[From basic research to the clinic. Regulations for preclinical and clinical studies with stem cells]. / Von der Grundlagenforschung in die Klinik. Regulative Anforderungen an präklinische und klinische Studien mit Stammzellen.

The discovery of human embryonic stem cells at the end of 1998 had a strong influence on the development of stem cell research and led to controversial discussions. The first therapeutic application of adult blood stem cells began after their discovery in 1963 and was accepted as an authorized therapy in the early 1980s. The way from basic research to therapeutic use needed about 20 years and was also discussed in a controversial way similar to the discussions of today. The regulatory environment at that time, however, allowed a quick translation of the results from basic research to the clinic. Today many new stem cell therapies for a multitude of diseases are under development. Their clinical realization is regulated by the AMG (Arzneimittelgesetz). For nonclinical research as well as for clinical research, specific regulations are enacted to guarantee a structured and safe launch. Time, know how and money for planning, request for authorization and conduction of a clinical trial should not be underestimated. For clinical application of stem cell products authorization by the proper authorities is mandatory.

[Interdisciplinary longitudinal curriculum "Medical Psychology, Psychotherapy and Psychosomatics." Experiences from the preclinical segment]. / Fachübergreifendes Längsschnittcurriculum "Medizinische Psychologie, Psychotherapie und Psychosomatik." Erfahrungen aus dem vorklinischen Abschnitt.

The departments of Medical Psychology, Psychosomatics and Psychotherapy developed an interdisciplinary longitudinal curriculum in order to coach medical students for the whole length of their medical education. Experiences from the first four undergraduate semesters are reported. 46 students (33 females, 13 males), mean age 22.3 +/- 2.6 years, attended 60 hours of interdisciplinary group sessions. Frequent motives to join the course were interest in psychosocial disciplines and relevant previous experience. The students expected to benefit from this project in their study, their future practice as a physician, and in their personal development. Important educational goals that could be attained were the adoption of a patient-centred view in medicine as well as strengthening of the students' critical capacities and sensitivity. The students especially appreciated the possibility of group discussions and the opportunity to participate actively in the course. Based on a critical review of the evaluation, the possibility of a transfer of our model is considered and perspectives for the future are developed.

Maternal nicotine exposure enhances cutaneous axon reflexes in the neonatal rat.

Chronic nicotine exposure enhances axon reflexes in adult rats. Since smoking mothers expose their infants to nicotine, this study investigated whether late gestational and or lactational maternal nicotine exposure affects neonatal axon reflexes. Osmotic pumps, implanted subcutaneously in adult female rats, delivered either nicotine (5 mg kg-1 day-1) or saline. Axon reflex responses of infant progeny, evoked by iontophoresis of 2 mC acetylcholine, were measured by laser Doppler flowmetry. Nicotine-exposed infants showed significantly enhanced axon reflexes during both gestational and lactational nicotine exposure, which recovered after exposure ceased. Controls did not exhibit these changes. Maternal nicotine exposure reversibly sensitized nicotinic cholinoceptors on infant cutaneous sensory nerves, but not muscarinic cholinoceptors on vascular endothelium. This may result from upregulation of cutaneous nicotinic cholinoceptors.

Chronic nicotine exposure enhances cutaneous axon reflexes in the rat.

The effect of chronic nicotine exposure on the cutaneous neurogenic flare response was investigated non-invasively in rats. Axon reflexes were evoked by transdermal iontophoresis of acetylcholine, and resultant changes in skin microvascular blood flux were measured by laser Doppler flowmetry. Rats given five injections of nicotinesulphate (1 mg kg-1 i.p.) daily for 14 days were compared to saline-injected littermates. Axon reflexes were enhanced by 143% after 7 days exposure to nicotine, and by 336% after 14 days exposure. Controls did not display these increases. Axon reflexes measured 7 days after nicotine cessation were similar to pre-nicotine levels. These results may suggest that nicotinic cholinoceptors on skin nociceptors and primary afferents upregulate in response to chronic nicotine exposure, and return to normal following nicotine cessation.

Hepatocyte-mediated SCE induction by indirect mutagens: importance of hepatocyte density and cell-to-cell contact.

The SCE-inducing effects of the indirectly acting mutagens cyclophosphamide (CP), dimethylnitrosamine (DMN) and aflatoxin B1 (AFB1) were analysed in hepatocyte (hpc)/mammalian cell coculture systems with regard to the importance of the hpc density. V79 cells and human lymphocytes served as target cells. For all 3 compounds steadily increasing genetic effects were observed when the hpc density was increased from 3.2 X 10(4) up to 3.2 X 10(6) viable hpc per culture (25-cm2 flask), i.e. the more hpc available for metabolisation, the more genetic effects induced. The frequency distributions of the CP-induced SCE values were clearly different from those obtained with DMN, especially when high hpc densities were used: distribution patterns obtained for the mutagen with stable metabolites (CP) are characterized by the presence of distinct maxima and the absence of cells with SCE control values, whereas distribution patterns for the mutagen with very short-lived metabolites (DMN) can be described by the absence of maxima and the presence of cells with SCE control values. The frequency distributions of the AFB1-induced SCE values were more similar to the CP type than to the DMN type. From these results it is deduced that close contact between metabolising and target cells is necessary for the detection of the genotoxic effect of DMN. For CP and AFB1 a direct contact seems not to be essential, i.e. reactive intermediates may also be transported via the culture medium to the target cells.

Comparison of S9 mix and hepatocytes as external metabolizing systems in mammalian cell cultures: cytogenetic effects of 7,12-dimethylbenzanthracene and aflatoxin B1.

Two external metabolizing systems, S9 mix from Aroclor-induced rat livers and freshly isolated hepatocytes, were used for activation in cultures of human lymphocytes and V79 cells. 7, 12-dimethylbenzanthracene (DMBA) and aflatoxin B1 (AFB1) were employed as indirectly acting reference mutagens. Mutagenic effects were measured by induction of sister chromatid exchange (SCE). With DMBA, SCE-inducing effects were found to be quite similar after activation by S9 mix and activation by hepatocytes. In human lymphocytes nearly the same dose-effect relationships were found with both metabolizing systems; in V79 cells the hepatocyte-mediated induction of SCE was detectable at slightly lower concentrations than the S9-mediated SCE induction. In contrast with AFB1, S9 activation led to a stronger SCE induction than hepatocyte activation in both target cells. The induction of chromosomal aberrations by AFB1 after activation by the two metabolizing systems was also analysed in V79 cells. This experiment again revealed that AFB1 was more efficiently activated by S9 mix than by hepatocytes, and it appeared that AFB1 is a more potent inducer of chromosomal aberrations than of SCE. The different activation capacities of the two metabolizing systems for AFB1 may be due to the maintenance of inactivation mechanisms in hepatocytes or to the Aroclor induction of the S9 fraction. Our experiments have shown that the suitability of hepatocytes as an activation system is not restricted to microbial or eukaryotic point mutation assays, but that hepatocyte metabolism can also be successfully included in cytogenetic tests with short- and long-term cultures of mammalian target cells.

Verbal rationales and modeling as adjuncts to a parenting technique for child compliance.

The purpose of this study was to examine whether the effectiveness of a behavioral parenting technique with children in 2 age groups (3-4 1/2 or 5 1/2-7 1/2 years) is facilitated by introducing the procedure to the child by verbal rationales and/or modeling adjuncts. Mothers were taught to implement a procedure in which they ignored their children following child noncompliance to a maternal command. 80 mother-child pairs were assigned to 1 of 4 conditions: ignoring training, ignoring plus verbal rationale, ignoring plus verbal rationale and modeling, or control. Each mother issued a set of 20 standard commands to her child in a laboratory playroom. Dependent measures included observations of child compliance and inappropriate behavior and self-report of parental satisfaction and child comprehension. Children in the rationale and rationale-plus-modeling conditions were more compliant and less inappropriate than children in either of the other 2 conditions, and their mothers reported greater satisfaction than mothers in the ignoring condition. Older children were more compliant, were quicker to comply, and demonstrated a greater comprehension of the contingencies than younger children. There was no differential responsivity in either age group between the rationale and rationale-plus-modeling adjuncts.