PubMed Health⌕ Search

Biomedical subjects

L Hasholt

Publications and source records attributed to L Hasholt.

At least 37 records · Page 2Linked to original sources
PubMed1996

The utility of single-strand conformation polymorphism (SSCP) analysis: results obtained in families with Fabry's disease.

Single-strand conformation polymorphism (SSCP) analysis is a widely used and relatively simple method for detection of sequence polymorphisms in DNA fragments. We have used this technique to screen the alpha-galactosidase gene, with the aim of identifying the disease causing mutations in families with Fabry's disease. Five single-base shift mutations were found, but a single base-pair deletion could not be recognized by SSCP. The risk of mistaking a neutral polymorphism for a mutation is illustrated, and the utility as well as the limitations of SSCP in screening and diagnostic use are discussed.

Fabry Disease↗
PubMed1995

Elongated CAG repeats of the B37 gene in a Danish family with dentato-rubro-pallido-luysian atrophy.

Dentato-rubro-pallido-luysian atrophy (DR-PLA) is considered to be rare in Europe. We describe a Danish family in which affected individuals in at least three generations have been diagnosed as suffering from Huntington's disease. Because analysis of the Huntingtin gene revealed normal alleles and various of the patients had seizures, we analysed the B37 gene and found significantly elongated CAG repeats as have been reported in DRPLA. Affected individuals with almost identical repeat lengths presented very different symptoms. Both expansion and contraction in paternal transmission was encountered.

Adult↗
PubMed1995

Correlation between magnitude of CAG repeat length alterations and length of the paternal repeat in paternally inherited Huntington's disease.

An increasing number of diseases are being found to be due to elongation of specific trinucleotide repeat sequences. Inverse correlation between the age at onset and the length of the repeat has been found in most of these. The elongated CAG repeat causing Huntington's disease is highly unstable when inherited from an affected father. In this study we found an average parent-to-offspring difference of +0.08 repeat units in maternally inherited repeats, significantly less than the average difference of +2.92 repeat units with paternal transmission. Large repeat expansions, of more than 5 repeat units, were seen only in paternally inherited cases. With paternal transmission the magnitude of repeat length alterations was directly correlated to increasing paternal repeat length. Increasing variation in repeat length among siblings was correlated to increasing average repeat length in the sibship in both maternally and paternally inherited HD. Comparison of the magnitude of repeat length alterations to parental age at the time of birth of the offspring showed no correlation.

Fathers↗
PubMed1993

Trinucleotide repeat elongation in the Huntingtin gene in Huntington disease patients from 71 Danish families.

IT15 is a novel gene, localized to chromosome 4, and encoding a protein named Huntingtin. A polymorphic CAG repeat in the proposed open reading frame of IT15 has been characterized, and an elongation of this repeat has been correlated to Huntington's Disease. We have investigated the CAG repeat in the Huntingtin gene in 71 unrelated Danish patients with Huntington's Disease, and found repeat lengths of 39 to 70 repeat units in contrast to 9 to 30 CAG's on normal chromosomes. Comparison of repeat length and age at onset of disease symptoms in 52 individuals indicates an inverse correlation between the age at onset and the number of CAG repeat units.

Adolescent↗
PubMed1990

A Fabry's disease heterozygote with a new mutation: biochemical, ultrastructural, and clinical investigations.

A Fabry heterozygote with early clinical manifestations of this X linked disorder is described. Her symptoms, including febrile attacks, arthralgia, abdominal pain, and neurological signs, were characteristic of Fabry's disease hemizygotes. The neurological findings were compatible with a brain stem infarction. The diagnosis was confirmed by the finding of low activities of alpha-galactosidase A (alpha-galA) in plasma, lymphocytes, and cultured fibroblasts, and by the observation of typical lamellar inclusions in the lysosomes of cultured fibroblasts. Increased levels of ceramide trihexoside were also found by TLC of urine sediment. The family history gave no indication of Fabry's disease in the patient's relatives, and biochemical and ultrastructural investigations of their cells were also normal. Our findings therefore suggest that the defective gene in the heterozygote has resulted from a new mutation.

Adolescent↗
PubMed1989

Fabry's disease.

Fifteen hemizygotes and 30 heterozygotes have been diagnosed since our investigations of Fabry's disease were started 10 years ago. They belong mainly to three Danish families. Genetic counseling and prenatal diagnoses have been performed, and in vitro studies of cultured fibroblasts and endothelial cells have been made with special reference to enzyme therapy.

Fabry Disease↗
PubMed1988

Enzyme replacement in Fabry endothelial cells and fibroblasts: uptake experiments and electron microscopical studies.

Endothelial cells are of particular interest for therapeutic strategies in Fabry's disease, because the accumulation of glycosphingolipids in the vascular endothelium as a result of alpha-galactosidase A (alpha-galA) deficiency is responsible for the major clinical manifestations of the disease. Electron microscopical observations of cultured endothelial cells obtained from the umbilical vein of a hemizygous Fabry fetus showed that the glycosphingolipids are deposited as lamellar material in the lysosomes, as has been found previously for cultured fibroblasts and many different tissues. Mannose 6-phosphate (man 6-P)-receptor mediated and Concanavalin A (ConA)-mediated uptake of purified alpha-galA was attempted in the endothelial cells as well as in cultured fibroblasts from the same fetus. Our results on high-uptake alpha-galA indicate that the endothelial cells do not internalize alpha-galA via the man 6-P receptor. Immunofluorescence studies after addition of the receptor antibody to the cells support the theory that they have no or very few man 6-P receptors on the surface. Morphological studies did not show lysosomal changes which could suggest that the enzyme is taken up into the endothelial cells; however, we found reproducible modifications of the lysosomes in Fabry fibroblasts after incubation with high-uptake alpha-galA. Cell-associated alpha-galA activity was found in both cell types, when the enzyme was added to cells preincubated with ConA; but the lectin treatment by itself induced considerable ultrastructural changes in the cytoplasm, which obscured a possible effect by the enzyme.

Biological Transport↗
PubMed1986

Lysosomal alpha-galactosidase in endothelial cell cultures established from a Fabry hemizygous and normal umbilical veins.

An endothelial cell line has been established from the umbilical vein obtained after abortion of a male fetus suffering from Fabry disease. This X-linked inborn error of glycosphingolipid catabolism results from deficiency of the lysosomal hydrolase alpha-galactosidase A. The clinical manifestations of the disease are mainly caused by glycosphingolipid depositions in the endothelium of all vessels. The hemizygous cell line and eight endothelial cell lines originating from the umbilical cords of normal newborns were grown for more than 10 passages. They had a short generation time that allowed us to get sufficient cells for qualitative and quantitative investigations of alpha-galactosidase. The enzyme in normal endothelial cells had a similar thermostability and isoelectric focusing pattern as that in fibroblasts, but the activity was essentially higher in endothelial cells. The hemizygous endothelial cells were deficient in alpha-galactosidase A. It is concluded that endothelial cell lines are an important alternative to fibroblasts for in vitro studies of the lysosomal storage diseases.

Cell Line↗
PubMed1983

ConA-mediated binding and uptake of purified alpha-galactosidase A in Fabry fibroblasts.

In most human tissues there are at least two different alpha-galactosidases, A and B. The former is deficient in patients hemizygous for Fabry disease. We have isolated it from human placenta and found that it was labile even at culture conditions, but was stabilized after binding to concanavalin A (conA). The alpha-galactosidase activity was markedly increased in Fabry fibroblasts when these were treated with conA and exposed to alpha-galA at 37 degrees C. The maximum activity was obtained after 1/2-2 h of incubation and was maintained for at least 4 h. The binding and uptake of conA into Fabry cells was followed by microscopical studies of fluorescein-labelled conA. We assume that alpha-galA is taken up by endocytosis of the enzyme-conA complex.

Biological Transport↗
PubMed1980

alpha-Galactosidase isozymes in normal individuals, and in Fabry hemizygotes and heterozygotes.

A method for staining of alpha-galactosidase with the synthetic substrate alpha-naphthyl-alpha-galactopyranoside after isoelectric focusing on gel slabs has been devised. Depending on the method used for cell extraction, at least seven isozymes could be detected in cell extracts of cultured fibroblasts from normal individuals. Thermal treatment revealed that both heat-stable and heat-labile isozymes occur in normal fibroblasts. The heat-labile isozymes were not detected in cells from Fabry hemizygotes and thus truly reflect products of the alpha-gal A locus. Three heat-stable isozymes observed in normal individuals were also found in Fabry heterozygotes and hemizygotes and are presumably determined by the alpha-gal B locus. The remaining isozymes were stained very weakly in the hemizygotes and were heat-stable. The relation of these isozymes to the A or B locus is uncertain. After treatment with neuraminidase the alpha-gal A isozymes could not be detected and one of the alpha-gal B isozymes appeared broader. The isozyme pattern observed in heterozygotes was almost identical to the normal one.

Child↗
PubMed1979

46,XY/45,X mosaicism in an amniotic fluid cell culture: suppression of abnormal cell line after subcultivation.

An abnormal cell population, 45,X, appeared in 3 of 4 cell lines established from an amniotic fluid specimen obtained from a normal mid-trimester pregnancy. Two of the cell lines were subjected to repeated chromosome analyses until VII passage. The abnormal cells were suppressed after repeated trypsinisations; simultaneously, fibroblast-like cells outgrew the cultures, which were previously predominated by epithelial-like cells. Polyploidy was found in 0 to 12% of the cells, the highest level existing in the early passages. The question of whether chromosomally abnormal cells present in primary cultures and the early subcultures reflect the karyotype of the fetus is discussed.

Amniotic Fluid↗
PubMed1976

Behaviour of cell cultures from human amniotic fluid.

The growth pattern of cell cultures originating from 11 amniotic fluid specimens have been observed. From each specimen 2 to 12 primary cultures were set up. In most cases growth started simultaneously in the primary cultures originating from one sample. The primary cultures lasted from 7 to 30 days. A variation was found both between cultures from different pregnancies as well as among cultures obtained from single amniotic fluids. The growth period from setting up the cultures until harvest of the cell lines for biochemical analysis ranged from 20 to 54 days. No connexion was noticed between the time spent in primary culture and the behaviour of the cell line before harvest. The effects of two types of serum (fetal calf serum and pooled human serum) on the behaviour of the cultures were compared. The cells grown in human serum were harvested a few days before those grown in fetal calf serum. The influence of different batches of medium was also examined; no significant effect of the growth pattern was found. The appearance of epithelial-like and fibroblast-like cells in cultures from 6 specimens was observed concurrently. At the time of harvest the cell lines originating from the same amniotic specimen contained the cell types in different proportions.

Amniocentesis↗
PubMedDate not supplied

Analysis of FMR1 (CGG)n alleles and FRAXA microsatellite haplotypes in the population of Greenland: implications for the population of the New World from Asia.

The fragile X syndrome is caused by the expansion of a polymorphic (CGG)n tract in the promoter region of the FMR1 gene. Apparently the incidence of fragile X syndrome is rare in the population of Greenland. In order to examine population-related factors involved in stability of the (CGG)n sequence, DNA samples obtained randomly from the Greenlandic population were analysed for size and AGG interspersion pattern of the FMR1 (CGG)n region and associated DXS548-FRAXAC1 haplotypes. In addition a large Greenland family with unstable transmission in the premutation range was analysed. The (CGG)n allele sizes in the Greenland population showed a narrow distribution similar to that reported for Asian populations. DNA sequencing of alleles with 36 CGG repeats revealed an AGG(CGG)6 insertion previously reported exclusively in Asian populations and a high frequency of alleles with a (CGG)10AGG(CGG)9AGG(CGG)9 or (CGG)9AGG(CGG)9AGG(CGG)6AGG(CGG)9 sequence pattern was found. Thus the data confirm the Asian origin of the Greenlandic (Eskimo) population and indicates that some (CGG)n alleles have remained stable for 15-30,000 years, since the population of the New World arrived from Asia via the Bering Strait.

Alleles↗