Talk:2009 Group Project 1: Difference between revisions

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Its says project due date 24th september.......if the due date had been brought foward it should be posted on the main project page!!!
Its says project due date 24th september.......if the due date had been brought foward it should be posted on the main project page


EVERYONE...WHY IS THE REST OF OUR PROJECT NOT DONE??  
EVERYONE...WHY IS THE REST OF OUR PROJECT NOT DONE??  

Revision as of 14:43, 17 September 2009

Its says project due date 24th september.......if the due date had been brought foward it should be posted on the main project page

EVERYONE...WHY IS THE REST OF OUR PROJECT NOT DONE??

  • vishnuu...its due TODAY!! how can you post things up next Monday? Please make sure youve referenced EVERY image and all text (i know youve said you need to do this...but its easiest done when writing the section as now you have to go back and find everything, insert numbers etc. Remember to put the reference in the reference section. For the current research section i thought this might help you (as during my lecture in another class they spoke about how rabbits are used in heart development. Is there anything that you've found to include this?). Also I found this website during my research so it may help you? Rabbit Experiments
  • sum - where is the timeline???? It doesn't exist? Where is it? Also, we need some sort of visual for the staging. Have you found an images? Could you draw the stages of embryo development? It just looks incredibly boring.
  • julianna...you need to put up more other than just two historians...there is NO referencing whatsoever in your entire section. where have you found this information? have you put it in your own words or copied it? You need to add some more refences to the reference section at the bottom..there just aren't many to back up your research.

seriously guys. ive added photos and tried to spice up the project but i am NOT going to finish your sections for you. ITS DUE IN 3 HRS! i cant believe you guys haven't bothered to even try finish this. Im very disappointed and i think its slack to let the team down. --Jenny Guy 10:34, 17 September 2009 (EST)


Hey all, just need to finish editing the current research part before i post it up, also need to edit some of my images under abnormal development and also references. Should be all done by Monday. --Vishnnu Shanmugam 07:02, 17 September 2009 (EST)

--Mark Hill 01:40, 8 September 2009 (EST) OK guys, this is still just a page of text......

--Jin Lee 14:50, 3 September 2009 (EST) I want to make a timeline?


--Mark Hill 08:42, 21 August 2009 (EST) z3187802 has contacted me and has been away sick. He should still complete his components of the group project.


Our group is Sum, Vishnnu, Juliana and Jenny. Today in the lab we have decided to research the RABBIT! Rabbit embryology from Mark Hill

(Juliana's email belebele85@msn.com)


This is apparently what we need to include in our case study:

  1. Timeline of Embryo Development - how long (SUM)
  2. Staging - are there species specific staging, what occurs when (SUM)
  3. History of Model Use - when was it first used, (JULIANNA)
  4. Genetics - chromosome number, sequencing (JENNY)
  5. Abnormal Development (VISHNNU)
  6. Current Embryology Research - research papers and findings (VISHNNU)

Hey guys, maybe we should add a section comparing rabbit to human development --Sumaiya Rahman 16:45, 6 August 2009 (EST)

That sounds like a good idea Sum....seeing that human development is the primary theme of the course, not including it would be criminal!. -vishnnu

Report:

  • Links to resources and discussions are to be posted on the group talk page, the project page is for the actual assignment
  • Final assignment will be marked by another group and everyone will be given a marking criteria
  • No information should be obtained from Wikipedia and all information (tables & graphs included) must be referenced
  • Please feel free to suggest any further topics which can be included


RESEARCH:

So i think the main rabbit used in research is the oryctolagus cuniculus. Lets focus mostly on that (or at least i, Jenny, will since im going genetics). This link is great for the specific genetics: Oryctolagus cuniculus complete mitochondrial genome

Here's some stuff about benefits of modeling from a textbook. I haven't yet written as my own so its still the authors material. Just thought it might benefit us all (and raise our morale as we thought the rabbit might suck..but it doesn't!) We're not "submitting" this as our own work so technically we're not yet copyrighting their material. Ive cited the book here and the website i got it from: Cibelli, J., Lanza, R., Campbell, K. and West, M. 2002. Principles of Cloning. Academic Press

“Rabbits were one of the first species in which blastomere nuclear transfer succeeded; as a model species, rabbits placed a central role in developing the micromanipulation technologies in embryos.” Other advantages for using rabbits are:

  1. “The costs to animal procurement, animal care, and oocyte production in rabbits are relatively low compared to large animals.” e.g. a cow embryo is 30x more expensive that a rabbit embryo
  2. “The developmental biology of rabbit embryos and fetuses resembles more closely that of large farm animals than that of rodent model species, including the transition from maternal to embryonic control of embryo development.”
  3. “The pregnancy of rabbits is relatively short (1 month), allowing rapid evaluation of fetal and postnatal development. In comparison, the gestation length for cattle is 9x longer.”
  4. “The sizeable milk production of rabbits allows their use as test animals for therapeutic protein expression in milk, or as a living bioreactor.”
  5. “Rabbits are induced ovulators. Domesticated rabbits are nonseasonal breeders and produce multiple offspring in one litter. These reproductive patterns make the use of rabbits for reproductive research highly efficient.”



Here are some links i (sum) found which may help. Need to go through all the info and sort it out, But there are a couple of good diagrams.

Links for group assignment

http://www.reproduction-online.org/cgi/reprint/48/1/43

http://books.google.com/books?id=RY0rXE2HgqsC&pg=PA344&dq=rabbit+embryo+stages&as_brr=3#v=onepage&q=rabbit%20embryo%20stages&f=false - good for what studies in rabbit embryo have been used for. And has a good table for embryological stages!!

http://books.google.com/books?id=ljAKtC-iIrIC&pg=PA264&dq=rabbit+embryo+stages&as_brr=3#v=onepage&q=rabbit%20embryo%20stages&f=false


http://books.google.com/books?id=73bbKzqRvLsC&pg=PA156&dq=rabbit+embryo+stages&lr=&as_brr=3#v=onepage&q=rabbit%20embryo%20stages&f=false - picture of implantation

http://books.google.com/books?id=aZ7DQYFyxswC&pg=PA122&dq=%22rabbit+development+stages%22&lr=&as_brr=3#v=onepage&q=&f=false


Hi I(Juliana) uploaded file, you guys can have a look. Go to 'Upload File' tab and click ' early growth of rabbit trophoblast' file.


also I found an interesting article! An Electron Microscope Study of the Embryology of the Intercalated Disc in the Heart of the Rabbit Alan R. Muir The Journal of Biophysical and Biochemical Cytology, Vol. 3, No. 2 (Mar. 25, 1957), pp. 193-202 Published by: The Rockefeller University Press

http://info.library.unsw.edu.au/cgi-bin/local/access/ej-access.cgi?url=http://links.jstor.org/sici?origin=sfx%3Asfx&sici=0095-9901(1957)3%3A2%3C193%3AAEMSOT%3E2.0.CO%3B2-S --

Jin Lee 10:48, 25 August 2009 (EST)


I found helpful book in the library Bensley's Practical Anatomy of the Rabbit 8thE by E.Horne Craigie, Toronto, University of Toronto Press 1948 --Jin Lee 13:27, 27 August 2009 (EST)


Vishnnu's Research

Background reading (Vishnnu)

Hey everyone. I'm starting my background reading section where I shall describe my research resources. They contain a summary and a link to the resource itself. I shall keep this "notes" section updated with each new entry I add.


Notes:

  • Articles 1 & 2 - Juliana this could be useful to you.
  • Article 2 - Sum this could be useful to you.
  • Articles 3 & 4 - Abnormal development articles (added: 02/09/2009)
  • Articles 5 & 6 - Abnormal development articles (added: 13/09/2009)


Article 1

The rabbit as a model for reproductive and developmental toxicity studies --Vishnnu Shanmugam 21:05, 30 August 2009 (EST)

Robert H. Foote and Edward W. Carney Reproductive Toxicology 14 (2000) 477–493 Department of Animal Science, Cornell University, 204 Morrison Hall, Ithaca, New York 14853-4801, USA Developmental and Reproductive Toxicology, The Dow Chemical Company Midland, Michigan 48674, USA


Summary

This is a review article of a study looking at the use of rabbits in toxicological studies. The article describes the advantages in using the rabbit experimental model as opposed to the rodent model (mice & rats) and outlines the differences that make toxicological studies on rabbit embryos more accurate than rodents to resemble similar toxicological effects in human embryos. The article describes various techniques that can be used (eg. blood collection from marginal ear vein, artificial insemination, embryo collection) and solutions to some common problems that researchers face when using animal models. Very interesting article with a great quote from Robert Koch to open the eyes of researchers to other animal models:

                 “Gentlemen, never forget that mice are not human beings” 

Want to find out more? Follow the link!

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TC0-41SBGDH-1&_user=37161&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000004218&_version=1&_urlVersion=0&_userid=37161&md5=4db60dc9352996fc4865b9d781b0128d



Article 2

Developmental stages in the rabbit embryo: guidelines to choose an appropriate experimental model --Vishnnu Shanmugam 21:05, 30 August 2009 (EST)

S. Beaudoin; P. Barbet; F. Bargy Fetal Diagnosis and Therapy; Nov/Dec 2003; 18, 6; Academic Research Library pg. 422


Summary

The article describes the various stages in the developing rabbit embryo and the rationale for using rabbits to study normal and abnormal embryology. The article details normal developments in the rabbit embryo and compares it to the developing human embryo. By making this comparison the article argues for the validity of rabbit embryology to better understand human embryology and also suggests that due to the similarities in the developing rabbit and human embryos, experiments on rabbit embryo’s yield more reliable results for human embryology. The article has some rare images on normally developing rabbits and breaks the developmental stages down (in days) describing the observable characteristics that form (eg. Limb development & body formation). I have decided to use the image provided in the journal.

Definitely worth reading people, follow the link!

http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=FDT2003018006422



Article 3

Acheiropodia is caused by a genomic deletion in C7orf2, the human orthologue of the Lmbr1 gene --Vishnnu Shanmugam 04:32, 2 September 2009 (EST)

P. Ianakiev, M. J. van Baren, M. J. Daly, S. P. A. Toledo, M. G. Cavalcanti, J. Correa Neto, E. Lemos Silveira, A. Freire-Maia, P. Heutink, M. W. Kilpatrick, P. Tsipouras Am. J. Hum. Genet. 68:38–45, 2001 Department of Pediatrics, University of Connecticut Health Center, Farmington, CT; Department of Clinical Genetics, Erasmus University, Rotterdam; Whitehead Institute for Biomedical Research, Cambridge, MA; LIM/25-D, University of Sao Paulo School of Medicine, And Private Practice, Sao Paulo; Private Practice, Porto Alegre, Brazil; Department of Genetics, UNESP-Universidade Estadual Paulista, Botucatu SP, Brazil


Summary

The article describes the developmental abnormality Acheiropodia can be passed down genetically from parent to offspring. Acheiropodia (also known as Horn Kolb Syndrome) is a condition where the distal extremities of the embryo fail to form. Although it is not fatal, the individual endures a very difficult life without hands and feet. The article notes that the disorder only affects the development of the limbs and has no other reported manifestations. The article defines this to be an autosomal recessive disorder which means that two copies of an abnormal gene must be present in the affected individual in order for the disease to develop. Thus, each parent passes an abnormal gene to the offspring. It is interesting to note the process of the malformation from genotype to phenotype: small deletions on the chromosomes produce abnormal genes, the abnormal genes are then passed down to the offspring, the offspring that inherits two of the abnormal genes is unable to code for the correct proteins and as a result, there is failure in normal development of limb extremities in the embryo phenotype. The article also has a shocking image of an individual with Acheiropodia which highlights the extent to which it can impact a person’s life and the urgent need to find a cure.

Read more about the exact nature of the abnormal gene using the link.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=1109034



Article 4

Epidemiology of congenital clefts of the lip and palate --Vishnnu Shanmugam 04:32, 2 September 2009 (EST)

JOHN C. GREENE D.M.D. ,M.P.H. Public Health Rep. 1963 July; 78(7): 589–602


Summary

This review article combines research to study the factors causing the developmental abnormalities cleft palate and cleft lip in populations. “Cleft palate (palatoschisis)” and “cleft lip (cheiloschisis)” are the terms used to describe the non- fusion of the upper lip, hard or soft palate and typically occur during the gestation phase of embryonic development. The article tables the occurrence of cleft palate and cleft lip in populations of people in various cities across the world. It also compares the occurrence of cleft palate and cleft lip in males and females. The article finds that the incidence of cleft palate and cleft lip is:

  • Is random in males and females (ie. Occurs approximately evenly in both sexes)
  • Is random in people living in different cities
  • Is higher in children of mothers over the age of 35
  • Is higher in white populations and lower in the negro populations which suggests possible role of environmental factors
  • No concrete proof that cleft palate and cleft lip is hereditary
  • Is higher in rats exposed to radiation and those fed riboflavin
  • Is higher in rabbits and other lab animals exposed to higher stress through cortisone injections

Although the article is now quite ancient, it is interesting to note the incidence of cleft palate and cleft lip among people. It also shows the historical foundation of research into the causes of cleft palate and cleft lip through animal experimentation.

Read more about cleft palate epidemiology using the link.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1915191



Article 5

Chromosome abnormalities in human embryos --Vishnnu Shanmugam 00:10, 13 September 2009 (EST)

Santiago Munne & Jaques Cohen The Center for Reproductive Medicine and science of Saint Barnabas Medical Center, New Jersey, USA Human Reproductive Update 1998, Vol. 4, No. 6 pp. 842-855 European Society of Human Reproduction and Embryology


Summary

As the title suggests, this article focuses on chromosomal abnormalities in the developing human embryo. To understand this article, it is necessary to first establish some basic definitions that are used throughout the article. Aneuploidy can be defined as the occurrence of one or more extra or missing chromosomes leading to an unbalanced chromosome number. Although most babies with an unbalanced amount of chromosomal material miscarry during the first trimester of pregnancy, those that are born have crippling conditions such as:

  • Birth defects
  • Turner's syndrome (disorder where a female child is born with only 1 X chromosome)
  • Down's syndrome (disorder where child is born with 3 copies of chromosome 21)
  • Edward's syndrome (disorder where child is born with 3 copies of chromosome 18)
  • Patau's syndrome (disorder where child is born with 3 copies of chromosome 13)
  • Klinefelter's syndrome (disorder where male child is born with 2 copies of the X chromosome and 1 Y chromosome)

Polyploidy is a type of aneuploidy where the baby has three, four, or more sets of chromosomes instead of the two present in diploids. Chromosomal mosaicism is when different cells within an individual, who has developed from a single fertilized egg, have a different chromosomal makeup. Most commonly there will be some cells with a typical number of chromosomes (46 chromosomes) and other cells with an altered number or structure of chromosomes.


The article explores the possible causes of chromosomal abnormalities resulting from pregnancy though techniques such as IVF (In-Vitro Fertilization) and ICSI (Intracytoplasmic Sperm Injection). It also analyses the role of FSH (follicle stimulation hormone), temperature, water and light in chromosomal abnormalities.

The article finds:

  • High FSH concentration increases likelihood of chromosomal abnormalities
  • ICSI & IVF techniques have increased likelihood of chromosomal abnormalities
  • Chromosomes exhibit temperature sensitivity and changes in temperature can cause chromosomal abnormalities

Although the article makes a number of findings, it is yet to be backed up with convincing evidence; the article has some really cool images of the developing embryo soon after fertilization. Overall, an interesting read.

Interested? Follow the link!

http://humupd.oxfordjournals.org/cgi/reprint/4/6/842.pdf



Article 6

Evaluation of the Safety and Pharmacokinetics of the Multi-Targeted Receptor Tyrosine Kinase Inhibitor Sunitinib During Embryo–Fetal Development in Rats and Rabbits --Vishnnu Shanmugam 00:10, 13 September 2009 (EST)

S. Patyna, J. Haznedar, D. Morris, K. Freshwater, G. Peng, J. Sukbuntherng, G. Chmielewski, and D. Matsumoto Pfizer Global Research and Development, San Diego, California Roche LLC, Palo Alto, California Pfizer Global Research and Development, Kalamazoo, Michigan Xenoport Inc., Santa Clara, California Pfizer Global Research and Development, Groton, Connecticut Birth Defects Research (Part B) 86:204–213 (2009)


Summary

The article looks at how toxicity affects embryo-fetal development. The article describes the abnormal changes that occur when Sunitinib (an oral inhibitor of multiple receptor tyrosine kinases) is administered to pregnant rabbits and rats. This experiment was performed in an attempt to mirror the effects of antiangiogenic agents used in cancer treatment. Sunitinib is an antiangiogenic agent and the use of antiangiogenic agents is not recommended for treating cancer in pregnant patients because of the potential harm to embryo-fetal development. Angiogenesis (the formation of blood vessels) plays a critical role in embryo–fetal development and antiangiogenic agents slow down and/or stop the formation of blood vessels in order to control cancer and stop its spread. In pregnant patients however, this has the potential to adversely affect the developing embryo and these adverse effects is what is investigated in this article.

The article finds the antiangiogenic agent Sunitinib at toxic levels can result in:

  • Embryo death
  • Fetal skeletal malformations including vertebrae malformation and cleft lip/palate
  • Teratogenic effects in rabbits
  • Decreased maternal and fetal body weight

This article is a recent study and provides important findings regarding the use of antiangiogenic agents, especially during pregnancy. Although the maternal effects are minimal, the adverse effects to the embryo are significant and permanent. The article makes good use of tables and graphs to juxtapose pieces of information and to show trends. It is very interesting to note the extent to which chemicals can impact the vulnerable developing embryo.

Read more at link. (Use institutional login from UNSW computers)

http://www3.interscience.wiley.com/journal/122262246/abstract?CRETRY=1&SRETRY=0




thank you so much Vishnuu~~^^ from Juliana


I also changed the format if you guys dont mind--Jin Lee 18:33, 31 August 2009 (EST)


Hey Vishnuu, that link you found with the stages is awesome! thanks so much. Do you know if i am allowed to use the embryo pics in that article on our wiki page?? i'm not sure about the copyright rules. It says at the bottom of the article "Reproduced with permission of the copyright owner. Further reproduction prohibited without permission." Does this mean we can only provide a link to it on our page? if so that's a shame, because those pics were fantastic!! SUM

Oh i also added an introduction - sum


Hey Sum, Unfortunately, since its copyright protected we can't use the image directly......but there is a way of getting around it....You can modify the image using picture editing tools, then simply reference where the original picture came from and state that it has been modified by you. Alternatively, you can trace around the picture and provide only an outline (this will be very difficult to do with detailed pictures, a good picture editing software is recommended). Either way according to whats written under editing basics we need to include a picture that has been drawn up ourselves in the project. Also, not sure if you are aware, but the project is NOT due on Thursday (3rd September), Dr. Hill has very generously given everyone an extension till after mid-session break. --Vishnnu Shanmugam 02:35, 2 September 2009 (EST)


[1] The rabbit as a model to study asthma and other lung diseases.Keir S, Page C. Sackler Institute of Pulmonary Pharmacology, Division of Pharmaceutical Sciences, 5th Floor Hodgkin Building, King's College London, Guy's Campus, London SE1 9RT, UK.

No single animal model is able to reproduce all the features of human asthma. However, the similarities between neonatally immunised rabbits and human asthma highlight the value of this model in the investigation of asthma pathophysiology and in the development of therapeutic agents. Airway inflammation and airway responses to various stimuli including histamine, adenosine 5'monophosphte and antigen in allergic rabbits have shown similarities with the responses observed in asthmatics. Furthermore, functional studies in rabbit airways show they are poorly responsive to capsaicin as are human airways. Chronic pre-treatment with capsaicin desensitises the TRPV(1) receptor enabling studies into the effect of this drug in both rabbits and man. The allergic rabbit model has been used extensively in assessing the various classes of anti-asthma drugs and is sensitive to similar drugs as patients with asthma, including beta-adrenoceptor agonists, corticosteroids, phosphodiesterase inhibitors and theophylline. This article highlights the usefulness of the rabbit as a species to study lung biology.


[2] Effects of strain and embryo transfer model (embryos from one versus two donor does/recipient) on results of cryopreservation in rabbit.Vicente JS, García-Ximénez F. Departamento de Ciencia Animal, Universidad Politécnica de Valencia, Spain.

Differential effects of 2 transfer models for normal thawed embryos of 1 donor doe were studied on the offspring rate and their embryo survival at birth from 3 selected rabbit strains (SY and SB: synthetic strains, NZ: New Zealand White). Morulae were obtained 64-66 h post-coitum from 93 adult does treated with 25 IU of hCG (SY:36, NZ:27, SB:30). Morphologically normal morulae were frozen in the presence of 1.5M DMSO and stored in liquid nitrogen. Normal thawed embryos were transferred into the oviducts of synchronized recipient does of the same strain 48 h after being injected with 25 IU of hCG (SY:28, NZ:21, SB:24). Each recipient received embryos from 1 (single transfer) or 2 different donor does (double transfer). Significant differences were observed in the post-thawing percentage of normal embryos between strains (SY:95 +/- 1% and SB:85 +/- 3%, P < 0.05; NZ: ,91 +/- 2%). After transfer, no significant differences were observed in pregnancy rate and offspring rate between the transfer models, whereas significant differences were only found in survival rate when all transfers were analyzed (double: 24 +/- 4% vs single: 14 +/- 3%, P < 0.05). An effect of strain was detected in the pregnancy rate (NZ: 33% vs SB: 71%, P < 0.05; SY: 61%) and in the survival rate per donor doe on pregnant recipient doe (SY: 42 +/- 5 vs SB: 19 +/- 5, P < 0.05; NZ: 34 +/- 7%). These results suggest a differential embryo sensitivity with respect to their genetic origin in both the freezing-thawing and transfer procedures.


Julianna's Research

[3] HISTORY OF THE RABBIT (IN RESEARCH)

    A.   Discovered in Spain about 100 B.C.
    B.   Domesticated in the 1500's
    C.   Standardization of breeds in 1800's
         1.   Research Uses
              a.   1852:  Rabbits have DL-hyoscyamine
                          (a)  Can survive belladonna
                          (b)  Endogenous atropine esterase
              b.   1884:  Pasteur develops rabies vaccine
              c.   1891:  Heape performs embryo transfer 
                         (a)   Influence on phenotype of the    
                             uterine environment
              d.   1908:  Ignatowsky produces atherosclerosis
                         (a)   Fed diets of milk, meat, and      
                               eggs
                         (b)   Produced intimal lesions
                         (c)   Believed lesions due to protein
              e.   1928:  Demonstrated intranuclear development
                          of herpes virus
              f.   Graafian follicle was first observed
              g.   Coat colors and Mendelian inheritance
              h.   Immunology studies
              i.   Testing of human use products
              j.   Basic science studies
              k.   Diagnostic requirements
              l.   Eye Research
              m.   Pyrogen testing
              n.   Fetal drug induced teratology
              o.   Parasite research



                 LITERATURE REVIEW OF RABBIT USE
    A.   1956 to 1800 ... Over 8000 citations
    B.   1966 to 1987 ... 130,000 citations linking the rabbit to
         all areas of research
    C.   1988 to present ... 821 citations under the search
         criteria:  Rabbit: Model: Human Disease 
    D.   Numbers of Rabbits Used (APHIS; ILAR records 1989)
         
                   1967   504,500
                   1978   439,986
                   1982   547,312
                   1983   466,810
                   1984   529,101
                   1985   544,621
                   1986   521,773
                   1987   534,385


                ADVANTAGES OF USING RABBITS
    A.   Provides repeatability of animal model studies
    B.   Large enough for single samples
    C.   Many stocks/strains as animal models
    D.   Easily managed
    E.   Quality of immunologic products
    F.   Ease of reproductive control



                 DISADVANTAGES OF USING RABBITS
    A.   Most colonies are a storehouse of diseases
    B.   Extremely variable to responses to general anesthetics

--Jin Lee 13:06, 3 September 2009 (EST)

More of vishnuu's research

[4]GROSS EFFECTS ON RABBIT EMBRYOS AND MEMBRANES OF X-IRRADIATION IN THE BLASTOCYST STAGE.

[5]Onset of zygotic transcription and maternal transcript legacy in the rabbit embryo.Brunet-Simon A, Henrion G, Renard JP, Duranthon V. Laboratoire de Biologie du Développement, INRA, Jouy en Josas Cedex, France.

Onset of zygotic transcription is progressive from the one-cell stage onward in the rabbit embryo. Maternal transcripts remain fairly stable until the 8-16 cell stage when major transcriptional activation of the zygotic genome takes place. To understand the mechanisms of the maternal-to-zygotic transition in the genetic information governing development, we asked whether a progressive synthesis of zygotic transcripts takes over the maternal molecules, or whether the synthesis of zygotic transcripts is very abrupt and independent of the persistence of the maternal counterparts. To answer this question, we set up mRNA differential display experiments comparing the mRNA content of rabbit embryos at different stages during the preimplantation period. We isolated eight zygotic transcripts whose synthesis is abruptly turned on at the 8-16 cell stage. These transcripts are involved in general cellular metabolism and their maternal counterparts are still present up to the four-cell and even the 8-16 cell stage. This identification of early zygotic transcripts suggests that global long range modifications of chromatin structure result in a rapid increase in transcription rates during the major transcriptional activation of the zygotic genome.

[6] Reconstruction of the heteroparental diploid condition in rabbit zygotes by nuclear transfer.Escribá MJ, García-Ximénez F. Departamento de Ciencia Animal Universidad Politécnica de Valencia, Spain. mescriba@dca.upv.es

Studies on genomic imprinting showed that parental genomes have complementary roles during embryogenesis, are both essential and need to be synchronized in their embryonic stage for successful development to term. To our knowledge, these studies have not been performed in species other than mice. We studied the in vitro and in vivo development of reconstructed zygotes by combining female haploid nuclear donors and androgenetic hemizygous recipients. Haploid donor embryos at the 8- or 32-cell stage were obtained from electroactivated young rabbit ova (eight pulses maximum, consisting of 0 6 kVcm(-1) for 60 microsec each, 38 min apart) which were further cultured for 24 h or 32 h. Couplets formed by both the haploid male hemizygous recipients and haploid female donor cells were electrofused (2.2 kVcm(-1) for 60 microsec duration each, 30 min apart) and their nuclear configuration determined 122 of those fused (43%: 122/286) were diploid. Reconstructed diploid zygotes developed in vitro up to the compacted morula, blastocyst and hatched stages (1/8-nuclei x 50%, 18% and 9% vs. 1/32-nuclei: 47%, 25% and 19%; P > 0.05), respectively. In embryo transfer assays, both 1/32-reconstructed zygotes and control, non-manipulated zygotes were transferred to synchronized does Four live reconstructed fetuses (4/49: 8 1% survival rate) and five in regression stage (9/49: 18% implantation rate) were observed on Day 21 post-ovulation, whereas from control zygotes, 11 fetuses were alive (11/53 21% fetal survival rate) and 2 degenerated (13/53 x 24 5% implantation rate). Similar results were obtained from a final experiment, in which development was allowed to progress to term. Six live rabbit pups derived front experimentally reconstructed zygotes (11%; 6/54) and three fetuses in regression stage were obtained; values slightly lower than those derived from non-manipulated and transferred control zygotes (18% 9/50, live born rate).

[7] Effects of leukaemia inhibitory factor on endometrial receptivity and its hormonal regulation in rabbits.Liu CQ, Yuan Y, Wang ZX. Shanghai Institute of Planned Parenthood Research, Shanghai, P. R. China.

The effects of hormones on production of leukaemia inhibitory factor (LIF) and the uterine receptivity in rabbits were studied. In ovariectomised rabbits, LIF protein was not detected in control but upregulated by progesterone alone. Oestrogen had a slightly negative effect when the rabbits were treated with both oestrogen and progesterone. Mifepristone (Mi) inhibited the progesterone-stimulated production of LIF in rabbit uterus. The transfer of embryos to LIF-treated recipients significantly increased pregnancy rate (70%) and implantation rate (27%) as compared with control (pregnancy rate=40% and implantation rate=17%). The transfer of embryos to LIF and mifepristone-treated recipients significantly decreased pregnancy rate (30%) and implantation rate (9%). The results indicated that LIF protein had a beneficial effect on uterine receptivity and mifepristone prevented this effect. Copyright 2001 Academic Press.

[8] Effects of strain and embryo transfer model (embryos from one versus two donor does/recipient) on results of cryopreservation in rabbit.Vicente JS, García-Ximénez F. Departamento de Ciencia Animal, Universidad Politécnica de Valencia, Spain.

Differential effects of 2 transfer models for normal thawed embryos of 1 donor doe were studied on the offspring rate and their embryo survival at birth from 3 selected rabbit strains (SY and SB: synthetic strains, NZ: New Zealand White). Morulae were obtained 64-66 h post-coitum from 93 adult does treated with 25 IU of hCG (SY:36, NZ:27, SB:30). Morphologically normal morulae were frozen in the presence of 1.5M DMSO and stored in liquid nitrogen. Normal thawed embryos were transferred into the oviducts of synchronized recipient does of the same strain 48 h after being injected with 25 IU of hCG (SY:28, NZ:21, SB:24). Each recipient received embryos from 1 (single transfer) or 2 different donor does (double transfer). Significant differences were observed in the post-thawing percentage of normal embryos between strains (SY:95 +/- 1% and SB:85 +/- 3%, P < 0.05; NZ: ,91 +/- 2%). After transfer, no significant differences were observed in pregnancy rate and offspring rate between the transfer models, whereas significant differences were only found in survival rate when all transfers were analyzed (double: 24 +/- 4% vs single: 14 +/- 3%, P < 0.05). An effect of strain was detected in the pregnancy rate (NZ: 33% vs SB: 71%, P < 0.05; SY: 61%) and in the survival rate per donor doe on pregnant recipient doe (SY: 42 +/- 5 vs SB: 19 +/- 5, P < 0.05; NZ: 34 +/- 7%). These results suggest a differential embryo sensitivity with respect to their genetic origin in both the freezing-thawing and transfer procedures.

[9] Developmental stages in the rabbit embryo: guidelines to choose an appropriate experimental model.Beaudoin S, Barbet P, Bargy F. Department of Pediatric Surgery, Groupe Hospitalier Cochin-Saint-Vincent de Paul, Paris, France. sylvie.beaudoine@svp.ap-hop-paris.fr

Researchers involved in the field of congenital malformations are often forced to work on an animal model. Both accurate description of its normal development and comparative staging with human development will be mandatory. To complete the lacking medical literature, we herein provide such data for the rabbit model. Sampled rabbit embryos were staged using the Carnegie criteria, in order first to determine if they were consistent with the rabbit developmental pattern, and second to compare this pattern with the human one. Our results show a suitable comparison of rabbits and humans in early developmental stages, except for the neural growth. Copyright 2003 S. Karger AG, Basel