一种确定地球化学异常下限的简便方法

本文从地球化学场元素的分布形式出发 ,探讨了理论分布形式的频率与含量双对数坐标图示特征 ,从而提出了一种确定地球化学异常下限的简便方法。将该方法应用于湖南柿竹园钨多金属矿区 ,效果显著     

The role of DNA microarrays in the evaluation of fetal death

Fetal death occurs in 15% of clinically recognized pregnancies. Cytogenetic abnormalities are present in 50% of spontaneous abortions (fetal deaths < 20 weeks) whereas the rate is 6% to 13% for stillbirths (fetal deaths ≥ 20 weeks). Microarray has been demonstrated to increase the diagnosis of genetic abnormalities by providing coverage of the entire genome at a higher density, detecting as small as 50 to 100 kb deletions or duplications, known as copy number changes. Microarray is particularly suited for evaluation of fetal death because DNA can still be analyzed in macerated fetuses and nonviable tissue, two situations where culturing and karyotyping is known to have low yield. Microarray has already proven successful in providing additional genetic information beyond karyotype in spontaneous abortion. The few studies on the use of microarray in stillbirth evaluation have been promising, demonstrating an increase in the diagnosis of clinically relevant genetic abnormalities when compared with karyotype. As the cost and technology improve, microarray may ultimately become the first line screen for genetic abnormalities in stillbirth. The accurate diagnosis of a genetic abnormality as the cause for fetal death may provide closure for families, prevent unnecessary treatments, and enable clinicians to more accurately counsel and manage subsequent pregnancies. © 2012 John Wiley & Sons, Ltd.     

Transvaginal sonographic detection of skeletal anomalies in the first and early second trimesters

We report the detection of 42 cases of musculoskeletal anomalies routinely screened by transvaginal sonography at 12-16 weeks of gestation out of 7325 examined pregnant women (incidence of 0·57 per cent).     

Prenatal diagnosis of congenital non-bullous ichthyosiform erythroderma (lamellar ichthyosis)

We report the first positive prenatal diagnosis ofcongenital non-bullous ichthyosiform erythroderma or lamellar ichthyosis. Fetal skin samples were obtained by fetoscopy at 21 weeks' gestation and examined by light and electron microscopy. Light microscopy revealed a thickened interfollicular epidermis with multiple layers of flattened cells and excessive keratinization of the epidermal lining of the follicular infundibulum. Electron microscopy of the thickened epidermis revealed granular cells that contained larger-than-normal keratohyalin granules and multiple layers of parakeratotic cornified cells. Although there was regional variation in the degree of interfollicular keratinization, follicles from all regions showed greater and more complete keratinization, indicating that they express the abnormality early enough in development to permit prenatal diagnosis at about 20 weeks' gestation.