Biomedical subjects

G Quade

Publications and source records attributed to G Quade.

9 recordsLinked to original sources

PubMed2001

Changes of cerebral blood flow following dexamethasone treatment in brain tumour patients. A Xe/CT study.

BACKGROUND: It is not exactly known how dexamethasone improves the function of brain that is affected by tumour. Whether and in what sense dexamethasone influences cerebral blood flow has rarely been addressed and previous investigations have yielded inconsistent results. METHOD: Stable xenon-enhanced computed tomography (Xe/CT) was used to assess the regional cerebral blood flow (rCBF) in 67 patients with supratentorial primary and secondary brain tumours. rCBF studies were done at least once prior to resection or stereotactic biopsy of the tumours. In nine patients repeated studies before surgery and in 15 patients additional studies after resective surgery were obtained. Dexamethasone was administered according to the clinical needs before surgery and systematically after surgery. Of the preoperative studies 30 were obtained before and 47 during dexamethasone treatment. The rCBF data were analysed upon correlations with daily dose, cumulative dose, and duration of dexamethasone treatment. Moreover, individual courses before and after surgery were examined. FINDINGS: Mainly inverse correlations were found between the treatment parameters, particularly the daily dose of dexamethasone, and rCBF. Only in the subgroup of glioblastoma patients, a positive correlation was found of both duration and cumulative dose of dexamethasone with rCBF in oedema. Serial observations of individual patients confirmed the above findings, yet with possible exceptions. After tumour resection a clear improvement of rCBF was regularly observed. INTERPRETATION: The beneficial effect of dexamethasone is not attributed to an increase of cerebral blood flow, because rather decreases of rCBF are mostly observed.

Adult↗

PubMed2000

[CancerNet online--a contribution to improving oncologic management].

OBJECTIVE: We started the CancerNet project to evaluate the suitability of the internet to improve the quality of health care and the physician-patient relationship by offering worldwide access to high quality guidelines and standards. METHODS: Since early 1994 we have offered access to the National Cancer Institute's guidelines for current cancer therapy to physicians via WWW. These guidelines, which are provided by the NCI in accordance with the rules for evidence-based medicine, are accompanied by general information for non-professionals. Every month about 500 text-documents are HTML-encoded, linked together to about 10,000 abstracts available online as well as to MEDLINE. CancerNet is offered in English, Spanish, and German (only patient information) (http://www.meb.uni-bonn.de/cancernet/). RESULTS: From analyzing log files and user surveys in 1996, 1997, 1998, 1999, and 2000, we know that offering guidelines and patient information via the web fits most expectations of our users (physicians, health professionals, scientists, and laymen) on a high quality medical information service. Since 1994 nearly 2 million users, including more than 200,000 physicians, used our service. About 95% rated our service excellent or good.

Data Collection↗

PubMed2000

Differences in demographic data regarding physicians and patients in the US or abroad using a medically oriented Internet information service.

Since early 1994 we have offered access to the National Cancer Institute's guidelines for current cancer therapy to physicians via WWW. These guidelines, which are provided by the NCI in accordance with the rules for evidence-based medicine, are accompanied by general information for non-professionals. Since we launched this comprehensive cancer-related WWW information service in 1994, more than about 1 million customers retrieved documents from our CancerNet service via WWW (http://www.meb.uni-bonn.de/cancernet/). From user surveys in 1996, 1997, 1998, and 1999, we obtained demographic data about our users, their interests, and their opinions regarding this information service. The following analysis shows how this service was used over the years and includes some unexpected differences between users in the US, Europe, and developing countries.

Adult↗

PubMed1999

Worldwide telemedicine services based on distributed multimedia electronic patient records by using the second generation Web server hyperwave.

A distributed multimedia electronic patient record (EPR) is a central component of a medicine-telematics application that supports physicians working in rural areas of South America, and offers medical services to scientists in Antarctica. A Hyperwave server is used to maintain the patient record. As opposed to common web servers--and as a second generation web server--Hyperwave provides the capability of holding documents in a distributed web space without the problem of broken links. This enables physicians to browse through a patient's record by using a standard browser even if the patient's record is distributed over several servers. The patient record is basically implemented on the "Good European Health Record" (GEHR) architecture.

Antarctic Regions↗

PubMed1998

Long-term evaluation of the CancerNet WWW service.

To improve the quality of healthcare, we offer access to high quality guidelines to physicians as well as information harmonized with these guidelines to concerned patients via internet. We launched this service in 1994. Since then, we have been offering user-friendly access to the NCI's CancerNet via WWW (http://www.meb.uni-bonn.de/). Among other information, CancerNet by the National Cancer Institute contains up-to-date summaries on the prognosis, staging, and treatment of more than 80 major tumor types. To obtain information about how users navigate through this service, all users' activities are logged by using cookies for tracking them without injuring privacy. To get additional information about our users and their interests regarding our service, we performed user surveys in 1996 and 1997. The analysis of 538 valid answers in 1996 and 1001 in 1997 show that the attempt to bring high quality information and guidelines to physicians and patients was successful. About 95% of our users rated our service "excellent" or "good".

Female↗

PubMed1996

CancerNet redistribution via WWW.

CancerNet from the National Cancer Institute contains nearly 500 ASCII-files, updated monthly, with up-to-date information about cancer and the "Golden Standard" in tumor therapy. Perl scripts are used to convert these files to HTML-documents. A complex algorithm, using regular expression matching and extensive exception handling, detects headlines, listings and other constructs of the original ASCII-text and converts them into their HTML-counterparts. A table of contents is also created during the process. The resulting files are indexed for full-text search via WAIS. Building the complete CancerNet WWW redistribution takes less than two hours with a minimum of manual work. For 26,000 requests of information from our service per month the average costs for the worldwide delivery of one document is about 19 cents.

Computer Communication Networks↗

PubMed1995

Toxoplasma gondii antibodies in pregnant women and their newborns in Dar es Salaam, Tanzania.

The sera of 849 Tanzanian pregnant women were tested at delivery for Toxoplasma gondii antibodies with the Sabin-Feldman dye test (DT) and an immunosorbent agglutination assay. A total of 296 (35%) of these women had DT titers greater than 1:4. The percentage of women with dye test titers greater than 1:4 was 34-37% regardless of the individual ages. The rate of positivity for human immunodeficiency virus 1/2 (HIV-1/2) using Western blotting was 11.5%. There was no relationship between prevalence of a positive DT result and HIV infection nor between the intensity of the DT result and HIV infection. Sixty-four parturients had a DT titer of 1:1,000 or more. From 57 newborns of these mothers, cord sera were available and were screened by the DT and the immunosorbent agglutination assay. Seven of these were found to be positive for IgM and/or IgA antibodies. It was concluded that the rate of serologic evidence for prenatal Toxoplasma infection in cord blood samples in the present study of Tanzanian pregnant women was approximately 0.8%.

Adolescent↗

PubMed1988

Intraoperative echocardiographic visualisation of coronary arteries, before and after aorto-coronary bypass grafting.

While angiography remains the standard evaluation method for the visualisation of coronary artery anatomy and morphology, the angiographic findings in patients referred for surgical treatment of coronary artery disease (CAD) often do not totally answer questions related to surgical management. We therefore explored a high-frequency ultrasonic technique that allows the surgeon to localize coronary artery lesions not demonstrated angiographically, such as the distribution of coronary artery calcification in myocardial vessels buried in fat or obscured by epicardial scarring frequently observed in patients who had previously been operated upon. Coronary arteries of 81 patients were investigated intraoperatively. Stenotic arteriosclerotic or fibrotic lesions of the arterial wall could be easily seen. This technique provides additional information to preoperative angiograms, especially in locating major coronary arteries that lie intramyocardially, or those deeply buried in fat. Intraoperative coronary artery dilatation procedures could be followed and the effects determined by measuring pre- and postoperative diameters.

Adult↗

PubMed1986

[Digital subtraction angiography of the aorta].

The results of 300 digital subtraction angiographies of the thoracic and abdominal aorta are analysed. Following intraarterial injection of contrast, all examinations were of good quality. Following I-V DSA, two thoracic (1.8%) and two abdominal (1.2%) aortograms were non-diagnostic. Anomalies in the position of the aorta, dilatation (aneurysm) or stenoses (coarctations, arteriosclerosis, occlusions) could be diagnosed by I-V DSA. One I-A DSA was performed for aneurysm of the ascending aorta in order to evaluate function of the aortic valve and for demonstrating the coronary artery origins, and pre-operatively for an aortic dissection.

Aortic Dissection↗