Major bleeding and severe thrombocytopenia after combined heparin and abciximab-c7E3 Fab therapy.
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Biomedical subjects
Publications and source records attributed to W Berg.
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We report the first measurements of z-dependent coherent optical transition radiation (COTR) due to electron-beam microbunching at high gains ( >10(4)) including saturation of a self-amplified spontaneous emission free-electron laser (FEL). In these experiments the fundamental wavelength was near 530 nm, and the COTR spectra exhibit the transition from simple spectra to complex spectra ( 5% spectral width) after saturation. The COTR intensity growth and angular distribution data are reported as well as the evidence for transverse spectral dependencies and an "effective" core of the beam being involved in microbunching.
INTRODUCTION: Inhibition of gastrointestinal motility by drugs used for anaesthesia or sedation in critically ill patients in the ICU is a major problem leading to various complications. Thus this study examines whether the thio- and oxybarbiturates thiopentone and pentobarbitone exert an inhibitory effect on intestinal peristalsis. METHODS: Peristalsis in isolated segments of the guinea-pig small intestine was elicited by distension of the gut wall through a rise of intraluminal pressure and recorded via the intraluminal pressure changes associated with the aborally moving peristaltic contractions. Thiopentone and pentobarbitone (0.1 - 300 microM)-induced inhibition of peristalsis was reflected by an increase of the peristaltic pressure threshold (PPT). RESULTS: Thiopentone (EC50 = 19,8 microM) and pentobarbitone (EC50 = 99.7 micro M) concentration-dependently increased the PPT. While the vehicle (saline) and 0.1 - 10 micro M thiopentone and pentobarbitone were without any effect on the PPT, 100 micro M caused a significant increase in PPT, and complete abolition of peristalsis occurred after 300 micro M thiopentone or pentobarbitone in all segments tested. Inhibition was reversed by changing the bath solution. CONCLUSIONS: Thio- and oxybarbiturates inhibit intestinal peristalsis in the guinea-pig ileum. It is assumed that thiopentone and pentobarbitone affect propulsive peristalsis also in the human small intestine.
Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and low-emittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report on the demonstration of self-amplified spontaneous emission gain, exponential growth, and saturation at visible (530 nanometers) and ultraviolet (385 nanometers) wavelengths. Good agreement between theory and simulation indicates that scaling to much shorter wavelengths may be possible. These results confirm the physics behind the self-amplified spontaneous emission process and forward the development of an operational x-ray free-electron laser.
OBJECTIVE: Current studies have proven that early, organ-confined stages of prostate cancer can be diagnosed through screening based on PSA levels, thus reducing cancer mortality. Here we report about our experience using an innovative one-step test for PSA in capillary blood. METHODS: The incubation time for a 50 microl blood sample with the indicator strip is 12 minutes until the qualitative visual results (<4.0 ng/ml or > or = 4 ng/ml) appear. In cooperation with urologists and accompanied by an extensive information campaign, the one-step test was made available free of charge to all men between the ages of 45 and 75 in all 28 pharmacies of our city (100,000 inhabitants). RESULTS: The test's acceptance rate among the 2,119 participants between the ages of 45 and 75 years amounted to 13.0%. Fifteen percent of all the tests conducted showed a positive PSA result (> or = 4 ng/ml). Prostate carcinoma was histologically confirmed in 14 (0.66%) of the men, nine times in the early stage (T2) and five times in the clinical stage (T3), corresponding to an incidence of circa 650 cases per 100,000 men in the target age group. CONCLUSIONS: This newly developed PSA test system can enhance the acceptance rate and effectiveness of medical check-ups for prostate cancer, because it is easy-to-use, cost-effective and accurate (specificity 81.3%, sensitivity 91.1%). The test should be always conducted by an experienced physician or pharmacist. It is not a substitute for a regular physical examination (DRE, TRUS, biopsy...).
Human immunodeficiency virus (HIV) fusion and entry involves sequential interactions between the viral envelope protein, gp120, cell surface CD4, and a G-protein-coupled coreceptor. Each interaction creates an intermediate gp120 structure predicted to display distinct antigenic features, including key functional domains for viral entry. In this study, we examined the disposition of these features during the fusion of HeLa cells expressing either HIV(HXB2) envelope (Env cells) or CXCR4 and CD4 (target cells). Cell-cell fusion, indicated by cytoplasmic dye transfer, was allowed to progress for various times and then arrested. The cells were then examined for reactivity with antibodies directed against receptor-induced epitopes on gp120. Analyses of cells arrested by cooling to 4( degrees )C revealed that antibodies against the CD4-induced coreceptor-binding domain, i.e., 17b, 48d, and CG10, faintly react with Env cells even in the absence of target cell or soluble CD4 (sCD4) interactions. Such reactivity increased after exposure to sCD4 but remained unchanged during fusion with target cells and was not intensified at the Env-target cell interface. Notably, the antibodies did not react with Env cells when treated with a covalent cross-linker either alone or during fusion with target cells. Immunoreactivity could not be promoted or otherwise altered on either temperature arrested or cross-linked cells by preventing coreceptor interactions or by using a 17b Fab. In comparison, two other gp120-CD4 complex-dependent antibodies against epitopes outside the coreceptor domain, 8F101 and A32, exhibited a different pattern of reactivity. These antibodies reacted with the Env-target cell interface only after 30 min of cocultivation, concurrent with the first visible transfer of cytoplasmic dye from Env to target cells. At later times, the staining surrounded entire syncytia. Such binding was entirely dependent on the formation of gp120-CD4-CXCR4 tricomplexes since staining was absent with SDF-treated or coreceptor-negative target cells. Overall, these studies show that access to the CD4-induced coreceptor-binding domain on gp120 is largely blocked at the fusing cell interface and is unlikely to represent a target for neutralizing antibodies. However, new epitopes are presented on intermediate gp120 structures formed as a result of coreceptor interactions. Such findings have important implications for HIV vaccine approaches based on conformational alterations in envelope structures.
Experimental evidence for self-amplified spontaneous emission (SASE) at 530 nm is reported. The measurements were made at the low-energy undulator test line facility at the Advanced Photon Source, Argonne National Laboratory. The experimental setup and details of the experimental results are presented, as well as preliminary analysis. This experiment extends to shorter wavelengths the operational knowledge of a linac-based SASE free-electron laser and explicitly shows the predicted exponential growth in intensity of the optical pulse as a function of length along the undulator.
Escape-maintained aberrant behavior may be influenced by two outcomes: (a) a break from the activity and (b) subsequent access to preferred activities. To assess this hypothesis, a treatment was developed that analyzed response allocation across two break options: break alone and break with access to preferred social activities. The break with preferred activities decreased aberrant behavior and increased appropriate behavior.
In order to increase the acceptance rate of early detection testing for prostate cancer, a qualitative prostate-specific antigen (PSA) one-step test has been developed. Determining the PSA level with this test system takes 10 min. The blood samples of 190 men were tested in this qualitative assay, which uses 50 microl of EDTA whole blood and in which the results are ascertained visually. Parallel samples were tested in serum-based, quantitative assays (Abbott Imx, EIA). The findings of the two kinds of assays were compared and evaluated regarding their correspondence (<4.0 and > or = 4.0 ng/ml). For the 74 blood samples in which the quantitative assay showed PSA levels <4.0 ng/ml, the PSA one-step test showed 83.8% correct negative results (corresponds to diagnostic specificity). For the 116 samples in which the classic assay showed PSA levels > or = 4.0 ng/ml, the one-step test showed 90.5% correct positive results (sensitivity). The noted deviations appear especially around the cut-off value of 4.0 ng/ml, i.e. within the PSA concentration range of 3.0 < 4.0 and 4.0 < 5.0 ng/ml. The qualitative PSA one-step test presented here demonstrates good reproducibility. It can be conducted by the patient and is easy to use. The test offers a simple, feasible method for early detection programs for prostate cancer.
PURPOSE: To identify prognostic factors and a model predictive for survival in patients with metastatic renal-cell carcinoma (RCC). PATIENTS AND METHODS: The relationship between pretreatment clinical features and survival was studied in 670 patients with advanced RCC treated in 24 Memorial Sloan-Kettering Cancer Center clinical trials between 1975 and 1996. Clinical features were first examined univariately. A stepwise modeling approach based on Cox proportional hazards regression was then used to form a multivariate model. The predictive performance of the model was internally validated through a two-step nonparametric bootstrapping process. RESULTS: The median survival time was 10 months (95% confidence interval [CI], 9 to 11 months). Fifty-seven of 670 patients remain alive, and the median follow-up time for survivors was 33 months. Pretreatment features associated with a shorter survival in the multivariate analysis were low Karnofsky performance status (<80%), high serum lactate dehydrogenase (> 1.5 times upper limit of normal), low hemoglobin (< lower limit of normal), high "corrected" serum calcium (> 10 mg/dL), and absence of prior nephrectomy. These were used as risk factors to categorize patients into three different groups. The median time to death in the 25% of patients with zero risk factors (favorable-risk) was 20 months. Fifty-three percent of the patients had one or two risk factors (intermediate-risk), and the median survival time in this group was 10 months. Patients with three or more risk factors (poor-risk), who comprised 22% of the patients, had a median survival time of 4 months. CONCLUSIONS: Five prognostic factors for predicting survival were identified and used to categorize patients with metastatic RCC into three risk groups, for which the median survival times were separated by 6 months or more. These risk categories can be used in clinical trial design and interpretation and in patient management. The low long-term survival rate emphasizes the priority of clinical investigation to identify more effective therapy.
More than 500 uroliths from dogs, cats, minks, rabbits and 9 further animal species originating from various regions of former East Germany were analysed. The observations were made between 1980 and 1989 using X-ray diffraction and infrared spectroscopy. The urinary stones consisted of struvite, whewellite, weddellite, cystine, ammonium urate, brushite, whitlockite, hydroxyapatite or carbonate-apatite, calcium carbonate, silicon dioxide and organic matrix stones. In dogs, the most frequent types were struvite and apatite concrements, followed by calcium oxalate and cystine uroliths. Among the diseased animals poodles, dachshunds and terriers ranked first. In the analysed material from cats apatite and struvite predominated. With few exceptions, minks formed struvite uroliths only. The analysed calculi from rabbits consisted principally of calcium phosphate or calcium carbonate concrements. The present analysis has been compared with results of former studies, differences are discussed.
Clinical trials of phase I to III are the basis of testing drugs before their wide use among patients. In order to provide high quality treatment in oncology, particularly in palliative care of tumour patients, it is of critical importance to pay attention both to study characteristics and to the relevant German laws for clinical drug testing. For more than 20 years interleucin-2 and interferon-alpha based immunotherapy of metastatic renal cell carcinoma has been in controversy. In spite of various clinical protocols no consensus concerning the value of these concepts has been reached. Therefore, high quality oncological studies are necessary to determine the effectiveness of this type of immunotherapy and to avoid an uncritical application of a toxic and expensive treatment.
A four-phase study was conducted in the homes of 4 young children who displayed aberrant behavior. Phases 1 and 2 consisted of a series of descriptive and experimental analyses to identify the environmental antecedents and consequences that controlled aberrant behavior. Phases 3 and 4 evaluated the short- and long-term effects of treatment on aberrant behavior, target mands, and collateral (social and toy play) behaviors. The effects of treatment were monitored for up to 27 months to assess long-term suppression of aberrant behavior. The assessment results successfully identified environmental events that occasioned and maintained aberrant behavior for all children. The short-term treatment resulted in immediate decreases in aberrant behavior for 3 of 4 children. Long-term treatment was successful for all children and was correlated with substantial response generalization. These results are interpreted in relation to functional equivalence, pivotal responding, and response generalization.
In this paper we describe a simple ion chromatographic method for determination of oxalate in urine. Acidified urine was diluted 1:2 with 0.03 mol/l benzidine hydrochloride in 0.3 mol/l boric acid to precipitate sulphate. The supernatant was passed through a C18-cartridge and 100 microliters of eluant were injected into an ion chromatographic system. Oxalate was measured by nonsuppressed conductivity detection. The detection limit for urinary oxalate was 0.05 mmol/l. The recovery for spiked urine samples was 101.5% with a CV of 4.5%. The within- and between-assay coefficients of variation were less than 4.5% and 2.5%, respectively. We found the results obtained by this method to be statistically equivalent to an enzymatic assay and a different ion-chromatographic method.
In order to optimally integrate radiotracer breast imaging within the breast clinic, anatomy and pathology should be easily correlated with functional nuclear medicine breast images. As a first step in the development of a hybrid functional/anatomic breast imaging platform with biopsy capability, a conventional X-ray mammography gantry was modified to image the compressed breast with positron emitters. Phantom studies with the positron emission mammography (PEM) device showed that a 1-cc hot spot could be detected within 5 min. A preliminary clinical trial demonstrated in vivo visualization of primary breast cancer within 4 min. For sites where positron-emitting radionuclides are available, PEM promises to achieve low-cost directed functional examination of breast abnormalities, with the potential for achieving X-ray correlation and image-guided biopsy.
OBJECTIVE: Five methods for oxalate analysis in urine are compared with respect to reliability, accuracy, and practicability. RESULTS: Suppressed and unsuppressed ionchromatography, as well as the enzymatic Sigma-Kit, achieve low coefficients of variation for the within-batch imprecision (1.1-8.0%) and between-day imprecision (1.6-7.2%). The results of these methods are comparable and the mean recovery rate ranges between 99.7% and 100.9%. The enzymatic Boehringer-Kit gives higher CV (3.1-9.5%) and the results are lower than those obtained by the methods mentioned above; the recovery rate is sufficient (92.4%). CONCLUSION: The handling of the chromatographic methods is very easy, whereas the enzymatic methods require more manual work. In relation to sample throughput, charges for the enzymatic methods are about twice as high as for the chromatographic methods. In respect to reliability and accuracy, the chromotropic acid method cannot be recommended (recovery rate 68%).
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Computed tomography (CT) is the non-invasive staging procedure of choice for assessment of metastasis to mediastinal lymph nodes in patients with bronchial carcinoma. Cervical mediastinoscopy can provide histologic evidence of mediastinal spread to the peritracheal, tracheobronchial and subcarinal lymph nodes. Sub-aortic and para-aortic nodes cannot be sampled via this route. The present study was performed to assess the staging value of the parasternal mediastinoscopy as a separate entity. Cervical and parasternal mediastinoscopy was performed in 37 patients with a proven diagnosis of non-small cell carcinoma of the left upper lobe. In 16 patients lymph node or tumor tissue could be biopsied via the parasternal route, in 21 patients no parasternal biopsy was taken. Of the 16 cases with biopsies, only one was positive (6%). Histologic examination of lymph node biopsy tissue was false negative in one other patient (6%). Of the 21 patients without biopsies taken during parasternal mediastinoscopy, three (14%) had proven lymphogenic spread to the subaortic and para-aortic nodes, detected at thoracotomy. The parasternal procedure changed treatment in only one patient (3%). Diagnostic sensitivity was 20%. It is concluded that parasternal mediastinoscopy should not be used as a routine staging procedure in patients with left upper lobe lung cancer.