CD24 is a marker of exosomes secreted into urine and amniotic fluid

Exosomes are small membrane vesicles that are secreted from a variety of cell types into various body fluids including the blood and urine. These vesicles are thought to play a role in cell-cell interactions. CD24 is a small but extensively glycosylated protein linked to the cell surface by means of a glycosyl-phosphatidylinositol anchor. In this study we found that CD24 is present in membrane vesicles characterized as exosomes that were isolated from the urine of normal individuals. CD24 was expressed by both tubule cells and podocytes and treatment of the latter with a cholesterol-extracting agent, but not with a calcium ionophore, caused the release of CD24-containing exosomes. Using CD24 as a marker, we found exosomes in the urine of newborn infants and in the amniotic fluid of pregnant women with similar findings made in mice. Interestingly, studies with CD24 knockout mice showed that the exosomes are released from the fetus but not from the mother; however, exosome release was similar from both the knockout and the wild-type mice. This indicates that CD24 is not essential for exosome formation or release but may be a convenient exosome marker. Our studies suggest that exosomal secretion from the embryonic kidney could play a biological role at the fetal-maternal interphase.

Multiplex FISH telomere integrity assay identifies an unbalanced cryptic translocation der(5)t(3;5)(q27;p15.3) in a family with three mentally retarded individuals

Cryptic rearrangements involving the terminal regions of chromosomes are suspected to be the cause of idiopathic mental retardation in a significant number of cases. This finding highlights the necessity of a primary screening test for such chromosome aberrations. Here we present a multiplex fluorescence in situ hybridization telomere integrity assay which allows the detection of submicroscopic aberrations in the telomeric regions of all chromosomes. This novel approach identified an unbalanced cryptic translocation der(5)t(3;5)(q27;p15.3) in a family with three cases of unexplained mental retardation and dysmorphic features. The symptoms of the patients represent neither the classical dup(3q)- nor cri du chat syndrome, although all affected individuals demonstrate several features of both syndromes. The identification of two balanced translocation carriers emphasizes the significance of the telomere integrity assay for genetic counseling and prenatal diagnosis.

Evidence for infection of the human embryo with adeno-associated virus in pregnancy

Previous reports have demonstrated the presence of DNA of the human helper virus-dependent adeno-associated parvovirus (AAV) in uterine tissue and curettage material from early miscarriage. To examine infection of embryonic tissue during pregnancy, amnion fluids were analysed for the presence of AAV. Using polymerase chain reaction, AAV DNA was detected in 64 out of 238 DNA samples extracted from amnion cells. DNA of helper viruses were found in 12% (papillomavirus) and 18% (cytomegalovirus) of the samples (double infections with AAV in eight and nine cases, respectively). Furthermore, infectious AAV virions were found in 13 out of 43 AAV DNA-containing samples. In mothers with AAV DNA-positive amnion fluids, premature amniorrhexis and premature labour occurred significantly more frequently (P < 0.001). Using an immunofluorescence assay, 24% of newborn sera (unrelated to the amnion fluid samples) were found to contain IgM antibodies to AAV, in most cases paralleled by IgM antibodies in the mother's sera. The data demonstrate that AAV infection can occur in utero at early and at late stages of pregnancy. The observed complications at delivery should encourage studies to clarify possible pathological consequences of AAV infection in pregnancy and a possible latent infection of the fetus.

Wolf-Hirschhorn syndrome: case report and review of the chromosomal aberrations associated with diaphragmatic defects

A female fetus showing severe growth retardation was delivered at 31 weeks of gestation because of fetal distress. At birth, the infant showed bradycardia and no spontaneous breathing. Although high frequency oscillatory ventilation was started, severe asphyxia persisted and the infant died of respiratory insufficiency. At the autopsy, the propositus showed microcephaly, prominent glabella, broad bridge of the nose, ocular hypertelorism, poorly differentiated and low-set ears, bilateral palatoschisis, and micrognathia. Midline closure defects of the cervical spine bodies, lower jaw, and skull base were seen at postmortem radiography. An extreme hypoplasia of both lungs, a large defect of the left diaphragm with upward displacement of viscera, and multiple cortical cysts in both kidneys were seen at postmortem examination. Karyotyping revealed a chromosomal imbalance with 46, XX, del(4) (pter-->13), characterizing the Wolf-Hirschhorn syndrome. Because diaphragmatic defects can occur in association with specific recognizable patterns of human malformation careful pathologic and genetic workup of all affected infants in crucial for accurate genetic counseling.

Clinical, cytogenetic and molecular investigations in three patients with Wolf-Hirschhorn syndrome

Clinical, cytogenetic and molecular studies were performed in three patients with Wolf-Hirschhorn syndrome (WHS). In all cases the altered chromosome 4 appeared to be the result of a de novo deletion. Cytogenetic investigations located the breakpoint at 4p15.3 and 4p13. With cytogenetic methods it was not possible to decide whether these deletions were terminal or interstitial. DNA methods also failed to define a distal breakpoint within the 4p16.3 region which might have indicated an interstitial deletion. According to the literature, the paternal chromosome 4 is preferentially deleted in most patients with WHS. DNA analysis with polymorphic markers out of the 4p16.3 region revealed that in two of the cases reported here the deleted segment was of paternal and in one case of maternal origin.

Chorionic villus metaphase chromosomes and interphase nuclei analysed by chromosomal in situ suppression (CISS) hybridization

Metaphase chromosomes and interphase nuclei of chorionic villus samples (CVS) in five cases were studied after treatment with trypsin and post-fixation in formaldehyde by chromosomal in situ suppression (CISS) hybridization. Our modified protocol enables the use of in situ hybridization techniques on CVS preparations after 42 h of culture. A balanced translocation and trisomy 13 were identified with the aid of CISS hybridization.

[Early amniocentesis]

Preliminary clinical experience with early amniocentesis is reported. Fifty-two amniocenteses were performed before the end of the 14th week following the last menstrual period. Cytogenetic and biochemical analyses (AFP, AChE) were performed. Increasing experience with amniotic fluid samples containing small-cell populations and the use of combined culture media improved the poor initial results to a 100% level, thus enabling the use of this technique for diagnostic purposes. The sampling technique and the post-procedural evolution of twelve amniocenteses in pregnant women, whose pregnancy is to be continued, are presented. The possibility of performing amniocentesis in early pregnancy is discussed with reference to anatomical aspects (amniotic and chorionic cavity).

[Transabdominal chorionic villi aspiration in the 1st and 2d trimester in 120 cases with reference to placental location]

At the Gynecological Clinic of the Klinikum Ludwigshafen prenatal transabdominal diagnostic aspiration of villi was performed in 120 cases in the first and second trimesters between October 1986 and April 1988. The puncture was performed using a cannula system comprising a guide and an aspiration needle. The ultrasonographically controlled removal technique is described with special consideration of the procedure in cases with placental insertion in the posterior wall. Successful tissue removal (at least 5 mg of tissue) was achieved in 97.5% of the cases. Cytogenetic, biochemical, and molecular biologic studies were performed. The most frequent indication was to detect chromosome disorders in older mothers (74.2%). Such disorders were diagnosed in 4.2% of all cases and pregnancy was terminated in seven of them; the indications were aneuploidies, metabolic disease, or severe developmental anomalies detected by ultrasonography in normal karyotypes. In the remaining 113 pregnancies one miscarriage was seen nine weeks after aspiration of villi. On the basis of these results the abortion risk following transabdominal chorionic biopsy is 0.88% and is thus similar to that following amniocentesis.

Prenatal enzymatic diagnosis and exclusion of Krabbe's disease (globoid-cell leukodystrophy) using chorionic villi in five risk pregnancies

Galactosyl ceramide beta-galactosidase activity was determined in chorionic villi (CV) samples obtained between the 9th and 11th weeks of gestation from 5 women with pregnancies at risk for Krabbe's disease (globoid-cell leukodystrophy, KD). These enzyme activities were compared with those in controls, as well as with those in cultured amniotic fluid cells (AFC) from one of the five at-risk pregnancies and from 29 KD-risk pregnancies studied previously. The results of these CV enzyme analyses were such that one case of fetal KD was clearly diagnosable, one fetal genotype heterozygous for KD was presumed, and three normal fetal genotypes were suggested. The use of both uncultured and cultered CV can be recommended for prenatal KD testing, but AFC may continue to play an important role, too. Of the 58 prenatal KD tests we have evaluated since 1974, a positive diagnosis of Krabbe's disease was made (and confirmed after termination of pregnancy when feasible) in 23 which is significantly more than 25% of 58.

[Transabdominal chorionic biopsy: indications and timing of the procedure]

The article reports on the introduction of transabdominal chorionic biopsy in the Gynaecological Hospital of Ludwigshafen in cooperation with the Department of Human Genetics at the University of Heidelberg. After completion of a pilot study 15 diagnostic transabdominal chorionic biopsies were performed between the 15th and 23rd pregnancy week. Sampling was successful in all cases; the median estimated weight of the biopsied samples was 35 mg. Cytogenic, biochemical and molecular-genetic examinations were conducted. No complications were seen except for one subserous haematoma. Indications and time of performance are discussed. The transabdominal chorionic biopsy is easier to conduct in the 2nd trimenon than during the first, and can therefore be considered to be a favorable "entry" into the technique. Shifting the biopsy to an earlier date, namely, into the first trimenon, can be aimed at as the familiarity with the technique increases. The obvious advantages of transabdominal removal of villi compared with the transcervical method lead us to expect that in course of the time the transcervical method will be replaced by the transabdominal one. No indication for invasive prenatal diagnosis should be implied without previous detailed genetic counselling.

[Transcervical chorion biopsy--hitherto experiences and results of more than 200 cases]

This is a report on more than 228 chorionic biopsies performed at the Department of Gynaecology of the University of Heidelberg. After having completed the pilot study (about 100 cases before planned termination of pregnancy) with a success rate of 87% in obtaining useful chorionic villi we initiated chorionic biopsy for diagnostic purposes. A cytogenetic result was obtained in 95% of all cases after the villi had been sampled, using the method of transcervical aspiration. In 1% of the cases the obtained tissue could not be used; in another 1% a chromosomal mosaic-like pattern was seen, whereas in 3% of the cases no cytogenetic result was obtained despite the fact that partly the available tissue quantities were quite sufficient. No false sex diagnosis was made in any of the examined cases. In 98% of all instances of sampling of chorionic villi, a sufficient amount of useful chorionic villi tissue was obtained. Vaginal bleeding after chorionic biopsy occurred only in about one-third of the cases within 1-7 days after sampling. In another third of the patients questioned accordingly, no vaginal bleeding was reported following chorionic villi sampling. The remaining patients stated that there had been only short-term haemorrhages after biopsy. 122 of 226 patients have since delivered, 39 are at present in the 16th to 28th week of gestation, 41 beyond the 28th week and the remaining 13 were before the 16th week at the time they were questioned. Abortion or foetal death after chorionic biopsy was seen in four cases only (1.8%). No malformations were seen so far in the delivered infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of chromosome aberrations in the human interphase nucleus by visualization of specific target DNAs with radioactive and non-radioactive in situ hybridization techniques: diagnosis of trisomy 18 with probe L1.84

The localization of chromosome 18 in human interphase nuclei is demonstrated by use of radioactive and non-radioactive in situ hybridization techniques with a DNA clone designated L1.84. This clone represents a distinct subpopulation of the repetitive human alphoid DNA family, located in the centric region of chromosome 18. Under stringent hybridization conditions hybridization of L1.84 is restricted to chromosome 18 and reflects the number of these chromosomes present in the nuclei, namely, two in normal diploid human cells and three in nuclei from cells with trisomy 18. Under conditions of low stringency, cross-hybridization with other subpopulations of the alphoid DNA family occurs in the centromeric regions of the whole chromosome complement, and numerous hybridization sites are detected over interphase nuclei. Detection of chromosome-specific target DNAs by non-radioactive in situ hybridization with appropriate DNA probes cloned from individual chromosomal subregions presents a rapid means of identifying directly numerical or even structural chromosome aberrations in the interphase nucleus. Present limitations and future applications of interphase cytogenetics are discussed.

Two subsets of human alphoid repetitive DNA show distinct preferential localization in the pericentric regions of chromosomes 13, 18, and 21

We have isolated and characterized two human middle repetitive alphoid DNA fragments, L1.26 and L1.84, which localize to two different sets of chromosomes. In situ hybridization revealed both repeats to have major and minor binding sites on the pericentric regions of several chromosomes. Probe L1.26 maps predominantly to chromosomes 13 and 21. Probe L1.84 locates to chromosome 18. Minor hybridization sites for both probes include chromosomes 2, 8, 9, and 20; in addition, L1.26 revealed minor sites on chromosomes 18 and 22. The binding to these sites strongly depends on hybridization conditions. In Southern blot hybridizations to total human DNA, both L1.26 and L1.84 give the same ladder pattern, with a step size of 170 bp, indicating their presence as tandem repeats, but with different band intensities for each probe. The chromosome-specific nature of particular multimers was confirmed by Southern blot analyses of a human-rodent hybrid cell panel. We conclude that L1.26 and L1.84, with their related sequences, constitute subfamilies of alphoid DNA that are specific for subsets of chromosomes and, in some cases, possibly even for single chromosomes.

Specific staining of human chromosomes in Chinese hamster x man hybrid cell lines demonstrates interphase chromosome territories

In spite of Carl Rabl's (1885) and Theodor Boveri's (1909) early hypothesis that chromosomes occupy discrete territories or domains within the interphase nucleus, evidence in favor pf this hypothesis has been limited and indirect so far in higher plants and animals. The alternative possibility that the chromatin fiber of single chromosomes might be extended throughout the major part of even the whole interphase nucleus has been considered for many years. In the latter case, chromosomes would only exist as discrete chromatin bodies during mitosis but not during interphase. Both possibilities are compatible with Boveri's well established paradigm of chromosome individuality. Here we show that an active human X chromosome contained as the only human chromosome in a Chinese hamster x man hybrid cell line can be visualized both in metaphase plates and in interphase nuclei after in situ hybridization with either 3H- or biotin-labeled human genomic DNA. We demonstrate that this chromosome is organized as a distinct chromatin body throughout interphase. In addition, evidence for the territorial organization of human chromosomes is also presented for another hybrid cell line containing several autosomes and the human X chromosome. These findings are discussed in the context of our present knowledge of the organization and topography of interphase chromosomes. General applications of a strategy aimed at specific staining of individual chromosomes in experimental and clinical cytogenetics are briefly considered.

Sex chromosome positions in human interphase nuclei as studied by in situ hybridization with chromosome specific DNA probes

Two cloned repetitive DNA probes, pXBR and CY1, which bind preferentially to specific regions of the human X and Y chromosome, respectively, were used to study the distribution of the sex chromosomes in human lymphocyte nuclei by in situ hybridization experiments. Our data indicate a large variability of the distances between the sex chromosomes in male and female interphase nuclei. However, the mean distance observed between the X and Y chromosome was significantly smaller than the mean distance observed between the two X-chromosomes. The distribution of distances determined experimentally is compared with three model distributions of distances, and the question of a non-random distribution of sex chromosomes is discussed. Mathematical details of these model distributions are provided in an Appendix to this paper. In the case of a human translocation chromosome (Xqter----Xp22.2::Yq11----Yqter) contained in the Chinese hamster X human hybrid cell line 445 X 393, the binding sites of pXBR and CY1 were found close to each other in most interphase nuclei. These data demonstrate the potential use of chromosome-specific repetitive DNA probes to study the problem of interphase chromosome topography.

Ultrasonographic diagnoses of major lymphatic system abnormalities prior to 20 weeks of pregnancy

Prenatal ultrasound diagnoses of severe lymphatic system abnormalities were obtained in three fetuses. In all three cases the diagnosis was established prior to 20 wk of pregnancy, i.e. early enough to allow selective termination. In all three cases male fetuses with a chromosomal anomaly were found. Alpha-fetoprotein values were not elevated. In all cases the fetal abnormalities were of such size that surgical excision could not be taken into consideration to provide satisfactory results for the infants.

Position of chromosomes in the human interphase nucleus. An analysis of nonhomologous chromatid translocations in lymphocyte cultures after Trenimon treatment and from patients with Fanconi's anemia and Bloom's syndrome

The problem of localization of chromosomes in relation to each other in the interphase nucleus of human lymphocytes was investigated by analysis of chromatid and chromosome aberrations observed in lymphocyte cultures of three patients with Fanconi's anemia, one patient with Bloom's syndrome, and in Trenimon-treated (Trenimon, Bayer) normal cells. Distribution of open gaps and breaks is highly correlated with chromosome length and distribution of breaks involved in chromatid translocations in Fanconi's anemia and in Trenimon-treated cells. Both correlations are much lower in Bloom's syndrome. In Fanconi's anemia and in normal cells after Trenimon-treatment, the majority of chromatid translocations are between nonhomologous chromosomes, whereas in Bloom's syndrome mainly homologous chromosomes are involved. Statistical localization of chromosomes in relation to each other in the three-dimensional space by multidimensional scaling gives results consistent with the limited amount of independent evidence.

[Genetic amniocentesis: technique and results in 1,000 first trimester amniocenteses (author's transl)]

The results of 1,000 transabdominal amniocenteses between 15 and 20 weeks gestation are reported. The method is described. The bio-chemical and cytogenetic results are reported. - Amniocentesis in the first trimester is not a routine investigation since fetal and maternal risks are associated with this procedure. The risk of abortion following amniocentesis was lowered from 6/1000 to 2/500 by improvement of the technique under ultra-sound control. The worst maternal complication observed was a septic abortion one day after amniocentesis. 96% of all cyto-genetic examinations showed normal karotypes. The largest group at risk were mothers over 35 years of age. In this group chromosome anomalies were found in 17 cases. All neural tube defects were found by determination of the alpha-fetoprotein in the amniotic fluid. 26 terminations of pregnancy for fetal indications were carried out. Two patients refused therapeutic abortions despite trisomy 21 for ethical reasons. One patient continues her pregnancy with a 47 XYZ pregnancy.

The problem of partial endoreduplication

Partial endoreduplication (PE) as defined by Lejeune et al. (1966) has only been found in a few instances. Similar configurations, also called PEs, seem to originate from a different process. A series of 12 PEs is presented in this paper, discovered in metaphases from healthy individuals, and in patients with or without chromosome-breakage syndrome and after treatment with chromosome-breaking agents. Interpretations of the microscopic appearance of each configuration led to the conclusion that there are three different modes of origin for such rare events, one being true partial endoreduplication, the second a partial pseudoendoreduplication, and the third a homologous triradial chromatid translocation.

[Sexchromatin determination in a corneal graft in adult cystinosis (author's transl)]

On the basis of the distribution of F-bodies (Y-Chromatin) and Barr-bodies (X-Chromatin) in a lamellar keratoplasty from a female donor and in the surrounding male corneal tissue of a 55-year-old male patient with adult cystinosis a few female corneal epithelial cells could be identified 7 years after corneal tissue-graft had been performed. It was concluded that after keratoplasty epithelial cells grow into each other, i.e. from the graft to the host tissue and vice versa. The fact that even after 7 years female epithelial cells from the donor can still be detected is put down to the metabolic condition resulting in cystinosis.