PubMed Health⌕ Search

Biomedical subjects

L Wolter

Publications and source records attributed to L Wolter.

6 recordsLinked to original sources
PubMed2001

Prenatal RHD gene determination and dosage analysis by PCR: clinical evaluation.

BACKGROUND: Use of the polymerase chain reaction (PCR) for detection of the RHD gene can measure the RHD gene status for unborn babies at risk for hemolytic disease of the newborn (HDN). The occurrence of D gene variants has led to errors in prenatal typing. Previous reports have highlighted the danger of assigning a positive fetus as negative, resulting in intrauterine fetal deaths. OBJECTIVE: To evaluate the effectiveness of a testing strategy whereby PCR was not only performed to determine the presence/absence of the RHD gene, but also used to assess the D gene copy number (zero, one or two RHD genes) in family studies for at risk pregnancies. METHODS: Samples comprising maternal (57) and paternal (42) peripheral blood samples, amniotic fluid (64), and matching cord blood (64) were collected. Rhesus (Rh) serotyping was performed on all blood samples. For RHD genotyping, DNA was extracted from all samples except for 28 cord samples, where only serotyping was performed (total 199 DNA genotyping). RHD gene PCR amplified exon 4 and exon 7 regions of the RHD gene. The dosage of RHD gene was determined by comparing the intensity of the RHD gene to that of the RHCE gene. RESULTS: A total of 197/199 samples showed concordance between exon 4 and exon 7 PCR results. Two discrepant results occurred in one family: the father carried one normal D gene and one D gene variant where PCR was tested to be positive using exon 4 but negative using exon 7. One of a pair of dizygotic twins inherited this abnormal D gene and was mildly affected by HDN. This was correctly identified antenatally and the pregnancy successfully managed. The concordance rate between serotypes and genotypes for 135 blood samples was 100%. Amongst the family groups, 8/14 heterozygous fathers transmitted the D gene and 26/26 homozygous fathers transmitted the D gene to the babies. The concordance rate between RHD genotypes from amniotic fluid and Rh D serotypes from cord blood was also 100%. CONCLUSION: The present study demonstrates the effectiveness of using PCR in a clinical setting. It verifies the importance of testing more than one region of the gene, and also the need for a testing strategy where both maternal and paternal testing for RHD gene dosages are performed.

Amniotic Fluid↗
PubMed2001

Development of ligase-assisted spacer addition for the measurement of microsatellites.

Conventional methods for detecting differences in microsatellite repeat lengths rely on electrophoretic fractionation on long denaturing polyacrylamide gels, a time-consuming and labor-intensive method. Therefore, there is a need for the development of new and rapid approaches to routinely detect such length polymorphisms. The advent of techniques allowing the coupling of DNA molecules to solid surfaces has provided new prospects in the area of mutation detection. We describe here the development and optimization of the ligase-assisted spacer addition (LASA) method, a novel and rapid procedure based on an ELISA format to measure microsatellite repeat lengths. The LASA assay was successfully applied to a set of 11 bird samples to assess its capabilities as a genotyping method.

Animals↗
PubMedDate not supplied

[Antacids for postoperative prevention of stress ulcer in infants: a dose finding study].

UNLABELLED: In the prophylaxis of stress ulcers with antacids in young infants there are no recommendations of dosages that consider the physiologic maturation of gastric acid secretion. During the first six month of life the amount of gastric acid secretion in relation to body weight and body surface area increases exponentially. Therefore adult dosages of antacids cannot be transferred to infants. METHODS: In a cross over study 12 infants aged between 4 and 174 days, who had been undergoing a cardiosurgical intervention with the heart lung machine, were treated during 48 hours with 2 different antacid regimens over a period of 24 hours each, monitoring the gastric pH continuously. The used antacid consisted of an aluminium-magnesium complex (Al(OH)3, 90 mg/ml and Mg(OH)2, 60 mg/ml): Regimen A: 6 x 0.5 ml per kg body weight. Regimen B: 0.25 ml per kg body weight at a gastric pH less than 3, with the pH read every 30 minutes. RESULTS: Compared to 28 applications under regimen B, 72 single doses were given under regimen A, 58 of them at a gastric pH of higher than 3. Thus, the mean administered dose was significant lower under regimen B (2.2 ml) than under regimen A (12.0 ml). Consequently, the mean level of gastric pH was higher under regimen A (median: 5.96 +/- 1.31 versus 4.94 +/- 1.16). pH-values lower than 3 were more often measured under regimen B, whereas the phases at this pH-level were longer under regimen A. CONCLUSION: The usual body weight related dosage of antacids seems to be to high for early infancy. In the face of the discrepancy of the administered antacid quantity comparing regimen A with regimen B, it seems to be reasonable for the studied age group to reduce the single antacid dose to 0.25 ml/kg body weight while adhering to a high application frequency of 6 times a day.

Antacids↗