Biomedical subjects

Joachim Gerss

Publications and source records attributed to Joachim Gerss.

6 recordsLinked to original sources

PubMed2007

The effect of dose reduction and feasibility of edge-preserving noise reduction on the detection of liver lesions using MSCT.

The purpose of this study was to assess the effect of dose reduction and the potential of noise reduction filters on image quality and the detection of liver lesions using MSCT. Twenty-nine patients with a total of 40 liver lesions underwent 16-slice CT (120 kV; 180 mAs). Virtual noise was added to CT raw datasets simulating effective mAs levels of 155, 130, 105, 80, 55, 30 and 10 mAs. All datasets were post-processed with an edge-preserving noise-reduction filter (ANR-3D), yielding a total of 15 datasets per patient. Ten radiologists performed independent evaluations of image quality, the presence of liver lesions and diagnostic confidence. Quantitative noise and contrast-to-noise ratios (CNR) were obtained. Superior image quality (P < 0.02), reduction of image noise (P < 0.001) and the increase of lesion-to-liver CNR (P < 0.001) were observed in images processed with the ANR-3D filter. Sensitivity for lesion detection remained unchanged down to 105 mAs (CTDI(w) 6.6 mGy) without filter and 80 mAs (CTDI(w) 5.1 mGy) with ANR-3D. Confidence was rated significantly higher for datasets reconstructed with ANR-3D. The use of a noise-reducing, but edge-preserving filter (ANR-3D) is a promising option to reduce further the radiation dose in liver CT.

Adult↗

PubMed2006

Preliminary normative values for foot loading parameters of the developing child.

The purpose of the present study was to provide normative data for foot loading patterns and foot shape parameters in order to support decisions about the normal or abnormal development of the growing foot during childhood. In a longitudinal design, 90 healthy German children were followed over the course of 6-48 months. The children had a mean age of 15 months at the first appointment and 63 months at the last appointment. The children participated in 11 measurement appointments every 3 months or 6 months. Dynamic foot loading was evaluated with plantar pressure measurements during walking and static footprints were taken to determine changes in foot shape. During the investigation period a significant increase of peak pressure in almost every foot region was observed. Peak pressure of the total foot increased by 92%. Only for the midfoot region a significantly decreased impulse by about 15% per year and a significant decrease of the contact area by 9% per year could be observed. A significant influence of gender was observed for peak pressures and impulses in some foot regions as well as for the midfoot width and the foot shape index. The established database can be used as comparative values for clinical decisions about the normal development.

Child, Preschool↗

PubMed2006

Electrocardiographic risk stratification in families with congenital long QT syndrome.

AIMS: The QT interval in the surface ECG is one of the most often used risk stratifiers in families with congenital long QT syndrome (LQTS). The best ECG lead for clinical management of LQTS families remains unclear. METHODS AND RESULTS: The predictive power of the QTc interval in all ECG leads was studied in 200 consecutive genotyped LQTS family members to identify mutation carriers (n = 103; age: 35+/-19 years) and high-risk LQTS patients (n = 16 with survived sudden cardiac arrest) using receiver operating curve (ROC) analysis (ROC = area under curve). Additionally, the risk for events (syncope and sudden cardiac arrest) was calculated for QTc decile in all individuals. The predictive power was highest in lead II and lead V5 for identifying carriers in LQTS families. These ECG leads were optimal for risk stratification (ROC range 0.83-0.87). In these leads, positive predictive value (PPV) and negative predictive value (NPV) were highest for suggested QTc cut-offs (440 and 500 ms) for identification of LQTS mutation carriers and high-risk patients (PPV between 78-81 and 73-80%, respectively). The risk for events in QTc deciles increased exponentially from 10 to 80% and was 40% for QTc > 500 ms. CONCLUSION: On the basis of these data, QTc is the best diagnostic and prognostic ECG parameter in LQTS families. A single measurement should be obtained in lead II if measurable and then in left precordial leads (preferably V5) as a second choice.

Adult↗

PubMed2006

Clinical significance of Vascular Endothelial Growth Factor-A expression in Ewing's sarcoma.

The aim of our study was to gain further insight into the role of angiogenesis in Ewing's sarcoma. To this end, expression of Vascular Endothelial Growth Factor-A (VEGF-A), its receptors VEGFR-1 and -2 and microvessel density (MVD) were evaluated by quantitative immunohistochemistry in pretherapeutic biopsies of 40 patients with Ewing's sarcoma treated within standardised neoadjuvant protocols. Median expression levels were 1.5 arbitrary units (AU) for VEGF-A, 8.2 AU for VEGFR-2 and median MVD was 96/0.26 mm(2). VEGFR-1 was expressed in 12.5% of the samples, only. Ten-year relapse free and overall survival rates were significantly higher for patients with high VEGF-A expression (60% versus 29%, p=0.0216 and 65% versus 25%, p=0.013, respectively). Multivariate Cox regression analysis revealed that VEGF-A expression was an independent prognostic factor for survival. In conclusion, these data suggest that the angiogenic mediator VEGF plays an important prognostic role in Ewing's sarcoma.

Adolescent↗

PubMed2006

Phase II study of gemcitabine in children with solid tumors of mesenchymal and embryonic origin.

The therapeutic benefit and side-effect profile of gemcitabine in adults with relapsed solid tumors is well known. So far, few data are available about its significance in pediatric relapsed solid tumors. To determine the efficacy and tolerability of gemcitabine in children, the drug was administered by intravenous short-term infusion over 30 min at a dose of 1200 mg/m2 weekly for 3 weeks as one cycle in children with relapsed solid tumor of embryonic or mesenchymal origin. From May 2003 to September 2004, 14 male and six female patients (2-23, median 15.8 years) were recruited for this prospective open-label phase II study (two-step Simon design). The patients suffered from rhabdomyosarcoma (n=8), Ewing's sarcoma (n=4), osteosarcoma (n=2), neuroblastoma (n=3), hepatoblastoma (n=2) and nephroblastoma (n=1). Median duration of therapy was 27.5 days (7-99), corresponding to 4.0 (2-11) infusions of gemcitabine. Two patients (neuroblastoma and Ewing) had stable disease documented for 69 and 70 days, whereas no objective responses were observed. In 34/94 administered infusions; doses had to be reduced or omitted for grade 3-4 hematotoxicity. Minimal activity was observed in this cohort of children with a wide spectrum of mesenchymal and embryonic tumors. Given the relatively low dose of gemcitabine administered, this study does not exclude the possibility of activity at higher doses. Secondly, the tolerability of gemcitabine in children was consistent with that expected in adults. For further studies in this population, we recommend the use of gemcitabine in combination with other agents.

Adolescent↗

PubMed2006

Prognostic implications of atypical histologic features in choroid plexus papilloma.

The prognostic significance of atypical histologic features in choroid plexus tumors remains uncertain. Therefore, a series of 164 choroid plexus tumors was evaluated for the presence of atypical histologic features, including mitotic activity, increased cellularity, nuclear pleomorphism, blurring of papillary growth pattern, and necrosis. The impact of histopathologic and clinical features on the probability of recurrence and survival was investigated. Twenty-four tumors displaying frank signs of malignancy were diagnosed as choroid plexus carcinoma according to World Health Organization criteria. Of 124 choroid plexus papillomas that had not received adjuvant treatment, 46 tumors (37%) displayed at least one atypical feature, including increased cellularity (n = 25 [20%]), mitotic activity (> or =2 mitoses per 10 high-power fields; n = 19 [15%]), nuclear pleomorphism (n = 16 [13%]), solid growth (n = 15 [12%]), and necrosis (n = 5 [4%]). Only one tumor-related death, but 10 recurrences, were observed on a mean observation time of 58 months. On univariate analysis, incomplete surgical resection (p = 0.03) and mitotic activity (p < 0.001) were the only clinicopathologic factors associated with recurrence. Using a multivariate model, an independent effect of mitotic activity on the probability of recurrence could be confirmed (p = 0.001). Because mitotic activity is the sole atypical histologic feature independently associated with recurrence, we propose to define atypical choroid plexus papilloma by mitotic activity (> or =2 mitoses per 10 high-power fields) corresponding to World Health Organization grade II, thus adjoining other intermediate tumor entities associated with increased mitotic activity such as atypical meningioma. Close follow up of patients harboring atypical choroid plexus papillomas may be warranted.

Adult↗