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Biomedical subjects

G Bernaschek

Publications and source records attributed to G Bernaschek.

At least 55 records · Page 3Linked to original sources
PubMed1999

Isolated Dandy-Walker malformation: prenatal diagnosis in two consecutive pregnancies.

We report a family with recurrent Dandy-Walker malformation (DWM). The first offspring was found prenatally to have isolated DWM at 30 weeks' gestation. Ultrasonography at 19 weeks' gestation in the subsequent pregnancy revealed isolated DWM in both dizygotic twins. Chromosome analysis was normal in all three infants, and autopsy confirmed that no other congenital abnormalities were present. Evidence suggests that rare families transmit the disorder in an autosomal or X-linked recessive pattern, with a high recurrence risk.

Adult↗
PubMed1999

Antepartum fetal and maternal carboxyhemoglobin and cotinine levels among cigarette smokers.

The objective of this study was to examine the association of carboxyhemoglobin (COHb) and plasma cotinine levels among pregnant women who smoke cigarettes and their fetuses. Fifteen pregnant women who smoked and their fetuses undergoing cordocentesis had blood samples analysed simultaneously for COHb and cotinine. Linear regression was used to test for associations among study variables. Significant maternal-fetal associations were observed both with COHb (r = 0.72, p = 0.003) and with cotinine (r = 0.96, p = 0.003). Maternal cotinine levels were correlated with maternal and fetal COHb levels (r = 0.96, p = 0.003; r = 0.99, p = 0.0003, respectively). Fetal cotinine levels were correlated with COHb in maternal and in fetal blood (r = 0.81, p = 0.0003; r = 0.88, p<0.0001, respectively). The strong direct associations of maternal and fetal levels of COHb and cotinine indicate that maternal COHb and cotinine measurements may be interpreted as surrogates of fetal COHb levels. However, the specificity, ex vivo stability and ease of measurement of cotinine offer advantages over using COHb in quantifying fetal CO exposure following maternal cigarette smoking.

Adult↗
PubMed1999

Ultrasound evaluation of fetal spine length between 14 and 24 weeks of gestation.

The objective of our study was to establish a nomogram of fetal spine length in the second trimester of pregnancy by using two and three-dimensional ultrasound. Fetal spine length was measured prospectively by means of transabdominal ultrasonography in 114 normal singleton pregnancies between 14 and 24 weeks of gestation. Regression analyses were performed on spine length, gestational age, biparietal diameter and femur length. Supplementary three-dimensional ultrasound to assess fetal spine length was performed in 75 cases. Fetal spine length, as a function of gestational age, was expressed by the following regression equation: spine length (mm) = -47.2 + 7.16 x gestational age (weeks), with a Pearson correlation coefficient of R(2)=0.956. The results of the measurements revealed no difference between two and three-dimensional ultrasound. Our study defines the normal limits of fetal spinal length in the second trimester of pregnancy and demonstrates a high correlation between spinal length, gestational age, biparietal diameter and femur length. However, there are still too few prenatal research data to say whether and to what extent an assessment of fetal spine length at this stage of pregnancy can be used for prenatal diagnosis of congenital syndromes, which, among other manifestations, are marked by fetal spine lengthening or shortening.

Female↗
PubMed1998

A role of the tuberous sclerosis gene-2 product during neuronal differentiation.

Tuberous sclerosis is an autosomal dominant disorder. Besides the development of benign growths (hamartomas) in different tissues, one hallmark of this disease is the presence of highly epileptogenic dysplastic lesions in the cerebral cortex (tubers) composed of abnormal shaped neurones. Patients often show evidence of severe mental retardation. Linkage analysis revealed two disease-determining genes on chromosome 9 and chromosome 16. The TSC2 gene on chromosome 16 encodes a 1784-amino acid putative tumour suppressor protein, tuberin, that functions as a GTPase-activating protein. Here we show that tuberin expression is upregulated upon induction of neuronal differentiation in the neuroblastoma cell lines SK-N-SH and LAN-1. This upregulation occurs at post-transcriptional level and is independent of the proliferation status. TSC2 expression is unaffected during differentiation of C2C12 myoblasts into myotubes and of F9 embryonal carcinoma cells into cells resembling parietal endoderm. Antisense inhibition of tuberin expression in SK-N-SH or LAN-1 cells inhibits neuronal differentiation, but does not affect the differentiation of F9 cells. Ectopic overexpression of TSC2 not only reverts the antisense-associated phenotype but furthermore accelerates the neuronal differentiation process. Our data show for the first time that tuberin plays a critical role in neuronal differentiation. Such role is consistent with the phenotype of tuberous sclerosis patients, who inherit one defective TSC2 allele, and frequently lose the remaining normal allele in many of the tubers/hamartomas which develop in the central nervous system of these patients.

Animals↗
PubMed1998

Three-dimensional ultrasound evaluation of fetal tooth germs.

OBJECTIVE: A total of 126 genetic syndromes are associated with oligodontia or anodontia. The most frequent of these are ectodermal dysplasias, all types of facial cleft and Down's syndrome. With the advent of three-dimensional ultrasonography, accurate assessment of many fetal abnormalities has become possible. The objective of this study was to determine the effectiveness of three-dimensional ultrasonography in the visualization of fetal tooth germs. DESIGN: We examined 45 women with singleton pregnancies between 16 and 36 gestational weeks who were undergoing routine ultrasound check-ups for fetal tooth germs with conventional two-dimensional ultrasonography, followed by three-dimensional ultrasonography using multiplanar reconstruction. RESULTS: In the 45 fetuses studied, fetal tooth germs were visualized at the first attempt in 36 cases (80%). In the group of fetuses aged between 19 and 36 weeks of gestation, the overall detection rate in both jaws was at least 86% for three-dimensional ultrasonography, compared to at least 56% for two-dimensional ultrasonography. CONCLUSIONS: Three-dimensional ultrasonography was clearly superior to conventional ultrasonography in the visualization and evaluation of fetal tooth germs. Three-dimensional ultrasonography therefore has a potential for enhanced visualization of fetal tooth germs and may aid in the antenatal detection of syndromes associated with oligodontia or anodontia.

Cleft Lip↗
PubMed1998

Cystic adenomatoid malformation of the lung: prenatal diagnosis, prognostic factors and fetal outcome.

AIM: To evaluate 14 cases of cystic adenomatoid malformation (CAM) of the lung with regard to antenatal management and fetal outcome. RESULTS: Intrauterine shunts were placed in 3 fetuses to avoid pulmonary hypoplasia. Prenatal sonography showed that the lesions had a tendency to resolve in 4 cases. Of the 9 infants who survived, 5 were treated surgically (lobectomy). CONCLUSIONS: The antenatal evolution of these lesions is highly variable; the lesions may even resolve spontaneously, therefore the diagnosis of CAM types II and III should be followed by a period of observation. Intrauterine drainage is recommended in cases of CAM type I if unfavorable prognostic factors are encountered.

Abortion, Induced↗
PubMed1997

Activation of c-Myc uncouples DNA replication from activation of G1-cyclin-dependent kinases.

Proto-oncogenes like c-myc are thought to control exit from the cell cycle rather than progression through the cell cycle itself. We now present a different view of Myc function. Exponentially growing Rat1-MycER fibroblasts were size-fractionated by centrifugal elutriation. In these cells, activation of cyclin E- and cyclin A-dependent kinases, degradation of p27, hyperphosphorylation of retinoblastoma protein and activation of E2F occur sequentially at specific cell sizes. Upon activation of Myc, however, these transitions all occur simultaneously in small cells immediately after exit from mitosis. In contrast, Myc has no discernible effect on the cell size at which DNA replication is initiated. These data show first that Myc controls the activity of G1 cyclin-dependent kinases independently from the transition between quiescence and proliferation and from any effect on cell growth in size. These data also provide evidence of at least one dominant mechanism besides activation of E2F and of cyclin E/cdk2 kinase, which prevents DNA replication unless a critical cell size has been reached.

Animals↗
PubMed1997

Fetal cells in the peripheral blood of pregnant women express thymidine kinase: a new marker for detection.

Fetal cells occur in maternal blood in a substantial proportion of normal pregnancies. Several different approaches have been used to detect and enrich these cells for non-invasive prenatal diagnosis. However, before these fetal cells can routinely be used for prenatal diagnosis, perfectly reproducible procedures for detection and enrichment need to be established. We found that these fetal cells express high intracellular levels of the DNA precursor pathway enzyme thymidine kinase. Since normal adult peripheral blood cells do not exhibit any thymidine kinase activity, this enzyme is a potent new marker to detect and enrich fetal cells from maternal blood. We further describe the first successful application of a cytofluorometric thymidine kinase assay to detect fetal cells in the maternal circulation by virtue of their high thymidine kinase activity.

Adult↗
PubMed1997

Endometrial volume change during spontaneous menstrual cycles: volumetry by transvaginal three-dimensional ultrasound.

OBJECTIVE: At present, only limited data are available on endometrial volume during the menstrual cycle. Most of these studies deal with animal models and use magnetic resonance imaging for volume measuring. The application of three-dimensional ultrasound in endometrial volume estimation is the subject of this study. SETTING: Patients visiting the outpatient unit of the division of endocrinology and reproductive medicine of a university hospital. PATIENT(S): Twenty patients with a history of a normal menstrual cycle were selected. INTERVENTION(S): Ultrasound examinations were performed during a single menstrual cycle in addition to routine laboratory tests. MAIN OUTCOME MEASURE(S): Uterus-endometrial volume ratio. RESULT(S): Data from 18 patients could be evaluated. In 81 examinations the endometrium volume could be determined. Mean endometrial volume measured by three-dimensional ultrasound was 1.23 cm3. Mean uterus volume was 48.93 cm3. The change of the uterus-endometrial volume ratio showed a good correlation with the day of menstrual cycle. Quadratic regression analysis of volume and cycle length was R2 = 0.432. CONCLUSION(S): Three-dimensional ultrasound allows assessment of volume data of the female internal genitalia. In this study changes of the endometrial volume in menstrual cycles were measured. Additional studies are required to give information on the clinical impact of this new technique of endometrial volume estimation.

Endometrium↗
PubMed1997

Umbilical artery Doppler velocimetry in fetuses with a single umbilical artery.

OBJECTIVE: Doppler waveform analysis of the umbilical artery is an important tool for the evaluation of high-risk pregnancies. Yet, available data are based on normal values from three-vessel umbilical cords. Our purpose was to evaluate the value of umbilical artery Doppler velocimetry in fetuses with a single umbilical artery. METHODS: One hundred thirteen consecutive singleton fetuses with a single umbilical artery between 16 and 40 weeks' gestational age were studied prospectively at a tertiary referral center for prenatal diagnosis and therapy. Complete follow-up was obtained from 103 cases. RESULTS: The systolic-diastolic ratio in the umbilical artery was abnormal in 31 fetuses (30%) and normal in 72 fetuses (70%). Fetuses with abnormal Doppler waveform analysis in the umbilical artery were significantly more likely to be growth restricted (55 compared with 15%), to have complex malformations (58 compared with 1%) or an abnormal karyotype (29 compared with 0%), or not to survive the fetal/perinatal period (42 compared with 0%) than those with normal Doppler waveform analysis. CONCLUSION: Fetuses with a single umbilical artery and abnormal umbilical Doppler velocimetry had a significantly increased risk of adverse fetal and neonatal outcome compared with those with a single umbilical artery but normal Doppler studies.

Adult↗
PubMed1997

Dandy-Walker malformation diagnosed before 21 weeks of gestation: associated malformations and chromosomal abnormalities.

This study examined rates of concomitant structural and chromosomal abnormalities in 14 fetuses with a diagnosis of Dandy-Walker malformation or Dandy-Walker variant before 21 weeks' gestational age, compared to 14 fetuses with a diagnosis of Dandy-Walker malformation or variant between 21 weeks' gestation and delivery. A total of 24 fetuses had Dandy-Walker malformation and four had Dandy-Walker variant. Eight of the fetuses with the malformation had ventriculomegaly: one of the fetuses with early diagnosis and seven with later diagnosis (p = 0.027). None of the fetuses with Dandy-Walker variant had ventriculomegaly. The overall prevalence of concomitant structural abnormalities was 13/28; 8/14 for fetuses with early prenatal diagnosis and 5/14 for fetuses with late prenatal diagnosis of the malformation or the variant. Chromosomal abnormality rates were significantly higher among fetuses with early prenatal diagnosis (7/14) than among those with later prenatal diagnosis (1/14; p = 0.032). Abnormal karyotypes were more prevalent among fetuses without ventriculomegaly (7/20), compared to fetuses with ventriculomegaly (1/8). We conclude that fetuses with an antenatal diagnosis of Dandy-Walker malformation or Dandy-Walker variant before 21 weeks' gestational age have worse prognosis than fetuses with a later prenatal diagnosis of the same defect.

Adult↗
PubMed1997

Intrauterine device localization by three-dimensional transvaginal sonography.

Our objective was to investigate the possible role of three-dimensional transvaginal ultrasound in the visualization of an intrauterine device (IUD) for routine follow-up after insertion. A total of 96 women were examined after insertion of a TCu380A IUD. Three-dimensional ultrasonographic imaging was carried out using a special vaginal probe and a commercially available ultrasound machine at a mean interval of 22 days after insertion. Complete simultaneous imaging of all parts of the IUD was possible in 95% of cases. In the three-plane mode, all parts of the IUD could be visualized in 64% and in a further 30 cases this was possible only after volume rendering. In two women, incomplete opening of the two arms of the device was demonstrated. In one of these cases, the entire IUD was displaced into the cervical canal. In another case, an intrauterine pregnancy was found together with an IUD in the correct position. Three-dimensional ultrasound provides useful information on the location of the IUD following insertion. It enables imaging of the entire IUD, i.e. the shaft and the arms, simultaneously. Additionally, the examination time can be kept to a minimum with this new technique.

Adult↗
PubMed1997

Cellular targets for activation by c-Myc include the DNA metabolism enzyme thymidine kinase.

Although a remarkable number of genes has been identified that are either activated or repressed via c-Myc, only few of them obviously contribute to Myc's biological effect--the induction of proliferation. We found that in logarithmically growing cells overexpression of Myc specifically induces thymidine kinase (TK) mRNA expression and enzyme activity, whereas loss of one allele of Myc causes downregulation of this enzyme. We show that activation of Myc triggers high levels of this normally strictly S-phase-regulated DNA metabolism enzyme in serum arrested G0 cells and causes high and constant levels of TK expression throughout the entire ongoing cell cycle. Induction of TK by Myc requires an intact transcriptional activation domain. Myc-induced deregulation of this enzyme is paralleled by alterations of protein binding at the E2F-site of the TK promoter. We further show that cell growth arrest by the cyclin-dependent kinase inhibitor p16 is abrogated by overexpression of Myc and that co-overexpression of p16 cannot inhibit the Myc-induced up-regulation of TK expression. Our data demonstrate TK to be a cellular target of Myc independently of the status of cell proliferation and provide evidence that the transcription factor E2F might be involved in this process.

Animals↗