CONTACT

Prof. Dr. med. Dr. rer. nat.
Hans-Werner Denker
email:
Hans-Werner Denker – University Duisburg-Essen Deutsche Version English Version

Stem Cells and Bioethics

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Overview

“Pluripotent” stem cells (i.e. embryonic stem cells = ES cells, and induced pluripotent stem cells = iPS cells) are considered a promising material for cell and tissue replacement therapy. A well-known reason why they receive so much interest is that they possess differentiation potential as well as a proliferation capacity. Whereas this combination of (and the interrelationships between) proliferation and differentiation potential is in the focus of most investigators, these cells show an additional peculiarity which deserves much more attention than it usually receives: pattern formation potential. This latter property bears important implications for safety aspects (tumor formation) as well as for the ethics of stem cell research and application in the human. It has led to confusion in terminology, and we have discussed the use of the terms totipotency/omnipotency/pluripotency and proposed more stringent definitions.

For the embryologist it is no surprise that early embryo-derived (or early embryo-like) cells show pattern formation capacities in connection with their differentiation potential. Stem cell researchers and bioethicists, however, often appear to disregard this. In fact developmental biology tells us that we must expect “pluripotent” cells to have an inclination to initiate processes of pattern formation, i.e. to create a degree of order in any groups of such cells while they differentiate. They may even form rudimentary organ anlagen as seen clearly in teratomas derived from these cells.

This pattern formation potential becomes ethically problematical if it can lead to the creation of a basic body plan (individuation). During in vitro culture and after transplantation of “pluripotent” cells any autonomous development of a basic body plan appears to be a very rare event (apparently due to the unfavourable environmental conditions met in these cases). However, the morphogenetic potential can be fully expressed when tetraploid complementation (TC) is performed: This technique allows to clone viable individuals from ES and iPS cells as has been shown in the mouse. The technique would most probably be applicable in the same way in the human (if ever attempted) which points to an ethical problem that has largely been overlooked so far. This fact definitely needs to be considered when obtaining informed consent but at present it is not being communicated to cell donors. It is also relevant for questions of patentability: Indeed patenting must be regarded non-acceptable in case of human cells possessing this complete “pluripotency”, i.e. cells which would enable direct cloning of identical individuals using TC or any related technologies (including any “pluripotent” cells that have not been tested specifically for this property but must be considered suspect of possessing it).

Logically these considerations should have consequences for research strategies as well as for legislative actions:

  • Any use of human cells which are fully totipotent/pluripotent/omnipotent in the sense that they have embryo-forming potential (e.g. when TC is performed) bears these ethical problems and must thus be avoided.
  • The goal to abandon sacrificing human embryos (for the derivation of stem cells) is basically laudable. However, in the search for alternative stem cell sources the focus should not be on the induction of “pluripotency” (as in iPS cells) because this creates exactly the ethical problem just described, since it endows these modified cells with properties possibly enabling direct cloning of individuals by TC.
  • This asks for a re-focussing of research strategies in the sense that the goal should not be to induce full “pluripotency” (iPS cells) but rather to endow cells with a more limited developmental potential that would exclude early embryonic pattern formation (e.g. gastrulation).
  • The state of the art of mammalian developmental biology would now indeed allow for such a re-focussing of research activities. Legislative initiatives should encompass this.

My publications on these topics comprise: (1) ethical considerations with respect to stem cell use in the human; (2) a discussion of the theoretical background provided by developmental biology, specifically with respect to the implications of “pluripotent/omnipotent/totipotent” properties of cells for possessing an individuation potential; (3) some own experimental studies involving (nonhuman) primate embryonic stem cells.

List of Publications

Note: Opening the pdf-files requires a pdf-reader (e.g. Adobe Reader).

DENKER, H.-W.:
Embryoids, models, embryos? We need to take a new look at legal norms concerning the beginning of organismic development.
Molec. Hum. Reprod. 30(1): gaad047 (2024). DOI: 10.1093/molehr/gaad047
PubMed   MHR   pdf-download (615 KB)

DENKER, H.-W.:
Stem Cell-Derived Organoids, Embryoids, and Embryos: Advances in Organismic Development In Vitro Force Us to Re-Focus on Ethical and Legal Aspects of Model Choice.
Organoids 2: 231-238 (2023). DOI: 10.3390/organoids2040018
Organoids Website   pdf-download (247 KB)

DENKER, H.-W.:
Wir brauchen eine Neudefinition des Begriffs "Embryo".
Deutsches Ärzteblatt 120 (33-34): A-1383 / B-1191 (21. August 2023).
Deutsches Ärzteblatt   pdf-download (315 KB)

DENKER, H.-W.:
Autonomy in Stem Cell-Derived Embryoids.
Encyclopedia Platform, encyclopedia.pub/14708 (2021).
Encyclopedia

DENKER, H.-W.:
Autonomy in the Development of Stem Cell-Derived Embryoids: Sprouting Blastocyst-Like Cysts, and Ethical Implications.
Cells 10: 1461 (2021) (Open Access). DOI: 10.3390/cells10061461
PubMed   Cells Website   pdf-download (1.54 MB)

DENKER, H.-W.:
Blastocyst-like cysts sprouting autonomously from stem cell cultures: Self-organization and implantation potential.
(Comment on: KIME, C., KIYONARI, H., OHTSUKA, S., KOHBAYASHI, E., ASAHI, M., YAMANAKA, S., TAKAHASHI, M. & TOMODA, K.: Induced 2C Expression and Implantation-Competent Blastocyst-like Cysts from Primed Pluripotent Stem Cells. Stem Cell Reports 13:485-498, 2019).
Preprint (2020). DOI: 10.13140/RG.2.2.34000.74242
pdf-download (311 KB)

DENKER, H.-W.:
Recent embryo twinning data prompt reconsideration of theories on a crucial role of segregation of oocyte cytoplasmic constituents in mammals.
(Comment on: CASSER, E., WDOWIK, S., ISRAEL, S., WITTEN, A., SCHLATT, S., NORDHOFF, V., BOIANI, M.: Differences in blastomere totipotency in 2-cell mouse embryos are a maternal trait mediated by asymmetric mRNA distribution. Molec. Hum. Reproduct. 25/11, 729-744, 2019. DOI: 10.1093/molehr/gaz051)
Molec. Hum. Reprod. 26: 193-198 (2020). DOI: 10.1093/molehr/gaaa005
PubMed   MHR   PDF-Download AOV (214 KB)

DENKER, H.-W.:
Embryonen, Embryoide, Gastruloide... Ethische Aspekte zur Selbstorganisation und zum Engineering von Stammzellkolonien und Embryonen.
In: M. Rothhaar, M. Hähnel, R. Kipke (Eds.): Der manipulierbare Embryo. Potentialitäts- und Speziesargumente auf dem Prüfstand. Münster: Mentis (Brill), 2018, pp. 15-47. DOI: 10.30965/9783957438393_003 (Open Access)
Mentis (Brill) (Open Access)   Google Scholar   Abstract (40 KB)   pdf-download (196 KB)

DENKER, H.-W.:
Embryonen und Embryoide: Gedanken eines Entwicklungsbiologen zu ethischen Implikationen von Autonomie und Machbarkeit.
(Lecture) Der manipulierbare Embryo: Potentialitäts- und Speziesargumente auf dem Prüfstand (Auftakttagung zum BMBF-Projekt "Der manipulierbare Embryo"), Eichstätt, Katholische Universität Eichstätt-Ingolstadt, 3.-5. Nov. 2016.
lecture pdf (4.70 MB)

DENKER, H.-W.:
Self-Organization of Stem Cell Colonies and of Early Mammalian Embryos: Recent Experiments Shed New Light on the Role of Autonomy vs. External Instructions in Basic Body Plan Development.
Cells 5(4): E39 (2016) (Open access). DOI: 10.3390/cells5040039
PubMed   Cells Website   pdf-download (5.16 MB)

DENKER, H.-W.:
„Totipotency“ of stem cells: Plasticity vs. self-organization capacity
(Comment on: ISHIUCHI, T., ENRIQUEZ-GASCA, R., MIZUTANI, E., BOSKOVIC, A., ZIEGLER-BIRLING, C., RODRIGUEZ-TERRONES, D., WAKAYAMA, T., VAQUERIZAS, J.M., TORRES-PADILLA, M.E.: Early embryonic-like cells are induced by downregulating replication-dependent chromatin assembly. Nature Struct. Mol. Biol. 22: 662-671, 2015).
Preprint (2015). DOI: 10.13140/RG.2.2.15761.25441
pdf-download (113 KB)

DENKER, H.-W.:
A Quest for Refocussing Stem Cell Induction Strategies: How to Deal with Ethical Objections and Patenting Problems.
In: M. Prasad and P. Di Nardo (Eds.): Innovative Strategies in Tissue Engineering. (River Publishers Series in Research and Business Chronicles: Biotechnology and Medicine; Vol. 2; A. Vertes, P. Di Nardo and P. Rameshwar, Ser.-Eds.) Aalborg, Denmark: River Publishers, 2015, pp. 117-134. DOI: 10.13052/rp-9788793237100
Google Scholar   River Publishers   River Publishers (Open Access)   pdf-download (385 KB)

DENKER, H.-W.:
Stem Cell Terminology and 'Synthetic' Embryos: A New Debate on Totipotency, Omnipotency, and Pluripotency and How It Relates to Recent Experimental Data
Cells Tissues Organs 199: 221-227 (2014).
PubMed   CTO Website (free access)

DENKER, H.-W.:
Comment on G. Herranz: The timing of monozygotic twinning: a criticism of the common model. Zygote (2013).
Zygote 23: 312-314 (2015).
PubMed   Zygote   pdf-download (41.8 KB)

DENKER, H.-W.:
Time to reconsider stem cell induction strategies.
Cells 1: 1293-1312 (2012) (Open Access).
PubMed   Cells Website   pdf-download (222 KB)

DENKER, H.-W.:
A quest for redefining stem cell induction strategies: How to deal with ethical objections and patenting problems.
(Lecture) 3rd Disputationes on Native and Induced Pluripotent Stem Cell Standardization, Florence (Italy), March 19–21, 2012.
pdf-download (5.40 MB)   Abstract (7.20 KB)

DENKER, H.-W.:
iPS cells: Ethical problems solved?
(Lecture) 22nd European Students' Conference, Charité Berlin, 23 September 2011.
pdf-download (924 KB)   Abstract (4.23 KB)

DENKER, H.-W., HOLM, S.:
Patenting and stem cell pluripotency.
(Comment on: SMITH, A.: 'No' to ban on stem-cell patents. Nature 472, 418, 2011. DOI: 10.1038/472418a)
Nature 472: 418, 2011; Online Comment #22079.
pdf-download (6.56 KB)   Nature Website

LITTWIN, T., DENKER, H.-W.:
Segregation during cleavage in the mammalian embryo? A critical comparison of whole-mount/CLSM and section immunohistochemistry casts doubts on segregation of axis-relevant leptin domains in the rabbit.
Histochemistry and Cell Biology 135: 553-570 (2011).
PubMed   SpringerLink

MARANCA-HÜWEL, B., DENKER, H.-W.:
Epithelial-mesenchymal transition in rhesus monkey embryonic stem cell colonies: the role of culturing conditions.
In Vitro Cell. Dev. Biol. - Animal 46(6): 516-528 (2010).
PubMed   pdf-download (951 KB; Please note the copyright regulations of the SIVBThis material has been published in In Vitro Cell. Dev. Biol. - Animal 46(6): 516-528 (2010), the only accredited archive of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by the Society for In Vitro Biology. This material may not be copied or e-posted without explicit permission of the copyright owner.
For more information about Reproduction Permission for this article, please visit the SIVB website by clicking on the link above or anywhere on this infobox.
!)

DENKER, H.-W.:
Comment on Draft NIH Guidelines for Human Stem Cell Research (2009) (Public Comment ID 16452).
pdf-download (15.1 KB)   NIH WebsiteUnfortunately, NIH has removed this webpage.
However, you are still welcome to download my comment as a PDF (15.1 KB).

DENKER, H.-W.:
Ethical concerns over use of new cloning technique in humans.
Nature 461: 341 (2009). PubMed   pdf-download (5.78 KB)

DENKER, H.-W.:
Induced pluripotent stem cells: How to deal with the developmental potential.
Reproductive BioMedicine Online 19 Suppl. 1: 34-37 (2009).
PubMed   pdf-download (287 KB)   RBMOnline

DENKER, H.-W.:
Human embryonic stem cell lines generated without embryo destruction: New strategies, new ethical problems
(Comment on: CHUNG, Y.; KLIMANSKAYA, I.; BECKER, S.; LI, T.; MASERATI, M.; LU, S.-J.; ZDRAVKOVIC, T.; ILIC, D.; GENBACEV, O.; FISHER, S.; KRTOLICA, A.; LANZA, R.: Human embryonic stem cell lines generated without embryo destruction. Cell Stem Cell 2: 113-117, 2008.)
Deutsch (12.2 KB)   English (11.3 KB)

DENKER, H.-W.:
Totipotency/pluripotency and patentability.
Stem Cells 26: 1656-1657 (2008). PubMed   Stem Cells   pdf-download (14.4 KB)

DENKER, H.-W.:
Induzierte pluripotente Stammzellen (iPS) und das Omnipotenz-/Totipotenzproblem.
Leserbrief zu: Richter-Kuhlmann, E.: Stammzellenforschung: Reprogrammierungserfolge entzünden erneut Debatte. Deutsches Ärzteblatt 104: C 2799 - C 2800 (2007). pdf-download (12.5 KB)
Leicht gekürzt veröffentlicht (unter der Überschrift "Stammzellforschung: Ein anderes ethisches Problem") in: Deutsches Ärzteblatt 105 (Heft 11): A 577 - A 578 (2008). to the article

DENKER, H.-W.:
Human embryonic stem cells:
The real challenge for research as well as for bioethics is still ahead of us.

Cells Tissues Organs 187: 250-256 (2008). PubMed   pdf-download (155 KB)

DENKER, H.-W., BEHR, R., HENEWEER, C., VIEBAHN, C., THIE, M.:
Epithelial-mesenchymal transition in rhesus monkey embryonic stem cell colonies: a model for processes involved in gastrulation?
Cells Tissues Organs 185: 48-50 (2007). PubMed   pdf-download (162 KB)

DENKER, H.-W.:
Heureka!
(Comment on: DEVOLDER, K. and WARD, C. M.: Rescuing human embryonic stem cell research: The possibility of embryo reconstruction after stem cell derivation. Metaphilosophy, Vol. 38, No. 2, 245-263, 2007.)
pdf-download (14.2 KB)

LEI, T., HOHN, H.-P., BEHR, R., DENKER, H.-W.:
Influences of Extracellular Matrix and of Conditioned Media on Differentiation and Invasiveness of Trophoblast Stem Cells.
Placenta 28: 14-21 (2007). PubMed

SCHINDEL, M., VON RECKLINGHAUSEN, I., DENKER, H.-W., THIE, M.:
Differentiation potential of somatic versus embryonic stem cells analysed by microarray analysis.
(Abstr.) 3rd International Meeting of the Stem Cell Network North Rhine Westphalia, Münster (Germany), May 15-16, 2006, Abstract Volume p. 28.
SCN Website   PDF-Download (22 KB)

DENKER, H.-W.:
Comment on:
KLIMANSKAYA, I.; CHUNG, Y.; BECKER, S.; LU, S.-J.; LANZA, R.:
Human embryonic stem cell lines derived from single blastomeres.
Nature 444: 481-485 (2006). pdf-download (7.75 KB)

DENKER, H.-W.:
Potentiality of embryonic stem cells: an ethical problem even with alternative stem cell sources.
Journal of Medical Ethics 32: 665-671 (2006). PubMed   pdf-download (131 KB)

DENKER, H.-W.:
Totipotenz – Omnipotenz – Pluripotenz.
Ausblendungsphänomene in der Stammzelldebatte: Indikatoren für den Konflikt zwischen Norm- und Nutzenkultur?

In: Th. S. Hoffmann, W. Schweidler (Eds.): Normkultur versus Nutzenkultur. Über kulturelle Kontexte von Bioethik und Biorecht. Walter de Gruyter, Berlin/New York, 2006, pp. 249-272.
De Gruyter   Google Books   pdf-download (9.81 MB)

DENKER, U., DENKER, H.-W.:
Embryonale Stammzellforschung: Aufklärung notwendig.
Problematik der informierten Zustimmung der Spender.

Dtsch. Ärzteblatt 102 (Heft 13): A892-A893 (2005). pdf-download (56.7 KB)

BEHR, R., HENEWEER, C., VIEBAHN, C., DENKER, H.-W., THIE, M.:
Epithelial-mesenchymal transition in colonies of rhesus monkey embryonic stem cells: a model for processes involved in gastrulation.
StemCells 23: 805-816 (2005). PubMed   pdf-download (559 KB)

BEHR, R., HENEWEER, C., VIEBAHN, C., DENKER, H.-W., THIE, M.:
Epithelial-mesenchymal transition in colonies of rhesus monkey embryonic stem cells: a model for processes involved in gastrulation?
(Abstr.) Verh. Anat. Ges. 100 (Anat. Anz./Ann. Anat. Suppl. 187): 203, 2005.
pdf-download (517 KB)

DENKER, H.-W.:
Early human development: New data raise important embryological and ethical questions relevant for stem cell research.
Naturwissenschaften 91: 1-21 (2004). PubMed   pdf-download (853 KB)

DENKER, H.-W.:
Die Potenz von menschlichen ES-Zellen als Argument gegen ihre Patentierbarkeit.
Jahrbuch für Wissenschaft und Ethik, Bd. 9 (L. Honnefelder u. C. Streffer, Eds.). Walter de Gruyter, Berlin/New York, 2004, pp. 367-371. pdf-download (8.75 MB)
english abstract (0.99 MB): The developmental potential of human embryonic stem cells argues against their patentability

BEHR, R., DENKER, H.-W., HENEWEER, C., HOHN, H.-P., VIEBAHN, C., von RECKLINGHAUSEN, I., THIE, M.:
Epithelial-mesenchymal transition in colonies of rhesus monkey embryonic stem cells: a model for processes involved in gastrulation?
(Abstr.) Interne Klausurtagung des Kompetenznetzwerks Stammzellforschung NRW, Herne (Germany), November 19th-20th, 2004, Abstracts, p. 56.
pdf-download (1.27 MB)

KRUSE, L.H., HENEWEER, C., DENKER, H.-W. and THIE, M.:
Ko-Kultur von embryonalen Stammzellen (ES-Zellen) und Trophoblast: Expression von Stammzell- und Keimblattmarkern in ES-Zellen.
(Abstr.) Verh. Anat. Ges. 99 (Ann. Anat./Anat. Anz. 186), 249 (2004).
pdf-download (424 KB)   download poster (3.64 MB)

BEHR, R., HENEWEER, C., DENKER, H.-W., THIE, M.:
Epithelial-mesenchymal transition in colonies of rhesus monkey embryonic stem cells: a model for gastrulation?
(Abstr.) 2nd Internatl. Meet. Stem Cell Network North Rhine Westphalia, April 1st-2nd, 2004, Abstr. ID 005 (p. 24).
pdf-download (1.57 MB)   download poster (1.28 MB)

DENKER, H.-W.:
Experten-Stellungnahme zum Thema „Neue Entwicklungen in der Stammzellforschung“ vor der Enquete-Kommission „Ethik und Recht der modernen Medizin“ des Deutschen Bundestags.
Nichtöffentliche Anhörung am 8.12.2003. Text der schriftl. Stellungnahme: Kom.-Drs. 15-92:
Statement Denker (in the Web Archive of the German Bundestag, 26.5 KB)
All documents of the hearing (in the Web Archive of the German Bundestag)
pdf-download (26.5 KB)

DENKER, H.-W.:
Totipotenz oder Pluripotenz? Embryonale Stammzellen, die Alleskönner.
Dtsch. Ärztebl. 100 (Heft 42): A 2728-2730 (2003).
aerzteblatt.de   pdf-download (57.0 KB)

DENKER, H.-W.:
Embryonale Stammzellen als entwicklungsbiologisches Modell: Frühembryonale Musterbildung und Totipotenz.
In: Die Frühphase der Entwicklung des Menschen. (G. Rager /A. Holderegger, Eds.); Reihe: Herausforderung und Besinnung, Band 19; Universitätsverlag Freiburg/Schweiz, 2003: 23-71. pdf-download (104 MB)

THIE, M., BEHR, R., BRUCKMANN, E., HOHN, H.-P., DENKER, H.-W.:
Markerprofile und Musterbildungseigenschaften von embryonalen Stammzellen: Zell- und molekularbiologische Befunde zum Selbststrukturierungs-Potential.
(Abstr.) Klausurtagung des Kompetenznetzwerks Stammzellforschung NRW, Hagen 14.-15.7.2003 (Abstractband) (www.stammzellen.nrw.de).
pdf-download (1.00 MB)

BEHR, R., THIE, M., BRUCKMANN, E., KROMBERG, I., DENKER, H.-W.:
Rhesus embryonic stem cell colonies express marker genes for early embryonic patterning.
(Abstr.) Verh. Anat Ges. 98; Anat. Anz./Ann. Anat. 185 (Suppl.): 224, 2003.
pdf-download (403 KB)

BRUCKMANN, E., BEHR, R., THIE, M., DENKER, H.-W.:
Rhesus embryonic stem cell culture on feeder cells vs. cell-free laminin.
(Abstr.) Verh. Anat Ges. 98; Anat. Anz./Ann. Anat. 185 (Suppl.): 231, 2003.
pdf-download (416 KB)

DENKER; H.-W.:
Forschung an embryonalen Stammzellen: Eine Diskussion der Begriffe Totipotenz und Pluripotenz.
In: Stammzellenforschung und therapeutisches Klonen. (F. S. Oduncu, U. Schroth und W. Vossenkuhl, Eds.) Vandenhoeck und Ruprecht, Göttingen; 2002, pp. 19-35. pdf-download (35.1 MB)

THIE, M., BEHR, R., BRUCKMANN, E., HOHN, H.-P., DENKER, H.-W.:
Gene profiling and pattern formation of embryonic stem cells: culture of Rhesus embryonic stem cells on feeder cells vs. cell-free laminin.
(Abstr.) First Internatl. Meet. of the Stem Cell Network North Rhine Westphalia, Düsseldorf, November 27th, 2002, pp. 30-31.
pdf-download (1.20 MB)

THIE, M., BRUCKMANN, E., BEHR, R., DENKER, H.-W.:
Culture of rhesus embryonic stem cells (rESC) on feeder cells vs. cell-free laminin: effects on the expression of stem cell markers.
(Abstr.) 2nd Symposium on Therapeutic Applications of Human Stem and Precursor Cells. Hannover, Nov. 6 - 8, 2002, P16/p.80.
pdf-download (1.12 MB)

DENKER, H.-W.:
Grundbegriffe: Welches naturwissenschaftliche Konzept liegt dem Begriff der Stammzelle zugrunde?
In: Perspektiven der Stammzellenforschung (Ministerium für Schule, Wissenschaft und Forschung des Landes Nordrhein-Westfalen, Hrsg.). Diskussionsveranstaltung, CCD Düsseldorf, 30. August 2001 (Reihe: Wissenschaft und Forschung im Dialog), S. 1-6.
pdf-download (3.45 MB)

DENKER, H.-W.:
Embryonale Stammzellen und ihre ethische Wertigkeit: Aspekte des Totipotenz-Problems.
In: Jahrbuch für Wissenschaft und Ethik, Band 5 (L. Honnefelder und C. Streffer, Eds.). Walter de Gruyter, Berlin/New York, 2000, pp. 291-304. pdf-download (16.6 MB)

DENKER, H.-W.:
Stellungnahme zur Leitfrage „Kann, unter Berücksichtigung der verschiedenen naturwissenschaftlich verwendeten Definitionen von ‚Pluripotenz‘ bzw. ‚Totipotenz‘, gegenwärtig zuverlässig ausgeschlossen werden, dass die Biopsie an Zellen durchgeführt wird, aus denen sich ein lebensfähiger Embryo entwickeln könnte?“.
In: Deutscher Bundestag, 14. Wahlperiode, 11. Sitzung der Enquete-Kommission Recht und Ethik der modernen Medizin, 13. November 2000. Öffentliche Anhörung von Sachverständigen zum Thema Präimplantationsdiagnostik, Statements der Sachverständigen, S. 9-10.
Statement Denker (in the Web Archive of the German Bundestag, 14.8 KB)
All documents of the hearing (in the Web Archive of the German Bundestag)
pdf-download (14.8 KB)

DENKER, H.-W.:
Zur Thematik „Embryonale Stammzellen“.
In: Marburger Bund – Ärztliche Nachrichten Nr. 8 vom 4.6.1999, S. 2. pdf-download (9.63 MB)

DENKER, H.-W.:
Embryonic stem cells: An exciting field for basic research and tissue engineering, but also an ethical dilemma?
Cells Tissues Organs 165: 246-249 (1999).
pdf-download (188 KB)   PubMed   CTO Website (free access)

DENKER, H.-W.:
Nature and status of the human embryo and its sanctity of life: biomedical points of view.
Third German-Israeli Symposium on Human Dignity and Sanctity of Life in Biomedical Ethics, Ramat-Gan (Israel), 20-21 May 1997 (Lecture Manuscript). Report in: Institut für Wissenschaft und Ethik (Bonn): Veranstaltungsarchiv, Abgeschlossene Fachtagungen.
lecture pdf-download (31.6 KB)   report pdf-download (134 KB)   report online version

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