Prenatal diagnosis of a true mosaic trisomy 20 substantiated by demonstration of a gene dosage effect for adenosine deaminase (ADA)

Fibroblasts from a fetus with the prenatal diagnosis of mosaic trisomy 20 were cloned by dilution plating. Adenosine deaminase (ADA), a biochemical marker for chromosome 20, was assayed in trisomic clones and normal clones as control. The cytogenetic diagnosis was substantiated by demonstration of a triplex gene dosage effect for ADA in the trisomic cells.     

Prenatal application of fluorescent in situ hybridization (FISH) for identification of a mosaic Y-chromosome marker,IDIC(Yp)

An amniocentesis was performed at 13.3 weeks' gestation for advanced maternal age. A mosaic sex chromosome pattern was found: of 50 cells examined, 34 had a 45,X karyotype. In 14 cells with a modal number of 46, a recognizable Y was substituted by a small non-fluorescent marker. C-banding identified the marker as an isodicentric in 12 cells. In two cells, the non-fluorescent marker appeared to be monocentric and looked like a non-fluorescent del (Yq), but could have been an isodicentric Y with inactivation of one of the centromeres. Two cells with a modal number of 47 showed two copies of the monocentric marker. Fluorescent in situ hybridization with an alpha satellite Y-specific centromeric probe confirmed the Y-chromosome origin of the markers and allowed for more accurate prenatal diagnostic information.     

Spillover of functionally important organisms between managed and natural habitats

Land-use intensification has led to a landscape mosaic that juxtaposes human-managed and natural areas. In such human-dominated and heterogeneous landscapes, spillover across habitat types, especially in systems that differ in resource availability, may be an important ecological process structuring communities. While there is much evidence for spillover from natural habitats to managed areas, little attention has been given to flow in the opposite direction. This paper synthesizes studies published to date from five functionally important trophic groups, herbivores, pathogens, pollinators, predators, and seed dispersers, and discusses evidence for spillover from managed to natural systems in all five groups. For each of the five focal groups, studies in the natural to managed direction are common, often with multiple review articles on each subject which document dozens of examples. In contrast, the number of studies which examine movement in the managed to natural direction is generally less than five studies per trophic group. These findings suggest that spillover in the managed to natural direction has been largely underestimated. As habitat modification continues, resulting in increasingly fragmented landscapes, the likelihood and size of any spillover effect will only increase.     

A further prenatal diagnosis of mosaic tetrasomy 12p (Pallister-Killian syndrome)

A case of mosaic tetrasomy 12p was detected in amniotic fluid cell cultures from a 28-year-old woman referred to us at 26 weeks' gestation because of hydramnios. The fetus was shown on ultrasonography to have an omphalocele and a short femur length. Labour was induced at 32 weeks. An infant with multiple congenital anomalies was delivered and died after 10 min. The diagnosis of i(12p) or Pallister-Killian syndrome was confirmed cytogenetically in fibroblast and lymphocyte cultures. Increased LDH-B activity was demonstrated in fibroblasts.     

Prenatal diagnosis,fetal pathology and cytogenetic analysis of A 46,XX/47,XX, + 15 mosaic

Mosaic trisomy 15 was prenatally diagnosed on amniotic fluid cells from two consecutive amniocenteses and was confirmed on cells from five different fetal tissues. The proportion of normal versus trisomic cells was consistently higher in the amniotic cell cultures and-with one exception-in the fetal tissues, while serial subcultures gave different results. The slightly atypical external features and internal malformations of the affected fetus as compared to the only clinical observation from the literature are not unusual enough to allow the delineation of a specific malformation pattern.     

Pallister Killian-mosaic tetrasomy 12 p syndrome. Another prenatally diagnosed case

A new case of mosaic tetrasomy 12 p (46, XY/47, XY, + i 12 p), diagnosed during pregnancy from ultrasonographic signs, is reported. We emphasize the peculiar position of the diaphragmatic hernia in this syndrome. Its presence or absence determines the vital prognosis and the age of diagnosis. The knowledge of its possible association with tetrasomy 12 p can contribute considerably to the neonatal diagnosis by directing the work of the cytogeneticist to tissue cultures which enable him to detect the presence of the tetrasomy.     

XX/XY chimerism encountered during prenatal diagnosis

46,XX/46,XY chimerism has previously been reported in patients with abnormal sexual development, and rarely in otherwise normal individuals. We report the first postnatally documented prenatal diagnosis of whole-body 46,XX/46,XY chimerism in humans, discovered by maternal age amniocentesis. The normal male phenotype in this child creates a dilemma in prenatal counselling, since genotypic male/female chimerism cannot be assumed to imply an abnormal sexual phenotype.     

Mosaic Isochromosome 20q found on amniocentesis with normal outcome

A case of mosaic isochromosome 20q found on amniocentesis is described. A normal male infant was subsequently born.     

1986～2015年棋盘山水库湿地保护地生态系统演变分析

为探讨沈阳市棋盘山水库湿地保护地近30年生态系统演变规律,文章运用3S技术和景观格局指数,分析了保护地1986~2015年生态系统时空变化及景观格局演变特征。结果表明:1986~2015年间,由于人类活动的干扰,保护地景观破碎度和空间异质性不断增加,水库周边建设用地围绕水库向南部、北部不断扩张,不利于生态系统服务功能的保护和提升,但总体上看,2000~2015年人类活动强度低于1986~2000年,说明该时期生态保护工作取得一定成效。为提升保护地景观质量和生态系统服务功能,提出了保护地生态系统服务可持续管理对策。     

Mosaic triple trisomy in amniocytes from a phenotypically and karyotypically normal fetus

We report the detection of a mosaic triple trisomy, 46, XY/49, XY, + 13, +20, +21, in two amniotic fluid specimens obtained from a pregnancy that yielded a normal infant. Traditional cytogenetic methods failed to detect the abnormal cell lineage in fetal blood, foreskin, amnion, umbilical cord, and three different biopsies of the chorion. In addition, fluorescence in situ hybridization study of cells from a buccal smear showed no evidence of cells with three copies of chromosome 20.