Biomedical subjects

M B Petersen

Publications and source records attributed to M B Petersen.

At least 91 records · Page 5Linked to original sources

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↗

PubMed1994

A review of neuromotor tests and the construction of a scored neuromotor examination for four-year-olds.

We have reviewed the methodologies in construction of some widely used tests and constructed a computer-compatible scored method for the neuromotor evaluation of four year olds. Using the data from 333 neurological assessments, factor analysis indicated five subscales. Alpha coefficients show high reliability for both subscales and total scores. Using data from a second sample, we describe predictive validity for the five subscales and total score.

Child Development↗

PubMed1994

Pseudodicentric chromosome 18 diagnosed by chromosome painting and primed in situ labelling (PRINS).

We report on a newborn white male infant with marked dysmorphic features and various congenital malformations. The initial clinical evaluation showed Crouzon-like features as well as some features of trisomy 18 syndrome and trisomy 13 syndrome. The results from conventional cytogenetic analysis showed a structurally abnormal chromosome replacing one normal chromosome 18, but only by applying molecular cytogenetic methods could the architecture of this abnormal chromosome be characterised clearly. The primed in situ labelling (PRINS) technique, using a newly synthesised alpha 18 oligonucleotide, showed the dicentric pattern and direct chromosome painting established the origin to be from chromosome 18. The combination of conventional cytogenetics and molecular cytogenetics showed the karyotype in the proband to be 45,XY,-14,-18,-21,+t(14;21),+psu dic(18) (qter-->cen-->p11.3: :p11.3-->psu cen-->qter). This was supported by molecular analysis using chromosome 18 specific DNA markers, which showed the paternal origin of the abnormal chromosome.

Abnormalities, Multiple↗

PubMed1994

"Compensatory" uniparental disomy of chromosome 21 in two cases.

Two cases of growth failure, microcephaly, facial dysmorphism, muscular hypertonia, and severe psychomotor retardation are described. At birth, both cases had cytogenetic mosaicism in lymphocytes and skin fibroblasts, in case 1 ring chromosome 21 and monosomy 21 and in case 2, deletion of chromosome 21 and monosomy 21. At a later age the lymphocyte karyotype changed almost completely to 46,XX, but the fibroblast karyotype remained as before. DNA polymorphism analysis described elsewhere indicated that the 46,XX lymphocytes contained two identical chromosomes 21 (isodisomy), in case 1 inherited from the father and in case 2 from the mother. The isodisomy was the result of duplication of a chromosome in mitosis after the loss of the homologous abnormal chromosome ("compensatory isodisomy"). We report here that this cytogenetic mechanism can result in false normal cytogenetic findings. The phenotypes were attributed to the cells with monosomy 21 in case 1 and to the deletion and monosomy of chromosome 21 in case 2.

Adolescent↗

PubMed1993

Unbalanced translocation, t(18;21), detected by fluorescence in situ hybridization (FISH) in a child with 18q- syndrome and a ring chromosome 21.

We report on an 8-year-old girl with minor anomalies consistent with 18q- syndrome and mild developmental delay. Initially cytogenetics showed a terminal deletion of chromosome 21 with mosaicism for a small ring chromosome 21 as the only apparent karyotypic abnormality: mos 45,XX,-21/46,XX,+r(21) (48%/52%). Further studies including FISH and DNA analysis demonstrated a de novo unbalanced translocation of chromosomes 18 and 21 with the likely breakpoints in 18q23 and 21q21.1. Most of 21q was translocated to the distal long arm of one chromosome 18, and this derivative 18 appeared to lack 18q23-qter. The small ring chromosome 21 [r(21)], present in only 52% of the patient's blood lymphocytes, did not appear to be associated with the abnormal phenotype since all 13 chromosome 21 markers that were examined in genomic DNA were present in 2 copies, and the phenotype of the patient was consistent with the 18q- syndrome. The karyotype was reinterpreted as mos 45,XX,-18,-21,+der(18) t(18;21) (q23;q21.1)/46,XX,-18,-21,+der(18) t(18;21) (q23;q21.1), +r(21) (p13q21.1) (48%/52%). These results demonstrate the power of FISH in conjunction with DNA analysis for examination of chromosome rearrangements that may be misclassified by traditional cytogenetic studies alone.

Cell Line↗

PubMed1993

A linkage map of human chromosome 21:43 PCR markers at average intervals of 2.5 cM.

A genetic linkage map of human chromosome 21q (HC21q) containing 43 markers genotyped by the polymerase chain reaction in the CEPH pedigrees is presented. The markers placed on this map are highly polymorphic with an average heterozygosity of 61%. The average interval size of the markers localized at 1000:1 odds is 2.5 cM. The map has a total length of 65.5 cM, with male and female lengths of 47.7 and 83.3 cM, respectively. The genotypes used in the construction of this map were subjected to rigorous error checking, which is reflected in the shorter map length compared to previous maps; the estimated error rate in genotyping is less than 0.04%. As noted in previous linkage maps there is increased recombination in females on proximal HC 21q and in the male in a region near the telomere. This map of HC 21 represents a highly informative and dense meiotic linkage map and will be useful in linking disease phenotypes to loci on this chromosome.

Chromosome Mapping↗

PubMed1993

Cytogenetic, FISH and DNA studies in 11 individuals from a family with two siblings with dup(21q) Down syndrome.

A Spanish family has previously been described with two siblings with dup(21q) Down syndrome. The father has a normal karyotype. The mother has a microchromosome. Cytogenetic, fluorescence in situ hybridization and DNA studies have now been carried out on the family. Findings include that the mother has three different chromosome anomalies, viz. (1) a chromosome 22 with an unusual pericentromeric region that contains alphoid DNA from chromosomes 21/13 and chromosome 22, (2) an isochromosome 21p in the frequent cell line and (3) an isochromosome 21q in a rare second cell line. A possible explanation is that the mother developed from a zygote with trisomy 21 and that mitotic error in early development resulted in the formation of two cell lines with karyotypes of 47,XX,+i(21p) and 47,XX,+i(21q), respectively. The unusual chromosome 22 represents a hitherto undescribed chromosome anomaly and one possible explanation is a translocation of the short arms between chromosomes 21/13 and 22 in the ancestry of the family. The relationship between the unusual chromosome 22 and the isochromosome formation in the mother is not known. However, all three chromosome anomalies involve the alphoid DNA of chromosome 21/13, indicating that this is not a chance finding.

Centromere↗

PubMed1993

Early manifestations of the carbohydrate-deficient glycoprotein syndrome.

We diagnosed the carbohydrate-deficient glycoprotein syndrome in five children who were seen during their first year of life with failure to thrive, feeding difficulties, psychomotor retardation, hypotonia, esotropia, inverted nipples, lipodystrophy, pericardial effusion, and hepatic dysfunction. Steatosis was observed in liver biopsy specimens, and cerebellar hypoplasia was present on computed tomography. The disorder is characterized by a complex carbohydrate deficiency in certain glycoproteins, notably transferrin, which can be used as a marker of the disease. The carbohydrate-deficient glycoprotein syndrome may be an important and easily identifiable cause of failure to thrive and neurologic dysfunction in infancy. The presence of the disorder in siblings of different gender and the finding of biochemical abnormalities in some unaffected parents suggest an autosomal recessive inheritance.

Biomarkers↗

PubMed1993

Paternal nondisjunction in trisomy 21: excess of male patients.

Paternal nondisjunction accounts for approximately 5% of cases of trisomy 21. We have studied 36 cases of free trisomy 21, in which the supernumerary chromosome was of paternal origin, with DNA markers in the pericentromeric region and along the long arm of chromosome 21. Fifteen of the paternal cases were consistent with meiosis II errors, 8 with mitotic errors and only 7 with meiosis I nondisjunction. This contrasts markedly with maternally derived trisomy 21, in which meiosis I errors predominate. An excess of males was observed in the meiotic cases (21 males:6 females), highly significantly different from a 1.06 ratio. A significant difference in mean maternal age was found between cases of paternal origin (28.1 years) and those of maternal origin (31.8 years, n = 429). This indicates that the maternal age effect is confined to maternal nondisjunction.

Adolescent↗

PubMed1993

Application of molecular and cytogenetic techniques to the detection of a de novo unbalanced t(11q;21q) in a patient previously diagnosed as having monosomy 21.

The occurrence of complete autosomal monosomy in man is extremely rare and generally considered to be incompatible with life. Since the introduction of banding techniques in human cytogenetics, several cases of presumptive monosomy for chromosome 21 have nevertheless been reported. However, it has been suggested that most, if not all, of these cases may represent unbalanced translocations or other structural aberrations resulting in only partial monosomy 21. Here we described a patient in whom full monosomy 21 was initially diagnosed by routine karyotyping. Re-examination with a combination of high resolution banding technique, chromosome painting and DNA polymorphism analysis demonstrated the presence of an unbalanced translocation between the long arms of chromosome 11 and 21, respectively. Consequently, the case was re-classified as a partial monosomy for the proximal long arm of chromosome 21.

Chromosome Banding↗

PubMed1993

Determination of the fructosamine concentration in bovine serum samples.

The study reports on a spectrophotometric assay for the determination of serum fructosamine concentration. The assay was evaluated for use in bovine serum samples by assessment of the precision, accuracy and detectability. A reference interval for the bovine serum fructosamine concentration was also established. Further, the effect of acute changes in blood glucose on serum fructosamine concentration as well as the diurnal variations of the serum fructosamine concentration were investigated. The main conclusions can be summarized as follows: Determination of bovine serum fructosamines may be achieved by a precise and accurate assay with a detection limit well below the serum fructosamine concentration normally found in bovine sera. As a reference interval for the bovine serum fructosamine concentration 213.4 mumol/l to 265.0 mumol/l may be used. Serum fructosamine concentration is not affected by acute changes in blood glucose, and it displays no significant diurnal variation in cows.

Animals↗

PubMed1992

D21S215 is a (GT)n polymorphic marker close to centromeric alphoid sequences on chromosome 21.

A plasmid, AWZ1, that contained a dinucleotide (GT)n repeat was identified from a chromosome 21-specific genomic library. When amplified by PCR from human genomic DNA, the repeat length was highly polymorphic between individuals; its location, D21S215, was mapped in the CEPH pedigrees by linkage analysis to the pericentromeric region of chromosome 21. It is the closest polymorphic marker to alphoid sequences on this chromosome.

Animals↗

PubMed1992

Uniparental isodisomy due to duplication of chromosome 21 occurring in somatic cells monosomic for chromosome 21.

Uniparental disomy has been recently recognized as an important phenomenon in non-Mendelian inheritance of human genetic disorders. Several mechanisms for uniparental disomy, i.e., the presence of two homologous chromosomes derived from one parent, have been proposed. We studied two independent cases of abnormalities of chromosome 21 in which there were abnormal karyotypes at birth but blood cells with normal karyotype predominated later in life, and the cells with abnormalities disappeared. Uniparental isodisomy was observed in the normal cells in these individuals. The uniparental disomy in these families was the result of duplication of a chromosome in mitosis after the loss of the homologous abnormal chromosome. The duplication can be seen as mechanism for cell survival and is called here "compensatory" isodisomy, which provided a selective advantage for the cell population with the normal number of chromosomes 21.

Abnormalities, Multiple↗