Boaz Weisz

Association of isolated short femur in the mid‐trimester fetus with perinatal outcome

To evaluate the prevalence of fetal isolated short femur in a cohort of women screened for Down syndrome by the integrated test, and to compare the outcome of fetuses with isolated short femur in the mid‐trimester with that of fetuses with normal femur length (controls).

Gene therapy progress and prospects: fetal gene therapy--first proofs of concept--some adverse effects.

Somatic gene delivery in utero is a novel approach to gene therapy for genetic disease based on the hypothesis that prenatal intervention may avoid the development of severe manifestations of early-onset disease, allow targeting of otherwise inaccessible tissues including expanding stem cell populations, induce tolerance against the therapeutic transgenic protein and thereby provide permanent somatic gene correction. This approach is particularly relevant in relation to prenatal screening programmes for severe genetic diseases as it could offer prevention as a third option to families faced with the prenatal diagnosis of a genetically affected child. Most investigations towards in utero gene therapy have been performed on mice and sheep fetuses as model animals for human disease and for the application of clinically relevant intervention techniques such as vector delivery by minimally invasive ultrasound guidance. Other animals such as dogs may serve as particular disease models and primates have to be considered in immediate preparation for clinical trials. Proof of principle for the hypothesis of fetal gene therapy has been provided during the last 2 years in mouse models for Crigler Najjar Disease, Lebers congenital amaurosis, Pompes disease and haemophilia B showing long-term postnatal therapeutic effects and tolerance of the transgenic protein after in utero gene delivery. However, recently we have also observed a high incidence of liver tumours after in utero application of an early form of third-generation equine infectious anaemia virus vectors with SIN configuration. These findings highlight the need for more investigations into the safety and the ethical aspects of in utero gene therapy as well as for science-based public information on risks and benefits of this preventive gene therapy approach before application in humans can be contemplated.

Growth inhibition of ras-dependent tumors in nude mice by a potent ras-dislodging antagonist

A lipophilic farnesyl moiety attached to the carboxyl terminal cysteine of ras proteins structurally supports their membrane anchorage, required for ras‐dependent growth‐factor signaling and for transforming activity of ras oncoproteins. It has been shown that inhibition of ras farnesylation can block tumor growth in nude mice but that some ras‐dependent tumors escape such blockage as a result of prenylation of ras. S‐trans‐transfarnesylthiosalicylic acid (FTS) is a potent ras‐dislodging antagonist that does not affect ras prenylation but rather acts on the mature, membrane‐bound ras and facilitates its degradation. Here we demonstrate that FTS induces reappearance of stress fibers in H‐ras‐transformed rat‐1 cells (EJ cells) in vitro, inhibits their anchorage‐independent growth in vitro, and blocks EJ‐tumor growth in nude mice. The anchorage‐independent growth of cells expressing ErbB2 (B104), but not that of v‐raf‐transformed cells, is also inhibited by FTS, suggesting specificity towards activated ras. FTS treatment (5 mg/kg i.p. daily) caused inhibition (75–80%) of tumor growth in nude mice implanted with EJ, but not in mice implanted with v‐raf‐transformed cells, with no evidence of systemic toxicity. Moreover, FTS treatment increased the survival rate of EJ‐tumor‐bearing mice from 48 to 68 days. Here we demonstrate anti‐tumor potency in a synthetic, non‐toxic, ras‐dislodging antagonist acting independently of farnesyltransferases. Int. J. Cancer 80:911–918, 1999.

The role of sonographic assessment of cervical length in the prediction of preterm birth in primigravidae with twin gestation conceived after infertility treatment

Objective. To identify the risk factors for preterm birth in primigravidae with twin gestation and the role of transvaginal ultrasonographic assessment of the cervix.

Prenatal Sonographic Diagnosis of Hemivertebra

Objective. To describe our experience in prenatal diagnosis of hemivertebra. Methods. This is a case series of patients referred to our tertiary medical center over a 3‐year period. All fetuses were scanned by high‐resolution real‐time scanners. The apparent vertebral anomaly was assessed in a real‐time manner by a joint team of obstetricians, sonographers, and pediatric orthopedic surgeons. A complete anomaly survey of other fetal organs was performed on each fetus. All patients were given proper counseling by the same joint team. All patients had detailed obstetric and neonatal follow‐up. Prenatal sonograms, neonatal medical records, and clinical courses were evaluated retrospectively. Results. During the 3 years, 6 cases of hemivertebra were identified in our department. Gestational age at diagnosis was 14 to 23 weeks. Two patients had conception by assisted reproductive technology. Associated anomalies included VATER syndrome (vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia), gastroschisis, and pyelectasis. Outcomes in fetuses without major associated anomalies were fair. Conclusions. Diagnosis of isolated hemivertebra might be associated with a favorable outcome. The 3 key factors in achieving an optimal spine at maturity, early diagnosis, anticipation, and prevention of deterioration, might be enhanced by our joint multidisciplinary approach to the diagnosis of skeletal anomalies.

Recombinant adeno-associated virus-mediated in utero gene transfer gives therapeutic transgene expression in the sheep.

Somatic in utero gene therapy aims to treat congenital diseases where pathology develops in perinatal life, thereby preventing permanent damage. The aim of this study was to determine whether delivery of self-complementary (sc) adeno-associated virus (AAV) vector in utero would provide therapeutic long-term transgene expression in a large animal model. We performed ultrasound-guided intraperitoneal injection of scAAV2/8-LP1-human Factor IX (hFIX)co (1 × 10(12) vector genomes/kg) in early (n = 4) or late (n = 2) gestation fetal sheep. The highest mean hFIX levels were detected 3 weeks after injection in late gestation (2,055 and 1,687.5 ng/ml, n = 2) and 3 days after injection in early gestation (435 ng/ml, n = 1). Plasma hFIX levels then dropped as fetal liver and lamb weights increased, although low levels were detected 6 months after late gestation injection (75 and 52.5 ng/ml, n = 2). The highest vector levels were detected in the fetal liver and other peritoneal organs; no vector was present in fetal gonads. hFIX mRNA was detectable only in hepatic tissues after early and late gestation injection. Liver function tests and bile acid levels were normal up to a year postnatal; there was no evidence of liver pathology. No functional antibodies to hFIX protein or AAV vector were detectable, although lambs mounted an antibody response after injection of hFIX protein and Freunds adjuvant. In conclusion, hFIX expression is detectable up to 6 months after delivery of scAAV vector to the fetal sheep using a clinically applicable method. This is the first study to show therapeutic long-term hFIX transgene expression after in utero gene transfer in a large animal model.

Outcome of severely anaemic fetuses treated by intrauterine transfusions

Background: Fetal anaemia is a well-known complication of pregnancy, which might have an ominous effect on the course of pregnancy, labour and the child’s development. Objective: To assess the effect of the severity of fetal anaemia on the child’s outcome. Methods: A retrospective cohort study. Pregnancies treated by intrauterine transfusions for fetal anaemia at Sheba Medical Center (1996–2004) were divided into two groups: mild to moderate anaemia (fetal haematocrit >0.50 multiples of the median (MoM)) and severe anaemia (hydrops fetalis or fetal haematocrit ⩽0.50 MoM). Data were retrieved from relevant obstetric and fetal medicine files. Results: During the study period, 54 fetuses were treated by 154 (median 3; range 1–7) intrauterine transfusions for red cell alloimmunisation. The sensitising antigen was D in 70% of cases; 18/54 patients were sensitised to more than one antigen. Thirty-three of the 54 fetuses (61%) were in the severely anaemic category (haematocrit range 3–20%); six were hydropic. Twenty-one of the 54 fetuses (39%) were in the mild–moderate anaemic category (haematocrit range 20–37%). On prenatal evaluation, there were no sonographic markers of central nervous system abnormalities or intraventricular haemorrhage. There were no differences in the neonatal outcome between the two groups. Developmental outcome was available in 14/18 (78%) mild–moderate cases and 26/29 (89%) severe cases. There were no significant differences in motor development score, percentage of abnormal cognitive development, and percentage of children needing supportive therapy between the mild–moderate and severe cases. Conclusion: Neonatal and developmental outcome of fetuses treated for severe anaemia is comparable to cases of mild anaemia.

Ultrasound findings after screening for Down syndrome using the integrated test.

OBJECTIVE: To evaluate the incidence and significance of fetal anomalies and “soft markers” after screening for Down syndrome using the integrated test. METHODS: This study is a retrospective study of 2,332 women at University College London Hospitals, United Kingdom. All women were screened for Down syndrome by the integrated test. Subsequently, a detailed anomaly scan was performed. All scan reports and screening results were analyzed statistically using SPSS 11.0 software. RESULTS: Sixty-eight (2.9%) patients were categorized as high risk. There were 12 cases affected by Down syndrome, 10 (10 of 68) in the high-risk group and two (two of 2,264) in the low-risk group. Soft markers or structural anomalies were found in 13.0% of the low-risk group, in 29.4% of the high-risk group, and in 50% of the fetuses affected by Down syndrome. Multiplying the likelihood ratio of each marker with the risk of Down syndrome from the integrated test reduced the false-positive rate of the integrated test from 2.5% to 1.8%, but was accompanied by a reduction in the detection rate from 83% to 75%. CONCLUSION: Absence of structural anomalies or markers should not prevent offering karyotyping to women in the high-risk group, because this would result in a significant reduction in the detection rate of Down syndrome. Women screened as low risk by the integrated test who have isolated soft markers should not be offered an amniocentesis. LEVEL OF EVIDENCE: II

Diffusion MRI Findings in Monochorionic Twin Pregnancies after Intrauterine Fetal Death

BACKGROUND AND PURPOSE: Monochorionic twin pregnancies complicated by the IUFD of 1 twin are associated with substantial morbidity to the survivor twin. The aim of this study was to determine whether fetal sonography, T2 MR imaging, and DWI can diagnose acute cerebral lesions in the survivor of an MC twin pregnancy shortly after fetal death of the co-twin. MATERIALS AND METHODS: During the study period (2007–2010) 34 cases of single IUFD were evaluated. Group A included 6 cases complicated by spontaneous IUFD. Group B had 10 cases of fetal death shortly after treatment of severe TTTS. These were compared with group C, with 18 pregnancies treated by selective termination due to severe complications in MC pregnancies. RESULTS: Altogether 9/34 patients had abnormal prenatal cerebral findings. In group A, in 2/6 of pregnancies with spontaneous death, MR imaging showed findings of severe cerebral infarct, while cerebral damage was not evident by sonography. In another case, the surviving fetus was found to be hydropic on sonography, while MR imaging findings were normal. In group B, in 1/10 cases, cerebral infarct was demonstrated only by DWI. In 2 other cases, sonographic findings were normal, but MR imaging showed germinal matrix bleeding. In group C, in 1/18 cases, only DWI showed bilateral cerebral ischemia. In 2 other cases, MR imaging findings suggested germinal matrix bleeding and focal changes in the basal ganglia. In both cases, fetal sonographic findings were normal. CONCLUSIONS: In our study, early manifestations of cerebral ischemia in monochorionic twin pregnancies were better diagnosed with MR imaging, especially with DWI.

Early detection of fetal structural abnormalities

Most published data on the detection of fetal anomalies at 11-14 weeks are from specialized centres with considerable experience in fetal anomaly scanning. However, there is still limited information on the feasibility and limitations of the screening of these anomalies compared with the now classical mid-gestation screening. This review indicates that overall, the detection rate of fetal anomalies at 11-14 weeks is 44% compared with 74% by the mid-pregnancy scan. Major abnormalities of the fetal head, abdominal wall and urinary tract, and of the umbilical cord and placenta, can be reliably detected at 10-11 weeks of gestation. Detection of other anomalies such as spina bifida, diaphragmatic hernia or heart defects is limited before 13 weeks of gestation. So far it cannot be stated that routine first trimester screening can be used on a large scale to evaluate the fetal spine and heart in the general population. In particular, in screening for congenital heart defects, the ability to perform a full cardiac examination increases from 20% at 11 weeks to 92% at 13 weeks. The early prenatal diagnosis of these anomalies may be improved by screening at 13-14 weeks rather than during the first trimester.