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S Schoenberg

Publications and source records attributed to S Schoenberg.

12 recordsLinked to original sources
PubMed2006

[Reliability of multicenter magnetic resonance imaging. Results of a phantom test and in vivo measurements by the German Dementia Competence Network].

BACKGROUND: Whereas a large body of evidence suggests the usefulness of volumetric measurement of cerebral atrophy for diagnosing Alzheimer's disease (AD), the clinical applicability of cerebral volumetry for early detection of AD across multiple clinical sites is not well known. In the current study, we assessed the precision of volumetric measurement of the brain based on magnetic resonance imaging (MRI) in a multicenter setting. METHODS: The reliability of MRI was assessed by a phantom test of the American College of Radiology and voxel-based morphometry applied to the images obtained from a single subject tested at 11 centers of the German Dementia Competence Network. RESULT: Nine of the 11 centers tested met the reliability criteria of the phantom test. Across all centers, a bias was found in the measurements of slice thickness and length. For voxel-based morphometry, the coefficient of variation yielded 5.02% for gray matter volume and 12.81% (SD 9.06%) for gray matter signal intensity in voxels. Power analysis showed that a sample size of 150 subjects is sufficient for statistically valid detection of reduced gray matter volume in patients with mild cognitive impairment. CONCLUSION: The reliability of measurements from multiple centers is sufficient to allow statistically valid analysis of MRI data.

Adult↗
PubMed2006

[Magnetic resonance imaging in the evaluation of pneumonia].

Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. Especially for follow-up examinations in immunocompromised patients and, in some instances, for the staging of malignant diseases (malignant pleural mesothelioma, lung cancer, respectively), MRI is very promising and may contribute to a decrease in the radiation exposure of the patients.

Humans↗
PubMed2006

[Cine MRI of the thorax in patients with pectus excavatum].

BACKGROUND: Morphologic and dynamic assessment of respiratory chest kinetics was performed in patients with pectus excavatum deformity (PE) using dynamic MRI: cine MRI. MATERIAL AND METHODS: Seven consecutive patients with PE (aged 20.3 years+/-4.0) and ten healthy volunteers of comparable age underwent real-time cine MRI of the chest during breathing on a 1.5 T MR scanner (Magnetom Sonata, Siemens Medical Systems, Erlangen, Germany) using a standard phased array body coil and a half-Fourier single-shot turbo spin echo sequence (HASTE) for dynamic imaging. During deep inspiration and expiration, single-shot sequences were performed in one slice level over 20 s at a frequency of 1 image/s covering the entire thoracic cage in three orientations. Morphology and chest kinetics in patients with PE were analyzed and compared with normal values, and typical patterns of chest kinetics were noted. RESULTS: Three different types of chest morphology in PE were identified: (1) the generally flattened thoracic cage, (2) the "tilted" sternum, and (3) the focally deepened sternum. Three patterns of motion correspond to these morphological types: (1) elevation of the sternum and the anterior thoracic wall, (2) angulated elevation of the parasternal rib cage with persistent deepening of the sternum resembling a "wing beat" movement, and (3) increased diaphragmatic movements with limited chest wall dynamics. CONCLUSIONS: Cine MRI is an adequate radiation-free diagnostic modality for the dynamic imaging of both chest morphology and chest wall kinetics in patients with PE. The pectus severity index can easily be determined and three typical movement patterns of chest wall kinetics identified.

Adolescent↗
PubMed2006

Application of intrathecal trastuzumab (Herceptintrade mark) for treatment of meningeal carcinomatosis in HER2-overexpressing metastatic breast cancer.

Leptomeningeal carcinomatosis represents a rare manifestation of metastatic breast cancer (MBC). A 39-year-old female presenting with HER2-overexpressing MBC and suffering from meningeal carcinomatosis was treated with the humanized antibody trastuzumab directed to HER2 by intrathecal administration. The patient was diagnosed with HER2-overexpressing stage III breast cancer in December 2003. In August 2004, the patient developed a singular intracerebral metastasis which was resected by neurosurgery followed by whole-brain radiotherapy. Since MRI and cerebrospinal fluid (CSF) analyses indicated meningeal carcinomatosis, the patient was commenced on trastuzumab (6 mg/kg q3w) and capecitabine (2.500 mg/m2 d1-14, q3w). Prompted by clinical deterioration, 5 repeated doses of intrathecal methotrexate (15 mg/dose) were administered, yet without clinical improvement. There is initial evidence that trastuzumab does not reach an adequate concentration in CSF after intravenous application. Nevertheless, infiltration of trastuzumab into CSF is facilitated under conditions of an impaired blood-brain barrier, as it is known for meningeal carcinomatosis. For patients with leptomeningeal disease, intrathecal application of trastuzumab may provide an interesting therapeutical approach for patients with HER2 overexpressing metastatic breast cancer. Therefore, an Ommaya reservoir for intrathecal treatment with trastuzumab was placed surgically and intrathecal therapy was begun with escalating doses of trastuzumab (5-20 mg), which proved to be effective and well tolerated by the patient. Within 2 weeks after treatment, the patients' condition improved significantly and cell counts in CSF obtained from the Ommaya reservoir remained low for 11 months after first diagnosis of meningeal carcinomatosis when clinical symptoms and MRI indicated progression of meningeal and cerebral disease.

Adult↗
PubMed2002

[Multi-slice CT in the planning of nephron-sparing interventions for renal cell carcinoma: Prospective study correlated with histopathology].

OBJECTIVE: For nephron sparing surgery of renal cell carcinoma knowledge of the intrarenal extension of the tumor and infiltration of the renal pelvis, the intrarenal vessels and the perinephric fat is essential. This question is much more difficult to answer compared to the description of staging parameters. Aim of this study is to evaluate the value of multi-slice CT in planning of nephron sparing surgery. MATERIAL AND METHODS: In a prospective study 46 patients with suspected renal cell carcinoma underwent a triphasic multi-slice CT (unenhanced, delay 30 s and 120 s). A reconstructed slice thickness of 2 mm in the arterial and parenchymal phase was used to create volume rendered 3D-reconstructions. Based on the source data and multiplanar reconstructed images the extent of the renal cell carcinoma was assessed in terms of size, hilar infiltration, arterial and venous invasions, capsula infiltration and perirenal growth. The results of two blinded readers were correlated with histopathological staging and intraoperative findings. RESULTS: 36 carcinomas were evaluated histopathologically. 10 patients showed no renal cell carcinoma histopathologically. Multi-slice CT allowed us to diagnose the localization and size of all tumors correctly. Infiltration into perinephric fat was correctly excluded in 24/30 and 8/30 cases. Infiltration of the renal pelvis could be excluded in 17/24 and 12/24 cases. The state of venous infiltration could be correctly diagnosed in 29/30 and 27 /30 carcinomas. CONCLUSION: Despite of the high temporal and spatial resolution of multi-slice CT, which allows the delineation of intrarenal arteries as well as renal hilus and the veins, the evaluation of tumor infiltration into the renal hilus, the intrarenal vessels and the perinephric fat remains a diagnostic problem. For planning of nephron sparing surgery, a knowledge of the infiltration in these structures is essential.

Carcinoma, Renal Cell↗
PubMed1993

Seroprevalence of hepatitis B viral markers in 52,000 Alaska Natives.

As a part of a program to screen and immunize as many Alaska Natives as possible against hepatitis B infection, hepatitis B virus seromarkers were measured in 52,022 Alaska Natives between 1983 and 1987. Hepatitis B surface antigen (HBsAg) was found in 1,603 persons (3.1%), and 7,155 persons (13.8%) exhibited hepatitis B virus seropositivity. While the prevalence of total seropositivity increased with increasing age (p < 0.001), the proportion of seropositive persons who were also positive for HBsAg was significantly higher in children under age 5 years than in persons over age 60 (p < 0.001). The total hepatitis B virus seropositivity was significantly higher in males than in females (p < 0.001), and a greater proportion of seropositive males than seropositive females had HBsAg (p < 0.001). The prevalence of HBsAg and total seropositivity differed significantly by geographic region (p < 0.001), ranging from 0.5% to 8.2% for presence of HBsAg and from 5.4% to 29% for total seropositivity. Of persons who were HBsAg positive, hepatitis B e antigen was found in 35.4%, and antibody to hepatitis e antigen was found in 49.6%. The prevalence of hepatitis B e antigen significantly decreased with age, while that of antibody to hepatitis e antigen significantly increased. The prevalence of hepatitis B virus seropositivity is high in Alaska Natives, and there are significant differences in both the prevalence of HBsAg and total hepatitis B virus seromarkers by age, sex, and geographic region.

Adolescent↗
PubMed1992

Response to hepatitis B vaccine of persons positive for antibody to hepatitis B core antigen.

The significance of antibody to hepatitis B core antigen (anti-HBc) present in a person's serum without hepatitis B surface antigen (HBsAg) or its antibody (anti-HBs) is unknown. Serum specimens from 281 persons initially positive only for anti-HBc by enzyme immunoassay (EIA) were retested by radioimmunoassay (RIA), and of these, 177 (63%) remained positive for anti-HBc by both assays. Of these 177 persons, 3 were positive for HBsAg, and 72 possessed low levels of anti-HBs [less than 10 sample ratio units; (SRU's)]. When persons positive for anti-HBc by EIA and RIA were given one 20-micrograms dose of plasma-derived hepatitis B vaccine and tested for anti-HBs 1 month later, a booster response was observed in 14 of 41 (34%) persons with low level anti-HBs and 3 of 50 (6%) persons negative for anti-HBs. Of those positive only for anti-HBc by EIA but negative by RIA, only 3 of 37 (8.1%) showed a booster response. Of those who completed the three-dose immunization series and did not show a booster response, 63 of 80 (78.8%) developed anti-HBs levels greater than 10 standard ratio unit. The majority of persons with isolated anti-HBc will have a primary rather than a booster response to hepatitis B vaccine.

Adolescent↗
PubMed1992

Biochemical, cytogenetic, and morphological characteristics of human primary and metastatic prostate cancer cell lines.

Metastatic properties of human prostatic cancer cell lines (ND-1 and DU-145) were examined using various biochemical techniques. DU-145 cells had a higher metastatic potential than ND-1 cells. Cytogenetic analysis by G-banding demonstrated an aneuploid karyotype with considerable structural rearrangement. ND-1 cells had a modal chromosome number range lower than DU-145 cells (45-66, compared to 54-62). Ploidy analysis revealed that DU-145 cells showed hyperdiploidy with a greater amount of proliferation than the majority of ND-1 cells. Electron microscopic studies revealed little change in the cell morphology of either line. DU-145 cells had lower phosphatidyl choline levels and higher sphingomyelin levels than ND-1. DU-145 cells had much lower arachidonic acid levels than ND-1 cells. SDS-polyacrylamide gel electrophoresis revealed protein differences between the two cell lines. This study demonstrates for the first time that lipids, proteins and cytogenetic parameters differ in human primary and secondary prostate cancer cell lines.

Adenocarcinoma↗
PubMed1983

Mechanisms of hypnotic and nonhypnotic forgetting.

Subjects participated in two experimental sessions designed to study laboratory-induced amnesia, one using a standard hypnosis paradigm and one using a non-hypnotic directed-forgetting paradigm. Two independent sources of variation were derived from the hypnotic amnesia data: retrieval inhibition and inhibition release. In the nonhypnotic directed-forgetting procedure, some items were cued to be forgotten shortly after presentation and some were cued to be remembered. At test, the subjects were asked to recall both the to-be-remembered and the to-be-forgotten items. Over 39% of the variance in the recall of the to-be-forgotten items could be accounted for by the inhibition and release constructs obtained with hypnosis. These relations between the two procedures were not mediated by verbal ability or cognitive style (field independence). We concluded that the mechanisms of forgetting involved in laboratory demonstrations of hypnotic and nonhypnotic amnesia are related, and the implication is that some of them are the same, namely, retrieval inhibition and inhibition release. We also argued that the possible demand characteristics that accompany the hypnosis procedure are not apparent with the nonhypnotic procedure. Therefore, the relationships observed in the present results were taken as evidence that hypnotically induced amnesia is not entirely the result of subjects' reactions to demand characteristics.

Amnesia↗
PubMed1983

Structure activity correlation for diuretic furosemide congeners.

The structure activity correlation of several groups of anthranilic acid derivatives was studied. 59 compounds, most of them possessing the anthranilic acid moiety, were synthesized and tested for diuretic and saluretic activities. Equations correlating the biological activities of these compounds with their physicochemical constants suggest positive dependence of the diuretic activity on log P (octanol:water partition coefficient). It is concluded that, within limits, the variation in biological activity is primarily governed by the lipophilicity of the molecule, and further increase in log P value will not enhance this activity.

Animals↗
PubMed1975

Application of the carbonic anhydrase inhibitory effect of furosemide to the study of furosemide release from two of its diuretic derivatives.

Bovine carbonic anhydrase B (CA) inhibitory effect of furosemide was established in two pH values at 26 degress. FFBu [N-furfuryl-4-chloro-5-(butoxymethylsulfamoyl)anthranilic acid] and FFMe [N-furfuryl-4-chloro-5-(methoxy-methylsulfamoyl)anthranilic acid], two of its alkoxymethyl derivatives, did not exert any CA inhibitory effect at those conditions but were found to inhibit the CA activity after their hydrolysis, which yielded the furosemide molecule. The CA inhibitory effect of furosemide was utilized for determining the kinetic rate constants for the hydrolysis of FFBu and FFMe at various pH and temperature levels. The hydrolysis rate constants of FFBu and FFMe were pH-independent in the pH range tested, and the temperature dependence for FFBu yielded an activation energy of 18 kcal/mol. It is pointed out that the hydrolysis rates of FFBu may be important for the explanation of its possible delayed diuretic effect.

Carbonic Anhydrase Inhibitors↗