Prenatal determination of a variable number of tandem repeats in intron 40 of the von Willebrand factor gene from maternal peripheral blood using the polymerase chain reaction.
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To determine a fetal variable number of tandem repeats (VNTR) without using fetal tissues, we amplified the whole VNTR region in intron 40 of the von Willebrand factor gene from maternal peripheral blood by the polymerase chain reaction and then separated the amplified fragments by a nonhydratable polyacrylamide gel with an electrolyte gradient. After water elution from the gel, each preliminary product was amplified for the second time and then digested by Alu I restriction endonuclease. Then the VNTR was examined using a hydratable polyacrylamide gel with an electrolyte gradient. We successfully identified the fetal VNTR from 6 cases of 10 maternal peripheral blood samples and 2 cases of 6 maternal blood samples after parturition. This study might offer a theoretical basis for the noninvasive diagnosis of genetic disorders and identification of disputed paternity with common primers. (+info)
Antenatal diagnosis of subependymal heterotopia.
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Subependymal heterotopia consist of gray matter nodules along the lateral ventricular walls and are associated with epilepsy and other cerebral malformations. Some cases have an X-linked inheritance, and early antenatal diagnosis of affected fetuses is important for appropriate management. We present a case of heterotopia diagnosed by sonography and MR imaging at 23 weeks' gestation and discuss the differential diagnosis, reviewing the evolution and imaging appearances of the germinal matrix and its implications for detection of heterotopia. (+info)
Six year survey of screening for Down's syndrome by maternal age and mid-trimester ultrasound scans.
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OBJECTIVE: To assess the effectiveness of antenatal screening for Down's syndrome by maternal age and routine mid-pregnancy ultrasound scanning. DESIGN: Retrospective six year survey. SETTING: Maternity units of a district general hospital. SUBJECTS: Pregnant women booked for delivery in hospital between 1 January 1993 and 31 December 1998. MAIN OUTCOME MEASURES: All cases of Down's syndrome occurring in district identified from regional congenital anomaly register and cytogenetic laboratory records. Women's case notes were examined to identify indication for karyotyping, gestation at diagnosis, and outcome of pregnancy. RESULTS: 31 259 deliveries occurred during study period, and 57 cases of Down's syndrome were identified, four in failed pregnancies and 53 in ongoing pregnancies or in neonates. The analysis was confined to ongoing pregnancies or liveborn children. Invasive antenatal tests were performed in 6.6% (2053/31 259), and 68% (95% confidence interval 56% to 80%) of cases of Down's syndrome were detected antenatally, giving a positive predictive value of 1.8%. There were 17 undetected cases, and in seven of these the women had declined an offer of invasive testing. In women aged less than 35 years the detection rate was 53% (30% to 76%). Most of the cases detected in younger women followed identification of ultrasound anomalies. CONCLUSIONS: The overall detection rate was considerably higher than assumed in demonstration projects for serum screening. As a result, the benefits of serum screening are much less than supposed. Before any new methods to identify Down's syndrome are introduced, such as nuchal translucency or first trimester serum screening, the techniques should be tested in properly controlled trials. (+info)
The ethics of anonymized HIV testing of pregnant women: a reappraisal.
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Seroprevalence monitoring of HIV in pregnant women by anonymized unlinked testing has been widely adopted in the UK and other countries. The scientific rationale is to eliminate participation and selection bias. The ethical justification is that the public good outweighs any harm to individuals. The assumption has been that individuals have had their autonomy respected by the offer of informed consent. In the light of new scientific evidence, it is doubtful that the public good is best served by the continuation of anonymously testing women receiving antenatal care. It is submitted that it is no longer ethical for health professionals to refrain from informing pregnant women of the benefits of voluntary named testing, or to request their consent to anonymized testing. The legal and moral concept of duty of care is examined, and the abrogation of this duty through anonymization is explained. (+info)
Ethics in the laboratory examination of patients.
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Various value problems are connected with the clinical examination of patients. The purpose of this literature review is to clarify: 1) in which patient examinations ethical problems are generally found; 2) what kind of ethical problems are found in the different phases of the examination process, and 3) what kind of ethical problems are found in connection with the use of examination results. Genetic testing, autopsy, prenatal and HIV examinations were ethically the most problematic laboratory examinations. The most problematic phase in the laboratory examination process proved to be the pre-analytic phase. At present the results of laboratory examination are used more and more often for the prediction of diseases. The problems appear when the examination results are used for discrimination and stigmatization. Because of the lack of empirical ethical research, it is important to chart empirical knowledge about present value conflict situations involved in the laboratory examination process. (+info)
Cri-du-chat syndrome: clinical profile and prenatal diagnosis.
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Prenatal diagnosis of cri-du-chat syndrome is described in 2 pregnancies. In Case 1, the mother was a balanced translocation carrier and had 2 previously affected off springs. Prenatal diagnosis by chorion villus sampling and cordocentesis was successful in diagnosing an affected conceptus and the pregnancy was electively terminated. Case 2 was referred for nonimmune foetal hydrops and cordocentesis revealed deletion 5p. This second case was noteworthy for the fact that deletion 5p has not been reported to cause foetal hydrops. (+info)
Temporal variability in birth prevalence of cardiovascular malformations.
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OBJECTIVE: To investigate changes over time in the prevalence at live birth of cardiovascular malformations and to compare "anatomical" and "physiological" diagnostic hierarchies within a population. DESIGN: Retrospective and prospective ascertainment of all congenital cardiovascular malformations diagnosed in infancy. SETTING: The resident population of one health region. PATIENTS: All infants live born from 1985 to 1997 with cardiovascular malformations confirmed by echocardiography, cardiac catheterisation, surgery or autopsy. MAIN OUTCOME MEASURES: Year to year variation in prevalence of individual malformations and of "complex", "significant", and "minor" groups. RESULTS: 2671 babies with cardiovascular malformations were confirmed in a denominator population of 477 960 live births (5.6 per 1000). There was no change over 13 years in the birth prevalence of "complex" or "significant" defects, but a highly significant increase in "minor" defects (p < 0.0001), mainly small ventricular septal defects. Termination of pregnancy increased from no cases in 1985 to 16 in 1997 with no demonstrable effect on live born babies with heart defects. A one dimensional "anatomical" diagnostic hierarchy led to under ascertainment of pulmonary atresia by 27%, coarctation of the aorta by 39%, and interruption of the aorta by 100%. CONCLUSIONS: The apparent increase in live born cardiovascular malformations results mainly from improved diagnosis of minor defects. There has been no change over time in birth prevalence of more serious defects. Spontaneous year to year variation in numbers will make it difficult to ascribe any short term changes to any particular intervention. A two dimensional diagnostic hierarchy is offered as a standard. (+info)
Women with a reduced ovarian complement may have an increased risk for a child with Down syndrome.
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Advanced maternal age is the only well-established risk factor for trisomy 21 Down syndrome (DS), but the basis of the maternal-age effect is not known. In a population-based, case-control study of DS, women who reported surgical removal of all or part of an ovary or congenital absence of one ovary were significantly more likely to have delivered a child with DS than were women who did not report a reduced ovarian complement (odds ratio 9.61; 95% confidence interval 1.18-446.3). Because others have observed that women who have had an ovary removed exhibit elevated levels of FSH and similar hallmarks of advanced maternal age, our finding suggests that the physiological status of the ovary is key to the maternal-age effect. In addition, it suggests that women with a reduced ovarian complement should be offered prenatal diagnosis. (+info)