules. OBJECTIVE: Here, the stable chlorine isotope ratios of the semi-volatile pesticide, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) were investigated. Specifically, the intramolecular stable chlorine isotopic compositions of DDT and the kinetic isotope effect (KIE) for the abiotic dehydrochlorination of DDT to 2,2-bis(p-chlorophenyl)-1,1-dichloroethene (DDE) were determined. METHODS: Selective chemical oxidation of DDT to dichlorobenzophenone (DCBP) and analysis of each compound was used to calculate the stable chlorine isotope ratios of the alkyl and aromatic chlorines in DDT. To determine the KIE for dehydrochlorination, DDT was reacted in a basic solution to yield DDE at 52 degrees C, 60 degrees C, and 72 degrees C for 3, 5, and 5 days, respectively. RESULTS AND DISCUSSION: Significant intramolecular stable chlorine isotopic differences were observed in one sample of DDT where the alkyl and aromatic delta 37Cl values were -5.76 +/- 0.45 and -2.21 +/- 0.24%@1000, respectively. Dehydrochlorination of DDT to DDE in basic solutions at 52, 60, and 70 degrees C resulted in a substantial intramolecular KIE where the alkyl chlorines of DDE shifted by approximately 3%@1000 relative to the alkyl chlorines in DDT. However, no temperature dependence was observed. The KIE, calculated by an iterative program, was 1.009. CONCLUSIONS: Intramolecular differences in the stable chlorine isotope ratios were observed in DDT and this is the first such finding. Dehydrochlorination of DDT yields a measurable and distinct intramolecular stable chlorine KIE. RECOMMENDATION AND OUTLOOK: The results of this study demonstrate the existence of significant intramolecular differences in chlorinated organic compounds. Many other chlorinated semi-volatile and volatile organic contaminants are synthesized from multiple sources of chlorine, and we recommend that similar studies be performed on many such molecules in order to attain a clear understanding of their intramolecular chlorine isotopic differences. The existence of a measurable KIE for the dehydrochlorination of DDT to DDE shows the potential strength of using isotopic measurements to investigate the biogeochemistry of these important compounds. For example, the isotopically depleted aqueous chloride produced by dehydrochlorination of DDT to DDE may be a useful tracer of these reactions in freshwater environments.     

Economics of dairy waste use as fertilizer in central Texas

Dairy manure is an unavoidable natural, but negative, byproduct of milk production. Its nitrogen, phosphate, and potash contents represent a potential substitute for commercial fertilizers on field crops. In the absence of subsidies, manure transportation and land application costs limit its utilization as a substitute for chemical fertilizer. The results from a study of the economics of manure use in Central Texas suggest that, at the current costs for loading, hauling, and spreading, dairy manure cannot be economically transported from surplus to deficit areas within the study area. The estimated breakeven transport distance for manure application to four crops varied from 28 to 41 km; however, the distances between manure-surplus and manure-deficit counties in the study region varied from 40 to 90 km. An analysis of potential subsidies paid by the government or dairy farmers showed that the breakeven distance could increase by up to 30 km. A decrease in the assumed moisture content of the manure from 50% to 40% is shown to increase the breakeven distance by 10 km. The study suggests that dairy manure loading, transportation, and land application, with appropriate subsidies or reductions in moisture content, has the potential to be profitably substituted for chemical fertilizers.     

Grassland songbirds in a dynamic management landscape: behavioral responses and management strategies.

In recent decades, earlier and more frequent harvests of agricultural grasslands have been implicated as a major cause of population declines in grassland songbirds. From 2002 to 2005, in the Champlain Valley of Vermont and New York, USA, we studied the reproductive success of Savannah Sparrows (Passerculus sandwichensis) and Bobolinks (Dolichonyx oryzivorus) on four grassland treatments: (1) early-hayed fields cut before 11 June and again in early- to mid-July; (2) middle-hayed fields cut once between 21 June and 10 July; (3) late-hayed fields cut after 1 August; and (4) rotationally grazed pastures. Both the number of fledglings per female per year and nest success (logistic-exposure method) varied among treatments and between species. Although birds initiated nests earlier on early-hayed fields compared to others, haying caused 99% of active Savannah Sparrow and 100% of active Bobolink nests to fail. Both the initial cutting date and time between cuttings influenced renesting behavior. After haying, Savannah Sparrows generally remained on early-hayed fields and immediately renested (clutch completion 15.6 +/- 1.28 days post-haying; all values are reported as mean +/- SE), while Bobolinks abandoned the fields for at least two weeks (mean clutch completion 33 +/- 0.82 days post-haying). While female Savannah Sparrows fledged more offspring per year (1.28 +/- 0.16) than female Bobolinks (0.05 +/- 0.05), reproductive success on early-hayed fields was low. The number of fledglings per female per year was greater on middle-hayed fields (Savannah Sparrows, 3.47 +/- 0.42; Bobolinks, 2.22 +/- 0.26), and late-hayed fields (Savannah Sparrows, 3.29 +/- 0.30; Bobolinks, 2.79 +/- 0.18). Reproductive success was moderate on rotationally grazed pastures, where female Savannah Sparrows and female Bobolinks produced 2.32 +/- 0.25 and 1.79 +/- 0.33 fledgling per year, respectively. We simultaneously conducted cutting surveys throughout the Champlain Valley and found that 3-8% of hayfield habitat was cut by 1-4 June, 25-40% by 12-16 June, and 32-60% by 28 June-2 July. Thus, the majority of grassland habitat was cut during the breeding season; however, late-hayed fields served as high-quality reserves for late-nesting female Bobolinks that were displaced from previously hayed fields. For fields first cut in May, a 65-day interval between cuts could provide enough time for both species to successfully fledge young.