砷细胞遗传毒理学研究的最近进展

本文对砷细胞遗传毒理学研究的最近进展进行了简要评述。着重介绍了砷对人体，试验动物及某些植物诱发染色体畸变，姊妹染色单体互换及微核的效应；对砷诱发体外培养的人类细胞和试验动物细胞染色体畸变，姊妹染色单体互换及微核效应也作了介绍。     

Parental decisions regarding termination of pregnancy following prenatal detection of sex chromosome abnormality

In the period of a retrospective study (1979–1984 inclusive) forty cases of sex chromosome aneuploidy were identified at amniocentesis in Oxford, England and in Kuopio, Finland; 25 of these pregnancies were subsequently terminated. A decision to continue was made more often for XYY and XXX karyotypes, by older mothers and older fathers, by couples with more previous children, and by couples living in England. A decision to terminate was made more often for XXY and non-mosaic 45,X karyotypes, by younger mothers and younger fathers, by couples with few previous children, in all cases with abnormal ultrasound findings, when post-amniocentesis counselling was given by an obstetrician, and by couples living in Finland. Previous miscarriages, or terminations of pregnancy, previous problems with infertility, marital status, or the type of counselling given before amniocentesis, appeared not to influence a couples' decision. Religious and ethical ideas were not studied systematically at the time and cannot be reported on.     

Postnatal confirmation of prenatally diagnosed trisomy 16 mosaicism in two phenotypically abnormal liveborns

Two phenotypically abnormal liveborns in whom trisomy 16 mosaicism was diagnosed prenatally by amniocentesis are described. Analysis of a percutaneous umbilical blood sample in one case revealed a normal chromosomal complement. Ultrasound examinations performed at the time of amniocentesis were normal. Serial sonography during the late second and third trimesters demonstrated progressive intrauterine growth retardation (IUGR) in both fetuses and a cardiac defect in one. At birth, both infants had dysmorphic features and multiple congenital anomalies. Trisomy 16 mosaicism was confirmed postnatally in both infants in skin fibroblasts; however, peripheral blood samples contained only chromosomally normal cells. The two mosaic trisomy 16 cases described in this report, together with the five confirmed cases reported previously, demonstrate the need for caution in the counselling of patients when trisomy 16 mosaicism is diagnosed prenatally in amniotic fluid samples. Such cases potentially can result in the birth of dysmorphic infants with significant birth defects, growth retardation, and possible developmental disabilities.     

Noninvasive prenatal diagnosis of aneuploidy using cell-free nucleic acids in maternal blood: promises and unanswered questions

The discovery of cell-free fetal (cff) DNA and RNA in the maternal circulation has driven developments in noninvasive prenatal diagnosis (NIPD) for the past decade. Detection of paternally derived alleles in cff DNA is becoming well established. Now much interest is focussing on NIPD of fetal chromosomal abnormalities, such as trisomy 21, which is a considerable challenge because this demands accurate quantitative measurements of the amounts of specific cff DNA or cff RNA sequences in maternal blood samples. Emerging strategies for distinguishing and quantifying the fetal nucleic acids in the maternal circulation promise continued development of the field, and pose a number of unanswered questions. Copyright © 2007 John Wiley & Sons, Ltd.     

Prenatal diagnosis of apparently isolated unilateral multicystic kidney: implications for counselling and management

Cases where initial prenatal diagnosis was made of isolated unilateral multicystic kidney (UMCK) were reviewed to determine appropriate counselling and management strategies. For the 73 cases, chromosome abnormalities, pregnancy complications and family histories were reviewed. In addition, subsequently diagnosed birth defects, and pediatric medical and surgical outcomes were available for 54 cases. Of those with outcome information available renal/genital–urinary tract abnormalities were diagnosed subsequently in 33% and non-renal abnormalities in 16% of cases. Of the non-renal abnormalities, congenital heart defects were most frequent (7%). One chromosome abnormality, a trisomy 21, was present among 32 cases where karyotypes were known (3%). Amniotic fluid volume abnormalities were present in 11 cases but not predictive of associated anomalies, with the exception of one case where polyhydramnios accompanied multiple malformations consistent with VATER association. A family history of structural renal anomalies was reported in 11 cases (20%). There were 14 cases of partial or complete involution (25%), including two cases of complete prenatal involution of the cystic kidneys. No long-term associated morbidity such as hypertension or malignancy was present in our cohort. Based on our study and corroborating literature, amniocentesis should be offered to women when a seemingly isolated UMCK is detected on routine prenatal ultrasound. Furthermore, a detailed ultrasound with careful assessment of the fetal heart and contralateral kidney is indicated at diagnosis and during the third trimester to assess for further evidence of structural abnormalities, as well as amniotic fluid volume abnormalities. Careful assessment of the newborn is indicated with appropriate speciality referral as required. Copyright © 2002 John Wiley & Sons, Ltd.