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M Haubitz

Publications and source records attributed to M Haubitz.

At least 19 recordsLinked to original sources
PubMed2006

Isolation and enumeration of circulating endothelial cells by immunomagnetic isolation: proposal of a definition and a consensus protocol.

BACKGROUND: Circulating endothelial cells (CECs) have been identified as markers of vascular damage in a variety of disorders, such as myocardial infarction, vasculitis, and transplantation. CD146-driven immunomagnetic isolation has gained widespread use, but the technique is hampered by the lack of a definition of CECs and the absence of a consensus for their enumeration. AIM: To evaluate several variables influencing immunomagnetic isolation of CECs, formulate a definition for CECs and propose a consensus protocol for their enumeration. METHODS: We devised a protocol based on CD146-driven immunomagnetic isolation and a subsequent confirmatory step with Ulex-Europaeus-Lectin-1 staining. In a multi-center effort, we evaluated the preanalytical and analytical phases of this protocol. We evaluated the effects of storage, anticoagulation and density centrifugation, and compiled previous experience with this technique. RESULTS: Our protocol permitted unequivocal identification of CECs with acceptable reproducibility. There was an effect of storage time in that median cell numbers declined to only 87.5% of their baseline values during 24 h of storage at 4 degrees C. Recovery was lower with citrate than with ethylene-diamine tetra-acetic acid after 4 h of storage; density centrifugation was also associated with lower recovery. We provide a comprehensive list of technical recommendations and potential pitfalls. Finally, based on our experience with this protocol and a recent consensus workshop, we formulated a working definition for CECs. CONCLUSION: Our work represents an important step toward consensus regarding the CECs. Our recommendations represent the experience of three major centers and should now be scrutinized by others in the field.

CD146 Antigen↗
PubMed2005

Circulating endothelial cells in relapse and limited granulomatous disease due to ANCA associated vasculitis.

OBJECTIVES: To evaluate numbers of circulating endothelial cells (CECs) in ANCA associated vasculitis and compare vasculitic relapse with limited granulomatous disease. METHODS: Sixteen patients with vasculitic relapse of ANCA associated vasculitis and 12 patients with limited granulomatous disease due to Wegener's granulomatosis (WG) were studied. Six patients with newly diagnosed vasculitic disease and six patients with vasculitis with infectious complications were also studied. Twenty two patients in remission were studied, as were 20 healthy controls. Counting of CECs was performed with anti-CD146 driven immunomagnetic isolation and staining with Ulex Europaeus lectin 1(UEA-1). RESULTS: Patients with vasculitic relapse had markedly increased numbers of circulating endothelial cells (12-800 cells/ml, median 88 cells/ml) as did patients with newly diagnosed systemic vasculitis (20-216 cells/ml, median 56 cells/ml). Patients with limited granulomatous disease due to WG had only slightly increased cell numbers (4-44 cells/ml, median 20 cells/ml), which were similar to those of patients in remission (4-36 cells/ml, median 16 cells/ml). Numbers of CECs in patients with granulomatous disease were significantly lower than in those patients with relapse or new onset vasculitis (p<0.001). Cell numbers in patients with relapse and new onset vasculitis declined with immunosuppressive treatment. Patients with infection had 4-36 cells/ml (median 10 cells/ml). A cut off value of 20 cells/ml for a positive result yielded 64% specificity and 95% sensitivity for active systemic vasculitis; the positive predictive value was 63% and the negative predictive value 95%. CONCLUSION: Markedly increased numbers of CECs discriminate active vasculitis from limited granulomatous disease and remission. These findings add further proof to the concept of CECs as a marker of ANCA associated small vessel vasculitis.

Acute Disease↗
PubMed2005

Smoking habits in patients diagnosed with ANCA associated small vessel vasculitis.

OBJECTIVES: To study the prevalence of smoking at onset of symptoms in patients with small vessel vasculitis associated with antineutrophil cytoplasmic antibodies (ANCA). METHODS: A retrospective study, in 197 patients with ANCA associated vasculitis, of the history of cigarette smoking at onset of symptoms. Prevalence of smoking in patients with ANCA associated vasculitis was compared with age-specific values for the general population in Germany. RESULTS: 27 (14%) patients were smokers at the time of first disease manifestation (p < 0.001, compared with the entire population); 54 (27%) had smoked previously with 1-110 pack-years (median 18) but had stopped > or = 2 years before onset of vasculitis; 116 (59%) patients were lifelong non-smokers. At onset of symptoms, active smokers were younger (median age 42 years) than patients with vasculitis (median 54 years, p < 0.01, Mann-Whitney U test) with a lower percentage of women (15%, p < 0.005, Fisher's exact test) than in the entire group (47%). Smokers, non-smokers, or ex-smokers did not differ in organ manifestation, mortality, and development of end stage renal disease and relapse rate. CONCLUSIONS: The proportion of active smokers in the group of patients with ANCA associated vasculitis is significantly lower than in the entire population. Cigarette smoking may be associated with a reduced risk of ANCA associated vasculitis.

Adolescent↗
PubMed2004

An improved assay for enumeration of circulating endothelial cells.

Circulating endothelial cells have been established as markers of vascular disease, such as small vessel vasculitis, acute vascular rejection in renal transplant recipients, and cyclosporine-induced endothelial damage. Enumeration of these cells by immunomagnetic isolation and acridine staining remains the gold standard but necessitates considerable experience and expenditure. A simpler test would therefore be of great utility. Hence, our aim was to develop an improved simple assay to enumerate endothelial cells in peripheral blood. We had already used various surface markers to corroborate the endothelial origin of cells. Here, we studied the enumeration of cell numbers with immunomagnetic isolation and a variety of subsequent stains, such as CD31, von Willebrand's factor (vWF) immunocytochemistry, and Ulex europaeus lectin-1 (UEA-1). Eventually, we devised a simple protocol for enumeration using immunomagnetic isolation and a subsequent UEA-1 lectin stain. We evaluated the use of this protocol in parallel to immunomagnetic isolation and acridine counting alone in 92 renal transplant recipients who underwent renal biopsy. Recovery of various concentrations of human umbilical vein endothelial cells from blood was also studied. Immunomagnetic isolation and subsequent UEA-1 staining permits easier enumeration of circulating endothelial cells in peripheral blood. The assay is simple and easy to use, thus allowing for a more widespread use of circulating endothelial cells as a marker of vascular damage.

Blood Cell Count↗
PubMed2004

Counting the cost: markers of endothelial damage in hematopoietic stem cell transplantation.

During hematopoietic stem cell transplantation (HSCT), endothelial damage is the pathological hallmark of veno-occlusive disease of the liver, thrombotic microangiopathy, capillary leak syndrome and graft-versus-host disease. Events prior to conditioning, the conditioning regimen itself as well as calcineurin inhibitors may all induce endothelial damage. Unfortunately, the relative importance of these factors and their interactions, the time frame of endothelial damage and individual susceptibility remain unknown. Moreover, it is conceivable that conditioning regimens differ markedly in their propensity to initiate endothelial damage. Monitoring endothelial damage and response to treatment is hampered by the current lack of suitable markers. In this regard, an ideal marker should be sensitive and specific and indicate the development of an endothelial disorder prior to the onset of symptoms and organ dysfunction. Soluble markers, such as thrombomodulin, are easily amenable with immunoassays; yet, the interpretation of their levels is hampered by the influence of comorbidity. Evaluation of circulating endothelial cells in HSCT demonstrated a marked and dose-dependent increase in cell numbers after conditioning. The challenge ahead is to establish and evaluate novel markers of endothelial damage to permit early detection of disease, monitor response to treatment and evaluate different conditioning regimens.

Biomarkers↗
PubMed2004

A novel multimedia tool to improve bedside teaching of cardiac auscultation.

Training in cardiac auscultation is a core element of undergraduate teaching but recent studies have documented a remarkable decline in auscultatory skills. Therefore there is an interest in new ways to teach cardiac auscultation. In analogy to phonocardiography, an electronic system for simultaneous auscultation and visualisation of murmurs was sought. For this purpose, an electronic stethoscope was linked to a laptop computer and software created to visualise auscultatory findings. In a preliminary trial in undergraduate students, this approach greatly facilitated teaching. Amalgamating traditional phonocardiography with a multimedia approach, this system represents a novel tool for bedside teaching of cardiac auscultation.

Education, Medical, Undergraduate↗
PubMed2004

Genetic impact of pathogenesis and prognosis of ANCA-associated vasculitides.

Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and the Churg-Strauss syndrome (CSS) are small vessel vasculitides associated with anti-neutrophil cytoplasmic antibodies (ANCA). Cytoplasmic (c)-ANCA mainly target proteinase 3 (PR3) and are often observed in WG patients, while perinuclear (p)-ANCA predominantly bind to myeloperoxidase (MPO) and are common in patients with MPA and CSS. It is suspected that a genetic background contributes to disease formation since the diseases are more prevalent in Caucasian populations. This article provides a detailed review of the genetic impact of the pathogenesis and prognosis of ANCA-associated vasculitides. Alpha-1 anti-trypsin is the physiological inhibitor of PR3 and carriage of the defective allele PI*Z was observed as the first genetic risk factor for the development of PR3-ANCA-associated vasculitis. Expression analyses have revealed that PR3 surface expression is genetically determined. Elevated levels of PR3 expression have been observed in WG patients and high levels of PR3 expression corresponded to increased risk of disease relapses. Furthermore, the non-carriage of CTLA-4 allele 86 was associated with WG formation, while homocygotic carriage of the CCR5 allele delta 32 seemed to prevent ANCA-negative WG. MPO-ANCA vasculitides were associated with certain alleles of CD18 polymorphisms. Lack of or only weak allelic associations of ANCA-vasculitides with polymorphic cytokine, HLA, and Fcgamma receptor genes have been shown. Although, in practice, it is sometimes difficult to differentiate between WG and MPA, the diseases appear to be based on different genetic backgrounds.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2002

Tolerance of mycophenolate mofetil in end-stage renal disease patients with ANCA-associated vasculitis.

BACKGROUND: Mycophenolate mofetil (MMF) has been used successfully in patients with ANCA-associated vasculitis as maintenance therapy. Only transient and moderate side effects have been reported with a daily dose of 2 g. Since all the treated patients who have been reported so far had no or only moderate renal insufficiency when MMF was initiated, no data are available regarding side effects in patients with end-stage renal disease (ESRD). METHODS: Five ESRD patients with ANCA-associated vasculitis and a relapsing course of their disease were treated. All patients had pretreatment with cyclophosphamide for at least 17 months. MMF was initiated as a remission maintenance therapy, and started with a dose of 1 g/d. The aim was to increase the MMF dose to 2 g/d. Blood counts, liver enzymes and gastrointestinal side effects were monitored. RESULTS: Four patients developed severe anemia, 2 requiring blood transfusion with permanent or temporary cessation of MMF treatment. One patient developed leukopenia. Gastrointestinal symptoms led to a dose reduction to 1 g/d (n = 2) or cessation of treatment (n = 1). Three patients remained on longer MMF treatment; however, their daily dose did not exceed 1 g. CONCLUSION: MMF, a promising drug regarding maintenance therapy in ANCA-associated vasculitis, seems to have more side effects in ESRD patients, leading to dose reduction or even cessation of treatment. Therefore, in this patient group a lower dose and closer monitoring for side effects seems to be required compared to patients with no or moderate renal insufficiency.

Adult↗
PubMed2001

Endothelial tissue factor stimulation by proteinase 3 and elastase.

In ANCA-associated vasculitis the activation of primed leucocytes by autoantibodies with subsequent release of proteases such as myeloperoxidase (MPO), proteinase 3 (PR3) and elastase is thought to play an important pathogenetic role. Whether these proteases contribute to the vascular lesions by stimulating the procoagulant activity of these cells is unknown. Tissue factor (TF) expression and activity were investigated in human umbilical vein endothelial cells after stimulation with MPO, PR3 and elastase. TF activity was measured using a one-stage clotting assay. Polyclonal antibodies to TF were used to prove specificity. TF mRNA was detected by reverse transcriptase-polymerase chain reaction. PR3 and elastase led to a significant increase in TF mRNA expression and increased activity. The stimulation was not mediated by IL-1. The stimulatory effect of PR3 did not depend on its proteolytic activity (no inhibition by alpha-1-antitrypsin), whereas the effect of elastase was blocked by alpha-1-antitrypsin. MPO had no effect on TF activity. These results show that PR3 and elastase stimulate TF expression in human endothelial cells. In ANCA-associated vasculitis the increased release of proteases may contribute to the development of microthrombi and consecutive necrosis.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2001

C-reactive protein and chronic Chlamydia pneumoniae infection--long-term predictors for cardiovascular disease and survival in patients on peritoneal dialysis.

BACKGROUND: Accelerated arteriosclerosis with cardiovascular disease is the main cause of death in end-stage renal disease patients. Increased, levels of C-reactive protein (CRP) and evidence of chronic Chlamydia pneumoniae infection have been identified as risk factors for cardiovascular disease in the general population. We tested the hypothesis that elevation of CRP, indicating chronic inflammation, and positive serum antibody titres for C. pneumoniae are associated with an increased cardiovascular mortality in patients on chronic peritoneal dialysis. METHODS: We measured CRP and antibodies to C. pneumoniae in 34 patients on peritoneal dialysis. CRP was measured by a sensitive ELISA and C. pneumoniae antibodies by microimmunofluorescence. In addition, risk factors such as lipids, smoking status and hypertension were assessed. Coronary artery disease (CAD) was defined by cardiac stress testing and/or angiography. Patients showing clinical evidence of systemic or peritoneal dialysis-associated infection during the investigation period of 6 months (between 1990 and 1991) were excluded. RESULTS: The incidence of CAD was significantly increased in patients with CRP values >1.5 mg/l (odds ratio 7.0, P<0.022) during 72 months of follow-up. In addition, in patients seropositive for IgA C. pneumoniae antibodies, the incidence of CAD was significantly increased (odds ratio 7.2, P<0.014). These findings resulted in an increased risk of death in patients with mean CRP values >1.5 mg/l at the start of the study (odds ratio 20.0, P<0.001). Furthermore, in patients seropositive for IgA C. pneumoniae antibodies, the risk of death (odds ratio 10.2, P<0.005) was significantly increased. There was a highly significant correlation between CRP and seropositivity for IgA C. pneumoniae antibodies (r=0.445, P<0.01). CONCLUSIONS: Increased circulating CRP and seropositivity for C. pneumoniae in patients on chronic peritoneal dialysis are associated with reduced survival due to cardiovascular complications. CRP and C. pneumoniae antibodies may indicate a chronic inflammatory process as an underlying cause and/or result of arteriosclerosis.

Adult↗
PubMed2000

Activation of the acute phase response and complement C3 in patients with IgA nephropathy.

UNLABELLED: Recently we showed systemic complement activation in patients with immunoglobulin A (IgA) nephropathy (measured by "activated C3" [actC3], in other words, neoantigens developing on breakdown products after C3 activation) and reported that plasma levels of actC3 can indicate disease activity and renal outcome. In this study we investigated whether plasma C3a and C-reactive protein (CRP), which require tests that are more readily available, have a similar diagnostic and predictive value. CRP was measured using a highly sensitive enzyme-linked immunosorbent assay and C3a using a specific immunoassay. CRP and C3a levels were significantly higher in 56 patients with IgA nephropathy as compared with 55 healthy controls. C3a levels in IgA nephropathy patients were also significantly increased in comparison with 42 patients with hypertension or nonimmune renal diseases. Neither C3a nor CRP levels correlated with those of actC3 in IgA nephropathy patients. We also compared 10 IgA nephropathy patients with stable, normal renal function with eight IgA nephropathy patients progressing from normal to impaired renal function during mean follow-ups of 7.1 and 5.1 years, respectively. Mean CRP but not C3a levels during the observation period were significantly higher in IgA nephropathy patients with disease progression than in those with stable renal function. CONCLUSION: Systemic complement activation can be detected by measurement of plasma C3a in IgA nephropathy, but C3a levels cannot substitute for actC3 in predicting renal prognosis. Subclinical induction of the acute phase response is also present in patients with progressive IgA nephropathy, but again its prognostic value is limited. Repeated determinations performed over prolonged time courses may possibly improve the prognostic value of CRP levels.

Acute-Phase Reaction↗
PubMed1999

Exhaled nitric oxide in patients with Wegener's granulomatosis.

In Wegener's granulomatosis (WG), a pathogenic role of infections, in particular of a chronic colonization of the nasal mucosa with Staphylococcus aureus, has been postulated. Nitric oxide (NO), which is thought to play a role in primary host defence and inflammation, is produced endogenously within the respiratory tract, mainly from the paranasal sinuses. In order to further characterize its role in WG, nasal and pulmonary NO excretion in WG patients in comparison to healthy volunteers was measured. Seventeen patients with WG were included in the study. Five patients had active disease (bloody rhinitis with ulceration and crusting) and immunosuppressive therapy (IST), and 12 were in remission (six with, and six without, IST). S. aureus was found in the swabs of all patients with active WG and in three patients in remission. NO was measured in exhaled gas using a chemiluminescence analyser. The NO excretion rate in nasally sampled gas was significantly reduced (p<0.05) in patients with active WG ((mean+/-SD)102+/-100 nL x min(-1)) compared to healthy controls (299+/-13 nL x min(-1)), and patients in remission (281+/-86 nL x min(-1) with IST, 280+/-133 nL x min(-1) without IST). Pulmonary NO excretion in active or nonactive WG patients did not significantly differ from that of healthy volunteers (48+/-21 nL x min(-1)). These results demonstrate a reduced nasal NO excretion in active Wegener's granulomatosis. This may be caused by destruction and/or functional impairment of sinus epithelium. The reduced NO concentration may well compromise host defence in the upper airways, thus contributing to colonization with Staphylococcus aureus and further promoting Wegener's granulomatosis.

Adult↗
PubMed1998

Intravenous pulse administration of cyclophosphamide versus daily oral treatment in patients with antineutrophil cytoplasmic antibody-associated vasculitis and renal involvement: a prospective, randomized study.

OBJECTIVE: There is growing concern about the toxic side effects of daily oral cyclophosphamide (CYC) treatment. Intravenous (i.v.) pulse administration of CYC has been shown to be effective in patients with systemic lupus erythematosus, but contradictory results have been reported in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. METHODS: The efficacy and toxicity of i.v. pulse administration of CYC (0.75 gm/m2) versus daily oral CYC treatment (2 mg/kg body weight) were investigated in a prospective, randomized, multicenter study in patients with ANCA-associated vasculitis and renal involvement. RESULTS: The cumulative CYC dose was reduced by 57% in patients with i.v. pulse treatment (n = 22) compared with patients treated with daily oral therapy (n = 25). Patient survival, remission rate, time of remission, relapse rate, and outcome of renal function were not different between the 2 treatment groups. However, the rate of leukopenia (P < 0.01) and severe infections (P < 0.05 by 1-tailed test) was significantly reduced in the i.v. pulse group compared with the group receiving daily oral treatment. Moreover, gonadal toxicity was reduced in the i.v. pulse group, as indicated by significantly lower levels of follicle-stimulating hormone. CONCLUSION: This randomized study shows that i.v. CYC administration is an effective therapeutic tool with low toxicity in patients with ANCA-associated vasculitis and renal involvement.

Administration, Oral↗
PubMed1998

Survival and vasculitis activity in patients with end-stage renal disease due to Wegener's granulomatosis.

BACKGROUND: In patients with end-stage renal disease (ESRD) due to Wegener's granulomatosis, a decrease in vasculitis activity after the development of ESRD, as described in other autoimmune diseases, has been postulated. However, up to now no data in a larger group of patients with Wegener's granulomatosis on chronic dialysis have been available. METHODS: We retrospectively analysed the clinical course of 35 patients with Wegener's granulomatosis and ESRD during chronic dialysis treatment. Diagnosis was based on clinical manifestation, antineutrophil cytoplasmic antibodies and/or histology. RESULTS: During a mean follow-up of 43 months (5-113 months), six patients died, three related to treatment toxicity. The patient survival rates (according to Kaplan-Meier calculation) were 93% after 2 years and 79% after 5 years. Twenty-nine relapses of Wegener's granulomatosis occurred in 17 patients (relapse rate 0.24/patient/year); 2/3 of the relapses were seen during treatment with steroids, 1/6 during cyclophosphamide therapy. The relapses were not related to the dialysis membrane used. Remission or partial remission could be achieved in 93% of the relapses. CONCLUSIONS: The survival of patients on chronic dialysis treatment due to Wegener's granulomatosis was comparable to that of other patient groups with ESRD. The relapse rate was not different from that of non-dialysed patients with Wegener's granulomatosis, and this finding underlines the need for a therapeutic strategy to maintain long-term remission in dialysis-dependent patients, too.

Adolescent↗