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Biomedical subjects

C Stephan

Publications and source records attributed to C Stephan.

At least 19 recordsLinked to original sources
PubMed2006

Early detection of cancer: ideas for a debate.

Even if the overall number of cancer is increasing, the mortality has started to decrease in the Western World. The role of early detection in this decrease is a matter of debate. To assess its impact on mortality it is important to distinguish between diagnosis of cancer in symptomatic patients, and early detection in asymptomatic individuals who may self-refer or who may be offered ad hoc or systematic screening. The policies for early detection and screening vary greatly between European countries, despite many similarities in their cancer burden, and this partly reflects the uncertainties surrounding asymptomatic testing for cancer. A Task Force of European expert, held in Azzate (VA), Italy, established to address these issues, acknowledged the need for more research in the field of individual risk assessment since general statistics are more and more perceived as inadequate to design personal early detection plans. The group also recognised that combinations of early detection and screening will enforce the effectiveness of new treatments in curbing mortality curves, although policies will vary with different cancers.

Breast Neoplasms↗
PubMed2006

The HUPO Brain Proteome Project--no need to hurry?

The HUPO Brain Proteome Project (HUPO BPP) is dedicated to the analysis of the brain proteome and has initiated two pilot studies in order to elaborate a standardised system for data collection and reprocessing. Samples of mouse brains (different developmental stages) and human brain tissue (biopsy and post-mortem samples) were shipped to different laboratories in Europe, Asia and the US that were invited to identify as many proteins as possible using their own approaches. In addition, a centralised data reprocessing strategy has been elaborated in an iterative way to generate highly reliable lists of identified proteins. This consortium could be a good example for a standardized proteomics workflow.

Animals↗
PubMed2006

Expression of human Kallikrein 14 (KLK14) in breast cancer is associated with higher tumour grades and positive nodal status.

Human kallikrein 14 (KLK14) is a steroid hormone-regulated member of the tissue kallikrein family of serine proteases, for which a prognostic and diagnostic value in breast cancer has been suggested. To further characterise the value of KLK14 as a breast tumour marker, we have carefully analysed KLK14 expression in normal breast tissue and breast cancer both on the RNA level by real-time RT-PCR (n = 39), and on the protein level (n = 127) using a KLK14-specific antibody for immunohistochemistry. We correlated KLK14 protein expression data with available clinico-pathological parameters (mean follow-up time was 55 months) including patient prognosis. KLK14 RNA expression as quantified by real-time RT-PCR was significantly more abundant in breast tumours compared to normal breast tissue (P = 0.027), an issue that had not been clarified recently. Concordantly with the RNA data, cytoplasmic KLK14 protein expression was significantly higher in invasive breast carcinomas compared to normal breast tissues (P = 0.003). Furthermore, KLK14 protein expression was associated with higher tumour grade (P = 0.041) and positive nodal status (P = 0.045) but was not significantly associated with shortened disease-free or overall patient survival time in univariate analyses. We conclude that KLK14 is clearly overexpressed in breast cancer in comparison to normal breast tissues and is positively associated with conventional parameters of tumour aggressiveness, but due to a missing association with survival times, the use of KLK14 immunohistochemistry as a prognostic marker in breast cancer is questionable.

Adult↗
PubMed2006

Loss of the tissue-specific proapoptotic BH3-only protein Nbk/Bik is a unifying feature of renal cell carcinoma.

We report for the first time inactivation of a tissue-specific Bcl-2 homology domain 3 (BH3)-only protein as a common aspect in human cancer. In detail, we show that loss of the BH3-only protein natural born killer (Nbk)/Bcl-2-interacting killer (Bik) is a common feature of clear-cell renal cell carcinoma (RCC). While strong Nbk expression is found in the renal tubuli and the epithelial lining of the glomerula, a consistent loss of Nbk expression was observed in primary RCC tissue and RCC cell lines. Mutation of Nbk is, however, rare, whereas deletion of the Nbk gene at 22q13.2 is frequent. In addition to loss of heterozygosity (LOH), DNA methylation mediates transcriptional silencing of the Nbk gene. The conditional restoration of Nbk/Bik expression led to apoptotic death of RCC but not of nonmalignant renal epithelia. A broader expression analysis of RCC cell lines for BH3-only proteins revealed that loss of Nbk coincides with failure to express Bim, whereas Puma, Bid and BNIP3 are readily detectable and, in case of Puma, inducible by p53. These data delineate a role for defects in BH3-only proteins as tumor suppressors in RCC and may explain at the same time the impressive clinical apoptosis resistance of RCC.

Adult↗
PubMed2006

[Motivational interviewing of unemployed acceptance and effects of counselling to improve health-related behaviour].

PURPOSE: Conception, implementation and evaluation of a risk-reducing and health-promoting brief intervention addressed to unemployed. METHOD: Control-group-study with repeated measurement. 131 unemployed took part in the intervention group and 95 persons were matched according to age and sex and served as a reference group. The intervention group were recruited via flyers, press articles and several institutions, the reference group via the journal of a health insurance company. The reference group received a questionnaire twice assessing the same health-related variables as the intervention group. INTERVENTION: In the intervention group, life style-related variables - eating habits, exercising, smoking, alcohol consumption - were assessed via questionnaire. In a one-hour counselling session based on Motivational Interviewing, participants received an individual feedback on their results of the questionnaire, including a comparison against standards and a review of their personal risks and negative consequences as well as advice and recommendations, while the decision for or against a behaviour change was left to the participant. RESULTS: 85.2 % of the participants of the intervention reported that the counselling met their expectations, and 86.2 % would recommend the intervention to a friend. Statistically significant effects for the intervention group compared to the control group from pre- to post-measurement could be shown for alcohol consumption, eating habits, and exercise (p <or= 0.0125 with a Bonferroni correction for multiple comparisons). Differences were also shown for the subjective state of health; however, they failed to attain statistical significance. CONCLUSIONS: The results of the study indicate that this kind of intervention might have positive effects regarding the promotion of health and a healthy life-style and that it might sensitize participants regarding their subjective state of health. The results of the pilot study will have to be substantiated by further studies.

Adult↗
PubMed2005

The Protease Inhibitor Transfer Study (PROTRA 1): abacavir and efavirenz in combination as a substitute for a protease inhibitor in heavily pretreated HIV-1-infected patients with undetectable plasma viral load.

OBJECTIVES: The aim of the study was to evaluate the safety and efficacy of abacavir (ABC) and efavirenz (EFV) instead of a protease inhibitor (PI) in HIV-1-infected subjects treated with two nucleoside reverse transcriptase inhibitors (NRTIs) and one PI with undetectable viral loads (< 50 HIV -1 RNA copies/mL). To be eligible for inclusion, patients had to have a history of viral load < 400 copies/mL for at least 3 months and had to be naive to treatment with nonnucleoside reverse transcriptase inhibitors (NNRTIs) and ABC, but multiple pretreatment and treatment failure were allowed. DESIGN: An open-label, single-centre pilot study of duration 48 weeks was conducted. ABC was added to the original treatment with two NRTIs and one PI at baseline, and at week 6 the PI was replaced by EFV. At each study visit, CD4 cell count, viral load [measured by polymerase chain reaction (PCR)] and clinical chemistry were measured. Fasting blood samples were taken at baseline and at weeks 12, 24, 36 and 48 to measure levels of cholesterol [high-density lipoprotein (HDL)/low-density lipoprotein (LDL)], triglycerides, insulin and C-peptide. Additionally, an oral glucose tolerance test (OGTT) was performed. A bioelectric impedance analysis (BIA) and a single slice abdominal and mid-thigh computed tomography (CT) scan were carried out to assess changes in body composition. RESULTS: Thirty patients were included in the study. Three patients experienced ABC-hypersensitivity and one patient demonstrated virological failure caused by nonadherence. At week 48, all remaining patients had viral loads < 50 copies/mL with stable CD4 counts. The fasting metabolic parameters and abdominal fat distribution remained unchanged. CONCLUSIONS: In heavily pretreated patients, ABC and EFV in combination provide an effective, simplified and well-tolerated alternative to PI treatment.

Adult↗
PubMed2004

Neutron capture cross section measurement of 151Sm at the CERN neutron time of flight facility (n_TOF).

The151Sm(n,gamma)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant branch stars. At a thermal energy of kT=30 keV the Maxwellian averaged cross section of this unstable isotope (t(1/2)=93 yr) was determined to be 3100+/-160 mb, significantly larger than theoretical predictions.

Journal Article↗
PubMed2004

["State of the HAART". Current strategies for antiretroviral therapy].

The goal of antiretroviral therapy is to interrupt the disease progression and to approach normal life expectancy for individuals with HIV. The condition for this is to deter the emergence of resistant HIV. This aim is achieved by improved patient drug adherence, sufficient enteral resorption and the control of interactions, as well as good tolerability and full antiviral activity. An insufficient drug exposure for protease inhibitors is overcome by the use of a booster agent. Emerging HIV-resistance can be described in a phase model:Phase 1:replication of wild-type HIV under incomplete suppressive therapy. Phase 2:transformation of wild-type into resistant HIV through accumulation of mutations. A preventive, resistance-guided switch of therapy preserves therapeutic options for the future. Phase 3:replication of resistant HIV (no more mutations possible).a)stable immunity: continue with failing therapy.b)threatening disease progression: resistance-guided switch to a salvage-regimen.

Antiretroviral Therapy, Highly Active↗
PubMed2003

Quantitative analysis of macrophage inhibitory cytokine-1 (MIC-1) gene expression in human prostatic tissues.

Macrophage inhibitory cytokine-1 (MIC-1) gene is a member of transforming growth factor-beta superfamily and was reported to be highly overexpressed in human prostate cancer using microarray technology. The aim of this study was to evaluate the quantitative expression of MIC-1 in malignant and benign prostate tissues and to associate expression levels with clinicopathological parameters of prostate cancer. Matched (paired) prostatic tissue samples from the cancerous and noncancerous parts of the same prostates were obtained from 66 patients who underwent radical prostatectomy. Quantitative RT-PCR was performed using SYBR Green I on the Roche LightCycler system. Macrophage inhibitory cytokine-1 gene overexpression in cancerous tissues was observed in 88% of cases, compared to noncancerous tissues (P<0.001). The expression level of MIC-1 in cancerous tissues was significantly higher than in noncancerous tissue (P<0.001). Higher expression of MIC-1 gene was significantly associated with higher Gleason score (P=0.004). The expression of the MIC-1 gene in prostate cancer is significantly higher than in noncancerous tissues, especially in more aggressive forms of the disease (Gleason score>5). This is in contrast to prostate-specific antigen that is downregulated in higher-grade tumours. The upregulation of MIC-1 in prostate cancer and in advanced and more aggressive prostatic tumours suggests that MIC-1 protein should be evaluated as a potential diagnostic and prognostic biomarker.

Aged↗
PubMed2003

[An artificial neural network as a tool in risk evaluation of prostate cancer. Indication for biopsy with the PSA range of 2-20 microg/l].

In this prospective study covering 5.5 years we evaluated the diagnostic power of an artificial neural network (ANN) based on PSA, %fPSA, and clinical data in the PSA range 2-20 microg/l as prostate biopsy indicator. A total of 944 patients with prostate cancer or benign hyperplasia (BPH) were analyzed. The calculation of the individual patient's risk before prostate biopsy was performed at the 90% and 95% specificity and sensitivity levels within the PSA ranges 2-4, 4.1-10, and 10.1-20 microg/l. For the low PSA range 2-4 microg/l, we recommend a first time biopsy at an ANN specificity level of 95%. For PSA range 4.1-10 microg/l, we recommend a first time biopsy at an ANN sensitivity level of 95%. A rebiopsy at the PSA range 10.1-20 micro g/l should be performed based on a 95% sensitivity level. The use of an ANN at PSA 2-20 microg/l enhances the specificity and sensitivity of %fPSA by 9-39%. The application of an ANN based on %fPSA and clinical data improves the diagnostic performance compared to %fPSA only.

Adult↗
PubMed2003

Primary cytomegalovirus infection in an outpatient setting--laboratory markers and clinical aspects.

BACKGROUND: Occasionally, primary cytomegalovirus (CMV) infection may give rise to more or less severe clinical illness in immunocompetent adults. We retrospectively analyzed cases of acute CMV infection in medical outpatients. PATIENTS AND METHODS: Over a 6-year period, we identified 22 patients with a febrile illness and hepatitis suffering from primary CMV infection. This was diagnosed on the basis of a strongly positive CMV IgM antibody test result and/or CMV IgG seroconversion. Clinical features as well as relevant laboratory results were analyzed. We also tested available samples for CMV glycoprotein B-specific antibodies and CMV IgG avidity and analyzed results of Epstein-Barr virus (EBV)-specific antibody assays. In addition, current age-specific CMV IgG seroprevalence rates were determined using 9,870 routine patient samples. RESULTS: At presentation, all patients complained of malaise and fever higher than 38 degrees C, and many also complained of cephalgia. Most patients who underwent abdominal ultrasonography had an enlargement of the spleen. Most patients had a relative lymphocytosis but only three had a mild leukocytosis. C-reactive protein was only slightly elevated in 13 patients; all 22 patients had elevated levels of alanine aminotransferase (ALT) and lactate dehydrogenase (LDH). Half the patients reported travel to areas outside western Europe, mostly to tropical and subtropical areas, within 3 weeks before onset of illness. Primary CMV infection was confirmed by negative anti-gB antibody test results and the absence of high-avidity CMV antibodies. In contrast, despite past EBV infection demonstrated by positive anti-EBNA-1 results, 15 out of 21 patients tested for EBV markers had positive or nonspecific IgM test results. The overall CMV IgG seroprevalence rate in the routine samples was 64.4%, with marked age-dependent increases. CONCLUSION: CMV is a relevant differential diagnosis in feverish illnesses accompanied by hepatitis in otherwise healthy adults, about 40% of whom are CMV-naïve. Half our patients seem to have acquired their CMV infection abroad, so that a diagnosis of CMV infection needs to be taken into account in travelers, in addition to infectious illnesses more commonly considered in this context, such as dengue or hepatitis A. For diagnosis, both CMV and EBV antibody studies should be performed and the inclusion of assays able to demonstrate past infection is helpful for achieving a definite diagnosis.

Acute Disease↗
PubMed2003

[MRI of prostate cancer using three different coil systems: image quality, tumor detection, and staging].

PURPOSE: To compare three MRI coil systems in terms of image quality, delineation of prostate cancer, and tumor staging. MATERIALS AND METHODS: 49 patients with prostate cancer underwent MRI at 1.5 Tesla using a combination of an endorectal coil with a phased-array body coil (combination coil) prior to radical prostatectomy. Images were reconstructed from the data sets acquired with the endorectal coil alone and from those acquired with the combined coil. In addition, 19 patients of the study patients were examined with the body phased-array coil alone without the endorectal coil. The prostate was imaged at a slice thickness of 3 mm using axial and coronal T 2 -weighted sequences and an axial T 1 -weighted sequence. Preoperative analysis of all images acquired was done to determine the accuracy of MRI in local staging of prostate cancer. An additional retrospective analysis served to compare the different coil systems in terms of overall image quality, delineation and localization of the tumor, and criteria for local staging of prostate cancer. RESULTS: Preoperative analysis showed MRI to have an accuracy of 59 % in local tumor staging. Retrospective coil-by-coil analysis demonstrated image quality and tumor delineation to be best for the combination coil and the endorectal coil. Regarding the staging criteria for transcapsular tumor extension and infiltration of adjacent organs, a significant advantage of the combination coil compared to the endorectal coil was identified only for the criterion of smooth bulging. In addition, the endorectal coil and the combination coil were found to be superior to the body phased-array coil in assessing 15 of 17 criteria for local tumor staging but the differences were not significant. CONCLUSION: In view of the achieved superior image quality, the combination coil or the endorectal coil is the preferred method for staging prostate cancer.

Aged↗
PubMed2002

Travel-acquired dengue infection: clinical spectrum and diagnostic aspects.

BACKGROUND: Dengue fever is increasingly recognized in travelers returning from endemic areas with acute febrile illness; however, its true burden in nonendemic countries is unknown. Only few studies focus on clinical manifestations and serological findings in primarily nonimmune individuals. PATIENTS AND METHODS: We analyzed the epidemiology, clinical manifestations and virological results in patients with imported acute dengue infection who presented at our travel clinic in Frankfurt am Main, Germany, between September 1998 and November 2000. An immunochromatographic test and an immunofluorescence assay were used for antibody testing. RESULTS: Dengue fever was confirmed in 13 patients, thus being the second commonest tropical infection after malaria in patients with fever and a travel history to a tropical country (18 cases per 1,000 patient visits per year). Most patients had only spent a short time abroad, either in South Central or South East Asia or in the Caribbean. CONCLUSION: The clinical features considered typical for dengue were not always present. Antibody assays were typically negative early in the course of disease, with seroconversion occurring only after cessation of clinical symptoms. A high index of suspicion is needed in these patients who often present without typical features of dengue and whose early antibody tests may be negative.

Acute Disease↗
PubMed2001

Molecular forms of prostate-specific antigen in serum with concentrations of total prostate-specific antigen <4 microg/L: are they useful tools for early detection and screening of prostate cancer?

Molecular forms of prostate-specific antigen (PSA) improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa) in men with total PSA concentrations between 4 and 10 microg/l. To evaluate the diagnostic utility of free PSA (fPSA) and complexed PSA forms for identification of men with PCa in the low PSA range of <4 microg/l, total PSA (tPSA), alpha(1)-antichymotrypsin complexed PSA (PSA-ACT) and fPSA (Roche Elecsys [ES] system) as well as tPSA and complexed PSA (cPSA) (Bayer Immuno 1 system) were measured in archival serum samples from 31 untreated patients with PCa, 66 patients with BPH, and 90 men without prostatic disease. The median ratios of fPSA/tPSA, PSA-ACT/tPSA and cPSA/tPSA were significantly different between patients with BPH and PCa (27.2 vs. 19.4%, 64 vs. 88%, 77.2 vs. 88.2%, p < 0.05). No associations between PSA forms and tumor stage and grade were found. Analysis of the receiver operating characteristic curves showed that these ratios could discriminate better between BPH and PCa patients than determination of the analytes tPSA, fPSA, cPSA and PSA-ACT alone. The use of one of the ratios would have eliminated roughly half of the unnecessary biopsies in this study. The ratios should be considered as potential tools to increase the selectivity of PCa detection at low PSA concentration. The ratios fPSA/tPSA and cPSA/tPSA can be determined using commercially available assays so that one of these ratios could be preferred instead of PSA-ACT determination. The ratios could be useful in assessing the risk of PCa in the individual and therefore in deciding on prostate biopsy for final diagnosis.

Aged↗
PubMed2001

A multicenter clinical trial on the use of alpha1-antichymotrypsin-prostate-specific antigen in prostate cancer diagnosis.

BACKGROUND: The aim was to evaluate the clinical performance of alpha(1)-antichymotrypsin prostate-specific antigen (PSA-ACT) for early diagnosis of prostate cancer (PCa) in a multicenter trial. METHODS: Three hundred sixty-seven white men with PCa and 290 with benign prostatic hyperplasia (BPH) with tPSA concentrations between 2 and 20 microg/L were analyzed. The Elecsys system 2010 (Roche Diagnostics, Germany) was used for determination of total PSA (tPSA) and free PSA (fPSA). The PSA-ACT test was a prototype assay used on the ES system (Roche Diagnostics). RESULTS: The median concentrations of tPSA (PCa: 8.43 microg/L vs. BPH: 6.60 microg/L) and PSA-ACT (8.30 microg/L vs. 6.46 microg/L) were significantly different, respectively. The median ratios of fPSA/tPSA (PCa: 12% vs. BPH: 16%) and PSA-ACT/tPSA (98% vs. 95%) were significantly different. Receiver operating characteristics (ROC) analysis for discrimination between PCa and BPH (tPSA between 2 and 20 microg/L) was performed with 252 matched pairs and showed that the area under the curve (AUC) of the ratio fPSA/tPSA (0.66) was significantly different from tPSA (0.50) and PSA-ACT (0.52). PSA-ACT alone or the ratio PSA-ACT/tPSA (0.56) were not significantly different from tPSA. For tPSA between 4 and 10 microg/L (n = 145 pairs), the AUC of the ratio fPSA/tPSA (0.65) was significantly higher than tPSA (0.50) and PSA-ACT (0.54). Significant differences between tPSA and PSA-ACT or PSA-ACT/tPSA (0.56) were not found. CONCLUSIONS: The determination of PSA-ACT as well as the PSA-ACT/tPSA ratio did not improve the diagnostic impact in patients undergoing evaluation for PCa compared to fPSA/tPSA ratio.

Adult↗
PubMed2001

Selective in vivo and in vitro effects of a small molecule inhibitor of cyclin-dependent kinase 4.

BACKGROUND: Cyclin-dependent kinase 4 (Cdk4) represents a prime target for the treatment of cancer because most human cancers are characterized by overexpression of its activating partner cyclin D1, loss of the natural Cdk4-specific inhibitor p16, or mutation(s) in Cdk4's catalytic subunit. All of these can cause deregulated cell growth, resulting in tumor formation. We sought to identify a small molecule that could inhibit the kinase activity of Cdk4 in vitro and to then ascertain the effects of that inhibitor on cell growth and tumor volume in vivo. METHODS: A triaminopyrimidine derivative, CINK4 (a chemical inhibitor of Cdk4), was identified by screening for compounds that could inhibit Cdk4 enzyme activity in vitro. Kinase assays were performed on diverse human Cdks and on other kinases that were expressed in and purified from insect cells to determine the specificity of CINK4. Cell cycle effects of CINK4 on tumor and normal cells were studied by flow cytometry, and changes in phosphorylation of the retinoblastoma protein (pRb), a substrate of Cdk4, were determined by western blotting. The effect of the inhibitor on tumor growth in vivo was studied by use of tumors established through xenografts of HCT116 colon carcinoma cells in mice. Statistical tests were two-sided. RESULTS: CINK4 specifically inhibited Cdk4/cyclin D1 in vitro. It caused growth arrest in tumor cells and in normal cells and prevented pRb phosphorylation. CINK4 treatment resulted in statistically significantly (P: =.031) smaller mean tumor volumes in a mouse xenograft model. CONCLUSIONS: Like p16, the natural inhibitor of Cdk4, CINK4 inhibits Cdk4 activity in vitro and slows tumor growth in vivo. The specificity of CINK4 for Cdk4 raises the possibility that this small molecule or one with a similar structure could have therapeutic value.

Animals↗