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[The alpha-fetoprotein level analysis in open neural tube defects and chromosomal aberrations in the fetus].

During the last 12 years 4258 amniocenteses were performed between the 12th and 20th week of gestation (including 323 early amniocenteses carried out before 15th week). In every case, cytogenetical examination was performed and concentration of AFP was determined. In cases with elevated AFP level electrophoresis of AchE izoenzymes was performed. The results of the tests enabled us to calculate laboratory standard values of AFP in the amniotic fluid for 12th to 20th weeks of gestation. In 22 of 44 pregnancies with Down's syndrome the value of AFP concentration was below the 25th percentile of the laboratory normal value. In 5 of 10 pregnancies with Edward's syndrome AFP level exceeded significantly the 75th percentile of the laboratory norm. In two cases it was due to coexisting spina bifida and in one case due to omphalocele. In 28 amniotic fluid samples AFP concentration exceeded normal level and electrophoresis of AchE revealed additional band. In 26 cases increased values of AFP were due to open neural tube defect in the fetus: 13 cases of anencephaly and 13 cases of spina bifida; in the remaining two other cases omphalocele was found.

Amniotic Fluid↗

Periconceptional vitamin use, dietary folate and occurrent neural tube defected pregnancies in a high risk population.

PURPOSE: This 5 year (1992-1997) population-based case control study was conducted to determine if supplemental or dietary folate taken during the periconceptional period reduces the risk of occurrent neural tube defect (NTD) affected pregnancies in a high risk population.METHODS: Cases were all NTD pregnancies including elective terminations, fetal deaths and live births in South Carolina. Only isolated, occurrent NTD affected pregnancies were included (N = 179). Controls (N = 288) were randomly selected from each hospital in proportion to the hospital's contribution to the total live births in the state for the previous year. All mothers were interviewed in person using a modified Centers for Disease Control and Prevention Birth Defect Risk Factor Surveillance Mother's Questionnaire and the Harvard Food Frequency Questionnaire.RESULTS: Women who used a vitamin with 0.4 mg or more of folate at least 3 times per week during the 3 months before and 3 months after conception had a lower risk of having an NTD affected pregnancy than women who took no folate supplementation at any time during pregnancy [adjusted odds ratio (AOR) = 0.42; 95% confidence interval (CI) = 0.19-0.94]; women who used a vitamin with 0.4 mg or more of folic acid for less than 3 times per week or in partial months during the 6 month periconceptional period also had a slightly lower risk of having an NTD affected pregnancy relative to women who used no folate supplementation at any time during pregnancy [AOR =.72; 95% CI = 0.41-1.30]. The risk of NTD affected pregnancy was also lower for women who daily consumed foods containing higher levels of folate: AORs were 0.36 (95% CI = 0.18-0.73), 0.72 (95% CI = 0.42-1.22), and 0.61 (95% CI 0.36-1.04) from the highest to lowest quartile of dietary folate which were 0.457-3.12 mg, 0.322-0.457 mg, and 0.236-0.322 mg respectively.CONCLUSIONS: A reduction in occurrent NTD risk associated with folate supplementation and dietary intake was observed.

Journal Article↗

Triple marker screening for trisomy 21, trisomy 18 and open neural tube defects in singleton pregnancies of native Japanese pregnant women.

OBJECTIVE: To report the results of prenatal triple marker screening on a population of Japanese pregnant women. METHODS: From April 1994 through March 1999, a total of 32,925 native Japanese women with singleton pregnancies requested a triple marker-screening test. Multiples of the median values for 3 markers and individual risks for each patient were calculated following adjustment for the Japanese weight correction factor. The risk cut-off values used for Down syndrome (T21), open spina bifida (OSB) and trisomy 18 (T18) were 1: 295, 1: 290, and 1: 100, respectively. Follow-up information was collected postpartum and statistically analyzed. RESULTS: Detection rates (DR) of T21 for women less than 35 years, over 35 years and overall were 58, 94, and 83%, respectively. DR of T18 for women less than 35 years, over 35 years and overall were 75, 79, and 79%, respectively. DR of open neural tube defects (ONTD) was 100%. CONCLUSIONS: The first cumulative data of an intervention program and prospective follow-up studies in Japan have proven to be similar to other published reports. Individual risk values were calculated for each pregnancy for T21, T18 and ONTD. This screening program is more effective than age-dependent screening for detecting T21, T18 and ONTD pregnancies.

Adult↗

Prenatal biochemical screening for Down's syndrome and neural tube defects.

Antenatal serum screening for Down's syndrome is now becoming established in many centers throughout the world. The screening method is based on the measurement of alpha-fetoprotein, unconjugated estriol, and human chorionic gonadotropin between 15 and 22 weeks of pregnancy. These measurements, used in conjunction with a woman's age, provide risk estimates of having a pregnancy with Down's syndrome for every woman screened. By identifying the 5% of women with highest risk and offering them an amniocentesis, about 60% of Down's syndrome pregnancies can be identified. If an ultrasound scan examination is used routinely to estimate gestational age, the detection rate can be increased by 5% to 10%. Recent information on the distribution of the three serum markers in twin pregnancies and pregnancies with insulin-dependent diabetes mellitus now means that screening can be carried out in such pregnancies. Various other serum markers of Down's syndrome have been reported, but at present they do not have a place in routine antenatal screening for Down's syndrome. The role of amniotic fluid acetylcholinesterase measurement, alone and in combination with amniotic fluid alpha-fetoprotein measurement, in the antenatal diagnosis of open neural tube defects has recently been clarified. The best policy is to perform an amniotic fluid alpha-fetoprotein measurement as the primary test and an acetylcholinesterase determination for those women who have an amniotic fluid alpha-fetoprotein measurement of two times the normal median or greater. The acetylcholinesterase can be measured either by the standard method (gel electrophoresis) or by a new quantitative monoclonal antibody method.

Acetylcholinesterase↗

Reduced SOD activity and increased neural tube defects in embryos of the sensitive but not of the resistant Cohen diabetic rats cultured under diabetic conditions.

BACKGROUND: The role of reactive oxygen species in the etiology of diabetes-induced anomalies was studied in a genetic model of nutritionally induced Type 2 diabetes mellitus: the Cohen diabetic sensitive (CDs) and resistant (CDr) rats. We have previously shown in this model that embryopathy may be induced by a combination of genetic and environmental factors. In our study we investigated the role of the antioxidant defense mechanism, genetic predisposition or environmental factors in embryos cultured under diabetic conditions. METHODS: CDs, CDr and Sabra rat 11.5-day old embryos were studied after 28 hr of culture in control (low glucose), high glucose, diabetic sub-teratogenic, and diabetic teratogenic media. Embryos were monitored for growth retardation and congenital anomalies. Activity of superoxide dismutase (SOD) and catalase-like (CAT) enzymes was measured in embryonic homogenates. RESULTS: In control medium, CDs embryos were significantly underdeveloped but exhibited no anomalies and SOD activity was not significantly different from that of CDr embryos. In high glucose medium, CDs embryos were smaller than CDr and Sabra embryos and smaller than CDs embryos cultured in control medium. Neural tube defects (NTD) were found predominantly in the CDs embryos starting from 14% in the high glucose medium and increasing to 29% in the sub-teratogenic medium. In the teratogenic medium, < 50% of the CDs and Sabra embryos were alive whereas all (100%) of the CDr embryos were alive. SOD activity significantly increased in CDs embryos when cultured in the high glucose medium but was significantly reduced in the sub-teratogenic medium. SOD activity was increased significantly in the Sabra embryos cultured in the sub-teratogenic medium but did not change in CDr embryos cultured in either one of the different culture media. CAT activity did not show any significant trend in either one of the rat strains or in any of the different culture conditions. CONCLUSIONS: Our results suggest that genetic susceptibility plays an important role in inducing underdevelopment and NTD in cultured CDs embryos in sub-teratogenic medium and in protecting the CDr embryos under the same conditions. The combination of a sub-teratogenic environment with genetic susceptibility is sufficient to reduce the activity of SOD, hence decreasing the ability of the CDs embryos to cope with diabetic sub-teratogenic environment and prevent NTD.

3-Hydroxybutyric Acid↗