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Biomedical subjects

Andreas Krause

Publications and source records attributed to Andreas Krause.

12 recordsLinked to original sources
PubMed2006

Estrogen-independent proliferation is present in estrogen-receptor HER2-positive primary breast cancer after neoadjuvant letrozole.

PURPOSE: To investigate the impact of human epidermal growth factor receptor (HER) 1 and HER2 gene amplification on endocrine therapy responsiveness, a fluorescence in situ hybridization (FISH) study was conducted on tumor samples from 305 postmenopausal patients with stage II and III estrogen receptor (ER) -positive (ER > or = 10%) breast cancers treated on two independent neoadjuvant endocrine therapy trials. PATIENTS AND METHODS: FISH analysis focused on HER1 and/or HER2 immunohistochemistry (IHC) -positive patients and a random selection of HER1/2 IHC-negative patients. HER2 FISH status was correlated with response and changes in the proliferation marker Ki67. RESULTS: HER1 was rarely amplified (< 1%), and HER2 amplification was observed in 9.2% of patients. Letrozole response by clinical measurement (71% HER2 FISH positive v 71% HER2 FISH negative), mammogram (44% HER2 FISH positive v 47% HER2 FISH negative), or ultrasound (47% HER2 FISH positive v 54% HER2 FISH negative) was not impaired by HER2 FISH-positive status. In contrast, HER2 FISH-positive tumors showed higher histologic grade (P = .009), higher pretreatment Ki67 (P = .005), and less Ki67 suppression after letrozole when compared with HER2 FISH-negative tumors (P = .0001). Similar observations regarding Ki67 were made in a smaller cohort of tamoxifen-treated tumors. CONCLUSION: Neoadjuvant letrozole is clinically effective in ER-positive HER2 FISH-positive tumors, indicating sensitivity to short-term estrogen deprivation. However, continued proliferation despite ongoing letrozole or tamoxifen treatment in the majority of ER-positive HER2 FISH-positive samples (88%) could imply therapeutic resistance that may manifest later in the clinical course of the disease. Discordance between clinical and biomarker findings in this study serves to emphasize the need for surrogate end point validation in neoadjuvant endocrine trials through correlation with information on long-term outcomes.

Aged↗
PubMed2006

Failure of catecholamines to shift T-cell cytokine responses toward a Th2 profile in patients with rheumatoid arthritis.

To further understand the role of neuro-immunological interactions in the pathogenesis of rheumatoid arthritis (RA), we studied the influence of sympathetic neurotransmitters on cytokine production of T cells in patients with RA. T cells were isolated from peripheral blood of RA patients or healthy donors (HDs), and stimulated via CD3 and CD28. Co-incubation was carried out with epinephrine or norepinephrine in concentrations ranging from 10(-5) M to 10(-11) M. Interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-10 were determined in the culture supernatant with enzyme-linked immunosorbent assay. In addition, IFN-gamma and IL-10 were evaluated with intracellular cytokine staining. Furthermore, basal and agonist-induced cAMP levels and catecholamine-induced apoptosis of T cells were measured. Catecholamines inhibited the synthesis of IFN-gamma, TNF-alpha, and IL-10 at a concentration of 10(-5) M. In addition, IFN-gamma release was suppressed by 10(-7) M epinephrine. Lower catecholamine concentrations exerted no significant effect. A reduced IL-4 production upon co-incubation with 10(-5) M epinephrine was observed in RA patients only. The inhibitory effect of catecholamines on IFN-gamma production was lower in RA patients as compared with HDs. In RA patients, a catecholamine-induced shift toward a Th2 (type 2) polarised cytokine profile was abrogated. Evaluation of intracellular cytokines revealed that CD8-positive T cells were accountable for the impaired catecholaminergic control of IFN-gamma production. The highly significant negative correlation between age and catecholamine effects in HDs was not found in RA patients. Basal and stimulated cAMP levels in T-cell subsets and catecholamine-induced apoptosis did not differ between RA patients and HDs. RA patients demonstrate an impaired inhibitory effect of catecholamines on IFN-gamma production together with a failure to induce a shift of T-cell cytokine responses toward a Th2-like profile. Such an unfavorable situation is a perpetuating factor for inflammation.

Adult↗
PubMed2006

Healthcare and burden of disease in psoriatic arthritis. A comparison with rheumatoid arthritis and ankylosing spondylitis.

OBJECTIVE: To compare quality of life and treatment among patients with psoriatic arthritis (PsA), rheumatoid arthritis (RA), and ankylosing spondylitis (AS) treated by German rheumatologists. METHODS: Data for outpatients with PsA (n = 1863), RA (n = 9627), or AS (n = 1378) enrolled in the national database of the German collaborative arthritis centers in the year 2002 were analyzed. Among those with PsA, 2 subgroups with predominantly peripheral arthritis (n = 1612) and predominantly axial disease (n = 251) were distinguished. RESULTS: We found a high burden of illness in patients with PsA treated by rheumatologists. Among the 2 subgroups, those with axial PsA had worse outcomes (pain, function) than those with peripheral PsA. However, compared with RA and AS, physician ratings of disease activity and severity were lower in PsA. Concerning access to rheumatology care, there were similarities between AS and axial PsA, with very long disease duration at first visit (mean of about 6 yrs), versus RA and peripheral PsA, with shorter duration (1.6 and 2.5 yrs, respectively). A majority (84%) of patients with PsA were treated with disease modifying antirheumatic drugs. Thirty percent of the patients with PsA currently were under therapy with glucocorticoids, mainly (89%) with a dose < 7.5 mg. CONCLUSION: Patients with PsA seen in rheumatologic care have a burden of illness comparable to that of patients with RA or AS.

Arthritis, Psoriatic↗
PubMed2005

Efficacy of rivastigmine in Alzheimer's disease patients with rapid disease progression: results of a meta-analysis.

BACKGROUND: Alzheimer's disease (AD) patients experiencing more rapid symptom progression are likely to have a poorer prognosis than those experiencing slow symptom progression. In a recent retrospective analysis, treatment effects of rivastigmine were more pronounced in AD patients with rapid cognitive decline than in those with slow cognitive decline. This warranted further investigation. METHODS: Rapidly and slowly progressing patients were identified by rates of cognitive decline [>/=4 points and <4 points, respectively, on the Alzheimer's Disease Assessment Scale -- cognitive subscale (ADAS-cog)] during 26 weeks of placebo treatment in four randomized controlled trials (weeks 0--26). This meta-analysis evaluated rates of cognitive decline in both subgroups during subsequent open-label rivastigmine 26-week extension studies (weeks 26--52). A longitudinal mixed effects model compared cognitive decline in rapidly and slowly progressing patients, including correction for possible regression to the mean. RESULTS: 180 (75%) rapidly and 337 (78%) slowly progressing patients provided ADAS-cog data after 26 weeks of open-label rivastigmine treatment. Improvements in cognitive symptoms were observed during the first 12 weeks, which were more pronounced in patients with rapid progression than in those with slow progression. Rapidly progressing patients experienced significantly greater cognitive benefits than slowly progressing patients (p=0.029), who experienced a modest decline in cognitive symptoms at the end of the study. COMMENT: Patients experiencing rapid symptom progression may receive greater benefit from rivastigmine than those with slow progression. In this study, cholinesterase inhibition appeared to be of particular utility in the management of AD patients whose symptoms were rapidly worsening.

Alzheimer Disease↗
PubMed2005

A standard curve based method for relative real time PCR data processing.

BACKGROUND: Currently real time PCR is the most precise method by which to measure gene expression. The method generates a large amount of raw numerical data and processing may notably influence final results. The data processing is based either on standard curves or on PCR efficiency assessment. At the moment, the PCR efficiency approach is preferred in relative PCR whilst the standard curve is often used for absolute PCR. However, there are no barriers to employ standard curves for relative PCR. This article provides an implementation of the standard curve method and discusses its advantages and limitations in relative real time PCR. RESULTS: We designed a procedure for data processing in relative real time PCR. The procedure completely avoids PCR efficiency assessment, minimizes operator involvement and provides a statistical assessment of intra-assay variation. The procedure includes the following steps. (I) Noise is filtered from raw fluorescence readings by smoothing, baseline subtraction and amplitude normalization. (II) The optimal threshold is selected automatically from regression parameters of the standard curve. (III) Crossing points (CPs) are derived directly from coordinates of points where the threshold line crosses fluorescence plots obtained after the noise filtering. (IV) The means and their variances are calculated for CPs in PCR replicas. (V) The final results are derived from the CPs' means. The CPs' variances are traced to results by the law of error propagation. A detailed description and analysis of this data processing is provided. The limitations associated with the use of parametric statistical methods and amplitude normalization are specifically analyzed and found fit to the routine laboratory practice. Different options are discussed for aggregation of data obtained from multiple reference genes. CONCLUSION: A standard curve based procedure for PCR data processing has been compiled and validated. It illustrates that standard curve design remains a reliable and simple alternative to the PCR-efficiency based calculations in relative real time PCR.

Algorithms↗
PubMed2004

Mobile decision support for transplantation patient data.

In high-critical medical fields instant information delivery is essential. Task-flow analyses within the transplantation unit of the Technische Universität München revealed that valuable time could be saved in pre-transplantation management being able to retrieve data of organ receivers ubiquitously. Inspired by this clinical scenario, a mobile application was designed and implemented providing surgeons with decision-relevant information on potential organ receivers. It assists them in considering the prospects of forthcoming organ transplantations and facilitates decision making and documentation with regard to high security demands. The described system services three organ receiver lists and is used by the surgeons in every transplantation procedure. After a 6-month period of clinical usage, the system has been evaluated in terms of handling, clinical benefit and total time savings. Intuitive, ubiquitous access to decision-relevant patient data and authenticated documentation were the major improvements with average total time savings of 50 min in comparison to the old system.

Computers, Handheld↗
PubMed2004

Serum KIT and KIT ligand levels in patients with gastrointestinal stromal tumors treated with imatinib.

Imatinib mesylate is a selective inhibitor of a few tyrosine kinases including KIT, and it is the first effective treatment for gastrointestinal stromal tumors (GISTs). We monitored the serum levels of KIT, KIT ligand (stem cell factor, SCF), and the vascular endothelial growth factor (VEGF) in patients with advanced GISTs treated with imatinib in a prospective randomized trial. Patients with GISTs (n = 66) had elevated pretreatment serum KIT and VEGF levels as compared with controls (median, 292 AU/mL [409 ng/mL] vs 238 AU/mL [333 ng/mL], P =.037; and median, 303 pg/mL vs 190 pg/mL, P =.013, respectively), but lower levels of SCF (median, 645 pg/mL vs 950 pg/mL; P < or =.0001). After 1 and 6 months of imatinib treatment the average serum KIT levels decreased 31% and 52% from pretreatment levels, whereas SCF levels increased 11% and 33%, respectively. Serum VEGF levels decreased during treatment in responding patients. The median serum SCF/KIT ratio increased with treatment duration, and was 7.7-fold higher after 12 months of treatment than at baseline (range, 3.1-259-fold). A high serum SCF/KIT ratio may increase SCF-induced cell signaling with prolonged imatinib treatment, at the time when imatinib treatment is withdrawn, and in patients whose GIST has wild-type receptors.

Adult↗
PubMed2003

Early prognosis of the development of renal chronic allograft rejection by gene expression profiling of human protocol biopsies.

BACKGROUND: Chronic allograft rejection (CR) is the major cause of failure of long-term graft survival and is so far irreversible. Early prognosis of CR by molecular markers before overt histologic manifestation would be a valuable aid for the optimization of treatment regimens and the design of clinical CR trials. Oligonucleotide microarray-based approaches have proven to be useful for the diagnosis and prognosis of a variety of diseases and were chosen for the unbiased identification of prognostic biomarkers. METHODS: Renal allograft biopsies were taken at month 6 posttransplantation (PT) from two groups who were, at that time, healthy recipients: one group developed CR at month-12 PT, the other group remained healthy. Gene expression profiles from the two groups at month-6 PT biopsies were analyzed to identify differentially expressed genes with prognostic value for CR development at month 12. RESULTS: A set of 10 genes was identified that showed differential expression profiles between the two patient groups and had a complete separation of the 15% to 85% quantile range for each individual gene. This set of genes was sufficient to allow the correct prediction of the occurrence or nonoccurrence of CR in 15 of 17 (88%) patients using cross-validation (occurrence for a patient was predicted on the basis of the other patients' data only). In addition, a correct prediction could be made that a recipient with a normal biopsy 12 months PT developed CR within the following 6 months. CONCLUSIONS: Identified expression patterns seem to be highly prognostic of the development of renal CR.

Adult↗
PubMed2003

Lyme disease (Lyme borreliosis).

Lyme borreliosis (Lyme disease) is a systemic infectious disease with a wide spectrum of symptoms affecting the skin, the heart, and the nervous and musculoskeletal systems. Lyme borreliosis is caused by the spirochaete Borrelia burgdorferi and transmitted by ticks. The disease occurs in endemic pockets with an incidence of from 50 to more than 100 cases per 100,000 inhabitants. Despite increasing knowledge about the virulence factors of the spirochaetes and the immune response of the host, many aspects of the pathogenesis, for example of chronic treatment-resistant disease, are still a matter of debate. The diagnosis is based on clinical findings and confirmed by serology. Diagnostic problems arise from patients with non-specific symptoms and a positive IgG serology. In about 80% of the patients, the disease can be cured by adequate antibiotic therapy. Evidence-based guidelines for treatment have been recently published. The only vaccine to prevent Lyme disease, licensed in the USA, has been discontinued due to disappointing sales despite good efficacy and tolerability.

Anti-Bacterial Agents↗
PubMed2003

Classification of rheumatoid joint inflammation based on laser imaging.

We describe a classification system for a novel imaging method for arthritic finger joints. The basis of this system is a laser imaging technique which is sensitive to the optical characteristics of finger joint tissue. From the laser images acquired at baseline and follow-up, finger joints can automatically be classified according to whether the inflammatory status has improved or worsened. To perform the classification task, various linear and kernel-based systems were implemented and their performances were compared. Based on the results presented in this paper, we conclude that the laser-based imaging permits a reliable classification of pathological finger joints, making it a sensitive method for detecting arthritic changes.

Algorithms↗
PubMed2002

Assessment of proximal finger joint inflammation in patients with rheumatoid arthritis, using a novel laser-based imaging technique.

OBJECTIVE: To evaluate a newly developed laser-based imaging technique for the study of soft tissue changes and acute inflammatory processes of the proximal interphalangeal (PIP) joints in patients with rheumatoid arthritis (RA). METHODS: A novel imaging device was developed which allows the transillumination of PIP joints using laser light in the near-infrared wavelength range. In a first clinical followup study, a total of 72 PIP joints of 22 patients with RA and 64 PIP joints of 8 healthy controls were examined both clinically and with the new laser device. At baseline and at followup after a mean of 6 weeks, clinical signs of synovitis, the joint circumference, and the degree of pain were assessed for each PIP joint in order to determine the clinical degree of inflammation. Different features were extracted from the laser images and evaluated by a neural network. RESULTS: At baseline, 72 PIP joints in the RA patients showed clinical signs of inflammation. At followup, 45 PIP joints showed clinical improvement, 13 showed steady active inflammation, and 14 showed deterioration compared with the first visit. None of the 64 PIP joints in the healthy individuals showed any signs of synovitis. The inflammatory status of 60 of the 72 RA joints examined was classified correctly by laser examination and joint circumference determination, giving a sensitivity of 80%, a specificity of 89%, and an accuracy of 83% in detecting inflammatory changes in affected joints. Laser data and joint circumference determination of healthy joints at followup resulted in an accuracy of 85% in reproducing the image. CONCLUSION: The new laser-based imaging technique allows the transillumination of PIP joints and gives information about the inflammatory status of the joint after processing through a neural network. Our data indicate that laser imaging may provide additional information in the early diagnosis of an inflammatory joint process and may prove particularly useful in assessing acute joint inflammation at followup.

Adult↗