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Biomedical subjects

I Kühne

Publications and source records attributed to I Kühne.

8 recordsLinked to original sources
PubMed2005

Hepatic arterial doppler sonography in patients with cirrhosis and controls: observer and equipment variability with use of the ultrasonic contrast agent SHU 508A.

PURPOSE: The aims of this study on hepatic arterial Doppler sonography were to ascertain interobserver and interequipment variability, to investigate any potential artificial influence of the ultrasonic contrast agent on the Doppler measurements and to compare the results in healthy and cirrhotic subjects. METHODS: Doppler sonography of the left hepatic artery was performed in nine healthy and nine cirrhotic subjects by three independent observers using three different devices. Continuous infusion of the ultrasonic contrast agent SHU 508A and placebo were administered in a double blind fashion. Systolic, mean and end diastolic peak velocities as well as resistive and pulsatility indices were measured. RESULTS: Equipment associated variances (5.8 - 12.7 %) of the five Doppler parameters were greater than interobserver variances (0.3 - 3.6 %). No significant differences were observed between the velocities using ultrasonic contrast agent and placebo. Systolic (65.9 +/- 3.6 vs. 47.7 +/- 4.2 cm/s mean +/- SE, p = 0.02) and mean peak velocity (35.4 +/- 1.6 vs. 24.5 +/- 1.8 cm/s, p = 0.007) were significantly higher in cirrhotic than in healthy subjects whereas the resistive and pulsatility indices were not different. CONCLUSIONS: Doppler sonography of the left hepatic artery performed by various observers is reproducible as long as the same device is used. Under clinical conditions, velocities are correctly measured with the use of ultrasonic contrast agent and are elevated in patients with cirrhosis.

Adult↗
PubMed2004

[Modular training in practical medicine: electronic evaluation of student education in general practice].

Effective from spring 2004, new regulations for undergraduate medical education in Germany require a two-week practical training in general practice. Similar to other forms of medical education, this practical training should be regularly evaluated by students. With regard to special conditions of the training, we preferred a web based evaluation. Since adequate models were not available, we designed, implemented and tested an electronic way of evaluation. The following aspects turned out to be of special importance: teamwork, time, data protection and cost. Meanwhile, the evaluation is established and still accessible as demo-version for visitors of the home page. This electronic evaluation of medical training in general practice is highly appropriate for a timely evaluation allowing us to obtain a comparison between students' expectations and actual experience as well as a continuous supervision and to provide feedback to the participating practices. This is an important step for quality assurance of medical education in practices inside and outside the university.

Computer-Assisted Instruction↗
PubMed1999

Rapid identification of nine microorganisms causing acute respiratory tract infections by single-tube multiplex reverse transcription-PCR: feasibility study.

Acute respiratory tract infections (ARIs) are leading causes of morbidity and, in developing countries, mortality in children. A multiplex reverse transcription-PCR (RT-PCR) assay was developed to allow in one test the detection of nine different microorganisms (enterovirus, influenza A and B viruses, respiratory syncytial virus [RSV], parainfluenzaviruses type 1 and type 3, adenovirus, Mycoplasma pneumoniae, and Chlamydia pneumoniae) that do not usually colonize the respiratory tracts of humans but, if present, must be assumed to be the cause of respiratory disease. Clinical samples from 1,118 children admitted to the Department of Pediatrics because of an ARI between November 1995 and April 1998 were used for a first clinical evaluation. Detection of one of the microorganisms included in the assay was achieved for 395 of 1,118 (35%) clinical samples, of which 37.5% were RSV, 20% were influenza A virus, 12.9% were adenovirus, 10.6% were enterovirus, 8.1% were M. pneumoniae, 4.3% were parainfluenzavirus type 3, 3.5% were parainfluenzavirus type 1, 2.8% were influenza B virus, and 0.2% were C. pneumoniae. Seasonal variations in the rates of detection of the different organisms were observed, as was expected from the literature. The levels of concordance with the data obtained by commercially available enzyme immunoassays were 95% for RSV and 98% for influenza A. The results show that the multiplex RT-PCR-enzyme-linked immunosorbent assay is a useful and rapid diagnostic tool for the management of children with ARI. Studies of the overall benefit of this method with regard to the use of antibiotics, the use of diagnostic procedures including additional microbiological tests, and hospitalization rate and duration are warranted.

Acute Disease↗
PubMed1998

A multi-centre longitudinal study comparing the sensitivity of monthly MRI after standard and triple dose gadolinium-DTPA for monitoring disease activity in multiple sclerosis. Implications for phase II clinical trials.

In this study we assessed the safety, efficacy and cost-effectiveness of the use of triple dose gadolinium-DTPA (Gd) in serial monthly brain MRI of patients with multiple sclerosis, such as could be selected for clinical trials. The number of enhancing lesions, the number of new enhancing lesions and the number of active scans were used to evaluate the sensitivity of the contrast-enhanced MRI to disease activity. The dose of Gd, and the effect of introducing a delay between the contrast injection and the scan were both appraised. Every 4 weeks for 3 months, and in two separate sessions, scans were obtained from 40 patients with relapsing-remitting or secondary progressive multiple sclerosis, 5 min (early) and 20 min (delayed) after a standard dose (0.1 mmol/kg) or triple dose (0.3 mmol/kg) Gd injection. There were 435 enhancing lesions (242 of which were new) on the early standard dose scans, 479 (263 new) on the delayed standard dose, 772 (365 new) on the early triple dose and 827 (404 new) on the delayed triple dose. There were 109 scans revealing active disease on the early standard dose scans, 112 on the delayed standard dose, 119 on the early triple dose and 120 on the delayed triple dose. Statistical simulations indicated that the sample sizes needed for both cross-over and parallel-group trials with similar powers are lower if serial monthly triple dose MRI is used. No side-effects were reported and no significant changes in blood test parameters were found throughout the study. This study shows that the serial use of triple dose Gd is safe, and that it increases the sensitivity of serial monthly enhanced MRI in detecting multiple sclerosis activity significantly. Its use should enable preliminary trials of experimental therapies for multiple sclerosis to be conducted in small patient populations, over a short period of time.

Adult↗
PubMed1997

[An unusual combination of carotid artery-cavernous sinus fistula and sinus thrombosis. Successful therapy with anticoagulation].

Dural carotid cavernous fistulas (DCCF) can be associated with venous thrombosis. We report on a rare case of a patient who developed a venous infarct, which was diagnosed on CT and MRI. The DCCF predominantly drained through a frontobasal cortical vein into the superior sagittal sinus. The shunt volume was small and was therefore thought not to be sufficient to explain the massive ocular signs, such as severe exophthalmus and reduction of visual acuity. We therefore postulated a venous congestion owing to a secondary spontaneous venous thrombosis of the draining venous pathways to be responsible for the ocular signs. Under anticoagulative medication, the patient's signs and symptoms improved gradually. Control angiography after 3 months showed that the DCCF had disappeared. In the presence of DCCF, anticoagulation should always be considered when a venous thrombosis is suspected.

Arteriovenous Fistula↗
PubMed1991

Furoquinoline alkaloids as photosensitizers in Chlamydomonas reinhardtii.

Seven naturally occurring furoquinoline alkaloids were investigated for their photobiological activity using arg-1 cells of Chlamydomonas reinhardtii. UV-A-mediated toxicity of the compounds was calculated from the colony-forming ability of the treated cells. The UV-A-mediated mutagenicity was measured by counting the number of Arg+ revertants induced by the treatment. Dictamnine was found to be the strongest mutagen as well as the most toxic compound of the group. The mutagenic activities were measured as mutation frequencies at equal substance concentration and ranked in the following order: An increase in the number of substituents on the lateral aromatic nucleus greatly decreased the photomutagenicity. Except for evolitrine, a similar ranking order was found as reported for the dark mutagenicity of these compounds in Salmonella typhimurium strain TA98. Based on the result that furoquinolines are able to intercalate into DNA, we assume that the different mutagenic potencies may reflect differences in the geometry of the intercalation complex, which is important for the subsequent photochemical reaction.

Alkaloids↗
PubMed1990

Mutagenic compounds in an extract from Rutae Herba (Ruta graveolens L.). II. UV-A mediated mutagenicity in the green alga Chlamydomonas reinhardtii by furoquinoline alkaloids and furocoumarins present in a commercial tincture from Rutae Herba.

A commercial tincture prepared from Rutae Herba (Ruta graveolens L.) exhibited a moderate photomutagenicity in an arginine-requiring mutant strain of Chlamydomonas reinhardtii. In the tincture some furocoumarins, e.g., bergapten, psoralen, imperatorin, and 3 furoquinoline alkaloids (dictamnine, gamma-fagarine, skimmianine) were detected. All compounds revealed photomutagenic properties but their activities were quite different. Bergapten was the most potent furocoumarin. Dictamnine, the furoquinoline with the strongest effect, reached only about 10% of the activity of bergapten. Based on the amount of these compounds in the tincture and their activities we conclude that bergapten is mainly responsible for the photomutagenicity of the tincture. The lower phototoxicity and photomutagenicity of the furoquinoline alkaloids may be due to the fact that furoquinolines form only monoadducts with DNA in the presence of UV-A in contrast to furocoumarins which also form biadducts.

Alkaloids↗