Thyroid antibodies are not a risk factor for pregnancies with down syndrome

The observation that thyroid disease is frequent in mothers of children with Down syndrome (DS) has suggested that maternal thyroid antibodies could be a factor predisposing to trisomy 21 in their offspring. In this study, the incidences of thyroglobulin (Tg) and thyroid peroxidase (TPO) antibodies were analysed with a sensitive solid-phase immunosorbent radioassay in sera from 29 mothers giving birth to children with trisomy 21 and 87 control mothers. The serum samples were collected at delivery. There was no statistical difference regarding the proportion of thyroid antibodies (against Tg and/or TPO) in the two groups. Thyroid antibodies were detected in 6/29 (20.7 per cent) of the DS mothers and in 23/87 (26.4 per cent) of the control mothers. Among the women with thyroid antibodies, 4/6 (66.7 per cent) of the DS mothers and 12/23 (52 per cent) of the control mothers had antibodies against both Tg and TPO. There was no increase in the relative risk of having a child with DS if the titre of either Tg or TPO antibodies or both were positive, i.e. ≥ 1/5. The results indicate that the presence of thyroid antibodies in the serum of a pregnant woman has no prognostic value for the birth of an infant with DS.     

Factors associated with multiple-pass procedures during chorionic villus sampling: A video analysis

Multiple placental passes during chorionic villus sampling (CVS) increase the risk of fetal loss; however, specific factors that predispose to repeat aspiration have not been delineated. To identify anatomic and technical variables associated with multiple-pass procedures, a detailed review of 205 videotaped CVS procedures (single pass = 163; multiple pass = 42) was performed, blinded to pregnancy outcome. The route of sampling did not influence the need for multiple aspiration attempts (transabdominal—30/ 135; transcervical—12/70), nor was placental location alone discriminatory. However, the combination of a posterior placenta and uterine retroversion was observed more frequently in the multiple-pass cohort (8/42 vs. 9/163; p<0.05). In transabdominal cases, suboptimal needle placement (e.g., perpendicular to the placental long axis) was more common in the initial aspiration of a multiple-pass procedure (21/30 vs. 38/105;p<0.01), while limited penetration of the catheter tip (e.g., just inside the placental edge) characterized a majority of multiple-pass cases in the transcervical subset (7/12 vs. 3/58; p<0.0001). A case-control cohort was constructed to evaluate the impact of these technical variables on sampling efficacy, independent of the influence of uterine position and placental site. In that analysis, suboptimal location and/or orientation of the sampling device remained characteristic of multiple-pass cases. We conclude that further reduction in the frequency of multiple-pass procedures might be achieved by consistent placement of the device tip in the central placental mass. Unlike amniocentesis, where any point of amnion entry will suffice, this technical nuance should be emphasized with CVS to maximize the single-pass success rate.     

Fluid Mechanics of Biological Surfaces and their Technological Application

 A survey is given on fluid-dynamic effects caused by the structure and properties of biological surfaces. It is demonstrated that the results of investigations aiming at technological applications can also provide insights into biophysical phenomena. Techniques are described both for reducing wall shear stresses and for controlling boundary-layer separation. (a) Wall shear stress reduction was investigated experimentally for various riblet surfaces including a shark skin replica. The latter consists of 800 plastic model scales with compliant anchoring. Hairy surfaces are also considered, and surfaces in which the no-slip condition is modified. Self-cleaning surfaces such as that of lotus leaves represent an interesting option to avoid fluid-dynamic deterioration by the agglomeration of dirt. An example of technological implementation is discussed for riblets in long-range commercial aircraft. (b) Separation control is also an important issue in biology. After a few brief comments on vortex generators, the mechanism of separation control by bird feathers is described in detail. Self-activated movable flaps (=artificial bird feathers) represent a high-lift system enhancing the maximum lift of airfoils by about 20%. This is achieved without perceivable deleterious effects under cruise conditions. Finally, flight experiments on an aircraft with laminar wing and movable flaps are presented.     

Internal circulating fluidized bed incineration system and design algorithm

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｐｒｏｃｅｓｓｏｆｍｕｎｉｃｉｐａｌｓｏｌｉｄｗａｓｔｅ(ＭＳＷ)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｓｅｒｉｏｕｓｉｓｓｕｅｓｉｎｔｅｒｍｓｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｐｒｏｔｅｃｔｉｏｎ.ＰｒｏｃｅｓｓｉｎｇｏｆＭＳＷｗｉｔｈｏｕｔｆｕｒｔｈｅｒｄｉｓａｓｔｒｏｕｓｃｏｎｔａｍｉｎａｔｉｏｎｃａｎｂｅａｃｈｉｅｖｅｄｏｎｌｙｉｎｍｏｄｅｒｎｉｚｅｄｍｅａｓｕｒｅｓ,ｓｕｃｈａｓｉｎｃｉｎｅｒａｔｉｎｇａｎｄｅｎｅｒｇｙｇｅｎｅｒａｔｉｎｇｃｏｎｃｕｒｒｅｎｔｌｙ(Ｓｈｅｎ…     

Transboundary air pollution balance in the new integrated European environment

Ten out of the 12 new EU members, used to belong to the so-called “former eastern block”, with a post WWII environmental policy radically different from the tendencies followed in Western Europe. The lack of conservation regulations has resulted in a rather harmful industrialization, regarding natural resources and environmental quality. While air pollution transfer is a phenomenon of transboundary level, there is a particular interest in examining the contribution of the new EU member states to the environmental pressure faced by the older member states and vice versa. The current study utilises the official data for almost 20 years published by the European Monitoring and Evaluation Program concerning the transboundary transfer of NO_x and SO₂ in order to analyse the situation and discuss the present and future environmental policy regarding air pollution.     

Uncommon chromosomal mosaicism in chorionic villi

Three cases of unusual chromosomal mosaicism are reported for which the cytogenetic data show inconsistent findings between CVS and AC or fetal tissue, and which cannot be explained simply by non-disjunction. For case 1, in CVS the karyotype was 46,XY, whereas lymphocytes and fibroblasts revealed 69,XXY. DNA fingerprinting indicated one paternal and two maternal chromosome sets, the latter most probably due to omission of maternal meiosis II. For case 2, in CVS mos 46,XX/47,XX,+mar de novo was observed. Amniotic fluid cells had the karyotype 46,XX. The origin of the marker chromosome might be explained by at least two events of unknown order (a somatic chromosome/chromatid deletion and non-disjunction of the homologous chromosome). In case 3 (CVS: mos 46,XY/46,XY,19q+ de novo; amniotic fluid cells, lymphocytes, and fibroblasts: 46,XY), the surplus of chromosome material in 19q+ might be explained on the basis of a somatic translocation. The idea of a chimera is less convincing, as the mosaic finding is restricted to one tissue. Furthermore, there was no hint of a vanishing twin. Hitherto, no case of structural chromosome mosaicism in CVS has been reconfirmed in fetal tissues.     

The significance of prenatal diagnosis of choroid plexus cysts

A case is described of the prenatal diagnosis of choroid plexus cysts at 17 weeks' gestation which persisted beyond 36 weeks but could not be detected after delivery. At birth the child was found to have trisomy 18.     

Carrier screening for cystic fibrosis

A number of different models of CF carrier screening have now been tested in pilot trials. Apart from opportunistic and cascade testing (which are strictly speaking not true forms of screening), the major programmes have been directed either to young adults in primary care or to pregnant women in antenatal clinics. Only in the latter form of screening has sufficient data been collected to allow conclusions to be reached on the optimum mode of delivery. It seems very probable that when CF carrier screening passes into routine service, it will be the antenatal couple model that is used.     

Neonatal lung function following mid-trimester amniocentesis

Three hundred and fifty-four women who underwent midtrimester genetic amniocentesis were matched for age, parity, indication, and smoking history, with an equivalent number of women who had declined the procedure, for the purpose of comparing the neonatal respiratory status of their offspring. There was no evidence that the infants exposed to genetic amniocentesis were compromised.