Maternal Serum CA 125 for aneuploidy detection in early pregnancy

Maternal serum CA 125 levels were determined at 9–11 menstrual weeks for 26 cases of trisomy 13 (n = 4), trisomy 18 (n = 7), trisomy 21 (n = 15), and appropriate controls. There were no statistically significant differences between groups.     

Vitamins,folic acid and neural tube defects: Comments on investigations in the United States

No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S.     

Anatomic correlates of ultrasonographic prenatal diagnosis

In utero sonographic diagnoses from forty-five malformed infants were correlated with their autopsy findings. Fifty-two malformations were diagnosed prenatally in 42 of the patients but 90 additional malformations were not. Nine sonographically diagnosed abnormalities were not confirmed at autopsy. Factors compromising sonographic diagnosis included: limited examinations, small fetal size, timing of examination, oligohydramnios, fetal position, nature of the malformation and unfamiliarity of the ultrasonographer with specific malformation syndromes. In vitro ultrasonography is an invaluable tool of diagnosing congenital malformations but has limitations.     

Persistently elevated AFP and AChE in amniotic fluid from a normal fetus following demise of its twin

Intrauterine fetal demise (IUFD) in one of twins at 12 weeks of gestation was accompanied by markedly elevated maternal serum alpha-fetoprotein (AFP) at 17 and 18 weeks. Amniotic fluid AFP from the healthy surviving twin's sac at 18·5 and 23 weeks was also greatly increased along with a positive acetylcholinesterase (AChE) band. Persistently elevated AFP and positive AChE so long after fetal demise–-6·5 and 11 weeks post IUFD–-has not, to our knowledge, been previously described. In similar cases, high level ultrasound and careful placental examination at birth should be utilized to search for fetal abnormalities or multiple pregnancy with IUFD.     

Effects of mid-trimester induced abortion on the subsequent pregnancy

The outcome of the pregnancy following (a) a mid-trimester termination of pregnancy (TOP) for fetal neural tube defect (NTD) (77 women=group 1); (b) mid-trimester TOP for fetal Down's syndrome (13 women=group 2); (c) delivery of a baby with NTD (119 women=group 3) was studied. The prenatal fetal loss was relatively high in all groups. In group 1 it was similar to that found in other studies after first trimester TOP, in group 2 it was associated with advanced maternal age and the unexpected finding in group 3 was not attributable to advanced maternal age. It is suggested that a previous NTD per se might increase the risk of fetal loss in the next pregnancy. A previous mid-trimester TOP for NTD was not associated with an increase in premature labour, small for dates babies or congenital abnormality in the next pregnancy, but there was a slight increase in the number of babies weighing less than 2500 g.     

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.     

TWO STRATEGIES FOR LEARNING A ROUTE IN A DRIVING SIMULATOR

The study of human navigation has long been dominated by the so-called stage theory, i.e. the notion that there are three distinct types of spatial knowledge (landmark, route, and survey knowledge), that are acquired sequentially during spatial learning and development. Based on the results of a route learning experiment in a driving simulator, an alternative to the stage theory is proposed. The authors suggest that subjects follow either a visually dominated or a spatially dominated strategy to solve a route-learning problem. In the visually dominated strategy, subjects base their wayfinding decisions on visually recognizing decision points along a route; the decision points are not integrated into any kind of survey representation. In the spatially dominated strategy, on the other hand, subjects represent the environment as a survey map right from the start; that is, they do not pass through a landmark or route stage. These strategies may be subserved by different cortical areas recently characterized in neurophysiological studies of animals solving maze problems.     

The Ethics of Constrained Choice: How the Industrialization of Agriculture Impacts Farming and Farmer Behavior

The industrialization of agriculture not only alters the ways in which agricultural production occurs, but it also impacts the decisions farmers make in important ways. First, constraints created by the economic environment of farming limit what options a farmer has available to him. Second, because of the industrialization of agriculture and the resulting economic pressures it creates for farmers, the fact that decisions are constrained creates new ethical challenges for farmers. Having fewer options when faced with severe economic pressures is a very different situation for farmers than having many options available. We discuss the implications of constrained choice and show that it increases the likelihood that farmers will consider unethical behavior.