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The Reynolds equations for viscoplastic lubricants can be quite complex, involving multiple branches which depend on the form of the boundary conditions invoked in their development. Methods of visualizing and understanding the branching problem are explored. This information is used, together with the Reynolds equations developed in the companion paper, in analyses of the lubrication of a wide slider bearing and a metalforming inlet zone. The results of these analyses are used to draw general conclusions regarding the influence of different types of non-Newtonian behavior.

Basic flow relationships are developed for three typical non-Newtonian lubricant models: the pseudo-plastic model, the circular viscoplastic model, and the ideal viscoplastic model. It is found that the conventional no-slip boundary conditions are inadequate to fully treat the latter two models. Conclusions regarding the appropriate boundary conditions for any viscoplastic model and the form of the resulting Reynolds equations are presented.

A model for the flattening of asperities on the surface of a sheet undergoing plastic deformation is proposed. A viscoplastic finite element analysis was used to determine the effect of strain rate and straining direction on the rate of flattening of two dimensional asperities resulting from a normal pressure applied with a smooth tool. The strain rate components in the plane of the sheet are treated as independent of the normal pressure. The results can be used to model the evolution of the contact area fraction at the interface as a function of the straining direction in the sheet and the normal pressure.

Twelve patients underwent conal enlargement for diffuse subaortic stenosis over a 3½-year period. The subaortic stenosis was due to tunnel outflow in 11 and malattached mitral valve in one. Mean age was 4.4 ± 4 years and mean subaortic gradient was 50 ± 21 mm Hg. Three infants had a malalignment ventricular septal defect In eight patients significant obstruction occurred 2 to 7 years (mean 4 ± 2) after simple resection of subaortic stenosis (n = 2), ventricular septal defect closure (n = 2), ventricular septal defect closure and subaortic stenosis resection (n = 2), and canal repair (n = 2). In three infants the tunnel outflow distal to a malalignment ventricular septal defect was enlarged and closed with the defect. In three patients with subaortic stenosis proximal to a previously repaired ventricular septal defect, transatrial conal enlargement through the ventricular septal defect was performed. Another patient without a ventricular septal defect had transatrial conal enlargement The remaining five patients had the modified Konno procedure. Two patients had postoperative complete heart block and one infant had insertion of an apicoaortic conduit for aortic anulus hypoplasia 9 months later. One patient died of pneumonia during the follow-up period. Postoperative echographic outflow gradients up to 3½ years (mean 1.2 ± 1) ranged up to 25 mm Hg (mean 7 ± 11) and were mainly at the aortic level. The 11 surviving patients are doing well up to 3½ years of follow-up (mean 1.5 ± 1). We conclude that conal enlargement procedures with aortic valve preservation are preferable, effective, and can be safely performed for diffuse subaortic stenosis in infants and children.

Over a 15-year period, 12 patients with endocardial cushion defects undergoing correction had subaortic stenosis requiring operative intervention. Ages ranged from 4 months to 17 years (mean, 7 +/- 6 years) and subaortic gradients from 15 to 100 mm Hg (mean, 60 +/- 25 mm Hg). Subaortic stenosis was due to discrete fibromuscular tissues in 7 patients, mitral valve malattachment in 3, and tunnel outflow in 2. In 2, the subaortic stenosis was clinically significant at the time of endocardial cushion defects repair, whereas in 10 it was noted 2 to 14 years postoperatively (mean, 6.3 +/- 5 years). Surgical relief of subaortic stenosis was accomplished by resection of muscle tissues in 7, apicoaortic conduit insertion in 2, modified Konno procedure (aortic valve preserved) in 2, and lifting of malattached mitral valve from the outflow in 1. There was no early death and one late death (infected conduit). Severe mitral insufficiency developed in the patient who had the mitral valve lifted and necessitated valve replacement. Postoperative echocardiographic gradient in 9 patients ranged from 0 to 36 mm Hg (mean, 10.5 +/- 14 mm Hg). Clinically significant subaortic stenosis has not developed in any patient in 15 years of follow-up (mean, 5 +/- 4 years). We conclude that in subaortic stenosis associated with endocardial cushion defects, resection is effective for discrete obstruction, whereas a modified Konno procedure is preferable for obstruction due to tunnel outflow or mitral valve malattachment.

Thirteen patients with single ventricle equivalents and subaortic stenosis underwent relief of the stenosis and subsequent Fontan operation. Nine patients, group 1, had the obstruction relieved at 3.6 ± 1.6 years of age whenever the pressure gradient became apparent. Four patients, group 2, had the subaortic stenosis operated on at the neonatal period, 10.5 ± 10 days old, before hemodynamic evidence of obstruction. Preoperative pressure gradient across the outflow tract was 44.2 ±4.7 mm Hg in group 1 versus 4.7 ± 5 mm Hg in group 2 ( p = 0.002). Ventricular muscle mass was 186% ± 18% in group 1 versus 114% ± 5% of normal in group 2 ( p = 0.0001), and mass/volume ratio was 1.12 ± 0.62 in group 1 versus 0.62 ± 0.16 in group 2 ( p = 0.003). Relief of subaortic stenosis was achieved by proximal pulmonary artery to ascending aorta or aortic arch anastomosis and by systemic to distal pulmonary artery shunt. There was no hospital mortality or complication related to the procedure. At evaluation before Fontan operation, 4.3 ±1.6 years after relief of subaortic stenosis in group 1 and 3.2 ± 0.9 years in group 2, the pressure gradient across the ventricular outflow tract was 4 ± 3 mm Hg in group 1 versus 3 ± 2 mm Hg in group 2 ( p = not significant), ventricular muscle mass was 184% ± 31% in group 1 versus 114% ± 5% of normal in group 2( p = 0.003), and the mass/volume ratio was 1.17 ± 0.2 in group 1 versus 0.62 ± 0.2 in group 2 ( p = 0.003). After Fontan operation, there were two perioperative deaths and two takedowns of Fontan operation in group 1. Postoperative mean right atrial pressure was 17.6 ± 2.1 mm Hg in group 1 versus 11.3 ± 1.7 mm Hg in group 2 ( p = 0.01). Serious postoperative effusions were present in 4 of 5 patients (80%) in group 1 versus 0 of 4 patients (0%) in group 2. Data suggest that early relief of subaortic stenosis in single ventricle equivalents using the modified techniques described optimizes ventricular compliance, protects the pulmonary vascular bed, and improves the outcome after Fontan operation.

An improved theoretical model for the hydrodynamic lubrication of axisymmetric, sheet metal stretch forming is presented. The infinite initial film thickness problem, encountered in a previous model, is removed by accounting for the squeeze action occurring during the initial stages of the process. Both isoviscous and thermoviscous theories are developed assuming that the lubricant is a Newtonian fluid. In the thermoviscous model, the lubricant viscosity is assumed to vary exponentially with temperature. The influence of plastic heating of the sheet on the entrainment and transport of the lubricant film is examined. The effects of variable punch speed are also investigated.

In order to test the validity of the theoretical model discussed in Part 1, an experimental technique, employing optical interferometry, has been developed to measure lubricant film thickness during axisymmetric stretch forming. Specially fabricated, transparent punches are used for both double and multiple beam interference studies. The choice of workpiece material, lubricant, and forming speed ensures that the punch/sheet conjunction will be hydrodynamically lubricated during most of the process. Interference patterns, due to the variable film of lubricant separating the punch and sheet surfaces, are formed as the sheet wraps around the punch. These patterns provide a contour map of the lubricant film thickness along the punch/sheet conjunction. The measured film thickness, as taken from an interpretation of the patterns, is compared with the theoretical predictions of Part 1.

Seven of 119 patients undergoing anatomical correction for transposition of the great arteries and Taussig-Bing anomalies without pulmonary stenosis had the Damus-Stansel-Kaye procedure and the rest, the arterial switch. The age of the patients having the Damus-Stansel-Kaye procedure ranged from 0.5 year to 5 years (mean age, 2.2 ± 1 years). Four patients had transposition, 2 had Taussig-Bing anomaly, and 1 had corrected transposition. Indications for the Damus-Stansel-Kaye procedure were side-by-side great arteries associated with difficult coronary anatomy (5 patients), single coronary system (1 patient), and subaortic stenosis (1). A graft between the ascending and descending aorta for interrupted aortic arch made mobilization and posterior displacement of the ascending aorta for the arterial switch difficult. Subaortic stenosis (1 patient), subpulmonary ventricular septal defect (2 patients), and restrictive ventricular septal defect (4) precluded the Rastelli procedure. In 6 patients, the main pulmonary artery was transected at the band, a proximal main pulmonary artery to aorta anastomosis was complemented with a synthetic patch, and a right ventricle to distal main pulmonary artery valved conduit was inserted. Four patients had closure of the aortic outflow. Two patients had postoperative bleeding and 2, heart block. The only patient who did not have transaction of the main pulmonary artery, an omission that led to an obstructed conduit at the distal anastomosis, died late. Two patients subsequently needed aortic outflow closure for critical aortic insufficiency. The Damus-Stansel-Kaye procedure has a definite role and can be safely performed in patients with transposition of the great arteries and Taussig-Bing anomalies. Aortic outflow closure minimizes the risk of aortic insufficiency. Transection of the distal main pulmonary artery allows a wide open conduit to main pulmonary artery anastomosis.

A population of 1639 patients were seen for chorionic villus sampling (CVS). Embryonic death was identified at ultrasound in 5.3 per cent of patients. The number of patients undergoing CVS was 1551, with 1416 transcervical procedures and 135 transabdominal procedures. The most common indication for CVS was advanced maternal age. Spontaneous pregnancy losses identified by increased risk of pregnancy loss with increasing aspiration attempts. The total fetal loss for this population was 5.4 per cent with the pregnancy loss estimated due to procedure being 1.2 per cent. Analysis of placentae from patients having CVS and amniocentesis showed no differences. Microbiological assessment prior to CVS was similar to previous publications.

Wilson and Shen’s semi-empirical equation for the effective hardness of a plastically deforming workpiece is used to develop models for tool-workpiece friction in metal-forming processes operating in the boundary lubrication regime. The models treat both steady and unsteady conditions and include the influence of tooling and workpiece topography, sliding speed, interface pressure, and workpiece strain rate on friction. Simplified models are suggested for conditions typical of bulk forming and sheet-metal forming processes.

Crystallization and subsequent grain growth processes in melt spun ribbons of amorphous Cu60Zr40 ribbon were studied. The average grain size of samples was correlated with heat treating over the time interval 0.1 to 100 h and the temperature range 525 to 825‡ C using an Arrhenius type relationship. X-ray diffraction studies showed the principal phase formed by crystallization of amorphous Cu60Zr40 was Cu60Zr7. A two-stage, grain growth mechanism is proposed. The activation energy for the second stage of grain growth is 109 kJ mol−1

OBJECTIVE To provide a Committee opinion on the present status and role of stem cells in fetal genetic therapy. OPTIONS Limited to discussion of new genetic information and technology related to stem cell therapy. EVIDENCE MEDLINE search to identify publications related to this topic after 1980. This document represents an abstraction of the information. VALUE: This Committee opinion is a consensus of the Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC). BENEFITS, HARMS, AND COSTS The benefit of this update is to educate the reader about genetic stem cells and their use in fetal therapy. At present there is no harm or cost (research with limited clinical application) identified. CONCLUSIONS 1. Stem cell therapy has the potential to be a powerful and successful therapy for certain human conditions. 2. There are significant ethical issues related to the use of stem cells derived from embryonic tissue. 3. Fetal therapy using stem cell replacement has been successful for immunodeficient conditions following early prenatal diagnosis for the "at risk" fetus. 4. Other conditions such as hemoglobinopathies, inborn errors of the metabolism and hemophilia require more research to overcome biological barriers.

sampling, as well as embryoscopy and fetoscopy (Table 2). Some diagnostic results may be obtained by more than one technique: for example, fetal karyotype can be obtained from cells from amniocentesis, chorionic villus sampling, or fetal blood sampling. First trimester screening for aneuploidy and congenital anomalies, using ultrasound for fetal nuchal translucency measurements and maternal serum biochemical markers, have been developed with trisomy 21 detection rate of 60 to 90% with a screen positive (false positive) of approximately 5% to 10%.1-7 Diagnostic invasive prenatal diagnosis with CVS at 10 to 14 weeks is offered for first trimester positive screening, while first or second trimester positive screening tests may undergo diagnostic invasive prenatal diagnosis with amniocentesis after 15 weeks. AMNIOCENTESIS

Objective To evaluate the impact of prenatal myelomeningocele repair on fetal head biometry. Methods Fifty fetuses underwent open fetal myelomeningocele repair at our institution between January 1998 and July 2002. All had serial head circumference (HC) and lateral ventricular diameter (VD) measurements taken preoperatively and weekly for 8 weeks after repair. Cortical index (CI) was defined as HC/VD. Measurements were compared with gestational age-matched values from nomograms. One-sample t-test, ANOVA and repeated measures analysis were used to assess HC, VD and CI after fetal repair. Results Preoperatively, the HC in fetuses with myelomeningocele was smaller than control values (186.4 vs. 198.8 mm, P = 0.0004). Eight weeks’ postoperatively this difference had resolved (293 vs. 301.6 mm, P = 0.76). The mean increase in CI after repair was 20% (P = 0.02) compared with the predicted 51% in normal cases. The average increase in VD was 3.9 mm (38.8%, P < 0.001). Conclusions Mid-gestational repair of myelomeningocele alters fetal head growth. Increased CI suggests HC changes are not due to ventriculomegaly alone. Copyright  2004 ISUOG. Published by John Wiley & Sons, Ltd.

To assess, in a randomized trial, the safety and accuracy of amniocentesis and transabdominal chorionic villus sampling (CVS) performed at 11-14 weeks of gestation, given that this time frame is increasingly relevant to early trisomy screening.We compared amniocentesis with CVS from 77 to 104 days of gestation in a randomized trial in a predominantly advanced maternal age population. Before randomization, the feasibility of both procedures was confirmed by ultrasonography, and experienced operators performed sampling under ultrasound guidance; conventional cytogenetic analysis was employed. The primary outcome measure was a composite of fetal loss plus preterm delivery before 28 weeks of gestation in cytogenetically normal pregnancies.We randomized 3,775 women into 2 groups (1,914 to CVS; 1,861 to amniocentesis), which were comparable at baseline. More than 99.6% had the assigned procedure, and 99.9% were followed through delivery. In contrast to previous thinking, in the cytogenetically normal cohort (n = 3,698), no difference in primary study outcome was observed: 2.1% (95% confidence interval 1.5, 2.8) for CVS and 2.3% (95% confidence interval, 1.7, 3.1) for amniocentesis. However, spontaneous losses before 20 weeks and procedure-related, indicated terminations combined were increased in the amniocentesis group (P =.07, relative risk 1.74). We found a 4-fold increase in the rate of talipes equinovarus after amniocentesis (P =.02) overall and in week 13 (P =.03, relative risk = 4.65), but data were insufficient to determine this risk in week 14.Amniocentesis at 13 weeks carries a significantly increased risk of talipes equinovarus compared with CVS and also suggests an increase in early, unintended pregnancy loss.I

Commercial finite element software, while quite powerful in their treatment of plasticity and constitutive modeling of materials, use quite simple friction and heat transfer models, usually being restricted to constant coefficients. Actual forging operations are known to be much more complex, with evolving friction and heat transfer. The present research presents a model that allows the lubricant film thickness and workpiece surface roughness to evolve with respect to time and location. The model obtains lubricant film thickness from the Reynolds equation, and estimation of a fractional contact area through a contact model approach appropriate for metal forming problems. Heat transfer and friction are then calculated by partitioning between asperity contact and lubricated areas.

OBJECTIVE To provide guidelines on use of anti-D prophylaxis to optimize prevention of rhesus (Rh) alloimmunization in Canadian women. OUTCOMES Decreased incidence of Rh alloimmunization and minimized practice variation with regards to immunoprophylaxis strategies. EVIDENCE The Cochrane Library and MEDLINE were searched for English-language articles from 1968 to 2001, relating to the prevention of Rh alloimmunization. Search terms included: Rho(D) immune globulin, Rh iso- or allo-immunization, anti-D, anti-Rh, WinRho, Rhogam, and pregnancy. Additional publications were identified from the bibliographies of these articles. All study types were reviewed. Randomized controlled trials were considered evidence of highest quality, followed by cohort studies. Key individual studies on which the principal recommendations are based are referenced. Supporting data for each recommendation is briefly summarized with evaluative comments and referenced. VALUES The evidence collected was reviewed by the Maternal-Fetal Medicine and Genetics Committees of the Society of Obstetricians and Gynaecologists of Canada (SOGC) and quantified using the Evaluation of Evidence guidelines developed by the Canadian Task Force on the Periodic Health Exam. RECOMMENDATIONS 1. Anti-D Ig 300 microg IM or IV should be given within 72 hours of delivery to a postpartum nonsensitized Rh-negative woman delivering an Rh-positive infant. Additional anti-D Ig may be required for fetomaternal hemorrhage (FMH) greater than 15 mL of fetal red blood cells (about 30 mL of fetal blood). Alternatively, anti-D Ig 120 microg IM or IV may be given within 72 hours of delivery, with testing and additional anti-D Ig given for FMH over 6 mL of fetal red blood cells (12 mL fetal blood). (I-A) 2. If anti-D is not given within 72 hours of delivery or other potentially sensitizing event, anti-D should be given as soon as the need is recognized, for up to 28 days after delivery or other potentially sensitizing event. (III-B) 3. There is poor evidence regarding inclusion or exclusion of routine testing for postpartum FMH, as the cost-benefit of such testing in Rh mothers at risk has not been determined. (III-C) 4. Anti-D Ig 300 microg should be given routinely to all Rh-negative nonsensitized women at 28 weeks' gestation when fetal blood type is unknown or known to be Rh-positive. Alternatively, 2 doses of 100-120 microg may be given (120 microg being the lowest currently available dose in Canada): one at 28 weeks and one at 34 weeks. (I-A) 5. All pregnant women (D-negative or D-positive) should be typed and screened for alloantibodies with an indirect antiglobulin test at the first prenatal visit and again at 28 weeks. (III-C) 6. When paternity is certain, Rh testing of the baby's father may be offered to all Rh-negative pregnant women to eliminate unnecessary blood product administration. (III-C) 7. A woman with "weak D" (also known as Du-positive) should not receive anti-D. (III-D) 8. A repeat antepartum dose of Rh immune globulin is generally not required at 40 weeks, provided that the antepartum injection was given no earlier than 28 weeks' gestation. (III-C) 9. After miscarriage or threatened abortion or induced abortion during the first 12 weeks of gestation, nonsensitized D-negative women should be given a minimum anti-D of 120 microg. After 12 weeks' gestation, they should be given 300 microg. (II-3B) 10. At abortion, blood type and antibody screen should be done unless results of blood type and antibody screen during the pregnancy are available, in which case antibody screening need not be repeated. (III-B) 11. Anti-D should be given to nonsensitized D-negative women following ectopic pregnancy. A minimum of 120 microg should be given before 12 weeks' gestation and 300 microg after 12 weeks' gestation. (III-B) 12. Anti-D should be given to nonsensitized D-negative women following molar pregnancy because of the possibility of partial mole. Anti-D may be withheld if the diagnosis of complete mole is certain. (III-B) 13. At amniocentesis, anti-D 300 microg should be given to nonsensitized D-negativeesis, anti-D 300 microg should be given to nonsensitized D-negative women. (II-3B) 14. Anti-D should be given to nonsensitized D-negative women following chorionic villous sampling, at a minimum dose of 120 microg during the first 12 weeks' gestation, and at a dose of 300 microg after 12 weeks' gestation. (II-B) 15. Following cordocentesis, anti-D Ig 300 microg should be given to nonsensitized D-negative women. (II-3B) 16. Quantitative testing for FMH may be considered following events potentially associated with placental trauma and disruption of the fetomaternal interface (e.g., placental abruption, blunt trauma to the abdomen, cordocentesis, placenta previa with bleeding). There is a substantial risk of FMH over 30 mL with such events, especially with blunt trauma to the abdomen. (III-B) 17. Anti-D 120 microg or 300 microg is recommended in association with testing to quantitate FMH following conditions potentially associated with placental trauma and disruption of the fetomaternal interface (e.g., placental abruption, external cephalic version, blunt trauma to the abdomen, placenta previa with bleeding). If FMH is in excess of the amount covered by the dose given (6 mL or 15 mL fetal RBC), 10 microg additional anti-D should be given for every additional 0.5 mL fetal red blood cells. There is a risk of excess FMH, especially when there has been blunt trauma to the abdomen. (III-B) 18. Verbal or written informed consent must be obtained prior to administration of the blood product Rh immune globulin. (III-C) VALIDATION: These guidelines have been reviewed by the Maternal-Fetal Medicine Committee and the Genetics Committee, with input from the Rh Program of Nova Scotia. Final approval has been given by the Executive and Council of the Society of Obstetricians and Gynaecologists of Canada.

Transient effects in the friction and lubrication of metal forming processes are reviewed. These occur in processes that are intrinsically unsteady, during the start-up of nominally steady processes or when self-induced vibration is present. They can have important implications on process economics and product quality. Some suggestions for future research are presented.

OBJECTIVE To assess the role of cystic fibrosis (CF) testing within the Canadian health care environment. METHODS The Genetics and Maternal Fetal Medicine Committees of the Society of Obstetricians and Gynaecologists of Canada (SOGC) reviewed Preconception and Prenatal Carrier Screening for Cystic Fibrosis Clinical and Laboratory Guidelines produced by the American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics (ACMG) and other educational material from ACOG and ACMG. RESULTS Background information related to cystic fibrosis, genetic mutation analysis, and one large clinical cystic fibrosis screening trial are reviewed. EVIDENCE The quality of evidence reported in this document has been described using the Evaluation of Evidence criteria outlined in the report of the Canadian Task Force on the Periodic Health Exam. RECOMMENDATIONS 1. CF testing in pregnancy is indicated for individuals who may be at increased risk for CF due to considerations of family history or clinical manifestations. (II-2A). 2. Before CF screening could be undertaken, each province/territory would have to review the ethnic diversity of its reproductive population to ensure that CF screening would be appropriate. (III-C). 3. Screening of all women during pregnancy for CF carrier status cannot be recommended at this time. (III-C).

In the practice of clinical genetics chromosomal aneuploidy in both mosaic and nonmosaic forms has long been recognized as a cause of abnormal prenatal and postnatal development. Traditionally, cytogenetic analysis of cultured lymphocytes has been used as a standard test for detection of constitutional aneuploidies. As lymphocytes represent only one lineage, chromosomal mosaicism expressed in other tissues often remains undetected. The purpose of this study was to assess the utilization of molecular cytogenetic analysis for detection of chromosomal aneuploidy in placental tissues. Using placentas from 100 pregnancies with viable nonmalformed livebirths, both trophoblast and chorionic stroma were analyzed using comparative genomic hybridization (CGH). In all cases with an indication of chromosomal imbalance by CGH, fluorescence in situ hybridization (FISH) analysis was performed to confirm the presence of aneuploidy. To differentiate between constitutional aneuploidy and confined placental mosaicism (CPM), amniotic membrane was analyzed by CGH and FISH techniques. Our results demonstrated five placentas with CPM for chromosomes 2, 4, 12, 13, and 18, respectively, and two constitutional nonmosaic aneuploidies (47,XXX and 47,XXY). Molecular cytogenetic studies of human placental tissues enables easy analysis of both embryonic (amnion) and extraembryonic (chorion) cell lineages. Detection at birth of chromosomal defects affecting intrauterine placental and fetal development is important because these chromosomal defects may continue to have an influence on postnatal development.

Research over the last 20 years has considerably changed the understanding of the natural history and prognosis for individuals with a diagnosis of sex chromosome aneuploidy (SCA). A cross-sectional retrospective analysis of factors influencing parental decisions following a prenatal diagnosis of SCA during the time period of 1971-97 was performed. The records of 169 fetuses with a prenatal karyotype of 45,X, 47,XXX, 47,XXY, and 47,XYY were reviewed. Mosaic karyotypes for SCA were also included. Information reviewed involved: parental decision, the type of SCA, the presence or absence of mosaicism, the presence or absence of a fetal anomaly diagnosed by ultrasound examination, indication for prenatal diagnosis, prenatal procedure performed, parental age, marital status, previous pregnancy history, family history, ethnicity, religion, education, and profession. A significant correlation was found between the decision to continue a pregnancy and the type of SCA and the presence of fetal abnormalities on ultrasound examination. In addition, this study examined differences in parental decisions over time for the years in question. A statistically significant trend was observed with a higher rate of pregnancy continuation in the more recent years.

An association between the occurrence of club foot and early amniocentesis has been reported. The largest of these randomised studies was the Canadian Early and Mid-Trimester Amniocentesis Trial. Data describing the neonatal outcome, focusing on this association, are presented. Possible mechanisms for the association and the implications for the development of club foot are discussed. Keywords: amniocentesis; early amniocentesis; club foot

The purpose of this study was to identify risk factors for fetal loss and other pregnancy complications associated with genetic amniocentesis. Data were acquired in the Canadian Early Amniocentesis Trial (CEMAT), a multicentered (12) prospective, randomized trial comparing continuous ultrasound-guided early amniocentesis (EA) and mid-trimester amniocentesis (MA) (CEMAT Group, 1998). Details of the procedure were recorded and analysed by allocation (EA versus MA), operator and centre, and correlated with pregnancy outcome. A total of 62 spontaneous pregnancy losses occurred between the procedure and 20 weeks' gestation among the 3691 patients who received their procedures within the allocated window (EA=53/1916, MA=9/1775). Technical factors correlating with these losses included procedures 'judged to be difficult' by the operator, and post-procedure amniotic fluid leakage or bleeding. Maternal risk factors included maternal hypertension (fetal loss 11. 1 per cent, compared with non-hypertensive women, 2.6 per cent) increased body mass index (BMI) and gravidity of three or greater. Allocation to EA was predictive of fetal loss, as well as failed procedure, multiple needle insertions, amniotic fluid leakage, failed culture and talipes equinovarus, in excess compared with MA. In conclusion, in this large prospective randomized trial evaluating amniocentesis, specific maternal, fetal and procedural variables were found to be predictive of fetal loss and adverse pregnancy outcome. Performing amniocentesis before 13 weeks' gestation (EA) was the major predictive factor for adverse outcome. These data suggest that first-trimester chorionic villus sampling (CVS) and MA will likely remain the invasive procedures of choice for evaluation of fetal karyotype.

Cytogenetic results from a large multicentre randomized controlled study of 2108 amniotic fluids obtained at 11+0-12+6 weeks (EA) and 1999 fluids at 15+0-16+6 weeks (MA) were compared. There was no statistically significant difference in the rate of chromosome abnormalities (EA =1.9 per cent; MA=1.7 per cent) or level III mosaicism (EA=0.2 per cent; MA= 0.2 per cent) between the groups. Level I and Level II mosaicism occurred more frequently in MA. Maternal cell contamination was not significantly different between the groups, but maternal cells only were analysed from one bloody EA fluid. The number of repeat amniocenteses because of cytogenetic problems was 2.2 per cent in the EA group compared with only 0.3 per cent in the MA group. On average, culture of EA fluids required one day more than MA fluids. Although both culture success (97.7 per cent) and accuracy (99.8 per cent) were high for patients randomized to the EA group, routine amniocentesis prior to 13 weeks' gestation is not recommended for clinical reasons including an increased risk of fetal loss and talipes equinovarus.

The invasive nature of vaginal sonography, recently introduced as an improved diagnostic method for imaging the contents of the pregnant uterus, has provoked discussion about patient preference for female sonographers. This study examined whether patients had a gender preference for the sonographer who would conduct such an examination.Over 3 months, a written survey was given to pregnant women to complete anonymously while waiting for their scheduled sonographic examination. The survey covered gender preference for the sonographer and education, ethnicity, and previous experience with the procedure. Surveys were turned in by 1,002 pregnant women.Of the women whose survey responses were analyzed, 62% preferred a female sonographer. The principal reason given for this preference was comfort with the same gender. The majority of respondents were 25-40 years old, married, white, and multiparous. The level of education varied widely.These findings point to a need to seek consumer input when new technology is introduced, to provide women with choices where possible, and to ensure that they have access to information about those choices.

This study was done to produce enhanced fetal biometry charts and graphs presenting percentile values as a function of fetal age.The relationships between the ultrasound measurements of 10 fetal parameters and menstrual age were determined by a cross-sectional study. Data were obtained from 508 to 790 fetuses. Anatomic structures were scanned and measured 3 times during 1 routine sonographic examination. The study group consisted of 1,396 Caucasian women who had normal singleton fetuses with confirmation of menstrual dates by sonography before 14 weeks and for whom complete pregnancy outcome information was available. For each of the 10 parameters, percentile curves were derived for the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles.Ready-to-use fetal measurement charts and graphs are presented in a format giving the percentile values as a function of fetal age. There were no significant differences between male and female fetuses.These fetal biometry charts and graphs, obtained from a North American Caucasian population, enhance previously published data.

Contrasts are drawn between dental care based on fee-for-service and managed care financial arrangements. The advantages of fee-for-service include (for the profession) slow acceptance of managed care in dentistry compared to medicine; (for society and the patient) more community service, higher technical quality of work, and stimulation of innovations; and (for the individual dentist) the strong dentist-patient bond as well as professionalism.

A retrospective study of cases of fetal anomalies associated with a normal karyotype was conducted (1) to evaluate the accuracy of prenatal diagnosis; and (2) to assess two different tools to assist in determining the correct diagnosis. A total of 201 charts were reviewed. The accuracy of the prenatal diagnosis was assessed subjectively by one physician. The London Dysmorphology Database and a locally developed non-computerized tool (Appendix) were assessed retrospectively using 36 test cases. The population studied presented a spectrum of 97 different groups of single (67%) or multiple (33%) anomalies. The prenatal diagnosis was accurate in 57% of the cases. The two proposed tools generated an average of 146 and 15 different diagnoses, respectively and the correct one in 26 and 22 of the 36 test cases. The two studied tools have the potential to generate a differential diagnosis in the presence of a fetal anomaly prior to and following normal karyotype analysis. The non-computerized tool presents the advantages of listing antenatal features and creating a shorter differential diagnosis list with a minimal decrease in the identification rate of the correct diagnosis. Its use should be studied prospectively.

Fetal cells that circulate in maternal peripheral blood (PB) during pregnancy offer a potential source of nucleated fetal material for noninvasive prenatal diagnosis. Fluorescence-activated cell sorting was used to target two populations of fetal cells: nucleated erythroid cells (NECs; CD71/glycophorin-A+ CD45(lo-int) CD34-) and hematopoietic progenitor cells (CD34+ cells; CD34++ CD71/glycophorin-A- CD45(int)). Fetal cells were detected by fluorescence in situ hybridization (FISH) using directly conjugated chromosome X and Y probes in 65% (13 of 20) of the maternal PBs (fetal karyotype 46,XY). The frequency of fetal cells isolated from the NEC and CD34+ fractions was, respectively, 0 to 14 and 0 to 7 cells per 2 x 10(7) previously frozen maternal cells (approximately 20 mL of blood). In nonfrozen samples, the yield and recovery of fetal cells was moderately improved. Culturing the CD34+ sorted fractions in serum-free media with cytokines improved the quality of the FISH preparations and resulted in a slight expansion in detectable fetal cells. The frequency of fetal cells isolated from cultured CD34+ fractions was 0 to 35 and 0 to 93 cells per 2 x 10(7) previously frozen and nonfrozen maternal PB cells, respectively. These results document the isolation, characterization, and enumeration of fetal cells from the maternal periphery that appear to be present in most, but not all, samples analyzed.

The present study provides detailed neonatal and congenital malformation follow-up from 695 women enrolled in a prospective randomized multicenter study comparing the safety and accuracy of early (11-12 weeks of gestation) and midtrimester amniocentesis (15-16 weeks of gestation). No differences were found for total pregnancy loss (difference 0.4%; CI -3.6 to 4.4%), obstetrical or neonatal outcome. The incidence of congenital anomalies was 2.4 and 2.6% for the early amniocentesis and midtrimester amniocentesis groups, respectively. Respiratory problems were present in 2.1 and 1.6%, respectively. Musculoskeletal problems were present in 0.9 and 2.4%, respectively. It must be emphasized that before early amniocentesis can be considered as an alternative to midtrimester amniocentesis or chorionic villus sampling, careful evaluation of any fetal effects must be considered and further large randomized trials are necessary.

Prenatal diagnosis by chorionic villus sampling (CVS) documents placental chromosomal mosaicism in approximately 2% of viable pregnancies at 9-12 weeks of gestation and can involve various chromosomes and placental cell lineages. Confined placental mosaicism (CPM) is the result of postzygotic mitotic errors occurring in either diploid or trisomic zygotes. With trisomic zygote rescue, depending on the parental origin of the chromosome which is lost, uniparental disomy (UPD) or biparental disomy (BPD) may arise [Kalousek et al., Am J Hum Genet 52: 8-16, 1993]. In this paper, we present 14 pregnancies which were diagnosed by CVS as mosaic trisomy 7. All follow-up amniocenteses showed a normal diploid karyotype. Using both classical cytogenetics and interphase analysis, studies of term placentae showed variable levels of trisomy 7. DNA analysis was performed in nine cases to determine whether the diploid fetus had BPD 7 or UPD 7. Fetal UPD 7 was present only in one case; in eight other cases biparental inheritance was demonstrated. DNA analysis to establish the origin of trisomy 7 in the placenta was fully informative in six cases. One trisomy resulted from a meiotic error and was associated with fetal UPD 7, while the rest were somatic in origin. It is difficult to compare the effect of CPM for trisomy 7 to other trisomies confined to the placenta, as for most chromosomes there are few available cases. It appears that intrauterine fetal growth is not greatly affected by the presence of a trisomy 7 cell line in the placenta. This finding is in contrast to the serious effect of high levels of trisomy 16 within the placenta on fetal intrauterine growth in a series of well-documented cases of CPM 16 [Kalousek et al. 1993].

Objective: Prenatal ultrasonography can localize the level of the spinal cord malformation, allowing prediction of the potential postnatal neurological deficit and functional prognosis. Methods: This study has two evaluations: (a) a retrospective prenatal review of 26 fetuses with spinal dysraphism (1987–1991), and (b) a follow-up descriptive study of patients (1971–1981) who underwent closure of the spinal lesion and ventricular shunting in the neonatal period. Results: Prenatal ultrasound evaluation enabled the accurate definition of the last intact vertebral level which allows separation of fetuses into three functional groups (last intact level L2, L3–4, L5–sacral). Patterns of ambulation, urinary and bowel continence, and school performance vary according to level of spinal lesion and the neurological deficit. The need for ventricular shunts, the incidence of other spinal malformations and surgical interventions did not vary with the level of the spinal lesion. Conclusions: The functional outcome for patients with myelomeningocele is variable; however, distinct patterns emerge based on the level of spinal dysraphism and the resultant neurological deficit. By relating the level of the fetal spinal lesion to outcome data, more precise functional prognoses can be given to families.

The primary purpose of this pilot study was to determine whether the safety of early amniocentesis (EA; 11 weeks to 12 weeks and 6 days) is similar to midtrimester amniocentesis (MA; 15 weeks to 16 weeks and 6 days). The secondary objectives were to determine the cytogenetic success and accuracy of EA compared with MA.This prospective, randomized clinical trial compared continuous ultrasound-guided EA and MA (22-gauge needle) in patients at a late maternal age (or = 35 years). The procedures were compared for safety, success and accuracy.Among the 683 women randomized and followed to pregnancy completion, there was a total of 27/344 (7.8%) and 25/339 (7.4%) fetal losses (spontaneous and induced abortions) in the EA and MA groups, respectively (difference 0.4%; CI -3.6 to 4.4%). The rate of postprocedure spontaneous fetal loss was 2.4% (8/330) in the EA group and 3.3% (10/299) in the MA group (NS). The procedure success rate at the first attempt was 97.6% in the EA group and 99.7% in the MA group. There were no diagnostic errors, and all but 2 EA cultures were successful (both repeated successfully). The perinatal outcome was similar in both groups.EA appears to be as safe and accurate as MA. A large multicentered, randomized trial is currently underway to verify these results.

Considerations of friction, wear and surface modification are important in many metal forming operations. A better understanding of the fundamentals of lubrication in metal forming can lead to more effective lubrication systems and to better process models. Research on lubrication in different regimes and on the modeling of lubrication and friction is reviewed. Special emphasis is placed on the influence of the plastic deformation of surfaces on lubrication, and on special lubricants, such as emulsions, which are used in metal forming.

Reactive synthesis directly forms compounds from their elemental constituents. In this U.S. Bureau of Mines study the microstructure, hot-hardness and tensile properties of alloys and composites based on TiAl and Ti2AlNb were studied. Ti2AlNb sheets were processed from elemental Ti, Al and Nb foils. The elemental foils were consumed during processing, leaving a microstructure consisting of three phases: O (orthorhombic Ti2AlNb), B2 (ordered cubic Ti), and α2 (Ti3Al). The composite sheet structures were heat-treated to produce a microstructure consisting of O lathes in a B2 matrix. A significant advantage of reactive synthesis is the ease of formation of complex shapes prior to synthesis of the aluminide. TiAl-based alloys and in situ TiAl/boride and TiAl/Ti5Si3 composites were produced from elemental mixtures of Ti and Al with either additions of B or Si powders. The hot-hardness and tensile properties of these alloys and composites are reported. The Kirkendall porosity associated with reactive sintering of TiAl can be eliminated by simultaneously reactive sintering TiAl and Ti5Si3.

Capacitor Discharge Welding (CDW) is a rapid solidification joining process capable of cooling rates greater than 106 K/s. The Bureau of Mines is investigating the CDW process as a method of joining TiAl, Fe3A1 and MoSi2. Experimental results show that the fusion zone of the CDW welds is less than 0.1 mm wide, is uniform in composition, and has a cellular solidification microstructure. This paper compares the CDW microstructure of several intermetallics to the microstructures obtained from the gas tungsten arc welding.

The U.S. Bureau of Mines is investigating the wear behavior of a variety of advanced materials. Among the many materials under evaluation are intermetallic alloys based on the compounds: Fe3Al, Ti3Al, TiAl, Al3Ti, NiAl and MoSi2. The high hardness, high modulus, low density, and superior environmental stability of these compounds make them attractive for wear materials. This paper reports on the abrasive wear of alloys and composites based on the above compounds. The abrasive wear behavior of these alloys and composites are compared to other engineering materials used in wear applications.

As the number of women undergoing invasive prenatal diagnosis for cytogenetic, molecular, or biochemical testing is increasing, the development of new non-invasive methods of analyzing fetal cells is imperative. We have analyzed blood from 27 pregnant women (gestational age of 10-11 weeks) by the polymerase chain reaction (PCR) with oligonucleotide primers specific for Y sequences. The sensitivity of our assay, which did not include a step for fetal cell selection prior to PCR analysis, was 45% and the specificity was 89%. A review of the published studies of non-invasive prenatal diagnosis is provided. We conclude from our results and those of others that it is feasible to amplify fetal-specific sequences from maternal blood. However, techniques such as fluorescence-activated or magnetic-activated cell sorting of the maternal blood, as used in other studies, are necessary to enrich for fetal cells prior to analysis. With further improvements of these techniques, it is likely that fetal cell typing from maternal blood will be a feasible method of non-invasive prenatal diagnosis.

The U.S. Bureau of Mines has studied the capacitive discharge weld interface between Al and Fe using optical and transmission electron microscopy (TEM). Capacitive discharge welding (CDW) is a rapid solidification process in which the amount of molten metal at the interface is small compared to the sample size. As a result, high cooling rates (106 K/s) can be achieved, providing a weldment made up of small grains. Large magnetic fields produced by the process tend to mix the molten metals at the interface to form a complex alloy, the nature of which depends upon the starting electrode materials. This effect is characterized by a marblecake pattern in optical micrographs. The amount of mixing is related to the melting temperature of the cathode with respect to the anode. Increased mixing occurs when the melting temperature of the cathode is higher than the melting temperature of the anode. TEM has revealed that when aluminum is the anode material, the iron grains of the cathode are surrounded by a layer of aluminum. When the iron is the anode, a thin layer of iron surrounds the aluminum grains.

Capacitor discharge welding (CDW) is a rapid solidification joining process where high cooling rates (106 K/s) are obtained as a result of the large weld surface area to small weld volume. The objective of this study, directed by the U.S. Bureau of Mines and the Oregon Graduate Institute of Science and Technology, was to use ultra-high speed photography to quantify transient arc behavior during the CDW cycle. The simple cylindrical geometries of the CD welds have been used to formulate analytical models which are compared to the high speed photographs of the welding process. The high speed photographs were analyzed with respect to welding time and process weld variables and compared to predicted values from the analytical model. The detailed photographic analyses revealed that material is continuously ejected as a plasma from the weld area due to induced magnetic forces, rather than having the liquid metal squeezed out of the weld upon contact. It was found that welding time was controlled by tip length and drop height. Results from high speed photographs found the arc travel speed around tube welds to be 109m/s. Finally, the high speed photographs revealed that the velocity of arc propagation during ignition was fast enough to allow the CDW process to be modelled as onedimensional heat flow.

A 5-year prospective prenatal study in 151 pregnancies with 152 malformed fetuses detected by ultrasound was evaluated cytogenetically. Thirty-five fetuses (23%) had abnormal karyotypes. Specific anatomical fetal malformations identified by ultrasound increase the risk for fetal chromosome abnormalities. Risks of abnormal chromosomes in the fetus are present with both single and multiple anomalies including amniotic fluid volume although the risk is increased with specific anatomical systems and multiple malformations. An abnormal fetal karyotype was present in 17% with a single anatomical abnormality and 30% when two or more anatomical systems were involved. Fetal hydrops, duodenal atresia, and omphalocele were the most specific single ultrasound anomalies; fetal hydrops, IUGR, holoprosencephaly, congenital heart disease, diaphragmatic hernia, duodenal atresia, and omphalocele were the most specific multiple anomalies with abnormal amniotic fluid volume. Termination of pregnancy occurred in 32/58 patients diagnosed prior to the 20th week of pregnancy with most (31/32) having a chromosomal anomaly or severe fetal anomaly. Fetuses terminated after the 20th week had chromosomal (7/18) or lethal fetal anomalies (11/18). The most common aneuploidies were trisomy 21, trisomy 18, and 45,X. The decision to terminate the pregnancy was based in most cases on the fetal ultrasound findings. Correlation of ultrasound and clinical findings is important for accurate genetic counselling.

For pregnancies less than 17 menstrual weeks, increasing amounts of nuchal fluid increase the risks of chromosome abnormalities with localized nuchal fluid, diffuse nuchal fluid, cystic hygroma, and fetal hydrops having chromosomal risks of 12, 23, 50, and 78 per cent, respectively. The ultrasound appearance of localized or diffuse nuchal fluid is not a specific discriminator, but a fluid depth of greater than or equal to 5 mm may be an indicator of increased risk of fetal chromosomal abnormalities. If the fluid depth is less than 5 mm, there is a stronger negative predictive value and negative likelihood risk of a fetal chromosome abnormality. Gestational age did not improve the fluid depth predictive value. Differentiation of physiological from pathological requires chromosome analysis, serial ultrasound evaluation, and good clinical examination as a newborn and possibly as a young child. Long-term follow-up of those cases identified with resolving nuchal fluid abnormalities is not available and is required for a complete understanding of physiological and pathological aetiologies. Genetic counselling for fetal nuchal fluid would be recommended.