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Biomedical subjects

R Fijnheer

Publications and source records attributed to R Fijnheer.

At least 19 recordsLinked to original sources
PubMed2006

Neurologic and hematologic response to fludarabine treatment in IgM MGUS polyneuropathy.

We studied the efficacy of fludarabine in 16 patients with immunoglobulin M monoclonal gammopathy of unknown significance polyneuropathy in a prospective uncontrolled trial. The modified Rankin scale improved in 5/16 patients, all of whom had a demyelinating polyneuropathy. The motor conduction velocity improved by more than 10% in two or more nerves for four of five of these patients. Hematologic response in bone marrow occurred in three of five of these patients, whereas two of five already had small polyclonal B cell populations. There were no serious side effects.

Aged↗
PubMed2006

Risk factors for cystoid macular oedema in patients with uveitis.

PURPOSE: To determine ophthalmologic and systemic factors associated with the presence of cystoid macular oedema (CMO) in patients with uveitis. METHODS: Retrospective cross-sectional study in which 97 consecutive patients with uveitis filled in an extensive questionnaire for the presence of cardiovascular diseases and its risk factors. An analysis of the ophthalmologic and questionnaire data was conducted. RESULTS: CMO was present in 44% (43/97) of patients. Its presence was strongly associated with increasing age (P=0.001) and age at onset of uveitis (P<0.001). For patients older than 50 years, the risk of having CMO was 3.8-fold (95% confidence intervals 1.6-9.0) larger than for younger patients. The most frequent anatomic location of uveitis associated with CMO was panuveitis (49%). Papillary leakage on fluorescein angiography was associated with CMO (P<0.001), independently of other risk factors. After adjustment for age, multivariate logistic regression showed no association between cardiovascular disease and its risk factors and the presence of CMO. CONCLUSIONS: Age, independent of duration of uveitis, was a major risk factor for the presence of CMO in uveitis. A positive correlation between CMO and papillary leakage on angiography was noted.

Adolescent↗
PubMed2006

Acute activation of the endothelium results in increased levels of active von Willebrand factor in hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome.

BACKGROUND: HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome is a severe complication of pre-eclampsia in pregnancy, characterized by microvascular platelet thrombi. Activation of the endothelium is thought to play a key role in pre-eclampsia and HELLP syndrome. Activation of endothelial cells may lead to release of von Willebrand factor (VWF) multimers, which are highly reactive with platelets. Normally, newly released multimers are cleaved by ADAMTS13, resulting in less reactive derivatives. OBJECTIVE: We hypothesized that HELLP syndrome is characterized by increased amounts of active VWF compared with healthy pregnancy and pre-eclampsia, due to acute activation of endothelial cells. This might contribute to thrombocytopenia and thrombotic microangiopathy. METHODS: Active VWF and ADAMTS13 activity were measured in healthy pregnant volunteers (n = 9), patients with pre-eclampsia (n = 6) and patients with HELLP syndrome (n = 14) at similar gestational ages. To study the role of endothelial cell activation, the propeptide/mature VWF ratio was determined, and VWF released by cultured endothelial cells was analyzed. RESULTS: Active VWF levels were increased 2.1-fold in HELLP syndrome compared with healthy pregnant volunteers (P < 0.001) and 1.6-fold compared with patients with pre-eclampsia (P = 0.001). ADAMTS13 activity was moderately decreased in patients with HELLP syndrome compared with healthy pregnant volunteers (P < 0.004), but not compared with patients with pre-eclampsia. The propeptide/mature VWF ratio was increased 1.7-fold compared with healthy pregnant volunteers (P < 0.001) and 1.5-fold compared with patients with pre-eclampsia (P < 0.05). A significant correlation was found between this ratio and the activation factor of VWF (r = 0.68, P < 0.001). The amount of active VWF was increased 1.4-fold in medium of stimulated endothelial cells when compared with non-stimulated cells (P < 0.05). CONCLUSION: Acute endothelial cell activation in HELLP syndrome and decreased ADAMTS13 activity result in increased amounts of active VWF. This might explain the consumptive thrombocytopenia and thrombotic microangiopathy associated with HELLP syndrome. Inhibition of circulating active VWF could be a potential new approach in the treatment of patients with HELLP syndrome.

ADAM Proteins↗
PubMed2006

Pulmonary complications after T-cell-depleted allogeneic stem cell transplantation: low incidence and strong association with acute graft-versus-host disease.

Lung injury limits the success of allogeneic stem cell transplantation (SCT). The overall incidence varies from 30 to 50% and non-infectious causes occur in one-third to one-half of these. We reviewed pulmonary complications in 369 consecutive patients who received a partially T-cell-depleted myeloablative allogeneic hematopoietic SCT at our institution between 1993 and 2003. All patients were treated uniformly with cyclophosphamide followed by total body irradiation. Control subjects were matched on sex, underlying diagnosis, age, type of transplantation and cytomegalovirus (CMV)-serostatus. Sixty-one patients (16.5%) developed pulmonary complications. Twenty-one patients (5.7%) developed infectious pneumonia. Forty patients developed non-infectious complications which were further subclassified as bronchiolitis obliterans (3.5%), bronchiolitis obliterans-organizing pneumonia (0.5%), diffuse alveolar hemorrhage (0.8%), idiopathic pneumonia syndrome (5.5%) or mixed etiology (0.5%). Acute graft-versus-host disease (GVHD) > or =grade II was significantly more common in pulmonary patients than in the controls (36/61 versus 22/61 patients, P=0.02). There was no significant difference in the incidence of chronic GVHD (P=0.09). CMV reactivation was significantly more frequent in patients with lung injury (P=0.02). Median survival was 41 weeks for the pulmonary patients and 350 weeks for the controls (P=0.001). Altogether, the incidence of pulmonary complications is low after T-cell-depleted SCT and is associated with acute GVHD and CMV reactivation.

Acute Disease↗
PubMed2006

Multiple B-cell clones producing antibodies directed to the spacer and disintegrin/thrombospondin type-1 repeat 1 (TSP1) of ADAMTS13 in a patient with acquired thrombotic thrombocytopenic purpura.

BACKGROUND: The cysteine-rich/spacer domains of ADAMTS13 contain a major binding site for antibodies in patients with acquired thrombotic thrombocytopenic purpura (TTP). OBJECTIVE: To study the heterogeneity of the antibody response towards these domains an immunoglobulin V-gene phage-display library was constructed to isolate monoclonal anti-ADAMTS13 antibodies from the immunoglobulin repertoire of a patient with acquired TTP. METHODS: Combined variable heavy chain (VH) and variable light chain (VL) segments, expressed as single-chain Fv fragments (scFv), were selected for binding to an ADAMTS13 fragment consisting of the disintegrin/thrombospondin type-1 repeat 1 (TSP1)/cysteine-rich/spacer domains. RESULTS: Seven different scFv antibody clones were identified that were assigned to four groups based on their homology to VH germline gene segments. Epitope-mapping revealed that scFv I-9 (VH1-69), I-26 (VH1-02), and I-41 (VH3-09) bind to an overlapping binding site in the ADAMTS13 spacer domain, whereas scFv I-16 (VH3-07) binds to the disintegrin/TSP1 domains. The affinity of scFv for the disintegrin/TSP1/cysteine-rich/spacer domain was determined by surface plasmon resonance analysis and the dissociation constants ranged from 3 to 254 nM. The scFv partially inhibited ADAMTS13 activity. However, full-length IgG prepared from the variable domains of scFv I-9 inhibited ADAMTS13 activity more profoundly. Plasma of six patients with acquired TTP competed for binding of scFv I-9 to ADAMTS13. CONCLUSION: Our data indicate that multiple B-cell clones producing antibodies directed against the spacer domain are present in the patient analyzed in this study. Our findings also suggest that antibodies with a similar epitope specificity as scFv I-9 are present in plasma of other patients with acquired TTP.

ADAM Proteins↗
PubMed2006

Endothelial cell activation markers and delayed cerebral ischaemia in patients with subarachnoid haemorrhage.

BACKGROUND: Endothelial cell activation may be connected with the pathogenesis of delayed cerebral ischaemia (DCI) after subarachnoid haemorrhage (SAH). AIM: To assess the relationship between serial concentrations of circulating markers of endothelial cell activation (soluble intercellular adhesion molecule-1, soluble platelet selectin (sP-selectin), soluble endothelial selectin, ED1-fibronectin, Von Willebrand Factor (VWF) and VWF propeptide) and development of DCI. METHODS: 687 blood samples were collected from 106 consecutive patients admitted within 72 h after onset of SAH. Changes in levels were analysed in the last sample before and in the first sample after the onset of DCI (n = 30), and in subgroups with DCI occurring within 24 h after treatment of the aneurysm (n = 12) or unrelated to treatment of the aneurysm (n = 18). Patients without DCI (n = 56) served as controls. RESULTS: Concentrations of sP-selectin, but not of the other markers, were found to increase considerably after DCI unrelated to treatment of the aneurysm (increase 25 ng/ml, 95% CI 8 to 43), whereas they tended to decrease in the control patients without DCI (decrease 13 ng/ml, 95% CI -28 to 2.4). Surgery was found to profoundly influence the levels of the markers irrespective of the occurrence of DCI. CONCLUSION: The rise in sP-selectin level during DCI is suggested to be the result of platelet activation, as levels of the other markers of endothelial cell activation were not increased after DCI unrelated to treatment. Whether a causal role of platelet activation is implicated in the development of DCI should be determined in further studies in which the relationship between concentrations of markers and treatment is taken into account.

Adult↗
PubMed2006

A sensitive and reliable semi-quantitative real-time PCR assay to detect JAK2 V617F in blood.

Diagnosis of the myeloproliferative disorders, polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF) is difficult due to lack of diagnostic markers. Recently, the acquisition of a mutation in the Janus kinase 2 (JAK2) gene by hemopoietic cells has been described as a genetic defect underlying myeloproliferative disorders. The mutation leads to constitutive activation of JAK2, a tyrosine kinase involved in cytokine receptor signalling. Because of the clinical importance of this mutation (JAK2 V617F) in diagnosing myeloproliferative disorders and its relevance for disease progression, we developed a semi-quantitative real-time PCR test to detect JAK2 V617F. With this assay, quantities down to 0.8% JAK2 V617F amongst wild-type DNA could reliably be detected. For quantification purposes, low intra- and inter-assay variabilities ensure good reproducibility of the assay. Thus the JAK2 V617F qPCR assay described here is quick, robust, simple and more sensitive than direct sequencing, RFLP, ARMS assay and other methods published so far to detect JAK2 V617F. We therefore believe that the assay will contribute to early diagnosis of myeloproliferative disorders and to disease management, especially when JAK2-specific inhibitors have become available for therapeutic use.

Aged↗
PubMed2006

Early circulating levels of endothelial cell activation markers in aneurysmal subarachnoid haemorrhage: associations with cerebral ischaemic events and outcome.

OBJECTIVE: To investigate the relation of endothelial cell activation with delayed cerebral ischaemia (DCI) and outcome after subarachnoid haemorrhage (SAH). METHODS: Concentrations of soluble (s) intercellular adhesion molecule-1, sE-selectin, sP-selectin, ED1-fibronectin, von Willebrand Factor (vWf), and vWf propeptide were measured within three days of SAH onset. The associations with poor outcome were investigated at three months in 106 patients. In 90 patients in whom the occurrence of cerebral ischaemia could be dated accurately, two analyses were undertaken: one for all ischaemic events (n = 32), including those related to treatment, and another for spontaneous DCI (n = 11). Concentrations of markers were dichotomised at their medians. The associations of endothelial cell activation markers with outcome were expressed as odds ratios (OR) from logistic regression and those with ischaemic events as hazard ratios (HR) derived from Cox regression. RESULTS: Early vWf concentrations were associated with poor outcome (crude OR = 4.6 (95% CI, 2.0 to 10.9; adjusted OR = 3.3 (1.1 to 9.8). Early levels of vWf were also positively related to occurrence of all ischaemic events (crude HR = 2.3 (1.1 to 4.9); adjusted HR = 1.8 (0.8 to 3.9) and with occurrence of spontaneous DCI (crude HR = 3.5 (0.9 to 13.1); adjusted HR = 2.2 (0.5 to 9.8). None of the other markers showed any associations. CONCLUSIONS: Concentrations of sICAM-1, sP-selectin, sE-selectin, and ED1-fibronectin do not predict the occurrence of DCI or outcome. The positive associations of raised early vWf concentrations with ischaemic events and poor outcome after SAH may reflect a predisposition to further ischaemic injury through formation of microthrombi in the cerebral circulation.

Adult↗
PubMed2005

Splenectomy for the treatment of thrombotic thrombocytopenic purpura.

Plasma exchange is the treatment of choice for patients with thrombotic thrombocytopenic purpura (TTP) and results in remission in >80% of the cases. Treatment of patients who are refractory to plasma therapy or have relapsing disease is difficult. Splenectomy has been a therapeutic option in these conditions but its value remains controversial. We report on a series of 33 patients with TTP who were splenectomised because they were plasma refractory (n = 9) or for relapsed disease (n = 24). Splenectomy generated prompt and unmaintained remissions in all except five patients, in whom remission was delayed (n = 4) or who died with progressive disease (n = 1). Four postoperative complications occurred: one pulmonary embolism and three surgical complications. Median follow-up after splenectomy was 109 months (range 28-230 months). The overall postsplenectomy relapse rate was 0.09 relapses/patient-year and the 10-year relapse-free survival (RFS) was 70% (95% CI 50-83%). In the patients with relapsing TTP, relapse rate fell from 0.74 relapses/patient-year before splenectomy to 0.10 after splenectomy (P < 0.00001). Two patients died from first postsplenectomy relapse. Although these results are based on retrospective data and that the relapse rate may spontaneously decrease with time, we conclude that splenectomy, when performed during stable disease, has an acceptable safety profile and should be considered in cases of plasma refractoriness or relapsing TTP to reach durable remissions and to reduce or prevent future relapses.

Adolescent↗
PubMed2004

[Activity loss of Von Willebrand factor cleaving protein (ADAMTS-13) is diagnostic for primary and pregnancy-related thrombotic thrombocytopenic purpura].

OBJECTIVE: To determine whether the measurement of the Von Willebrand factor cleaving protease ADAMTS-13, such as is carried out at the University Medical Centre of Utrecht, The Netherlands, contributes towards the diagnosis and treatment of patients with thrombotic thrombocytopenic purpura (TTP). DESIGN: Descriptive. METHOD: In a group of 98 patients from 21 hospitals, with a Coombs-negative haemolytic anaemia and thrombocytopenia, the ADAMTS-13 activity was measured. Treatment was given irrespective of ADAMTS-13 activity. RESULTS: ADAMTS-13 activity was absent in 27 of 29 patients diagnosed with primary TTP and in all 5 pregnancy-TTP patients. In patients suffering from TTP after bone marrow transplantation (post-BMT) and in all other patients included in this study, ADAMTS-13 activity was normal. Of the 32 patients with absent ADAMTS-13 activity, 28 underwent plasmapheresis. This treatment proved effective as all 28 patients responded well. 17 patients with normal ADAMTS-13 activity also underwent plasmapheresis; 5 (30%) responded well to treatment. In 2 cases a final diagnosis of primary TTP was made, in a further 2, haemolytic uraemic syndrome and in 1 case sepsis was diagnosed. CONCLUSION: In this study, the absence of ADAMTS-13 activity predicted primary TTP and TTP of pregnancy with a sensitivity of 93% and a specificity of 100%. Absence of ADAMTS-13 activity is a strong indication for plasma exchange.

ADAM Proteins↗
PubMed2004

[A woman suffering from systemic lupus erythematosus and acquired thrombotic thrombocytopenic purpura].

A 41-year-old woman with known systemic lupus erythematosus (SLE) was diagnosed with thrombotic thrombocytopaenic purpura (TTP). At the time of admission she was suffering from petechia, purpura and had neurological symptoms. At first a relapse of the SLE was suspected. Additional laboratory findings demonstrated haemolytic anaemia, thrombocytopaenia and high levels of fragmentocytes. After multiple plasmapheresis treatments and immunosuppressive therapy she recovered. TTP can be differentiated from other thrombotic microangiopathic syndromes by its normal levels of prothrombin time, partially activated thromboplastin time (APTT), fibrinogen and direct Coombs-test. Further investigation is needed to confirm the diagnosis by determination of the activity of Von Willebrand factor cleaving protease ADAMTS-13. In this patient, the ADAMTS-13 activity returned after plasmapheresis. This case demonstrates the importance of fast and appropriate laboratory testing in order to diagnose TTP quickly.

ADAM Proteins↗
PubMed2004

Spinal dural arteriovenous fistulas are not associated with prothrombotic factors.

BACKGROUND AND PURPOSE: The cause of spinal dural arteriovenous fistulas (SDAVF) is unknown. In intracranial dural arteriovenous fistulas, an association with factor V Leiden mutation has been found. Therefore, we studied the association between prothrombotic factors and SDAVF. METHODS: Factor V Leiden mutation, factor II mutation, protein S, protein C, factor VIII, von Willebrand factor, antithrombin III, and lupus anticoagulant were determined by means of standard laboratory tests in 40 patients and 119 control subjects matched for sex and age. RESULTS: Factor V Leiden mutation was not found in the patient group and was found twice in the control group. Factor II mutation was found in 1 patient and in none of the control subjects. There was no decreased activity of protein S, protein C, factor VIII, von Willebrand factor, or antithrombin III in patients in comparison with controls. Lupus anticoagulant was not found in the patient group and once in the control subjects. CONCLUSIONS: We conclude that it is unlikely that prothrombotic factors are involved in the pathogenesis of spinal dural arteriovenous fistulas, but subtle associations are not ruled out.

Activated Protein C Resistance↗
PubMed2004

Endothelial markers in chronic heart failure: training normalizes exercise-induced vWF release.

BACKGROUND: Chronic heart failure (CHF) is characterized by endothelial dysfunction. Vascular endothelium is important for control of haemostasis and vasoregulation. The aim of the present study was to investigate plasma levels of several endothelial markers and the exercise-induced changes on these plasma levels in CHF patients. Subsequently, the effect of a 6-month training programme on these markers is described. MATERIALS AND METHODS: Twenty-nine male CHF patients (NYHA II/III, age 60 +/- 8 year, body mass index 26.7 +/- 2.3 kg m(-2), left ventricular ejection fraction 26.3-7.2%; mean +/- SD) participated. Patients were randomly assigned to a training or control group. Training (26 weeks; combined strength and endurance exercises) was four sessions/week: two sessions supervised and two sessions at home. Before and after intervention, anthropometry, endothelial markers (haemostasis and vasoregulation), maximal workload and peak oxygen uptake were assessed. RESULTS: Physical training positively affected maximal workload. Plasma levels of endothelial markers were not affected by physical training and not related to exercise tolerance. After training, stimulated (maximal exercise) plasma von Willebrand Factor (vWF) release was present, whereas at baseline this release was absent. CONCLUSION: Physical training led to normalization of the stimulated plasma vWF release. Plasma levels of other endothelial markers were not affected by physical training either at rest or under stimulated (maximal exercise) conditions.

Aged↗
PubMed2004

Intraocular and plasma levels of cellular fibronectin in patients with uveitis and diabetes mellitus.

AIMS: To determine intraocular and plasma levels of cellular fibronectin (cFN) in patients with uveitis or diabetes mellitus (DM) and to assess the association with disease activity, macular oedema, and vascular leakage on fluorescein angiography. In addition, to examine whether cFN is locally produced in the eye. METHODS: Intraocular and plasma levels of cFN were determined by ELISA in 39 patients with uveitis (23 active, 16 non-active), in 11 patients with DM (eight with and three without diabetic retinopathy) and in 17 control patients. The influence of diabetic retinopathy, inflammatory activity, vascular leakage, and macular oedema (MO) on intraocular and plasma cFN levels was studied. Local production of cFN was determined by calculating absolute and relative intraocular to plasma ratios. Aqueous and vitreous levels of cFN were compared. RESULTS: No differences in plasma cFN levels were found between patients with uveitis, DM, or controls. Intraocular cFN levels were significantly raised in patients with uveitis and DM, specifically in those with active disease (active uveitis and active diabetic retinopathy versus controls: p = 0.001 and 0.002 respectively). Further, intraocular cFN levels were significantly elevated in patients with macular oedema or vascular leakage, irrespectively of whether associated with uveitis or DM (p = 0.001 and 0.002). Intraocular cFN levels were consistently higher in the vitreous than the aqueous. Intraocular production of cFN was documented by elevated absolute and relative intraocular to plasma ratios in nine out of 11 patients tested. CONCLUSIONS: Elevated intraocular cFN levels were found in uveitis and DM, especially in those with active processes, intraocular vascular damage, and MO. These results suggest that locally produced cFN levels reflect intraocular vascular damage.

Adolescent↗
PubMed2003

[Acquired von Willebrand syndrome].

Two patients, a man aged 69 and a woman aged 64, were diagnosed with Von-Willebrand syndrome caused by monoclonal gammopathy. The man, who was admitted for hip surgery, had a history of long episodes of epistaxis. The patient was treated with immunoglobulin and the hip operation was carried out with no complications. The woman suffered from haemorrhagic diathesis. She was advised that should she undergo an invasive procedure then treatment with a prophylactic with intravenous immunoglobulin or Von-Willebrand factor (VWF)/factor-VIII-concentrates must be administered. Acquired Von-Willebrand syndrome is a rare condition with an estimated prevalence of 0.04-0.13%. It is linked to a large number of underlying diseases such as paraproteinaemia, multiple myeloma (Kahler's disease), myeloproliferative disease, lymphoproliferative disease, auto-immune disease, solid tumours and hypothyroidism. Recognition depends on a careful case-history and identification of the underlying disease. For its diagnosis VWF antigen. VWF propeptide, activated partial thromboplastin time and factor VIII are of importance. Technically, it is difficult to show the presence of VWF antibodies as it concerns a heterogeneous group of antibodies. There are two pillars of treatment: symptomatic treatment of the bleeding tendencies using desmopressin, VWF-concentrate or intravenous gammaglobulin, and treatment of the underlying disease. The latter form of treatment can lead to acquired Von-Willebrand-syndrome disappearing altogether.

Aged↗
PubMed2003

[Withdrawing the use of acetylsalicyclic acid prior to an operation usually not necessary].

Acetylsalicylic acid (aspirin) induces an irreversible inactivation of cyclo-oxygenase in blood platelets which lasts for the entire period that the platelets remain in the circulatory system, 7 to 10 days. In order to prevent excessive bleeding, patients presenting for surgery are asked to stop using aspirin 10 days before the procedure. Some studies have found that aspirin causes increased peri-operative blood loss, whilst other studies have found that it does not. All effect studies found in Medline (January 1966-May 2002) on surgery and bleeding complications due to aspirin were analysed. The studies available were assessed for methodological quality and the results were summarised in an evidence table. No clinically relevant bleeding complications were reported for cardiovascular, vascular and orthopaedic surgery and epidural anaesthesia. Most studies reported an increase in clinically non-relevant bleeding induced by aspirin. The literature contains too little information on cataract surgery, dermatological surgery, gynaecological and abdominal surgery, ENT and dental surgery, urological surgery, lung biopsy and endoscopic biopsy. In those types of surgery in which even a minor bleeding leads to severe complications, e.g. neurosurgery, aspirin should be withdrawn 5-10 days in advance. Also in patients with coagulation disorders, aspirin should be withdrawn prior to the operation. There is no scientific evidence for the withdrawal of aspirin in all patients, 5-10 days prior to surgery. Indeed for heart patients in particular, the continued use of aspirin is recommended.

Aspirin↗