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M Thomsen

Publications and source records attributed to M Thomsen.

At least 73 records · Page 4Linked to original sources
PubMed1998

Optimization of a flow cytometric method for the simultaneous measurement of cell surface antigen, DNA content, and in vitro BrdUrd incorporation into normal and malignant hematopoietic cells.

We have designed an assay for the simultaneous measurement of cell surface phenotype, S-phase fraction, and DNA content by single laser instrumentation for the purpose of determining the labeling index (LI), duration of S-phase (Ts), and the potential doubling time (Tpot) of leukocyte subpopulations. The procedure was optimized with regard to: mode of bromodeoxyuridine (BrdUrd) incorporation, selection of suitable leukocyte differentiation antigens (LDAs) as well as PE-conjugated monoclonal antibodies (MoAbs) against myeloid cells, overnight permeabilization and fixation (paraformaldehyde 1% and 0.05% Nonidet P40), DNase I treatment (250 Kunitz units), concentration of FITC-conjugated anti-BrdUrd MoAb (dilution 1:5), and DNA staining with 7-amino-actinomycin (7-AAD) (10 microg/ml). We validated this assay by measuring LI, Ts, and Tpot repeatedly in four leukemic cell lines and found these to be stable (coefficients of variation (CV): 0.06, 0.13, and 0.08, respectively). Finally, we employed the assay on different leukocyte preparations from normal donors (including purified CD34 + cells) and patients with malignant myeloid disorders, and we concluded that it will yield valuable data regarding the cell cycle kinetics of subsets of leukocytes in heterogeneous mixtures of hematopoietic cells.

Acute Disease↗
PubMed1998

Mildly oxidized low-density lipoproteins suppress the proliferation of activated CD4+ T-lymphocytes and their interleukin 2 receptor expression in vitro.

Activated T-lymphocytes are present in early atherosclerotic lesions where they may interact with oxidized low-density lipoproteins (oxLDLs). In this study the non-specific effect of oxLDLs on the activation of T-cells in vitro was investigated. LDLs were oxidized by UV irradiation and characterized by a low level of lipid peroxidation and only slight apolipoprotein B modification. Peripheral blood lymphocytes from normal individuals were stimulated in vitro with the polyclonal activator phytohaemagglutinin in the presence of various doses of LDLs and oxLDLs. LDLs enhanced the proliferation of peripheral blood lymphocytes at doses up to 100 microg/ml but were inhibitory at 200 microg/ml, whereas low doses of oxLDLs (over 10 microg/ml) inhibited the proliferation. OxLDLs also inhibited the proliferative responses of an alloreactive CD4+ T-cell line immortalized by Herpes virus saimiri and an influenza haemagglutinin-specific CD4+ T-cell clone. Viability tests using Trypan Blue exclusion or expression of Apo2.7, an apoptosis marker, did not indicate any significant cell death at doses up to 100 microg/ml oxLDL. At this concentration, cell-cycle analysis showed an accumulation of cells at the G1/S interface in the CD4+ cell clone, without significant DNA fragmentation. The expression of the activation antigen CD25 on T-lymphocytes (on phytohaemagglutinin-activated T-cells and on CD4+ T-cell clone), requisite to the commitment of activated T-cells from G1 phase to S phase, was also inhibited by oxLDLs whereas expression of other activation antigens such as CD69 and HLA-DR was unchanged. In conclusion, these data show that mildly oxidized LDLs inhibit the proliferation and CD25 expression of activated T-lymphocytes and suggest that oxLDLs may slow down the T-cell response in atherosclerotic lesions.

CD4-Positive T-Lymphocytes↗
PubMed1998

Periprosthetic mineralization around cementless total hip endoprosthesis: longitudinal study and cross-sectional study on titanium threaded acetabular cup and cementless Spotorno stem with DEXA.

In a prospective longitudinal study over 2 years and a separate cross-sectional study more than 5 years after operation, we analyzed periprosthetic bone mineral density (BMD) after cementless total hip arthroplasty (THA) (press-fit cementless Spotorno stem, Mecron threaded acetabular cup) by dual-energy X-ray absorptiometry (DEXA). BMD was analyzed in a longitudinal prospective study (n = 53 patients: 29 women, 24 men) and in a separate cross-sectional study (n = 23 patients: 13 women, 10 men) with good clinical outcome (Merle d' Aubigne score > 12). Regions of interest were defined according to Gruen (ROI 1-7) and as netto average ROI (NETAVG I) for the periprosthetic femur, and according to De Lee and Charnley (ROI I-III) and as NETAVG II for the periprosthetic acetabulum. BMD during follow-up was compared with immediate postoperative values of the affected limb. Mean precision error (CV%) was 2.6 +/- 0.5% for ROI 1-7 and 1.3 +/- 0.9% for ROI I-III. BMD significantly decreased in the periprosthetic femur and acetabulum during the first 3 months after operation. At the femur, BMD (NETAVG I) for women and men, respectively, was 92.4% and 87.5% at 6 months, then 89.4% and 96.2% at 2 years. ROIs around the proximal stem showed the lowest absolute values and decreased most during follow-up (to 79.9% ROI 1 and 68.2% ROI 7, respectively). Mineralization around the cup (NETAVG II), respectively, amounted to 81.1%, 82.6% at 6 months, then 80.1% and 93.8% at 2 years. The medially placed ROI II demineralized most (respectively, 72.1% and 76.7%). More than 5 years after THA, BMD in the femur showed little change, but decreased significantly to 76.4% and 79.1%, respectively, around the cup (NETAVG II). DEXA is a useful method for analyzing changes of mineralization around cup and stem of cementless THA. The results reflect the different stress on the periprosthetic bone after implantation of THA in defined ROIs, supporting earlier reported good clinical results of the Spotorno stem and increased loosening rate of threaded acetabular cups after 5 years.

Absorptiometry, Photon↗
PubMed1998

Degeneration and regeneration in rabbit peripheral nerve with long-term nerve cuff electrode implant: a stereological study of myelinated and unmyelinated axons.

Selective and dynamically co-ordinated functional electrical stimulation (FES) of paralysed/paretic limbs in upper motor neuron lesioned people depends on optimal contact at the neural interface. Implanted nerve cuff electrodes may form a stable electrical neural interface, but may also inflict nerve damage. In this study the immediate and long-term effects of cuff implantation on the number and sizes of myelinated and unmyelinated axons have been evaluated with unbiased stereological techniques. Cuff electrodes were implanted in rabbit tibial nerves just below the knee joint, and the stereological analyses were carried out 2 weeks and 16 months after implantation. Myelinated axons were analysed at standardised levels proximal to, underneath, and distal to the cuff; unmyelinated axons underneath the cuff. A 27% loss of myelinated axons was found underneath and distal to the nerve cuff 2 weeks post surgery. All axonal sizes were equally lost except for the very smallest. At 16 months post surgery the number of myelinated axons was restored to control values at both levels. Except for the presence of regenerative sprouts at 2 weeks post surgery, no changes in the number or sizes of unmyelinated axons were revealed at either 2 weeks or 16 months post surgery. Our study demonstrates that implanted cuff electrodes may cause an initial loss of myelinated axons but with subsequent regeneration.

Anatomy, Artistic↗
PubMed1998

Increased urinary crosslink levels in aseptic loosening of total hip arthroplasty.

The diagnosis of aseptic loosening in total hip arthroplasty is predominantly based on clinical and radiographic evaluation. Loosening is usually associated with increased bone resorption at the interface. In this study we wanted to evaluate the diagnostic value of bone markers in aseptic loosening. We compared 50 patients with proven component loosening during surgery with 50 age-, sex-, and implant-matched patients without clinical or radiological signs of loosening. We measured serum markers of bone formation (bone-specific alkaline phosphatase, osteocalcin [OC], procollagen type I propeptides) and bone resorption (collagen n-telopeptide [NTX], deoxypyridinoline [DPYD], pyridinoline [PYD]). We found significantly increased levels of NTX, DPYD, PYD, and OC in the loosening group. The other markers showed no significant difference between both groups. We conclude that determination of urinary crosslinks may offer a new and valuable diagnostic method in the detection of aseptic loosening in total hip arthroplasty.

Adult↗
PubMed1998

Familial congenital horizontal gaze paralysis and kyphoscoliosis.

Congenital horizontal gaze paralysis is a rare disorder which may be associated with severe scoliosis of early onset. We present the clinical findings of two sisters with this syndrome. The additional finding of a unique pericentric inversion of chromosome 12 is considered to be incidental. Every child with congenital horizontal gaze paralysis should be evaluated for a possibly associated scoliosis. If present, a diagnosis of this presumably autosomal recessive syndrome can be made with appropriate treatment and genetic counseling.

Child↗
PubMed1998

The different appearance of the oculodentodigital dysplasia syndrome.

We report on two families with the oculodentodigital (ODD) dysplasia syndrome, also called Meyer-Schwickerath syndrome. It represents a rare disorder characterized by eye and facial abnormalities causing a unique facial appearance. The phenotype of the young patients resembles those of identical twins. We found syndactyly mostly at the hands and, additionally, characteristic phalangeal aberrations, defects in teeth enamel, and trichosis. In the one family, the ODD dysplasia syndrome seemingly originated in a new mutation. The affected child was treated surgically in our clinic (syndactyly separation). In the other family, three patients (grandmother, mother, and granddaughter) were subjects of syndactyly separation. The aim of our surgeries was to separate the webbed fingers so there would be a normal spread and to improve the function and appearance of fingers. The ODD dysplasia syndrome correlates with the Hallermann-Streiff syndrome, or oculomandibulodyscephaly, which is characterized by a typical skull shape (brachicephaly with frontal brossing), a bird-like face, and eye abnormalities (congenital cataracts and microphthalmia).

Abnormalities, Multiple↗
PubMed1998

Characterization of lymphocyte subpopulations in periapical lesions by flow cytometry.

The mechanisms by which the bacterial root-canal infection leads to periapical bone destruction (cysts or granulomas) are not yet well understood. Previous works have shown elements of an active immune response in the lesions. In the present study, flow cytometry was used to improve the characterization of immune cells. Semiquantitative immunohistochemical analysis showed the presence of plasma cells, macrophages and B and T cells. The simultaneous use of several antibodies in flow cytometry allowed a more precise phenotype of the lymphocytes. The cysts displayed an abundance of B lymphocytes at the same time as a relative scarcity of CD8+ cells. CD4+ lymphocytes were the dominant lymphocyte population in most cases. A small number of gamma delta T lymphocytes and natural killer cells was found. These preliminary results show that flow cytometry may be used to characterize immune cells from inflamed tissue and opens the possibility for further functional studies.

Adult↗
PubMed1998

Thanatophoric dysplasia type I: new radiologic, morphologic, and histologic aspects toward the exact definition of the disorder.

A comprehensive seven-step study on THANATOPHORIC DYSPLASIA without cloverleaf skull (TD Type I) was carried out postmortem on three aborted fetuses of 19, 26-27, and 34 weeks and one preterm neonate of 35 weeks gestation, respectively. The characteristic x-ray configuration of the spine in TD Type I presenting with H-, U- or reversed U-shape vertebrae were shown to correlate with the inclination or reclination of the vertebral bodies within a kyphotic or lordotic segment. The bowing of the tubular bones in TD Type I is explained by a diminished mechanical stability that is causally related to a specific cartilage structure. The perichondral spurs are defined by their morphologic structure, and their origin is attributed to a normal perichondral ossification in the presence of an impaired enchondral ossification. Impairment of enchondral ossification was more evident in the periphery than in the center of the metaphyses leading to a tongue-shaped osseous cone directed toward the epiphysis. The perichondral spurs and the linguiform enchondral growth plate resulted in a three-phase maple leaf-like contour of the metaphyses of tubular bones and acetabular roof. The nature of the perichondral fibrous bands, the fibrovascular bundles, and the fibrovascular bands of the growth plate and their significance in atypical ossification processes are discussed in detail. It is suggested that the diminished longitudinal growth of the skeleton is caused by a reduced mitotic activity of cartilage cells in the proliferative zone leading to a reduction of cell numbers in the columnar zone transversely oriented spongiosa bars resulting from desmal ossification of the metaphyseal fibrovascular structures.

Bone and Bones↗
PubMed1997

Influence of synchronous and sequential stimulation on muscle fatigue.

In acute experiments the sciatic nerve of the rat is electrically stimulated to induce fatigue in the medial Gastrocnemius muscle. Fatigue tests are carried out using intermittent stimulation of different compartments (sequential) or a single compartment (synchronous) of the sciatic nerve. The activation of different compartments is achieved by dividing nerve fibres into subbundles and placing them in separate grooves in a multigroove electrode. The aim of the investigation is to quantify the effect of sequential contra synchronised stimulation in reducing muscle fatigue, with no overlap between compartments. Overlap between two compartments is calculated using the combined and individual forces from both compartments. Sequential stimulation of two and three compartments is investigated. There is a significant decrease of fatigue in sequential stimulation compared to synchronous. After 2 min of intermittent stimulation the force time level is significantly increased in sequential stimulation, than in synchronous stimulation. The rate of force time decrease is significantly slower in sequential stimulation than in synchronous stimulation. With sequential stimulation it takes significantly longer before the maximal force time is reached than with synchronous stimulation.

Animals↗
PubMed1997

Microsatellites in the HLA region: on overview.

Microsatellites are repeats of a DNA base motif (1-6 bp, mostly CA repeats) up to 100 times; they are distributed regularly all over the genome. Many of them are polymorphic and their high polymorphism is based upon a variable number of repeats. They are widely used for genetic mapping, linkage analysis, population genetics, evolutionary studies and in forensic medicine. Such markers have also been described in the HLA region since 1991, and a growing interest in their potential applications is being expressed. The aims of this review are: 1) to outline the presently available information from literature and molecular databases concerning 53 microsatellites in the HLA region (localization, type of repeat, number of alleles, heterozygosity, primers used for amplification); 2) to address the question of technical pitfalls when using such markers; 3) to discuss specific features such as their mutation rate (10 (-3) to 10 (-6), which is higher than that reported for HLA genes, and their linkage disequilibrium with HLA alleles; 4) to present an integrated map of microsatellites and genes of this region; and 5) to provide a synopsis of their different applications in HLA-related fields (disease studies, population genetics, recombination point studies, HLA region mapping, transplantation) along with perspectives for future use. Although some HLA region microsatellites have already been applied to the analysis of more than 10 diseases, it is now evident that their use in population genetics and the determination of genomic compatibility in bone marrow transplantation represent growing areas of application.

Animals↗
PubMed1997

Dominant clones in immortalized T-cell lines from rheumatoid arthritis synovial membranes.

Transformation of human T cells by herpesvirus saimiri allows the production of an unlimited number of T cells which express a functional T-cell receptor. In this study we transformed four T-cell lines derived from rheumatoid arthritis synovial membranes. The transformed T cells were mainly CD4+ and expressed the phenotype of activated T cells. They were grown for more than 1 year in the absence of mitogen or feeder cells, and three of them could be maintained without exogenous IL-2. The presence of viral DNA in the transformed cells was shown by in situ hybridization with a probe from the H-DNA region of the virus. No infectious virus could be recovered from the transformed cells. The relative proportion of the 24 different Vbeta families between the four transformed lines showed variations that increased with time. In the two T-cell lines transformed at an early stage of culture, the Vbeta2 family was maintained at about 10%. The dominant Vbeta2 clones that previously have been characterized in the patient were found in all transformed T-cell lines. We have thus shown the feasibility of obtaining transformed T cells from synovial membranes. They contain the dominant clones that are considered of potential importance for the disease, permitting further functional studies.

Arthritis, Rheumatoid↗
PubMed1997

Middle-term results of threaded acetabular cups. High failure rates five years after surgery.

We report our results using three different threaded acetabular components (Mecring A, Mecring B and Weill) in 715 hips with a follow-up of between one and ten years (median: 99.1, 56.5, 38.3 months, respectively). All cups were implanted with one type of cementless stem. The clinical results were good or acceptable in about 70% of the hips, but signs of loosening with radiolucency and/or migration were found in 10.1%. Radiological evidence of loosening did not correlate significantly with the clinical outcome. Pain was not a reliable indicator of loosening and its absence sometimes allowed severe osteolysis to develop. Twenty-five hips were revised (3.5%) for aseptic loosening of the acetabular component. Kaplan-Meier estimates of the cumulative rate of failure showed a rapid increase five years after the initial operation, but no significant correlation with gender, age or weight. The high rate of failure indicates that further use of these acetabular components cannot be recommended. Annual radiographs are required to assess osteolysis even if the patients are free from pain.

Acetabulum↗
PubMed1996

Secondary aortoenteric fistulae--changes from 1973 to 1993.

AIM: To investigate a series of patients with secondary aortoenteric fistulas and compare it with a previous series (1985-93 vs. 1973-84). DESIGN: Retrospective study of medical records. SETTING: Sixteen vascular surgical centers in Sweden. PATIENTS: Twenty-seven patients were identified making an overall incidence of 0.5% of all aortoiliac operations. Among aneurysm patients the incidence was significantly lower than in the previous series. One patient record could not be identified. Fourteen primary operations were for aortic aneurysm, 12 for occlusive disease and one was an aortorenal vein bypass. RESULTS: Symptoms of the fistula occurred after a median interval of 90 months which is significantly later than the previous series (32 months; p<0.05). The commonest presentation was bleeding followed by septis. The median diagnostic delay was 10.5 days, which was significantly shorter than in the previous series. Most fistulas involved the duodenum (88%). One patient died before surgery. The postoperative mortality was 28%, significantly lower than in the previous series (58%) (p<0.05). At the end of follow up (median 43 months) significantly more patients were alive than in the previous series (42% vs 18%) (p<0.05). CONCLUSION: Over a 21 year period there seems to have been a decrease in the frequency of secondary aortoenteric fistulas after aneurysm surgery, a longer interval before they occur, a shorter diagnostic delay, and a better survival.

Aorta, Abdominal↗
PubMed1996

Role of polymorphic residues of human leucocyte antigen-DR molecules on the binding of human immunodeficiency virus peptides.

A study was made of the binding properties of 96 human immunodeficiency virus peptides to human leucocyte antigen (HLA)-DR1 and HLA-DR103 molecules, which differ by three amino acids at positions 67, 70 and 71 in the beta chains. The affinity of the peptides was characterized by their inhibitory concentrations in competitive binding assays which displace half of the labelled influenza haemagglutinin peptide HA306-318 (IC50). Among the high-affinity peptides (IC50 < or = 1 microM), seven bound to DR1, three to DR103 and five equally well to both alleles (promiscuous peptides). Thirty-two other peptides showed medium or low affinity for DR molecules. The role of polymorphic residues was analysed using six mutated DR molecules, intermediates between DR1 and DR103 and differing by one or two substitutions at positions 67, 70 or 71. We reached the same conclusions when using DR1-specific or DR103-specific peptides: modification of residue 70 had no effect on peptide affinity, but single substitution at positions 67 or 71 decreased the allele specificity of the peptides while double substitution at 67 and 71 completely reversed the peptide specificity. In functional assays, DR-binding peptides are able to outcompete specific T-cell proliferation. Furthermore, modification at position 67 or 70 significantly affects the T-cell response and mutation at position 71 abolishes completely the T-cell proliferation. Thus, the polymorphic positions 67 and 71 contributed to the peptide binding with direct effects on T-cell receptor (TCR) recognition while position 70 seems to be mostly engaged in TCR interactions. Furthermore, our results suggest that polymorphic residues may select allele-specific peptides and also influence the conformation of promiscuous peptides.

Amino Acid Sequence↗
PubMed1996

Localization of the recombination points in a family with two DR/DP recombinations.

In a family with a maternal DR/GLO recombination, cellular DP typing showed it to be located between DR and DP. RFLP studies done during the 9th international histocompatibility workshop gave anomalous segregation patterns of DPA and DPB bands that could be interpreted as being due to a second, paternal DR/DP recombination. This assumption was confirmed later by PCR-SSO typing. A more precise mapping has been done by new markers showing the maternal recombination to be within the TAP2 locus and the paternal recombination to be between DQB1 and DQB3. This supports earlier suggestions of a hot spot of recombination in the TAP region. The recombinations involve parental haplotypes that presently show DR/DP linkage disequilibrium in the French population and it is proposed that DR/DP recombinations occur randomly while B/DR recombinations preferentially occur on haplotypes without strong linkage disequilibrium. Existing DR/DP linkage disequilibria in a given population will thus be broken down with time. The mixed lymphocyte culture response towards an isolated DP difference was tested in this and another DR/DP recombinant family. It showed that an alloresponse towards DP may be highly variable and this suggests that it might be important to define the rules for the strength of this reaction and the possible implications for allotransplantation.

Female↗
PubMed1996

Juvenile progressive scoliosis and congenital horizontal gaze palsy.

Eleven articles reporting 39 patients with the combination of progressive scoliosis and familial congenital gaze palsy have now been published. This disorder appears to be caused by a malfunction of the normal equilibrial control mechanism related to the brainstem or the central nervous system. The scoliosis progresses when the children begin to walk. Even when they are treated with physiotherapy or brace, they often require early operation. We consider that progressive juvenile or infant scoliosis associated with familiar congenital horizontal gaze palsy constitutes a clinical entity. We report two sisters with congenital gaze palsy, in one of whom scoliosis of at least 70 degrees (Cobb) developed, and review and analyze all cases published until now.

Child, Preschool↗