Biomedical subjects
Publications and source records attributed to R Hornung.
alpha 1-Adrenoceptors in rat brain membranes, labeled by the antagonist [3H] prazosin, increase their affinity for clonidine several-fold when sodium ions are added. The conversion of alpha 1-adrenoceptors, buy sodium ion, into a conformation, which has higher affinity for the agonist clonidine, indicates that these receptors as the alpha 2-adrenoceptors are modulated by cations in vitro.
26 obese persons were treated in 3 groups of similar size with a behavior modification programme. The group sessions were led by a physician and a socialpsychologist and lasted 10 weeks. The average loss of weight in the 3 groups at the end of the programme was between 3,8 and 5,5kg. The results form a basis for developing a new and more broadly aimed programme.
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The so-called calcium antagonist D-600 and agents that enhance the influx of calcium ions into nerve terminals during action potentials (4-aminopyridine, tetraethylammonium, guanidine) interact with alpha-adrenoceptors. The interaction was revealed by binding experiments in vitro with the alpha 2- and alpha 1-specific ligands [3H]clonidine and [3H]prazosin, resp. D-600 binds in a competitive manner to alpha 2- and alpha 1-adrenoceptors in rat-brain membranes. [3H]Prazosin was used to identify alpha 1-adrenoceptors in rat-heart-membrane fragments. D-600 inhibited the binding of the tritiated antagonist, in a manner similar to that seen in rat-brain membranes. 4-Aminopyridine, guanidine and tetraethylammonium blocked no-competitvely the binding of [3H]clonidine in brain membranes. There ws little or no effect of these agents on the binding of [3H]prazosin to alpha 1-adrenoceptors in rat heart or brain. The results indicate that D-600 binds to a region common to alpha 1- and alpha 2-adrenoceptors, whereas the potassium-channel blockers reveal a structural feature of the alpha 2-adrenoceptors in brain membranes which is also present in voltage-dependent potassium channels but is not shared by alpha 1-adrenoceptors.
Tritiated prazosin was used to characterize high affinity binding sites with characteristics similar to alpha 1 adrenoceptors in rat brain membranes. These sites were compared with alpha 2 adrenoceptors labeled with tritiated clonidine. The prazosin sites had an association constant of 2 nM-1 and bound to ligand optimal around pH 7.0. The density of the sites was 300 fmoles per mg of protein; the half time of dissociation of prazosin was 7 min at 30 degrees C. The order or potencies of agonists, determined from binding-inhibition experiments with labeled prazosin, was: naphazoline greater than clonidine greater than adrenaline greater than noradrenaline greater than phenylephrine greater than alpha-methylnoradrenaline greater than dopamine. The order of potencies of antagonists was: prazosin greater than phenoxybenzamine greater than phentolamine greater than clozapine greater than yohimbine. Sodium ions and divalent cations as well as guanyl nucleotides have little or no effect on the binding of the labeled antagonist. This is in contrast to the binding of the labeled agonist clonidine (Glossmann and Presek, 1979a, 1979b). Labeled prazosin may be a useful tool to characterize alpha 1 adrenoceptors.
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Health Education can be understood as a communication process, in which a communicator gives a message to receivers through a certain channel with a specific destination. The application of the results of communication research to problems of Health Education is difficult since, on the one hand, communication research does not sufficiently relate to the problems of Health Education and, on the other, the Health Educators often ignore the results of empirical research. Moreover, it is inherent in communication theory to overstimate knowledge as a vehicle of behavior change. The norms, laws and institutions of society often limit the possibilities of Health Education. Another limitation consists in the lack of information concerning many of the factors which cause health damaging behavior. The consequences of these considerations are that efficient Health Education has to be carried out not only on the personal but also on the societal level and that knowledge about the causes of health-injuring behavior must be improved. A model of integrated Health Education is presented.
Discussions concentrated on ways of influencing the behavior of healthy individuals. The following was concluded; 1. Health education is an interdisciplinary activity. It should not merely be aimed at the behavior of individuals but also respect and influence values and institutions of society as well as legislation. 2. Family and school are the most important fields of activity. 3. Health education should be based on experiences from communication sciences. 4. In school, health education should be integrated in as many subjects as possible. Of special importance are the example of the teachers and adequate preparation and training. 5. Health education cannot limit itself to giving information, it also must motivate to a healthy way of life. 6. Exchange of experiences and information in health education should be improved. In Switzerland this can be done by a working party of the Swiss Society for Social and Preventive Medicine. 7. The intervention trials of the Swiss National Research Program can provide important stimuli for innovative approaches to health education is Switzerland.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Calcium alginate encapsulated, in vitro culture derived shoot tips of the florist's auricula, cultivar Embley, were successfully cryopreserved using the encapsulation/dehydration technique. The use of preculture media containing both sucrose and mannitol was essential for post-thaw growth. After 2 weeks cold acclimatisation at 10 degrees C, shoot tips were encapsulated and incubated in culture medium containing 0.25 M sucrose and 0.25 M mannitol for 48h, followed by 23h dehydration with silica gel (water content of beads approximately 16%) prior to plunging into liquid nitrogen. Post-thaw growth of the shoot tips was without callus formation. The morphology of frozen and non-frozen shoots was comparable.
Callus growth has been observed from plumules of ecotype Laguna Tall after cryopreservation using an encapsulation/dehydration protocol. Sucrose preculture treatment and silica gel dehydration both significantly influenced the frequency of callus formation from non-frozen and frozen plumules. The greatest frequency of post-thaw callus growth occurred after incubation of the encapsulated plumules for 72-96 h in medium containing 0.75 M sucrose followed by desiccation over silica gel for 7-8 h down to approximately 30% moisture content (fresh weight basis). Freezing and thawing were carried out rapidly. Post-thaw recovery rates in excess of 80% were recorded.
BACKGROUND: The aim of this study was to develop and characterize a mouse xenograft model for the hypercalcemic-type of small cell carcinoma of the ovary (HTSCCO). PATIENTS AND METHODS: Tumor fragments were removed from a patient and cultured in six subsequent generations of nude mice. Histology, comparative genomic hybridization (CGH), electron microscopy and serum calcium levels were investigated. RESULTS: Morphology remained the same from the primary tumor of the patient through the 6th passage in the mouse. Serum calcium levels were significantly higher in the tumor-bearing mice compared to controls. CGH of the HTSCCO did not show evidence of a close relationship to either a germ cell tumor or an epithelial ovarian cancer. CONCLUSION: Some evidence was provided that the HTSCCO is an inhomogeneous tumor that is neither related to a germ cell tumor nor to an epithelial ovarian cancer, but is a distinct tumor entity.