ICP-MS法测定饮用水中金属元素

利用ICP-MS法对饮用水中的多种元素进行全定量分析,结果表明,ICP-MS法可同时测定饮用水中的多种元素;快速,一个样品仅需3～5 分钟;灵敏度和准确度高;精密度好,相对标准偏差一般小于3%;检出限低,达到ng/L-ug/L级;线性范围宽,达到8～9 个数量级.     

Prenatal analysis of the insulin receptor gene in a family with leprechaunism

Leprechaunism is an autosomal recessive disease characterized by intrauterine and postnatal growth restriction, loss of glucose homeostasis, and severe insulin resistance. This disease is caused by a failure of function of the insulin receptor and is lethal early in life. Here we report the prenatal diagnosis of leprechaunism in one consanguineous family, Atl-1, in which two homozygous-affected siblings died with leprechaunism. The mutation in their insulin receptor impaired insulin binding and altered receptor signalling. Prenatal diagnosis could not be accomplished using insulin binding to cultured amniocytes, but was possible using mutational analysis of the insulin receptor gene in DNA from amniotic cells.     

Cytogenetic prenatal diagnosis and its relative effectiveness in the mersey region and North Wales

The relative effectiveness of cytogenetic prenatal diagnosis in the Mersey Region and North Wales is presented by estimating the percentage detection rates of Down's syndrome annually following amniocentesis from 1978–1984 inclusive. Tables indicating the percentage of screened pregnancies, types of chromosomal aberrations detected and the occurrence of Down's syndrome in mothers in age groups of five-year intervals are also presented. The average prenatal detection rate for Down's syndrome (estimated at the time of birth) was 15–15 per cent over the years 1978–1984 and was above 22 per cent for the last two years when 44–13 per cent of all pregnancies to mothers of 35 years and over were investigated.     

Prenatal exclusion of metachromatic leukodystrophy by estimation of arylsulphatase a activity in chorion and cultured amniotic fluid cells

Chorion biopsy specimens were used for prenatal assay of arylsulphatase A activity in a pregnant woman whose two children had died from metachromatic leukodystrophy (MLD). As in two subsequent pregnancies chorion arylsulphatase A was in the control range, it was concluded that both fetuses were healthy. Absence of MLD in the fetus from the first pregnancy was confirmed after assay of arylsuphatase A activity in fetal organs. The second pregnancy resulted in delivery of a healthy child.     

Prenatal detection of congenital hypospadias in the wolf-hirschhorn (4p —) syndrome

Hypospadias is one of the most prominent and characteristic midline defects in male infants with the Wolf-Hirschhorn (4p —) syndrome. In this report we present a case in which hypospadias was identified prenatally at 29 weeks' gestation in association with intrauterine growth retardation. Cytogenetic evaluation after birth confirmed a 46, XY, del(4)(p14) karyotype. The prenatal identification of hypospadias in fetuses with intrauterine growth retardation and normal amniotic fluid should suggest a diagnosis of Wolf-Hirschhorn syndrome.     

Landscape dynamitic change in Mu Us Desert derived from Landsat TM data

Landscpae ecology emphasizes large areas and ecological effects of the spatial patterning of ecosystem.Recent developments in landscape ecology emphasized the important relationship between spatial patterns and many ecological processes.Quantitative methods in landscape ecology link spatial patterns and ecological processes at broad spatial and temporal scales.In turn the increased attention on temoral change of ecosystem has highlighted the need for quantitative methods that can analyze patterns.This research applies quantitative methods-change detection to assess the ecosystem temporal change in the arid and semiarid area.Remote sensing offers the temporal change of ecosystem on landscape characteristics.     

Psychological impact of amniocentesis on low-risk women

The study comprised 85 young (25–34 years old) women who underwent genetic amniocentesis, 80 comparable young women who had an ultrasoundscan at the same gestational age and 74 women (35–40 years old) who had amniocentesis. The State-Trait Anxiety Inventory and Visual Analogue Scales concerning anxiety and worry were used on four occasions to evaluate psychological changes during pregnancy. The anxiety level in the younger women decreased after amniocentesis and a further decrease was observed after the results were communicated to them. However, similar changes were seen in the group of younger women after ultrasonography, and there was no difference in anxiety level between the two groups of younger women in the 16th or in the 35th week of pregnancy. Thus, in younger women at low genetic risk amniocentesis was neither anxiety-relieving, nor anxiety-creating. The level of anxiety before amniocentesis was not higher in the older than in the younger women having amniocentesis. However, in the younger women a significant decrease in anxiety was seen as soon as amniocentesis had been performed, while in the older women this decrease was delayed until after the results were known.     

Cardiac flow after fetal blood sampling in normally grown and growth-retarded fetuses

The objective of this study was to evaluate the effect of fetal blood sampling on cardiac flow velocity waveforms. Flow velocity waveforms were measured from the ascending aorta and pulmonary artery immediately before and after fetal blood sampling in 29 normally grown and 12 growth-retarded fetuses. The latter group was characterized by abnormal Doppler indices in the umbilical artery and middle cerebral artery suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. The flow velocity parameters studied were the peak velocity, the time to peak velocity, and the left and right cardiac output and their ratio. In normally grown fetuses, the peak velocity and right and left cardiac output values increased significantly after fetal blood sampling, while no significant changes were observed in the other indices considered. The gestational age at the time of the procedure was positively related to the amplitude of these changes. In growth-retarded fetuses, fetal blood sampling did not induce any significant increase in cardiac output or peak velocities, while in more than 50 per cent of the fetuses these Doppler indices decreased. The amplitude of the decrease was significantly related to the severity of acidosis in the umbilical vein. In conclusion, the cardiac haemodynamic response to fetal blood sampling differs between normally grown and growth-retarded fetuses. This difference may explain the higher rate of complications occurring in the latter group of fetuses after blood sampling.     

Carrier detection and microsatellite analysis of duchenne and becker muscular dystrophy in spanish families

Duchenne and Becker muscular dystrophy (D/BMD) are usually problematical when trying to determine the carrier status of at-risk women, which usually has to be based on haplotype or dosage analysis on Southern blots. Using multiplex polymerase chain reaction (PCR) analysis, we have detected deletions in 20 out of 44 D/BMD families with living affected members (45·5 per cent), more often in sporadic cases of DMD (14/22 with detectable deletion) than in familial ones (4/15), the majority (15/20) occurring in the distal region of the D/BMD gene. Four highly informative short tandem repeat polymorphisms (STRPs), which lie within the distal deletion hot spot of the D/BMD gene, can show loss of heterozygosity in carrier females, providing direct evidence of their carrier status. These STRPs greatly improve informativity, with a combined heterozygosity of 100 per cent and with the majority of families informative for three of the four STRPs. In 14/15 (93 per cent) of the families with distal deletions, the STRPs provided direct information on carrier status, and in some cases, they provide valuable information on recombination breakpoints and non-paternity.     

Prenatal sonographic appearance of foramina parietalia permagna

Foramina parietalia permagna (FPP) is an extremely uncommon congenital defect, inherited as an autosomal dominant condition. Its characteristics are two symmetrical orifices in the parietal bones (not of fixed size) on both sides of the midline. This defect does not affect either the psychic or the physical development of the affected person. This paper describes the sonographic appearance of FPP in utero as an enlargement of the posterior fontanelle.