Reproduktionsmedizin

Since the introduction of in vitro fertilization in 1978, reproductive medicine and its associated scientific fields have developed rapidly. In Germany, progress in this field is impeded by the German Embryo Protection Act. Exemplary are the prohibition of embryo selection and the ban on genetic testing of the pre-implantation embryo. Nevertheless, infertility treatment outcome has to be optimized within the framework of this law, with the aim of making treatment more efficient, lowering the incidence of multiple gestations, making ovarian hyperstimulation safer, as well as reducing the financial costs for the couple.     

Der Einsatz des Prophy-Jet®-Gerätes zur Schmelzpolitur nach der Bracketentfernung

Zusammenfassung In einer In-vitro-Studie wurde die Einsatzfähigkeit des Prophy-Jet-^®-Gerätes für die Schmelzpolitur nach Bracketentfernung untersucht. In die Studie wurden drei verschieden stark gefüllte orthodontische Kleber einbezogen: Concise^®, Genie^® und Mono Lok^®. Alle Proben wurden rasterelektronenoptisch untersucht und fotografisch dokumentiert in Vergrößerungen zwischen 20- und 10 000fach. Die Oberflächenanalyse ergab, daß das Prophy-Jet^®-Gerät allein zur Schmelzpolitur nach Bracketentfernung nicht ausreicht, um unter klinisch vertretbarem Zeitaufwand (1 Minute/Zahn) eine kunststofffreie Schmelzoberfläche zu erzielen. Nach konventioneller makroskopischer Vorreinigung mit Scalern oder rotierenden Hartmetallfinierern zeigten sich nach fünfsekündiger Prophy-Jet^®-Bestrahlung noch geringe Kleberreste. Nach zehnsekündiger Expositionsdauer waren beim Mono Lok^®-Adhäsiv keine Kleberreste mehr nachweisbar, beim Concise^®-bzw. Genie^®-Adhäsiv fanden sich noch vereinzelte geringe Kleberinseln. Das Prophy-Jet^®-Gerät erscheint zur Unterstützung der Schmelzpolitur nach Bracketentfernung sinnvoll; eine sorgfältige Vorreinigung mit Hand- oder rotierenden Instrumenten ist jedoch erforderlich, um eine weitgehende Adhäsivreduktion zu erreichen. Die konventionelle Gummi- und Bimssteinpolitur kann nach 20sekündiger Prophy-Jet^®-Bestrahlung entfallen.

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Summary The purpose of this in vitro investigation was to ascertain the effects of the Prophy-Jet^® air-powder abrasive system for enamel polishing after debonding. Three adhesives differing in filler content were included in this study: Concise^®, Genie^®, and Mono Lok^®. All specimens were examined by scanning electron microscopy and documented photographically at magnifications from 20 to 10 000. Surface analysis showed that using the Prophy-Jet^® exclusively is not sufficient to produce a clean and smooth enamel surface without residual adhesive after debonding and after one minute of exposure time, as might be justifiable in a clinical situation. After macroscopic conventional clean-up with scalers or rotary finishing instruments and five seconds of exposure time to the Prophy-Jet^® some occasional adhesive remnants could be located. After ten seconds of Prophy-Jet^® treatment all Mono Lok^®-adhesive was removed from the enamel surface; in the Concise^® and Genie^®-group few isolated adhesive remnants could be detected. The Prophy-Jet^® air-powder abrasive system was found to be efficient in supporting enamel polishing after debonding; but an accurate pretreatment with scalers or rotary finishing instruments is essential to achieve an extensive reduction of adhesive. Final polishing of the enamel surface with rubber wheels or prophy cup and pumice can be omitted after treatment with the Prophy-Jet^® for 20 seconds.

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Résumé Le but de ce travail était d'éxaminer à l'aide d'une étude in vitro, l'emploi du Prophy Jet^® pour le polissage de l'émail après l'arrachage des brackets. Dans l'étude on a analysé trois substances adhésives différentes: Concise^®, Genie^® et Mono Lok^®. Après avoir examiné les spécimens par le microscope électronique à balayage, on les a documentés à l'aide de photos d'un grossissement de 20 à 10 000. L'analyse de la surface montre que la seule application du Prophy Jet^® (après l'arrachage des brackets) ne suffit pas pour obtenir une surface d'émail sans substance adhésive en un temps clinique d'une minute par dent. Après prétraitement macroscopique selon la méthode conventionnelle (scaler ou instruments montés sur tour) il demeurait encore de petits restes de la substance adhésive après l'application du Prophy Jet^® pendant cinq secondes. Après une durée d'application de dix secondes, on ne pouvait pas déceler de restes de Mono Lok^®, tandis qu'il y avait sporadiquement des restes de Concise^® et Genie^®. Ces résultats indiquent, que le Prophy Jet^® est efficace pour le polissage de l'émail après l'arrachage des brackets, mais on a tout de même besoin d'un nettoyage précédent minutieux avec des instruments convenables (scaler ou instruments montés sur le tour) pour obtenir une réduction considérable de la substance adhésive. On peut renoncer au polissage conventionnel à l'aide de caoutchouc ou de la pierre ponce après l'application du Prophy Jet^® pendant 20 secondes.

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Vortrag auf der wissenschaftlichen Jahrestagung der Deutschen Gesellschaft für Kieferorthopädie 1985.     

Orthodontic fine adjustment after vertical callus distraction of an ankylosed incisor using the floating bone concept.

The outcome of vertical callus distraction of a segment of tooth-supporting alveolar process might be functionally and esthetically unsatisfactory because of the unidirectional impact of intraoral distraction devices. In this case report, we describe how, with a shortened consolidation phase and application of the floating bone effect, the tooth-supporting osteotomy segment can be successfully aligned 3 dimensionally. We applied orthodontic force systems that went beyond the unidirectional vector preset by the mechanical properties of the distraction device.     

EndocrinologyHormonal profile during the follicular phase in cycles stimulated with a combination of human menopausal gonadotrophin and gonadotrophin-releasing hormone antagonist (Cetrorelix)

A third-generation gonadotrophin-releasing hormone antagonist(Cetrorelix) was used during ovarian stimulation in 32 patientsundergoing assisted reproduction, in order to prevent the prematureluteinizing hormone (LH) surge. In all patients, ovarian stimulationwas carried out with two or three ampoules of human menopausalgonadotrophin (HMG), starting on day 2 of the menstrual cycle.In addition, 0.5 mg of Cetrorelix was administered daily fromday 6 of HMG treatment until the day of ovulation inductionby human chorionic gonadotrophin (HCG). A significant drop inplasma LH concentration was observed within a few hours of thefirst administration of Cetrorelix (P<0.005). Moreover, noLH surge was detected at any point in the treatment period inany of the 32 patients. A mean oestradiol concentration of 2122±935ng/1 was observed on the day of the HCG administration, indicatingnormal folliculogenesis. Like LH, progesterone concentrationalso dropped within a few hours of the first administrationof Cetrorelix (P< 0.005). A 0.5 mg daily dose of Cetrorelixprevented a premature LH surge in all the 32 patients treated.     

Amplification of the c-erbB oncogene is associated with malignancy in primary tumours of neuroepithelial tissue

Summary In various primary brain tumours of neuroepithelial tissue recombinant DNA techniques were used to demonstrate changes of the epidermal growth factor receptor gene, which is homologous to the c-erbB oncogene. Twenty-one of 40 grade III/IV tumours, but only 1 of 16 grade I/II tumours were found to contain amplified and/or rearranged c-erbB sequences. This highly significant difference suggest that c-erbB amplification, rearrangement, or both, are important steps in malignant transformation in a subset of patients with neuroepithelial tumours.     

A lower ongoing pregnancy rate can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing IVF with GnRH antagonists

BACKGROUND: Eliciting an endogenous LH surge by GnRH-agonist for the induction of final oocyte maturation may be more physiological compared with the administration of HCG. However, the efficacy of this intervention in patients treated for IVF with GnRH antagonists remains to be assessed. METHODS: 106 patients were randomized to receive either 10 000 IU urinary HCG or 0.2 mg Triptorelin for triggering final oocyte maturation. Ovarian stimulation for IVF was performed with a fixed dose of 200 IU recombinant FSH and GnRH antagonist was started on stimulation day 6. Luteal phase was supported with micronized vaginal progesterone and oral estradiol. The study was monitored continuously for safety and stopping rules were established. RESULTS: No significant differences were present in the number of cumulus-oocyte complexes retrieved, in the proportion of metaphase II oocytes, in fertilization rates or in the number and quality of the embryos transferred between the two groups. However, a significantly lower probability of ongoing pregnancy in the GnRH agonist arm prompted discontinuation of the trial, according to the stopping rules established (odds ratio 0.11; 95% confidence interval 0.02-0.52). CONCLUSIONS: Lower probability of ongoing pregnancy can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing ovarian stimulation for IVF with GnRH antagonists.     

Vestibular control of sympathetic activity

It has been proposed that a vestibular reflex originating in the otolith organs and other body graviceptors modulates sympathetic activity during changes in posture with regard to gravity. To test this hypothesis, we selectively stimulated otolith and body graviceptors sinusoidally along different head axes in the coronal plane with off-vertical axis rotation (OVAR) and recorded sympathetic efferent activity in the peroneal nerve (muscle sympathetic nerve activity, MSNA), blood pressure, heart rate, and respiratory rate. All parameters were entrained during OVAR at the frequency of rotation, with MSNA increasing in nose-up positions during forward linear acceleration and decreasing when nose-down. MSNA was correlated closely with blood pressure when subjects were within +/-90 degrees of nose-down positions with a delay of 1.4 s, the normal latency of baroreflex-driven changes in MSNA. Thus, in the nose-down position, MSNA was probably driven by baroreflex afferents. In contrast, when subjects were within +/-45 degrees of the nose-up position, i.e., when positive linear acceleration was maximal along the naso-ocipital axis, MSNA was closely related to gravitational acceleration at a latency of 0.4 s. This delay is too short for MSNA changes to be mediated by the baroreflex, but it is compatible with the delay of a response originating in the vestibular system. We postulate that a vestibulosympathetic reflex, probably originating mainly in the otolith organs, contributes to blood pressure maintenance during forward linear acceleration. Because of its short latency, this reflex may be one of the earliest mechanisms to sustain blood pressure upon standing.