Amniocentesis for the detection of congenital toxoplasmosis: results from the nationwide Austrian prenatal screening program.

Prenatal diagnosis of congenital toxoplasmosis (CT) influences therapeutical management in pregnant women and their offspring. In Austria, a nationwide serological healthcare program to identify potential maternal toxoplasma infections during pregnancy exists. We assessed the clinical use of amniocentesis for toxoplasma-specific polymerase chain reaction (PCR) on amniotic fluid to detect CT. Data on serology, amniocentesis, PCR, complications, treatment, and paediatric clinical outcome were collected retrospectively among the birth cohort 1992-2008. There were 1386 women with amniocentesis, but only in 707 cases (51%) was acute maternal infection confirmed serologically. A high proportion (49%) of amniocenteses with negative PCR results in women with chronic infection or seronegativity were performed without clinical justification for the women or their foetuses. The positive and negative predictive values of PCR were 94.4% and 99.3%, respectively. Thirty-nine foetuses with CT, including four deaths, were reported. The five PCR-negative but infected infants were identified by the serological and clinical follow-up program. Thirty percent of amniocenteses were performed in the third trimester, and gestational age or treatment did not influence PCR sensitivity. Amniocentesis is indicated in women with acute maternal infection, and facilitated targeted therapies in pregnant women and their offspring. In women with late toxoplasma infection, negative amniotic fluid PCR made treatment of infants unnecessary. Serological and clinical follow-up of infants is important to confirm the infection status of the infant. Recommendations, based on our 17-year experience, to improve the current diagnostic strategies and to reduce unnecessary amniocentesis, are given.

Preterm neonates display altered plasmacytoid dendritic cell function and morphology.

Bacterial and viral infections cause high rates of morbidity and mortality in premature newborns. In the setting of viral infection, pDCs play a key role as strong producers of IFN-α upon TLR9 activation. We analyzed pDC frequency, phenotype, morphology, and function in CB of preterm and term newborns in comparison with adults. Whereas all age groups show similar pDC numbers, BDCA-2, CD123, and TLR9 levels, the expression of BDCA-4 and capacity to produce IFN-α upon TLR9 challenge were decreased significantly in preterm neonates. Furthermore, we show by means of electron microscopy that pDCs from preterm newborns exhibit a distinct, "immature" morphology. Taken together, these findings suggest decreased functionality of pDCs in the premature newborn. The reduced capacity to produce IFN-α is likely to render such infants more susceptible to viral infections.

Prenatal diagnosis of a de novo inversion of chromosome (2)(p21q11).

Prenatal diagnosis of "apparently balanced" chromosomal rearrangements, if not inherited from a parent, are problematic for genetic counsellors and families. Although the parents need to be informed about the increased risk of multiple congenital anomalies, the anomalies that the fetus is at risk can not be discussed unless a similar breakpoint and accompanying phenotype have been reported in the literature. In the reported case prenatal ultrasound examination revealed a massive hydrocephalus internus and IUGR. The karyotype of the fetus was inv(2)(p21q11) de novo. Postmortem examination revealed short palpebral fissures, hypertelorism, atypical nasiolabial configuration, microgenia, extended position of the fingers, atypical proximal inserted first toe, hydrocephalus internus, hypoplasia of the cerebellum and bulbi olfactorii, bilateral hypoplastic lungs, atrial septal defect II, small right ventricle, dysplasia of the pulmonary valve, hypoplastic pulmonary artery, right proximal ureterostenosis, hypoplastic gall bladder. This is the first description of a de novo inversion (2)(p21q11) in a fetus with multiple malformations.

Prenatal diagnosis of a supernumerary aberrant chromosome 9.

For counselling of parents, as well as to basically understand how chromosome aneuploidies affect embryonic or fetal development, it is of great importance to analyse and collect genotypes of fetuses with clinical anomalies. This report describes the first prenatal diagnosis of a supernumerary chromosome 9 with deletion of the chromosome region 9q34. Ultrasound examination in the 13th week of gestation detected increased nuchal translucency of 6.9 mm, fetal ascites and a pronounced facial anomaly. Hysteroscopic examination before curettage made it possible to describe this facial anomaly as a double-sided, median defect of the superior lip with protrusion of parts of intersegments. This report provides evidence that the absence of trisomy 9 in 9q34 does not prevent abnormal facial development.

Evaluation of a netilmicin-loading dose in very low birthweight infants.

BACKGROUND: The bactericidal efficacy of aminoglycosides is directly related to maximum serum concentrations, particularly the initial one. Therefore, several groups have recommended an aminoglycoside loading dose. Our goal was to develop a simplified dosage regimen for preterm infants which would result in therapeutic maximum serum concentrations early in the course of therapy. METHODS: Open, noncomparative study during November 2000 to April 2001. The modified netilmicin-dosing protocol included a loading dose of 5 mg/kg in the first week of life, followed by a maintenance regimen of 3.5 mg/kg every 24 h. After the first week of life the corresponding doses were 6 (loading) and 5 mg/kg (maintenance). A peak level was measured 30 min after the second dose, and a trough level immediately before the third dose. RESULTS: Thirty-five very low birthweight infants (mean birthweight 876 +/- 170, range 536-1,385 g; mean gestational age 26 +/- 1.8, range 23-30 weeks) who had 46 episodes of netilmicin treatment were included in the analysis. Mean netilmicin peak and trough values were 15.9 +/- 3.7 (range 8.9-28.9) and 3.4 +/- 1.3 (range 1.0-7.8) micromol/l, respectively. Ninety-one percent of all peak levels were within the targeted range of > or =10 micromol/l. Eleven trough values (24%) were > or =4 micromol/l: in 7 instances netilmicin was administered within the first week of life, 5 of these patients had concomitant indomethacin treatment. Only 1 of the 35 neonates had a rise in serum creatinine of > or =0.5 mg/dl during netilmicin therapy. Hearing evaluations were performed in 25 of the 29 surviving infants at discharge home, all of which gave normal results. CONCLUSIONS: The new netilmicin-dosing protocol yielded therapeutic maximum serum concentrations in 91% of cases after the second dose. However, a significant number of very low birthweight infants had elevated trough levels, particularly when netilmicin was administered in the first week of life with concomitant indomethacin treatment. We speculate that a longer interval between the loading dose and the first maintenance dose would result in fewer elevated trough levels with a similarly high number of therapeutic peak levels.

Cell cycle and cell size regulation in Down syndrome cells.

Although the neuropathological features typical for Down Syndrome obviously result from deregulation of both, cell cycle control and differentiation processes, so far research focused on the latter. Considering the known similarities between the neuropathology of Down Syndrome and Alzheimer's disease and the knowledge, that in Alzheimer's disease neuronal degeneration is associated with the activation of mitogenic signals and cell cycle activation, it is tempting to investigate the consequences of an additional chromosome 21 on mammalian cell cycle regulation. We analysed the distribution of cells in different cell cycle phases on the flowcytometer and the cell size of human amniotic fluid cells with normal karyotypes and with trisomy 21. We could not detect any significant differences suggesting that the presence of an additional copy of the about 225 genes on human chromosome 21 does not trigger cell cycle effects in amniotic fluid cells. These data provide new insights into the cell biology of trisomy 21 cells.

Stem cell marker expression in human trisomy 21 amniotic fluid cells and trophoblasts.

Down Syndrome is the most frequent genetic cause of mental retardation. Deregulation of specific differentiation processes is a major cause for the neuropathological cell features typical for this syndrome. The molecular mechanisms leading to Down Syndrome are likely to be operative from the very earliest time of embryonic/fetal development. We therefore analysed human amniotic fluid cell samples and cytotrophoblastic cells from placental biopsies, both with normal karyotypes and with trisomy 21, for the mRNA expression of stem cell marker genes. Here we describe for the first time that these human primary cell sources contain cells that express telomerase reverse transcriptase, leukemia inhibitory factor receptor, and bone morphogenetic protein receptor II. A specific difference between aneuploid and normal cells could not be detected. These data provide evidence that human amniotic fluid and cytotrophoblastic cell cultures might provide a new source for research on primary cell systems expressing these stem cell markers. In addition, it is suggested that early deregulation of the expression of these genes in the here analysed cell sources does not contribute to the molecular development of Down Syndrome.

Knowledge-based interpretation of toxoplasmosis serology test results including fuzzy temporal concepts--the ToxoNet system.

Transplacental transmission of Toxoplasma gondii from an infected, pregnant woman to the unborn that occurs with a probability of about 60 percent [1] results in fetal damage to a degree depending on the gestational age. The computer system ToxoNet processes the results of serological antibody tests having been performed during pregnancy by means of a knowledge base containing medical knowledge on the interpretation of Toxoplasmosis serology tests. By applying this knowledge ToxoNet generates interpretive reports consisting of a diagnostic interpretation and recommendations for therapy and further testing. For that purpose it matches the results of all serological investigations of maternal blood with the content of the knowledge base returning complete textual interpretations for all given findings. The interpretation algorithm derives the stage of maternal infection from these that is used to infer the degree of fetal threat. To consider varying immune responses of particular patients, certain time intervals have to be kept between two subsequent tests in order to guarantee a correct interpretation of the test results. These time intervals are modelled as fuzzy sets, since they allow the formal description of the temporal uncertainties. ToxoNet comprises the knowledge base, an interpretation system, and a program for the creation and modification of the knowledge base. It is available from the World Wide Web by starting a standard browser like the Internet Explorer or the Netscape Navigator. Thus ToxoNet supports the physician in Toxoplasmosis diagnostics and in addition allows to adopt the way of making decisions to the characteristics of the particular laboratory by modifying the underlying knowledge base.

Sleep-wake cycles in preterm infants below 30 weeks of gestational age. Preliminary results of a prospective amplitude-integrated EEG study.

In the newborn, presence of sleep-wake cycles indicates integrity and maturity of the central nervous system. By spectral EEG analysis and polygraphic recordings subtle variations of EEG background activity and behavioural patterns corresponding to early sleep-wake cycles have been found in preterm infants as young as 27 weeks of gestation. The emergence of sleep-wake cycles at early gestational ages may have a positive predictive value for long-term neurological outcome. Sleep-wake cycles and their significance for later outcome have not been studied in very preterm infants so far. Accordingly, we prospectively investigated maturational changes of EEG activity and sleep-wake cycles in preterm infants below 30 weeks of gestational age using the Cerebral Function Monitor, an amplitude-integrated EEG. We present preliminary data on the emergence of sleep-wake cycles in preterm infants from this ongoing study. Of 100 infants enrolled during a 1-year period, 38 infants without neurological complications were included in the reference group. In this group (mean gestational age 27 weeks), we observed cyclical variations of EEG background activity resembling early sleep-wake cycles at a mean gestational age of 28 weeks and a median postnatal age of 6 days. It is hypothesised that these cyclical variations of EEG background activity may represent switches between thalamo-cortical and neo-cortical pattern generators and indicate integrity of central nervous system function. Amplitude-integrated EEG may thus serve as a useful noninvasive test for brain function in preterm infants.