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Rapid procedure for globin chain analysis in blood samples of normal and beta-thalassemic fetuses.

Reversed-phase high pressure liquid chromatography (HPLC) was used for the separation of the alpha, beta, (A)gamma and (G)gamma chains from human blood samples. The alpha and beta chains were normally eluted close together, but their separation was improved by coupling 2 or 3 columns in series, or by increasing the temperature of the columns. This method has been applied for the determination of beta/gamma ratios in blood samples obtained at fetoscopy from normal pregnancies and fetuses at risk for beta-thalassemia. The values obtained by high pressure chromatography were similar but slightly lower than those found by carboxymethyl cellulose (CMC) chromatography. The average (G)gamma/(A)gamma ratio of the chains labeled after a 2-hr pulse with [3H] leucine was almost identical to the actual (G)gamma/(A)gamma measured by absorbance at 280 nm, indicating a constant rate of synthesis and accumulation of both globin chains in the first trimester fetus.

Chromatography, High Pressure Liquid↗

Antenatal genetic diagnosis: current status and future prospects.

The current status of antenatal genetic diagnosis is reviewed and the limitations of present techniques are discussed. It is suggested that multidisciplinary clinics are the most efficient means of providing this aspect of health care. Advances in cell culture techniques, in ultrasonography and in fetoscopy will extend the services available, and the impact of this will be felt by the community. Education of the medical profession and the public in this area is necessary so that informed decision-making can take place.

Abortion, Therapeutic↗

[Prenatal diagnosis after abortus imminens--further progress of pregnancy and peculiarity of amniotic cell cultivation (author's transl)].

Among 1600 pregnancies, in which amniocentesis for prenatal diagnosis had been performed, were 73 cases with previous threatened abortion. In none of these abortion occurred after amniocentesis. 56 children have been born so far. There is evidence for a slight but not statistically significant increase in the number of multifactoral anomalies in this group. This study supports former findings of a higher prematurity incidence after vaginal bleeding in early pregnancy. If amniocentesis took place after imminent abortion, brownish discoloured amniotic fluid has been withdrawn in 53%. This phenomenon probably results from transfer of blood substances from hematomata between uterine wall and amniotic sac. Cultivation of amniotic fluid cells may be impaired by those degradation products, prolonging the cultivation period for an average of 2 days. Special methodological modifications to enhance the success of amniotic fluid cell cultivation in those heavily contaminated specimens are discussed. There seems to be no interference with AFP-estimation. Fetoscopy vision may be impaired.

Abortion, Threatened↗

[Prenatal diagnosis. Review, personal and prospective studies].

1. In a review of methods developed for the identification of fetal malformations, the technique, risks and results of amniocentesis are presented. 2. Large series already published have demonstrated the relative simplicity and feasibility of the procedure as well as current indications for its utilization. These include the detection of chromosomal anomalies, the determination of sex (in certain sex-linked disorders), documentation of enzymatic and metabolic deficiencies, and the demonstration of open lesions of the neural tube by appropriate techniques. 3. Experience with over 500 cases personally tested by the authors entirely confirms the major indications for and benefits of this modern method for the detection and prevention of severe congenital anomalies during early pregnancy. 4. The identification of chromosomal alterations is currently the major objective of the method. Increased risks are associated with pregnancies involving a maternal age of 35 years or older (which account for 1-3% of aneuploidies), the birth of a previous infant with free trisomy 21 (1% recurrence risk) or secondary to a parental chromosome translocation (as much as 10% risk of aneuploidy). Fetal karyotyping for determination of sex, in cases where the mother is a carrier of an X-linked recessive gene (on average, 50% of male offspring will be affected), is an inadequate method of diagnosis to be utilized only until alternative techniques render possible specific diagnosis of the anomalies under consideration (hemophilias A and B, muscular dystrophy, etc). 5. Several of these techniques are now nearing development through the advent of fetoscopy and advanced ultrasound methodology, and have already been applied to the detection of certain sex-linked disorders and also for diagnosis of hemoglobinopathies (thalassemias, sickel cell anemia) and other conditions requiring the obtaining of fetal blood for diagnosis. Technology allowing direct examination of fetal parts by means of optical instruments is particularly useful in cases where a severe fetal morphologic malformation cannot currently be identified by indirect visualization (ultrasound) or by analysis of cytogenetic or molecular markers. 6. Pathological accumulations of alpha-fetoprotein which are associated with diverse feto-placental abnormalities (particularly open malformations of the neural tube) can be detected in the amniotic fluid and/or maternal blood. In extension of this approach, it is foreseeable that conditions existing prenatally will be diagnosed in a growing number of cases from the study of fetal cells and molecules which can be isolated from the venous blood of pregnant women. This will become feasible as a result of some well-developed techniques which allow separation of fetal from maternal cells and metabolites, and also to some extremely fine analytic techniques, notably examination of the DNA itself by means of restriction enzymes.

Adult↗

[Minimally invasive techniques make fetal surgery possible. Disabling abnormalities can be corrected].

Increases in our knowledge of the fetus and improved skill in early prenatal diagnosis inevitably result in attempts to treat some of the abnormalities detected. Although most fetal malformations diagnosed prenatally in continuing pregnancies are best managed by medical and surgical intervention after planned delivery, some structural defects may require in utero-treatment to forestall subsequent sequelae. The article consists in a review of the current status of ultrasound-guided invasive fetal therapy, including multifetal pregnancy reduction, manipulation of amniotic fluid, drainage and shunting procedures, fetal transfusion therapy, operative fetoscopy, and in utero stem cell transplantation. Future prospects and developments in this rapidly expanding field are also outlined.

Amniocentesis↗

Plasma creatine kinase and myoglobin levels, before and after abortion, in human fetuses at risk for Duchenne muscular dystrophy.

Plasma levels of creatine kinase (CK) were measured in 14 abortuses, nine of which were at risk for Duchenne muscular dystrophy (DMD). The plasma CK level was found to be increased in all abortuses, compared with the value obtained by fetoscopy before the termination. The causes of the increase in CK level were found to be 1) method of termination, 2) physical state of the abortus at delivery, 3) delay between delivery of the abortus and taking the blood sample, and 4) site of blood sampling. It is concluded that even under optimum conditions of termination the plasma creatine kinase level of the abortus is significantly raised above the true level; hence, this measurement is not reliable as a guide to the genetic status of the fetus. Cardiac leakage was the main source of the raised plasma CK level in the abortus and this was corroborated by measurement of myoglobin levels.

Abortion, Therapeutic↗

Pyruvate kinase in fetal plasma and amniotic fluid unsuccessful for the prenatal diagnosis of Duchenne muscular dystrophy.

A specific spectrophotometric assay of muscle-pyruvate kinase (M-PK) was used to measure the activity of this isozyme in fetal muscle, fetal plasma and amniotic fluid at about 17-24 wk of gestational age to assess its predictive value for the prenatal diagnosis of Duchenne muscular dystrophy (DMD). Fetal muscle obtained after termination was found to contain a high M-PK specific activity. No significant activity was detected in amniotic fluid from normal or at-risk fetuses. Pure fetal blood was obtained in utero by fetoscopy; significant plasma levels of M-PK activity were measured in a series of control samples, but at-risk fetal plasma contained no higher levels. We conclude that M-PK is of no use for the prenatal diagnosis of DMD.

Amniotic Fluid↗

Fetal plasma carbonic anhydrase III in prenatal diagnosis of Duchenne muscular dystrophy.

Carbonic anhydrase III (CAIII), a skeletal-muscle-specific enzyme which is elevated in the plasma of Duchenne muscular dystrophy (DMD) patients, was measured by radioimmunoassay in fetal plasma in order to evaluate its application to prenatal diagnosis of DMD. Using fetoscopy, pure fetal blood samples were taken at 17-24 weeks gestation from 25 fetuses at risk for DMD and from 78 control fetuses. Care was taken in the handling and storage of all samples. Normal sons were born in eight cases at risk for DMD. The CAIII levels in the infants were not significantly different from those of the control infants. Pregnancies were terminated in the remaining 17 at-risk cases. The CAIII levels in the fetuses were significantly different (p = 0.0034) from those of the control fetuses, although the distributions overlapped. Based on prior maternal risk, seven affected fetuses were expected in the terminated group; five had CAIII levels at or above the 95th centile of the control range. It is suggested that measurement of CAIII achieves partial discrimination between affected fetuses and their normal at-risk brethren.

Carbonic Anhydrases↗

Reproductive choices in hemophilic men and carriers.

We have examined reproduction patterns in hemophilic men and carrier women seen at a hemophilia treatment center. The study group included 309 patients with hemophilia A or B: 194 adults and 115 children from 246 pedigrees; 93% of affected men and 96% of parents of affected children had received genetic counseling. In the collected pedigrees, 65% of affected males were born to women with family history of hemophilia. An additional 23% of mothers were later shown to be carriers. Fewer than 12% of cases could be due to a new mutation in the child. Among 209 hemophilia A carrier tests, 95% of obligate carriers were detectable, 87% of mothers of sporadic cases, 53% of sisters of hemophiliacs, and 24% of other relatives had a high risk of carriership. Of 49 high-risk women seen during or prior to pregnancy, one-half elected prenatal diagnosis. Amniocentesis was performed in 24 cases and 8 were referred for fetoscopy, resulting in 18 normal offspring. Among 25 pregnancies not tested, 14 continued and produced 3 affected males and 11 normal offspring. Of hemophilic men over age 25, 66% have married and 41% (62% of those married) have had children. These observations will serve as a baseline for assessing any change in reproductive patterns occurring with the introduction of new genetic techniques.

Adult↗

Hydrolethalus (Salonen-Herva-Norio) syndrome: further clinicopathological delineation.

Two brothers with severe CNS abnormalities, cleft lip/palate, polydactyly, and lung hypoplasia are reported as examples of the hydrolethalus syndrome, an autosomal recessive disorder. Death from cardiopulmonary arrest occurred in patient 1 at age 4 months and in patient 2 at age 17 days. Detailed radiological and neuropathological description is provided on patient 2. We recommend realtime ultrasonography and, when indicated, fetoscopy for antenatal detection of the craniofacial and limb malformations associated with this syndrome.

Abnormalities, Multiple↗

Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia by linkage analysis.

Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia was previously performed by the direct histological analysis of fetal skin obtained by late second trimester fetoscopy. The recent gene mapping of the locus for the disorder to the region of Xq11-21.1 now permits the indirect prenatal diagnosis of the disorder by the method of linkage analysis, based on closely linked marker loci, during the first trimester of pregnancy. We report the prenatal diagnosis of a male fetus with a high probability of the disorder by a linkage analysis utilizing restriction fragment length polymorphisms at the DXS159, PGK1, and DXS72 loci, from a DNA sample obtained by a chorionic villus biopsy at 9 weeks gestation. After further counseling, the pregnancy was terminated but the diagnosis could not be confirmed by histological analysis, even though analysis of skin samples by light and electron microscopy showed lack of hair germs, primary dermal ridges, and sweat gland primordia, due to the early developmental stage of the fetus. The use of DNA-based linkage analysis now offers the opportunity for an earlier diagnosis of X-linked hypohidrotic ectodermal dysplasia by a method other than fetal skin sampling. However, families must also fully understand the present limitations of the method prior to undertaking the procedure.

Adult↗

Desbuquois syndrome: clinical, radiographic, and morphologic characterization.

To further characterize the clinical, radiographic and chondro-osseous morphologic changes in the Desbuquois syndrome, 7 patients from three sibships are described. They all had prenatal onset severe rhizomelic and mesomelic shortness with marked joint laxity and marked micrognathia. Radiographic changes were distinct, consisting of a supernumerary ossification center between the proximal phalanx of the index finger and the second metacarpal, and variable thumb changes. The femoral necks showed enlargement of the lesser trochanter with metaphyseal breaking, producing a characteristic "monkey wrench" (Swedish key) appearance. Growth plate cartilage showed dilated cisterns of rough endoplasmic reticulum in reserve zone chondrocytes. Three of the 7 cases were diagnosed prenatally by second trimester ultrasound and one case by fetoscopy. This syndrome exhibits significant phenotypic variability and must be differentiated from the Catel-Manzke syndrome which exhibits similar radiographic changes in the hands.

Adolescent↗

Ex vivo evaluation of human fetal membrane closure.

BACKGROUND AND OBJECTIVE: This study compares stress and leak point pressure of human fetal membranes following closure with suture, laser welding, or a new tissue sealant, SynthaSeal. STUDY DESIGN/MATERIALS AND METHODS: Samples of fetal membrane were bisected and repaired with suture, laser welding with albumin solders, or a tissue sealant. Representative tissue samples were assessed by histology. Anastomotic strength was evaluated by tensiometry. Additionally, leak pressure was measured after membrane samples were placed onto an infusion pump/pressure transducer, incised, and repaired as above. RESULTS: Membrane stress was strongest (P<0.001) for the tissue sealant group. Sutured samples were stronger than laser-welded samples. Membrane leak pressure was greatest for the tissue sealant group. The suture group demonstrated a higher leak pressure than the laser-welded group. CONCLUSIONS: Human fetal membranes were not suited for repair with laser welding under the conditions tested. A new tissue sealant, SynthaSeal, may provide a simple, effective method for membrane closure following fetoscopy, amniocentesis, and open fetal surgery.

Anastomosis, Surgical↗

Successful selective termination at 17 weeks' gestation in monochorionic monoamniotic twin pregnancy affected by twin-twin transfusion syndrome and discordant for hypoplastic left heart syndrome.

OBJECTIVES: To report a successful selective feticide in a complicated monochorionic monoamniotic (MCMA) pregnancy. METHODS: A case of MCMA pregnancy with severe twin-twin transfusion syndrome and discordant for hypoplastic left heart syndrome was diagnosed at 16 weeks' gestation. A complete ultrasound and fetoscopic surveillance was performed, ruling out cord entanglement and, thus, precluding the necessity of transecting the cord. RESULTS: The selective feticide was successfully performed by bipolar coagulation of the umbilical cord of the abnormal fetus under ultrasound guidance. The survivor twin developed normally during the rest of the pregnancy and was born at term. At 6 months of age, the infant was healthy. CONCLUSION: Selective feticide in complicated monoamniotic pregnancies can be safely performed. Cord entanglement can be confidently excluded by both ultrasound and fetoscopy, thus making the systematic transection of the umbilical cord unnecessary.

Adult↗

Prenatal testing for inherited immune deficiencies by fetal blood sampling.

We attempted to develop a prenatal diagnosis in fetuses at risk for immunodeficiency by fetal blood sampling performed under fetoscopy at 18-22 weeks of gestation. In order to obtain normal values, we first investigated thirty-five control fetuses whose blood punctures were undertaken for the diagnosis of haemoglobinopathies. Surface markers and in vitro mitogen-induced proliferation of the fetal lymphocytes were studied using micromethods. We then examined two fetuses at risk for two different types of severe combined immunodeficiency and established their immunological integrity, hence avoiding an unjustified termination of pregnancy. This immunological integrity was confirmed after birth.

Antigens, Surface↗

Phenotypic analysis of fetal blood leucocytes: potential for prenatal diagnosis of immunodeficiency disorders.

Recent technological advances allow the detection and quantitation of subsets of leucocytes using monoclonal antibodies. We have taken advantage of this to study the ontogeny of fetal blood leucocytes, using very small blood samples obtained at fetoscopy. By 14 weeks gestation T cells represent 35 per cent or more of fetal leucocytes and the distribution of the helper/inducer and suppressor/cytotoxic subsets is similar to that of adults. B lymphocytes before 16 1/2 weeks are low (4-20 per cent), but rise to a mean of 28 per cent in 17-26 week fetuses. Granulocytic cells, many of which are phenotypically immature, represent 18-34 per cent of total leucocytes. The methodology employed is very reliable and offers the opportunity for the prenatal diagnosis of some immunodeficiency disorders, since using the same reagents we have diagnosed children with severe combined immunodeficiency shortly after birth.

Antibodies, Monoclonal↗

Further examples of trisomy-20 mosaicism in amniotic cell cultures.

Amniotic fluid cultures from two patients showed trisomy-20 mosaicism. No trisomy-20 cells were found in a normal full term infant and in multiple tissue biopsies and fetal blood from a fetus after a termination of pregnancy. No definitive advice is yet possible for parents where trisomy-20 amniotic cell mosaicism is detected. Fetoscopy and fetal blood sampling are of no value and termination of pregnancy is not indicated by empirical evidence. Preferential trophoblastic non-disjunction (Kalousek and Dill, 1983) is discussed as a possible partial explanation for the variable occurrence and distribution of this type of mosaicism.

Adult↗