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Biomedical subjects

A Tolksdorf

Publications and source records attributed to A Tolksdorf.

7 recordsLinked to original sources
PubMed1994

[The color-coded duplex sonography and contrast-enhanced magnetic resonance tomography of scintigraphically cold thyroid nodules].

In order to establish diagnostic criteria, colour-coded duplex sonography was performed on 40 patients who had a total of 43 operatively confirmed thyroid lesions which were scintigraphically "cold" (28 adenomas, 8 carcinomas, 4 cases of thyroiditis and 3 cysts). 32 of these patients also had MRT with T2- and T1-weighted images before and after injection of Gd-DTPA (0.1 mmol/kg). Adenomatous nodules and adenomas showed a peripheral vascular halo on colour-coded duplex sonography with a sensitivity of 96% and a specificity of 93%. Malignant lesions showed marked central vascularisation and on B-images irregular marginal structures. Adenomas and adenomatous nodules showed hyperintense areas on T1-weighted unenhanced MR images and/or homogeneous uptake in the lesion (sensitivity 100%, specificity 77%). Malignant lesions typically showed an irregular margin with increased contrast uptake on MRT. If sonography and colour-coded duplex sonography is unable to classify a lesion with any degree of assurance then MRT with Gd-DTPA enhancement should be performed.

Adult↗
PubMed1992

Averaged steady-state visual evoked cortical potentials at artificially raised intraocular pressure.

By recording steady-state visual evoked cortical potentials while intraocular pressure is artificially increased, information can be obtained on the pressure tolerance of the optic nerve head. Such experiments have previously been performed by a vector voltmeter technique. We studied the visual evoked cortical potentials in 30 healthy volunteers with artificially increased intraocular pressure, but we used an averager instead of a vector voltmeter. The results were similar except that the noise level in averaging was higher than with the vector voltmeter technique. This observation confirms that the signal-to-noise ratio is much better with the vector voltmeter technique than with the averaging technique. Our results show that averaging can be used in pressure tolerance testing, but the amplitude cannot be observed as far down as in the vector voltmeter technique. This limits the clinical value of averagers in this application.

Adult↗
PubMed1992

[Endoscopic sonography of the anorectum in inflammatory rectal diseases].

213 patients, classified in 3 groups, were examined in a prospective trial using endorectal ultrasound. 80 patients (group A) had no anorectal disease, the endorectal ultrasound showed normal structures of the anorectum and the perirectal tissue. 80 patients (group B) suffered from Crohn's disease, 30 of them had no clinical signs, the rest of this group (50 patients) felt pain in the anal/perianal region. 83 patients (group C) had perianal abscesses or fistulas, Crohn's disease could be excluded. In all 64 perianal fistulas and 66 perianal abscesses were diagnosed. The results of the rectal-proctological examination were compared with endorectal ultrasound. 100% of the perianal abscesses could be recognized using endosonography. The digital-proctological examination revealed only 57% of perianal abscesses and 48% of perianal fistulas; the supralevatory abscesses couldn't be detected proctologically at all. By endorectal ultrasonography we obtained useful informations about localization and extension of the inflammatory process. From a therapeutic and prognostic view the endorectal ultrasound is a simple, practicable and useful method to investigate perianal and anorectal diseases.

Abscess↗
PubMed1986

Successful in-vitro fertilization of frozen-thawed rabbit oocytes.

The objective of this study was to evaluate the capacity of frozen-thawed rabbit oocytes to be fertilized in vitro. After superovulation with FSH a total of 1040 oocytes was obtained by puncturing the follicles 6 or 9 h after the injection of LH or by flushing the oviducts 12 h after LH application. 1.5 M dimethylsulphoxide (DMSO) was used as cryoprotective agent and the oocytes were transferred into 0.25 ml French straws and cooled in a methanol bath to -30 degrees C and transferred to liquid nitrogen. After 1-14 days of storage the oocytes were thawed rapidly in a 15 degrees C water bath and DMSO was diluted in a stepwise manner. Subsequently the oocytes were cultured in Ham's F-10 + 10% fetal calf serum at 37 degrees C and 5% CO2 for 14, 7 and 4 h according to the time of oocyte collection. The survival rates of the oocytes based on morphological criteria were 5.4, 20.0 and 28.8%, respectively. For chromosomal analysis, morphologically intact frozen-thawed oocytes were fixed and stained using the technique described by Tarkowski. In 44 successful chromosomal preparations, 2 of 2, 10 of 19 and 22 of 23 preparations of oocytes collected 6, 9 and 12 h after LH application were in metaphase-II, respectively. Furthermore, the viability of the oocytes was also examined by using fluorescein diacetate. Out of 52 morphologically intact oocytes, 50 showed a positive intracellular fluorescence.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗