Ovarian stimulation for assisted reproduction with HMG and concomitant midcycle administration of the GnRH antagonist cetrorelix according to the multiple dose protocol: a prospective uncontrolled phase III study.

A total of 346 women with normal ovulatory function was stimulated with human menopausal gonadotrophins (HMG) to attain ovarian stimulation for IVF or intracytoplasmic sperm injection (ICSI). Stimulation with HMG started on cycle day 2 or 3. After 6 days of stimulation, Cetrorelix in its minimum effective multiple dose of 0. 25 mg/day, was administered daily until induction of ovulation. In total, 333 patients (96.2%) reached the day of HCG administration, and 324 (93.6%) underwent oocyte retrieval. A mean of 25.2 ampoules of HMG was applied for a mean of 10.4 days. Cetrorelix was administered for a mean time lapse of 5.7 days. The mean normal fertilization rate was 60% in the IVF group and 59% in the ICSI group. Seventy pregnancies were attained, reflecting an ongoing clinical pregnancy rate of 24% per transfer. The ongoing clinical implantation rate was 11.4%. Only three cases of raised luteinizing hormone (LH) (>/=10 IU/l) with increased progesterone secretion (>/=1 ng/ml) were observed after initiation of Cetrorelix administration, reflecting an incidence of premature luteinization of 0.9%. The abortion rate was 17%. The incidence of severe ovarian hyperstimulation syndrome (World Health Organization grade III) was as low as 0.6%.

Contribution of L-type calcium channels to epileptiform activity in hippocampal and neocortical slices of guinea-pigs.

The aim of the present investigation was to compare the antiepileptic efficacy of the specific L-type calcium channel blocker nifedipine in hippocampal and neocortical slice preparations in the Mg2+-free model of epilepsy. The main findings were as follows. (1) In hippocampal slices, in general, nifedipine (20-80 micromol/l) exerted a suppressive effect both on repetition rate and on area under epileptiform field potentials. This effect was clearly dose dependent. In the majority of cases, this suppression was preceded by an increase, which was transient in nature. Only in the lowest concentration (20 micromol/l) used, in normal K+, instead of a depression, a persistent increase occurred. (2) In neocortical slices, in the majority of experiments, nifedipine (20-80 micromol/l) showed a depressive action only on the area under the epileptiform field potentials. The depressive effect of nifedipine on the area was dose dependent, although to a lesser extent than in the hippocampus. In nearly half of the slices this suppression was preceded by a transient increase. By contrast, the repetition rate of epileptiform field potentials increased transiently in about 20% of the slices followed by a decrease. In the remaining 80% of the slices the repetition rate increased persistently. (3) An elevation of the K+ concentration accentuated the depressive actions of nifedipine only in the hippocampus. In contrast to elevated K+, in both the hippocampus and the neocortex, epileptiform field potentials were not suppressed in all experiments in normal K+. (4) The reversibility of the depressive effects of nifedipine was differential in the two tissue types. In the hippocampus, after suppression of epileptiform field potentials they reappeared in the overwhelming majority of slices. In the neocortex, this was the case in only one experiment. These findings may indicate the existence of L-type calcium channels with a differential functional significance for epileptogenesis and/or the existence of different forms of L-type channels in hippocampal and neocortical tissue. As a whole, the differential effects of L-type calcium channel blockade in the hippocampus and neocortex point to differences in the network properties of the two tissue types.

[MR tomography of astrocytic tumors (I-III)]. / MR-Tomographie astrozytärer Tumoren (I-III).

Magnetic resonance (MR) imaging was performed on 37 patients with histologically confirmed astrocytomas (I-III). In addition, the MR tissue parameters T1, T2 and proton density (RHO) were analysed by an interlaced CPMG spin echo sequence. Characteristic morphologic tumour patterns which subdivide astrocytomas into each different tumour grade are presented. Quantitative analysis of MR tissue parameters provides a statistically proven classification of each tumour grade and allows differentiation between "semibenign" astrocytomas (II) and "relatively malignant" astrocytomas (III), with high accuracy.

Information processing in nuclear magnetic resonance imaging.

An extended image analysis and classification system is presented to discuss the principal composition of the components as well as the methods of its realization in the field of reference based NMR diagnostics and tissue characterization.

[Gadolinium dimeglumine gadopentetate compared to CPMG sequencing and image synthesis]. / Gadolinium-Dimeglumin-Gadopentetat im Vergleich mit der CPMG-Sequenz und der Bildsynthese.

The skulls of 46 patients were examined by means of ordinary scans and after contrast. 24 of these patients with cerebral abnormalities had scans, using identical planes, with and without contrast and with CPMG sequences. Contrast in intracranial, but extracerebral (extra-axial), tumours (meningiomas, neurinomas) was much better after using contrast, but intracerebral (intra-axial) tumours were mostly shown as well on T2-rated CPMG sequences. Image synthesis has shown that contrast uptake occurred only in solid tumour regions.

[Reference substance for initialling the marker space in NMR tomography]. / Referenzsubstanz zur Initialisierung des Merkmalsraumes in der NMR-Tomographie.

Dimethylsiloxane polymers are tested to serve as a reference medium in quantitative MR imaging. Simultaneously measured during the patient's examination, the reference data are used to normalize the intrinsic MR tissue parameters. This method helps to achieve interindividual comparability of tissue vectors which are defined by proton density, spin-spin and spin-lattice relaxation times, thus leading to a remarkable improvement in tissue classification.

[MR tomography in intracranial meningiomas]. / MR-Tomographie intrakranieller Meningeome.

The typical findings of intracranial meningiomas seen in 24 patients are described. The signal intensities at different acquisition parameters are analysed and optimal pulse sequences derived from these data. In 90% of the patients MR-tissue parameters were measured and correlated with the histological findings. Marked prolongation of T2-times was found in tumours showing regressive changes.

[Initial clinical results of tissue characterization by T1, T2 and proton density in nuclear magnetic resonance tomography]. / Erste klinische Ergebnisse der Gewebecharakterisierung durch T1, T2 und Protonendichte bei der Kernspintomographie.

The NMR parameters (proton density, relaxation times T1 and T2) have been assessed by Carr-Purcell-Meiboom-Gill (CPMG) spin echo sequences. A computer assisted analysis of the data of 21 patients with cerebral tumours allowed a classification of tumour tissue in different tumours. The use of quantitative procedures for tissue characterisation allows the differentiation of benign and malignant brain tissue by characteristic colour coding demonstrating morphological details like tumour, edema and necrosis as well as indicating the histological types of the tumours of the central nervous system.

[Plain imaging of meningioma in NMR tomography--retrospective contrast optimization by image synthesis]. / Nativdarstellung von Meningiomen in NMR-Tomogramm-retrospektive Kontrastoptimierung durch Bildsynthese.

Synthetic images of the tumour region were computed in the case of ten meningiomas for the purpose of determining retrospectively pulse sequences and sequence parameters supplying an optimal contrast between tumour and adjacent tissue in plain imaging. It was found that best results were obtained via the partial saturation/spin-echo sequence with a long recovery time (TR approximately greater than 2,000 msec) and a long maximum echo delay (TE max approximately greater than 200 msec). A comparable contrast quality can be attained by using the inversion-recovery sequence with an inversion time T1 approximately 450 msec. Nevertheless, it was not possible in our study to identify two small meningiomas with a diameter of just below one centimetre by studying the MR tomogram.