| 11. |
- Ekström, Ulf, et al.
(författare)
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Mutations in the low-density lipoprotein receptor gene in Swedish familial hypercholesterolaemia patients: clinical expression and treatment response
- 1998
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Ingår i: European Journal of Clinical Investigation. - : Wiley. - 0014-2972. ; 28:9, s. 740-747
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Familial hypercholesterolaemia, an autosomal co-dominant disorder caused by defects in the low-density lipoprotein receptor gene, is strongly associated with premature development of cardiovascular disease. METHODS: In this study, we have applied a gene screening method in a population of familial hypercholesterolaemia patients in order to describe the genetic background of the disease in southern Sweden. These patients were studied with the aim of relating the presence of the different mutations to the clinical expression of the disease and to the response to pharmacological treatment. RESULTS: In 16 out of 21 patients, potentially disease-causing low-density lipoprotein receptor gene defects were found, including five not previously described alterations (C240-->F, C122-->stop, C356-->Y, 785insG, 165delG). No defects in apolipoprotein B were found. One group of patients (n = 4) carried the mutation C122-->stop and another group of patients (n = 4) a mutation causing the substitution W66-->G. Patients in the two genotype subgroups were very similar with respect to lipid levels before treatment. CONCLUSION: A tendency towards differential susceptibility to treatment with statins was observed for the patient groups, encouraging further comparative studies of heterozygous FH patients.
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| 12. |
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| 13. |
- Andreasson, Björn, et al.
(författare)
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The measurement of venous haematocrit in patients with polycythaemia vera.
- 1999
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Ingår i: Journal of internal medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 246:3, s. 293-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In clinical practice, patients with polycythaemia vera (PV) are monitored by measurement of venous packed cell volume (PCV). However, whereas treatment recommendations are still based upon studies in which the results were obtained with the centrifuged microhaematocrit, currently in most instances automated blood cell counters are used to calculate PCV. In a group of patients with polycythaemia we therefore compared the results obtained by the microhaematocrit method with PCV calculated by haematology analysers. DESIGN: The study was carried out on a prospective basis. Duplicate venous blood samples were collected. The centrifuged microhaemotocrit was obtained by using an IEC Micro-MB Centrifuge. Depending on different routine methods used in the participating hospitals, the blood cell counter PCV was calculated using Coulter STKS, Bayer Technicon H2 or H3. SETTING: Patients were included from four Swedish university hospitals: Akademiska (Uppsala), Huddinge and Karolinska (Stockholm) and Sahlgrenska (Göteborg). SUBJECTS: Seventy-four patients with PV and 10 patients with secondary polycythaemia were included and a total of 150 duplicate blood samples were analysed from these subjects. RESULTS: In the 150 measurements the mean blood cell counter calculated PCV was 0.448 +/- 0.037; the mean for centrifuged microhaematocrit was 0.467 +/- 0. 037 and the difference between means was highly significant (P = 6.8 x 10-25). The means for centrifuged haematocrit and calculated PCV differed significantly in the groups of PV patients treated with phlebotomy only, hydroxyurea or radiophosphorous (P < 0.0001, respectively). In PV patients treated with alpha-interferon and in patients with secondary polycythaemia the difference in means did not reach statistical significance (P = 0.07 and P = 0.13, respectively). The groups of patients with MCV <80 fL and >/=80 fL both presented significant differences between means for calculated PCV and centrifuged haematocrit. CONCLUSIONS: If PV patients are monitored with blood cell counter calculated PCV it appears that the therapeutic goal should be to maintain the calculated PCV below 0.43, provided the local differences in calculated PCV and centrifuged haematocrit are of the same magnitude as in this study.
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| 14. |
- Forsberg, B, et al.
(författare)
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The platelet-specific alloantigen PlA1 (HPA-1a): a comparison of flow cytometric immunophenotyping and genotyping using polymerase chain reaction and restriction fragment length polymorphism in a Swedish blood donor population.
- 1995
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Ingår i: Transfusion. - 0041-1132. ; 35:3, s. 241-6
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: There is an increasing interest in the development of rapid and reliable techniques for platelet alloantigen typing. STUDY DESIGN AND METHODS: By use of standardized flow cytometry and a specific human alloantiserum, 236 Swedish blood donors were immunophenotyped for the platelet-specific alloantigen, PlA1 (HPA-1a). RESULTS: Ten individuals (4.2%) had low fluorescence intensities and were considered PlA1-negative (HPA-1a-negative); all of them also demonstrated a PlA2/PlA2 (HPA-1b/1b) genotype in a polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) assay of the underlying DNA polymorphism. The remaining population had clear positive fluorescence and was regarded as PlA1-positive (HPA-1a-positive). The fluorescence distribution histogram among PlA1-positive (HPA-1a-positive) individuals was dome-shaped, and those individuals who were homozygous for PlA1 (HPA-1a) could not be distinguished from those who were heterozygous. This finding was further substantiated by PCR-RFLP analysis of the PlA1/PlA2 (HPA-1a/1b) genotype; a heterozygous genotype was found among those having a medium fluorescence intensity as well as among those having a strong fluorescence intensity. CONCLUSION: Flow cytometry is a valuable tool for large-scale detection of PlA1 (HPA-1a). However, flow cytometry based on only one antiserum cannot distinguish between homozygous and heterozygous carriers of PlA1 (HPA-1a). For zygosity testing and when platelets are difficult to obtain, the PCR-RFLP technique is the assay of choice.
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| 15. |
- Hou, Mingyan, et al.
(författare)
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Increase in cardiac P2X1-and P2Y2-receptor mRNA levels in congestive heart failure
- 1999
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Ingår i: Life Sciences. - 1879-0631. ; 65:11, s. 1195-1206
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Tidskriftsartikel (refereegranskat)abstract
- We wanted to study the expression of P2-receptors at the mRNA-level in the heart and if it is affected by congestive heart failure (CHF). To quantify the P2 receptor mRNA-expression we used a competitive RT-PCR protocol which is based on an internal RNA standard. The P2 receptor mRNA-expression was quantified in hearts from CHF rats and compared to sham-operated rats. Furthermore, the presence of receptor mRNA was studied in the myocardium from patients with heart failure. In the sham operated rats the G-protein coupled P2Y-receptors were expressed at a higher level than the ligand gated ion-channel receptor (P2X1). Among the P2Y-receptors the P2Y6-receptor was most abundantly expressed (P2Y6 > P2Y1 > P2Y2 = P2Y4 > P2X1). A prominent change was seen for the P2X1- and P2Y2-receptor mRNA levels which were increased 2.7-fold and 4.7-fold respectively in the myocardium from the left ventricle of CHF-rats. In contrast, the P2Y1-, P2Y4- and P2Y6-receptor mRNA levels were not significantly altered in CHF rats. In human myocard the P2X1-, P2Y1-, P2Y2-, P2Y6- and P2Y11-receptors were detected by RT-PCR in both right and left atria and ventricles, while the P2Y4-receptor band was weak or absent. In conclusion, most of the studied P2-receptors were expressed in both rat and human hearts. Furthermore, the P2X1- and P2Y2-receptor mRNA were upregulated in CHF, suggesting a pathophysiological role for these receptors in the development of heart failure.
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| 16. |
- Hou, M, et al.
(författare)
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Multiple quinine-dependent antibodies in a patient with episodic thrombocytopenia, neutropenia, lymphocytopenia, and granulomatous hepatitis.
- 1997
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Ingår i: Blood. - 0006-4971. ; 90:12, s. 4806-11
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Tidskriftsartikel (refereegranskat)abstract
- A 58-year-old man experienced episodes of fever, vomiting, and diarrhea over a 2-year period. The laboratory evaluation during these attacks consistently disclosed thrombocytopenia, leukopenia, and elevated liver enzymes. A liver biopsy performed at one of these attacks showed a typical picture of granulomatous hepatitis. In retrospect, all episodes seemed to be associated with the ingestion of quinine. Indeed, such a correlation was established by a challenge with quinine. By using flow cytometry, quinine-dependent IgG antibodies to platelets were detected in the patient serum. By a two-color flow cytometric assay, the patient serum was also found to hold quinine-dependent antibodies specific for neutrophils, T lymphocytes, and B lymphocytes. Moreover, serum absorbed with neutrophils in the presence of quinine continued to react with platelets, T lymphocytes, and B lymphocytes; serum that was absorbed with mononuclear cells continued to react with neutrophils and platelets. These experiments indicated that the antigen targets were different on platelets, neutrophils, and lymphocytes. Further, the patient serum in the presence of quinine immunoprecipitated surface-labeled platelet proteins with electrophoretic mobilities closely resembling those of glycoprotein (GP) Ib/IX and GPIIb/IIIa. By a modified monoclonal antibody-specific immobilization of platelet antigens assay, the patient serum in the presence of quinine reacted with platelet GPIb/IX and GPIIb/IIIa. Also, the patient serum in the presence of quinine immunoprecipitated an uncharacterized 15-kD double-band from surface-labeled granulocyte proteins. We conclude that our patient's thrombocytopenia, neutropenia, and lymphocytopenia were caused by quinine-dependent antibodies and that these antibodies recognized cell lineage-specific epitopes.
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| 17. |
- Jacobsson, Stefan, 1951, et al.
(författare)
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Flow cytometric analysis of megakaryocyte ploidy in chronic myeloproliferative disorders and reactive thrombocytosis.
- 1996
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Ingår i: European journal of haematology. - 0902-4441. ; 56:5, s. 287-92
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Tidskriftsartikel (refereegranskat)abstract
- Megakaryocyte (MK) ploidy patterns were analysed by flow cytometry in 29 newly diagnosed and previously untreated patients with chronic myeloproliferative disorders (MPD) and concomitant thrombocytosis, in 9 patients with reactive thrombocytosis (RT) and in 12 healthy individuals. Unfractionated bone marrow from routine aspirates was used. MKs were identified with a fluorescein labelled monoclonal antibody specific for glycoprotein IIIa (GPIIIa) and DNA was stained with propidium iodide. For the 12 healthy volunteers the mean modal ploidy number was 16 N; the 9 patients with RT displayed an identical MK ploidy pattern. The frequency of MKs with a ploidy > or = 32 N was 45% among the patients with essential thrombocythaemia (ET) compared to 32% among the healthy volunteers (p < 0.001). MKs with ploidy number > or = 64 N, comprising approximately 13% of the total number of MKs, was a characteristic finding in the patients with ET. Similar findings were present in 8 patients with polycythaemia vera (PV). In patients with PV 34% and 6% of the MKs displayed ploidies > or = 32 N and > or = 64 N, respectively. In contrast, a distinct shift towards lower ploidy number, with 63% of MKs < or = 8 N, was found among the 4 patients with chronic myeloid leukaemia (CML). The present results indicate that by using flow cytometric analysis of MK ploidy distribution in patients with thrombocytosis, those with a reactive cause are likely to be discriminated from patients with myeloproliferative thrombocytosis, i.e. PV and ET on one hand and CML on the other hand. The distinction between ET and PV, however, has to be made on other grounds.
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| 18. |
- Stockelberg, Dick, 1950, et al.
(författare)
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Detection of platelet antibodies in chronic idiopathic thrombocytopenic purpura (ITP). A comparative study using flow cytometry, a whole platelet ELISA, and an antigen capture ELISA.
- 1996
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Ingår i: European journal of haematology. - 0902-4441. ; 56:1-2, s. 72-7
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Tidskriftsartikel (refereegranskat)abstract
- Chronic idiopathic thrombocytopenic purpura (ITP) is a consequence of rapid platelet destruction caused by circulating platelet antibodies. In this study we compared three methods for detecting serum platelet antibodies in a population of 65 patients with chronic ITP. In two of the techniques intact platelets were used as the antibody target, i.e. the whole platelet ELISA and the flow cytometric assay; in the third an antigen-specific modified antigen capture ELISA (MACE) was employed. By using the whole platelet ELISA and the flow cytometric assay 35% and 45% of the patients, respectively, displayed an antiplatelet antibody. In most cases (26 or 29 patients) IgG was the predominant antiplatelet immunoglobulin. As analysed using the MACE-technique glycoprotein (GP) Ib/IX-specific antibodies occurred with the same frequency as antibodies specific for GPIIb/IIIa. Moreover, there was a poor correlation between the MACE results on the one hand and results from the intact platelet-based techniques on the other, i.e. several patients were positive in one assay whereas they were negative in the other. We conclude that all three techniques have their merits and demerits; it appears reasonable that they should be used together in the evaluation of the autoimmune process of chronic ITP.
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| 19. |
- Stockelberg, Dick, 1950, et al.
(författare)
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Evidence for a light chain restriction of glycoprotein Ib/IX and IIb/IIIa reactive antibodies in chronic idiopathic thrombocytopenic purpura (ITP).
- 1995
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Ingår i: British journal of haematology. - 0007-1048. ; 90:1, s. 175-9
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Tidskriftsartikel (refereegranskat)abstract
- To address the assumption of clonally restricted antibodies in immune thrombocytopenias we studied sera from 19 patients with chronic ITP known to possess antibodies reactive with glycoprotein (GP) Ib/IX and/or GPIIb/IIIa. These sera were re-analysed using the standard monoclonal antibody immobilization of platelet antigens (MAIPA) assay and 16 patients exhibited IgG antibodies reactive with GPIIb/IIIa; seven patients showed also a reactivity with GPIb/IX. Employing a light-chain-specific MAIPA assay, 75% (12/16) of these sera displayed GPIIb/IIIa-specific antibodies that were light chain restricted; only 13% (2/16) of the GPIIb/IIIa reactive sera showed a mixed kappa and lambda phenotype. A light-chain-restricted phenotype was also seen for the GPIb/IX reactive antibodies. To further substantiate these findings, the MAIPA assay was modified in order to avoid interference from human anti-mouse antibodies. A high frequency of light-chain restricted platelet antibodies was also found using the modified MAIPA technique. These results support the hypothesis of a clonal B-cell expansion in immune thrombocytopenias, producing antibodies with a restricted idiotype repertoire and reacting with a limited number of epitopes.
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| 20. |
- Stockelberg, Dick, 1950, et al.
(författare)
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Light chain-restricted autoantibodies in chronic idiopathic thrombocytopenic purpura, but no evidence for circulating clone B-lymphocytes.
- 1996
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Ingår i: Annals of hematology. - 0939-5555. ; 72:1, s. 29-34
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Tidskriftsartikel (refereegranskat)abstract
- In chronic idiopathic thrombocytopenic purpura (ITP) platelet destruction is caused by antibodies directed against platelet membrane glycoproteins (GP), and the predominant autoantigens are known to be GPIb/IX and GPIIb/IIIa. In a recent study we reported that these antibodies frequently had a restricted light chain phenotype, thereby supporting a clonal origin. Similar findings and the presence of clonal B-cell populations in immune thrombocytopenias have been reported by others. In the present study we further explored the hypothesis of clonal B-cell expansions in chronic ITP. Twenty patients with chronic ITP were investigated. Antibodies were detected with an ELISA (MAIPA) specific for GPIb/IX and GPIIb/IIIa; circulating clonal B lymphocytes were assessed by flow-cytometric (FACS) clonal-excess analysis and by analyzing Ig-gene rearrangements (CDR3) with the PCR technique. Nine patients displayed a GP-specific antibody restricted to either kappa or lambda phenotype. However, FACS analysis and Ig-gene rearrangement studies did not disclose any circulating clonal B-cell population. Considering the sensitivity of the FACs analysis and Ig-gene rearrangement for detection of clonal B-cell populations, the hypothesis of clonally derived autoantibodies in ITP is still valid. Most probably, the clonal B-cell expansion responsible for the production of autoantibodies in ITP, if present, is below the detection limit for the techniques employed.
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