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Biomedical subjects

G Holmlund

Publications and source records attributed to G Holmlund.

14 recordsLinked to original sources
PubMed1995

Flanking region sequences and internal repeat structure of the pYNH24 (D2S44) 2 kbp insert analyzed by polymerase chain reaction and partial digestion with RsaI.

The 2 kbp YNH24 pUC18 insert was partially sequenced, amplified with fluorescence-labeled primers, and characterized by incomplete digestion with the restriction enzyme RsaI. A characteristic RsaI profile with one restriction site in each repeat unit was obtained when the fragments were analyzed on a DNA sequencer. We developed this procedure with the specific aim of analyzing the internal repeat structure in recombinant alleles often observed in the YNH24 variable number of tandem repeat system (D2S44). Nonetheless, it should also be possible to apply the method when analyzing other tandem repeats, even when little information regarding their sequences is available. In addition, when the repeat array is amplified, either a 5' or a 3' fluorescence-labeled primer can be used to enable analysis from both directions of fairly long (> 3.6 kbp) alleles. The RsaI fragments obtained by partial digestion of the amplified pYNH24 insert corresponded well to the RsaI sites found in the sequenced regions. The 5' flanking region contained eight 30-34 bp sequences similar to the repeat unit and also several RsaI sites, whereas only a few RsaI sites and no repeat units were found in the 3' flanking region. Twenty-five consecutive RsaI sites were revealed, in the center of the pYNH24 insert, indicating a region with strictly repeated core sequences; this repetitive block comprised less than half of the total insert. Two approximately 2.24 kbp HinfI alleles from two different heterozygous individuals were found to have identical internal structure, which was very similar to that of the insert although it exhibited only 15 RsaI repeats.

Alleles↗
PubMed1994

A D12S11 (MS43A) allele with an internal HinfI restriction site.

An allele with an internal HinfI restriction site has been found in the D12S11 locus. A three-fragment phenotype was revealed when the HinfI cleaved DNA was hybridised with the probe MS43A. Only two fragments were found when TaqI was used. These results have been confirmed with tests on a new sample drawn on a different occasion. This is the only three-band phenotype found out of 2800 unrelated individuals tested for this variable number of tandem repeats (VNTR) marker.

Adult↗
PubMed1993

Lp(a) lipoprotein and HLA-DR genotype in early coronary artery disease.

The interest in Lp(a) lipoprotein [Lp(a)] has increased dramatically during the last few years due to the documented strong association between high Lp(a) levels and early atherosclerosis and its sequelae and the probable additional thrombogenic effect of inherited high Lp(a) levels. However, some paradoxes still remain to be solved in Lp(a) research. This pilot study was performed to test whether some criteria could be found for an association between Lp(a) levels, HLA genotype, and early coronary heart disease. If so, it could help to explain why some individuals with high Lp(a) levels get atherosclerosis while others with comparable lipid levels do not. It would also indicate that immunological processes could be involved in Lp(a) associated atherosclerosis. In this case-control study the HLA-DR genotypes 13 or 17 were significantly more frequently encountered in 30 male patients with early coronary heart disease than in 30 sex and age matched healthy controls (P = 0.012). These HLA-DR specificities were especially frequent in male patients with high Lp(a) levels. The same HLA-DR genotype pattern was not seen in 30 female patients, although there was a trend towards more frequent 13a genotype.

Adult↗
PubMed1992

Calculation of restriction fragment lengths by image processing.

The image processing system, LabEye Profile, calculates the size of DNA restriction fragments according to the formula MD = f(x); x = 1/log bp. The migration distances (MD) of known fragment sizes are interpolated by the use of cubic splines. Cubic splines are also used to correct for gel distortions. A comparison to the Biotrac system, which uses the reciprocal method, gives almost identical standard deviations for calculated sizes compared to known sizes, 0.88% for LabEye Profile and 0.89% for Biotrac. The measurement error for LabEye Profile is 0.24% of the size of the fragments.

Base Composition↗
PubMed1991

[DNA analyses in forensic investigations].

Variable number of tandem repeat (VNTR) polymorphisms are used as genetic markers in paternity testing and forensic investigation. The blot patterns obtained with single locus probes are easily interpreted, and the fragment sizes can be calculated for further statistical evaluation. Fragments cleaved with Hinf I and analysed with the probe YNH 24 were found to vary in estimated size within +/- 1.5 per cent of the number of base pairs. In paternity testing, a window of +2.5 per cent will yield a risk of false exclusion of less than 1 in 10(6), with an estimated exclusion rate of about 90 per cent. In paternity testing, electrophoresis of mixed DNA samples from the child and the suspected father yields significant information irrespective of exclusion. The mean calculated paternity index for non-excluded men obtained with the YNH 24 probe was 8.4 (range, 2.6-19.2).

Blood Grouping and Crossmatching↗
PubMed1986

Studies of HLA, factor B (Bf), complement C2 and C4 haplotypes in type 1 diabetic and control families from northern Sweden.

The HLA-A,-B,-C,-DR antigens and the complement factors C2, C4 and Bf were determined in 30 insulin-dependent diabetes mellitus (IDDM) patients and 30 healthy controls from northern Sweden. Family studies allowed the deduction of extended haplotypes in the HLA and complement systems. Phenotype studies revealed significant associations between IDDM and HLA-DR4 (p less than 0.001), HLA-DR3 (p less than 0.05), HLA-DR3/4 (p less than 0.025), C4-B3 (p less than 0.001) and Bf-S (p less than 0.025). Haplotype studies showed that the extended haplotype [HLA-B15, C2-1, C4-A3B3, Bf-S, HLA-DR4] had a particularly strong association to IDDM. This haplotype was found in 10 out of 30 IDDM probands but in none of 30 control children and accounts for practically all the C4-B3 allotypes among the 30 IDDM probands. The C4-B3 gene therefore seems to be a valuable marker for IDDM. No haplotype containing HLA-DR3 was increased in frequency among the IDDM probands. The extended haplotype [HLA-B7, C2-1, C4-A3B1, Bf-S, HLA-DR2] present among the controls was absent in the IDDM probands. The frequency of the extended haplotype [HLA-B15, C2-1, C4-A3B3, Bf-S, HLA-DR4] was increased also among the parents to the IDDM probands compared to those of the control parents, whereas the frequency of [HLA-B7, C2-1, C4-A3B1, Bf-S, HLA-DR2] was decreased. The extended haplotype [HLA-B8, C2-1, C4-B1, Bf-S, HLA-DR3] was more common among the males (p less than 0.05) compared to the females in the total material. The family analysis showed that 3 out of 5 affected sibs shared both haplotypes with their IDDM proband. This was the case for only 3 out of 35 unaffected sibs.

Adolescent↗
PubMed1985

Lymphocyte stimulation in Reiter's syndrome. A comparative study between patients and normal controls with special reference to HLA-B27.

The lymphocyte-stimulating capacity of bacterial antigens from Yersinia enterocolitica and Chlamydia trachomatis was studied in 14 patients with Reiter's syndrome and compared with 16 healthy controls. The influence of HLA-B27 was evaluated. There was an increased reactivity in patients compared with controls. The most pronounced reactivity was seen in HLA-B27-positive patients. These findings support the hypothesis that there is an impaired T-cell function in HLA-B27-associated diseases.

Adult↗
PubMed1983

Allo-immune anti-Iak sera of individual mice detect HLA-DR-associated polymorphism on human B cells.

A murine allo-immune A.TH anti-A.TL (anti-Iak) serum pool and sera from individual immunized mice were tested on a large panel of human DR typed B cells, obtained from peripheral blood (PBL-B cells), and human lymphoid tumour cells. The anti-Iak serum pool appeared to be a useful reagent both in cytotoxicity and immunofluorescence for the examination of the presence of class-2 HLA molecules on tumour cells. Only one discrepancy was observed when the pool was tested in parallel with a xeno-anti-human B-cell serum on the cells of 56 lymphoid tumours. Nine sera from individual mice were tested on a panel of 93 PBL-B cells. Some of these sera reacted significantly more weakly with human B cells positive for the DR5 and/or DR7 antigens.

Animals↗
PubMed1981

HLA-A, -B, -C and -DR antigens in patients with Graves' disease and their correlation with signs and clinical course.

Among 78 consecutive patients with Graves' disease, an increased frequency of HLA-B8 and HLA-DR3 antigens was found. The relative risk for Graves' disease among individuals with these HLA antigens was calculated as 4.4 and 3.9, respectively. Thus, genes promoting the development of Graves' disease are clearly associated to the B8 and DR3 haplotypes. In groups of patients with different clinical expressions of the disease, such as thyroid hormone levels, autoantibodies and relapse rates, the frequency of B8 and DR3 antigens was found to be similar. Consequently, factors influencing the clinical expression and the course of the disease do not have a stronger association to these antigens.

Adult↗
PubMed1977

The effect of HLA antibodies on platelet aggregation.

Twelve different HLA antisera, detecting antigens of both A and B series and the superspecificities w4 and w6, were tested for platelet-aggregating activity in 75 antiserum-platelet combinations. The correlation between the HLA specificities of the antisera and the aggregating effect on platelets carrying the corresponding antigens was significant (P = 0.011). Because the platelet aggregation test is being used for screening of circulating immune complexes, falsely positive reactions caused by HLA antibodies must be eliminated by adequate control experiments.

Antibody Specificity↗
PubMedDate not supplied

Rapid DNA purification for restriction fragment length polymorphism analysis.

This paper describes a method for isolation of DNA from blood samples involving a rapid chemical disintegration of proteins with 8 M urea and with a minimum of exposure to phenol. The DNA is further desalted and purified on Sephadex G-25 prepacked disposable columns. DNA isolated in this way was pure enough to be immediately cleaved by restriction enzymes.

Autoradiography↗
PubMedDate not supplied

Different ancestor alleles: a reason for the bimodal fragment size distribution in the minisatellite D2S44 (YNH24).

Three conserved repeat order motifs found in the D2S44 (YNH24) minisatellite by minisatellite variant repeat mapping by PCR (MVR-PCR) might be the remnants of three different ancestor alleles. One of the motifs is found in the group of alleles around the 2.8 kbp fragment size and the two others in the group of alleles around the 4.1 kbp fragment size in the bimodal frequency distribution of HinfI fragments characteristic for the D2S44 minisatellite. The conserved repeat-order motifs were found at the 3'-end of the alleles, whilst the 5'-end was highly polymorphic. This is the first time a minisatellite is shown to have repeat-order motifs that are associated with fragment length. These results were obtained by MVR-PCR mapping of 49 alleles with primers specific for the core nucleotide sequence variation ...(G)5TGTT, ...(G)4TTGTT or ...(G)4TGTT.

Alleles↗