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Biomedical subjects

M B Petersen

Publications and source records attributed to M B Petersen.

At least 19 recordsLinked to original sources
PubMed1997

Investigation of deletions at 7q11.23 in 44 patients referred for Williams-Beuren syndrome, using FISH and four DNA polymorphisms.

Williams syndrome (WS) is associated with a submicroscopic deletion of the elastin gene (ELN) at 7q11.23. The deletion encompasses closely linked DNA markers. We have investigated 44 patients referred for possible WS using fluorescence in situ hybridization (FISH) analysis with a P1 clone containing an insert from the ELN, as well as performing genotype analysis of patients and parents with four DNA polymorphisms. Twenty-four patients were found to have deletions, 19 of whom were found clinically to have typical WS. The facial features were especially characteristic. None of the patients without detectable deletions was reported to have typical WS features, although one had supravalvular aortic stenosis, hypercalcemia, and mental retardation. No evidence was found in this material for variability of the size of the deletion. Our study supports the usefulness of analysis of ELN deletion in WS patients, both for confirmation of diagnosis and for genetic counselling.

Adolescent↗
PubMed1996

Efficacies of different doses of ivermectin against male, female and L4 Oesophagostomum dentatum in pigs.

Efficacies of ivermectin against larval stages and adult males and females of Oesophagostomum dentatum were investigated in two slaughter assays. In Experiment A, 20 pigs were each infected with 6000 third-stage larvae on Day 0 and Day 24. Pigs were ivermectin treated on Day 28 at dose rates of 0, 75, 150, and 300 micrograms kg-1 bodyweight (bw) and slaughtered 6 days after treatment. In Experiment B, 20 pigs each received 6000 third-stage larvae and were treated 35 days after infection at dose rates of 0, 150, 300 and 600 micrograms kg-1 bw. Pigs were slaughtered 14 days after treatment. In Experiment A, the adult worm burden was reduced by 69.1% at a dose rate of 300 micrograms kg-1 bw and the larval burden was reduced by 68.7 and 90.9% at 150 and 300 micrograms kg-1 bw, respectively. In Experiment B, the adult worm burden was reduced by 88.8, 96.2 and 99.6% at dose rates of 150, 300 and 600 micrograms kg-1 bw, respectively. In the control group of Experiment A, the mean proportion of females among adults worms was 57.6%, but this decreased to 19.7% after ivermectin treatment at 300 micrograms kg-1 bw. In Experiment B, at 300 micrograms kg-1 bw, this proportion was reduced from 46.0% to 0.8%. The fecundity of female worms was reduced at dose rates of 150 and 300 micrograms kg-1 bw in Experiment A, but not in Experiment B. It is concluded that in O. dentatum, ivermectin not only reduces the egg output of female worms, but also is more effective against female than male worms.

Animals↗
PubMed1996

Apolipoprotein E allele distribution in parents of Down's syndrome children.

BACKGROUND: An increased risk of Alzheimer's disease (AD) has been reported in young mothers of Down's syndrome (DS) probands. Allele epsilon4 of the apolipoprotein E (apoE) gene is a genetic susceptibility factor for AD. We examined the distribution of apoE alleles in people with DS and their parents. METHODS: We studied 188 Danish people with non-mosaic free trisomy 21 of known parental origin (determined by DNA polymorphism analysis), and their parents, chosen from a population-based study of DS, and compared the frequency of apoE alleles with a previously published Danish control sample. FINDINGS: In people with DS, there was no significant difference in apoE allele distribution compared with controls. The frequency of allele epsilon4 in the fathers (11.8%) was significantly lower than in controls (17.4%, p=0.02). The frequency of allele epsilon4 in the mothers (19.4%) was not significantly different from that of controls. Nevertheless, in young mothers with a meiosis II error, epsilon4 frequency was 30.0%, significantly higher than in older mothers with a meiosis II error (13.0%, p=0.03). INTERPRETATION: We suggest that apoE allele epsilon4 is a risk factor for meiosis II non-disjunction in young mothers, but the biological role of apoE in oocytes remains to be investigated.

Adult↗
PubMed1996

Fatal congenital myopathy with actin filament deposits.

We present the clinical and morphological findings in a case of progressive congenital myopathy. The symptoms present at birth included severe general muscular hypotonia, diffuse muscular atrophy, arthrogryposis, absence of spontaneous movements, and left ventricular hypertrophy. A biopsy specimen taken from the gastrocnemius muscle when the patient was 2 weeks old revealed deposits which consisted of actin filaments as shown by electron microscopy. The infant was occasionally respirator dependent but was mostly able to breathe unassisted. At the age of 5 months he died of respiratory failure. The actin filament deposits may explain the clinical findings.

Actins↗
PubMed1996

The efficacy of ivermectin against nodular worms of pigs: the response to treatment using three different dose levels against Oesophagostomum dentatum and Oesophagostomum quadrispinulatum.

Anthelmintic efficacies of 3 different doses of ivermectin (IVM) were evaluated in 3 isolates of nodular worms in pigs. An isolate of Oesophagostomum quadrispinulatum (OQ) was recently obtained from a commercial farm where poor efficacy of IVM at the recommended dose (300 micrograms.kg-1 body weight) was detected. On this farm, IVM had been used for treatment of sows twice yearly for 6 years. Two other isolates, an O. dentatum (OD) and a mixed Oesophagostomum dentatum and Oesophagostomum quadrispinulatum isolate (ODQ) were obtained from a farm where anthelmintics had never been used. Efficacies of IVM against adult worms of the OQ-isolate at dose rates of 150, 300 and 600 micrograms.kg-1 body weight ranged from 40.5-78.6%. Efficacies against larval stages (L3 and L4) were superior. Efficacies against the OD-isolate were 88.7, 96.1 and 99.6%, respectively. In the ODQ-isolate the efficacies of IVM against adult stages furnished similar results. In conclusion, the efficacy of IVM against O. dentatum was high but against both isolates of O. quadrispinulatum poorer. This suggests that IVM is intrinsically less effective against O. quadrispinulatum and therefore not indicative of acquisition of anthelmintic resistance in the OQ-isolate.

Animals↗
PubMed1996

Susceptible chiasmate configurations of chromosome 21 predispose to non-disjunction in both maternal meiosis I and meiosis II.

The cause of non-disjunction of chromosome 21 remains largely unknown. Advanced maternal age is associated with both maternal meiosis I (MI) and meiosis II (MII) non-disjunction events. While reduced genetic recombination has been demonstrated in maternal MI errors, the basis for MII errors remains uncertain. We studied 133 trisomy 21 cases with maternal MII errors to test the hypothesis that segregation at MII may also be influenced by genetic recombination. Our data support a highly significant association: MII non-disjunction involves increased recombination that is largely restricted to proximal 21q. Thus, while absence of a proximal recombination appears to predispose to non-disjunction in MI, the presence of a proximal exchange predisposes to non-disjunction in MII. These findings profoundly affect our understanding of trisomy 21 as they suggest that virtually all maternal non-disjunction results from events occurring in meiosis I.

Adult↗
PubMed1996

Exclusion of one pedigree affected by adult onset primary open angle glaucoma from linkage to the juvenile glaucoma locus on chromosome 1q21-q31.

A locus for autosomal dominant juvenile onset primary open angle glaucoma (POAG) was recently assigned to chromosome region 1q21-q31. In the present study, a large Greek family with autosomal dominant adult onset POAG was investigated using microsatellite markers. Exclusion of linkage of the adult onset POAG gene to the region D1S194-D1S191 was obtained in this pedigree. Therefore, the data provide evidence that juvenile and adult onset POAG are genetically distinct disease entities.

Adult↗
PubMed1996

Tetrasomy 18p de novo: parental origin and different mechanisms of formation.

We have used eight PCR-based DNA polymorphisms to determine the parental origin and mechanisms of formation in 9 patients with de novo nonmosaic tetrasomy 18p. The 9 patients, 4 girls and 5 boys, had clinical features characteristic of i(18p) syndrome. The supernumerary marker chromosome was identified by fluorescence in situ hybridization (FISH) analysis using centromeric probes and a flow-sorted 18p-specific library. The isochromosome was of maternal origin in all 9 cases. The formation of tetrasomy 18p cannot be explained by a single model. In 6 cases, meiosis II nondisjunction, followed by subsequent postzygotic misdivsion, and in 1 case postzygotic nondisjunction and postzygotic misdivision were the most likely mechanisms of formation. Alternative mechanisms are suggested in the remaining 2 cases.

Adolescent↗
PubMed1996

In vitro activity of six macrolides, clindamycin and tetracycline on Streptococcus pneumoniae with different penicillin susceptibilities.

A collection of 99 clinical isolates of Streptococcus pneumoniae, chosen due to their different susceptibilities to penicillin, were investigated with respect to their susceptibility to the macrolides azithromycin, clarithromycin, dirithromycin, erythromycin, roxithromycin, spiramycin, and to clindamycin and tetracycline by the agar dilution method. We found complete cross resistance among the macrolides. The pneumococci were either susceptible, MIC < or = 0.5 micrograms/ml, or resistant, MIC > or = 16 micrograms/ml, to the tested macrolides, giving a bimodal distribution. In addition, complete cross resistance was observed between clindamycin and macrolides. Pneumococci resistant to macrolides were also resistant to tetracycline, and 26% of the macrolide-susceptible strains were tetracycline resistant.

Anti-Bacterial Agents↗
PubMed1995

[Prader-Willi syndrome--clinical picture and genetics].

Characteristics are hypotonia, problems with feeding and thriving in the neonate and infant, later hyperphagia and severe obesity. Other findings are dysmorphic traits, hypogonadism, short stature, developmental delay, mental retardation and behavioural problems. Diabetes mellitus (NIDDM) is frequent in adults. Treatment is symptomatic. Prognosis is determined by obesity. PWS occurs almost always sporadically and is found in all ethnic groups and in both sexes. The epidemiology of PWS in Denmark is unknown. In 95% of cases with PWS cytogenetic and molecular genetic investigations show either deletion of the paternal chromosome 15q11q13 or uniparental maternal disomy of chromosome 15. Since 1992 150 bloodsamples of patients suspected for PWS have been investigated by cytogenetic and molecular genetic techniques at the John F. Kennedy Institute, DK-2600 Glostrup; deletion of the paternal chromosome 15 was found in 15 and uniparental maternal disomy of chromosome 15 in eight cases.

Humans↗
PubMed1995

Prospective 5- to 6-year follow-up study of a cementless acetabular cup.

Twenty-seven patients in whom the Ti-Bac acetabular cup (Zimmer, Warsaw, IN) was placed were examined 5 to 6 years after surgery. The cup was inserted line to line, after reaming without further fixation. In all operations, a cemented Müller straight-stem Protazul femur stem (Zimmer) was used. The patients had good pain relief and improved mobility after the operation. Radiographically, only one hip showed radiolucency in the bone-metal interface after 5 to 6 years. One patient was reoperated 3 days after surgery because of dislocation of the acetabular cup. Apart from this, there were no signs of aseptic loosening of any of these uncemented cups.

Acetabulum↗
PubMed1995

Bone mineral density around femoral stems. DXA measurements in 22 porous-coated implants after 5 years.

In this cross-sectional study the bone mineral density (BMD) close to proximal porous-coated femur stems was measured by DXA 4.5-6 years after the stem implantation and compared to the contralateral non-operated femur in 22 cases. Measuring areas were defined by Gruen's method. The average precision error varied according to the zone assessed and ranged from 2.2 to 4.9 percent. The median BMD values of the operated femur were in 5 of 7 areas lower than those of the contralateral side. The largest differences were noted in the calcar region and the greater trochanteric region (21 and 20 percent, respectively). No correlation was found between the femoral BMD differences and the stem diameter.

Absorptiometry, Photon↗
PubMed1994

Monozygotic twins discordant for gastroschisis: case report and review of the literature of twins and familial occurrence of gastroschisis.

We describe a pair of monozygotic (MZ) female twins discordant for gastrochisis. To our knowledge, this is the first such case reported. The zygosity was verified by DNA analysis using highly polymorphic microsatellites. There was no family history of gastroschisis. During pregnancy there was no suspicion of any exposure responsible for the malformation. The number of twin cases described so far does not allow any conclusion as to hereditary factors in the cause of gastroschisis, but the number of families reported with familial gastroschisis suggests that the recurrence risk is higher than previously thought.

Abdominal Muscles↗
PubMed1994

Proximal deletion of chromosome 21 confirmed by in situ hybridization and molecular studies.

Foetal blood sampling was performed at 35 weeks of gestation due to abnormal foetal ultrasound findings. There was apparent monosomy 21 (45,XX,-21) in all mitoses analyzed. The infant died at 37 weeks during delivery. Examination disclosed facial anomalies, clubfeet, hypoplasia of the left urogenital tract, agenesis of corpus callosum, ventricular dilatation, and heterotopias. Reevaluation of the karyotype showed an unbalanced translocation t(1;21) (q44;q22.11) which resulted from a maternal balanced translocation. These findings were confirmed by fluorescence in situ hybridization and molecular studies with chromosome 21 specific markers. The latter showed a proximal deletion of the maternally derived chromosome 21 including all loci from centromere down to the D21S210 locus. This case illustrates the need for complementary cytogenetic and molecular investigations in cases of apparent monosomy 21.

Abnormalities, Multiple↗
PubMed1994

Highly polymorphic repeat marker within the beta-amyloid precursor protein gene.

We have identified a polymorphic compound dinucleotide repeat sequence in intron 1 of the beta-amyloid precursor protein (APP) gene on chromosome 21. Using polymerase chain reaction (PCR) amplification of the locus, designated APPivs1, we detected 13 alleles in the CEPH family members (heterozygosity = 0.69). Lod score analysis showed complete linkage of the marker to the loci D21S210 and D21221.

Alleles↗
PubMed1994

Non-disjunction of chromosome 21 in maternal meiosis I: evidence for a maternal age-dependent mechanism involving reduced recombination.

Over 300 cases of trisomy 21 were analyzed to characterize the causes of maternal non-disjunction and to evaluate the basis for maternal age-dependent trisomy 21. We confirmed the observation that recombination along 21q is reduced among non-disjoined chromosomes 21 and further demonstrated that the alterations in recombination are restricted to meiosis I origin. Analysis of the crossover distribution indicates that reduction in recombination is not due simply to failure of pairing and/or absence of recombination in a proportion of cases. Instead, we observed an increase in both zero- and one-exchange events among trisomy 21-generating meioses suggesting that an overall reduction in recombination may be the underlying cause of non-disjunction. Lastly, we observed an age-related reduction in recombination among the meiosis I cases, with older women having less recombination along 21q than younger women. Thus, reduced genetic recombination may be responsible, at least in part, for the association between advancing maternal age and trisomy 21.

Adult↗
PubMed1994

Congenital myopathy with fiber type disproportion: a family with a chromosomal translocation t(10;17) may indicate candidate gene regions.

A patient with myopathy and congenital fiber type disproportion presented at birth with arthrogryposis multiplex congenita, dislocation of the hips and mild scoliosis. Later in life she developed marked muscle weakness. A balanced chromosomal translocation t(10;17) (p11.2;q25), transmitted by the clinically healthy mother, who nevertheless showed discrete signs of myopathy, was demonstrated. DNA analysis excluded maternal uniparental disomy for loci on both chromosomes 10 and 17. We suggest that the translocation breakpoints are candidate regions for a myopathy gene.

Chromosomes, Human, Pair 10↗