- Damien G Harkin added an answer:From where can I get contact lens for rabbit?
I want to use a contact lens for rabbit for transplantation of stem cells to the corneal surface with substrate. i want to put a contact lens which can also able to diffuse gas (oxygen and CO2). I want to use this lens just to avoid the problems due to blinking. Please suggest me from where I can get this. Please also suggest me, what other methods would be possible. As I am also not able to suture the cell-substrate sheet. I also would like to get information about other ways to put the cell-substrate patch over the cornea other than chemically defined bioadhesive. Please do help in this. Thanks!!!
If nictitans is a problem, you can suture across the top of the implanted test material. Vets treating epithelial defects in cats and dogs often perform this.Following
- Wulligundam Praveen added an answer:What is the importance of high no. of passages in characterization of pluripotent stem cell lines?
I would like to know the possible upper limit of no. of passages for pluripotent stem cells.
Dear Clara, Jorg and Ajay,
thank you very much for the valuable inputs.
- Sandeep Rajput added an answer:What conditions do you use to induce a breast tumor in Nude/J mice with MDA-MB-231 cells?
I injected 1 x 106 MDA-MB-231 cells into mammary fat pad of Nude/J mice. It has been 22 days of the injection and the tumor did not developed.
Any suggestion? Thanks
Please use 50% matrigel to suspend cells. Matrigel provide cells cushion and growth factors to survive and proliferate.Following
- Dina Hazem Gomaa added an answer:How can I interpret scanning electron microscope photos of salivary gland stem cells?
My PhD thesis title is "isolation and charecterization of submandibular and parotid salivary glands stem cells of albino rats". And one of the investigations i used was scanning electon microscope. So i have photos of salivary glands stem cells but cant write comments. I searched alot and cant find any related articles. Would appreciate it if i can get any help. Thanks a lot
Dear Dr Yash,
thanks a lot for your concern and reply, really appreciate itFollowing
- Maria Goes added an answer:Does anybody have problems using ALDEFLUOR assay buffer?
I am trying to perform and aldefluor assay but whenever I use the buffer, the FSCxSSC scatter gets messed up and a great part of my population dies.
But if I run the same cells on PBS the scatter is perfectly normal... Is there any other alternative to using this buffer ?
Thats the point, I am performing the same centrifugation with other cells in PBS and they don't die - their scatter is just fine . In the beggining I was performing a slower centrifugation (300g) but I was having very few events - sometimes 10% of the cells I had originally + bizarre scatter. Now I have about 50% yield. I wonder if it could be because I am centrifuging them at 4oC, right after they left the 37oC incubation. But, again, the other half in PBS survives this just fine.
I might email the sales representative with the bizarre scatters and ask for a solution though.. sounds like a good plan !Following
- Bin Jiang added an answer:What is the important time point in mesenchymal stem cell differentiation?
Hello, everyone. One thing I just want to ask you, because I am a freshman in bone engineering.
We all know that Mesenchymal stem cell could differentiate into osteocyte. In this process, Mesenchymal stem cell may first differentiate into osteoprogenitor, and then into pre-osteoblast, then into osteoblast, finally into osteocyte.
My question may state as following, "what is the important time point in Mesenchymal stem cell differentiation in every differentiation stage??" For instance, when Mesenchymal stem cell differentiate into osteoprogenitor or pre-osteoblast or osteoblast or osteocyte??
Thanks a lot.
young cells with few passages in vitro，start from low density for differentiationFollowing
- Augustine Thambaiah added an answer:Is it feasible to obtain 100 Million Mesenchymal Stem Cell in a 2 Layered Cell Factory?
I would be using 2 layered cell factory (1272cm2) for Mesenchymal stem cell culture.
Source - P1 Umbilical cord Mesenchymal Stem Cell.
If it is feasible to culture and arrive at the magical number (I100 Million mesenchymal stem cell ). what would be the ideal media to use, Supplement ( FBS % and bFGF concentration ) and Seeding density ?
70-80% confluent flask (any type) will have ~20,000 - 30,000 cells/sq.cm. if you calculate based on this a two layer cell factory (~1260 sq cm) should not have more than 40 million msc at 70-80% confluence. and the recovery of cells from the flask by trypsinization will not be 100% you will still have some cells left in the cell factory. recovery will be around 80-90%. so the final yield from a two layer cell factory will be 30-35 million msc.Following
- Nick Asbrock added an answer:How do you analyse FACS data obtained by the ALDEFLUOR kit?How do you analyse the FACS data obtained by the ALDEFLUOR kit? Where do you set the gate on the inhibited sample (DEAB)? What should be the cut-off on the inhibited sample? If you set the ALDHhi gate really close to the cell popluation in the DEAB sample then you have a rather high intra-experimental variation.
Look forward to hear from anybody who worked with this kit.
EMD Millipore has recently commercialized a red-shifted fluorescent substrate for aldehyde dehydrogenase (ALDH) that works in a similar fashion as ALDEFLUOR but allows the concurrent use of green fluorescent cell lines, antibodies, transgenic animals and reporter assays.
Attached is the Nature publication describing the AldeRed reagentFollowing
- Balasubramani pk added an answer:Are collagenase IV (gibco) and Hyaluronidase (sigma) harmful to cells?I digested umbilical cord tissue with collagenaseIV(0.5mg/ml) and Hyaluronidase(0.1mg/ml) for 12h, but after digestion very small number of cells were collected, and it took 2 weeks to form MSCs colonies. In many papers , the MSCs colonies were observed after several days, and collagenase I or II are usually used. So, are the two enzymes harmful to cells?
If my starting material (Umbilical cord is 5cm in length) and both artery and vein removed from the tissue !! What would be ideal volume of C & H added ? Please specify the concentration of the C & H enzyme too?Following
- MOHD AQDAS added an answer:Cells remain adherent irrespective of trypsin treatment?I am working on Mesenchymal stem cells derived from murine bone marrow. One thing I have noticed that MSCs when trypsinized remain adhered and trypsinized for 8 minutes. The cells which float are unable to adhere in plates after subculturing.
I use TPEG solution (0.2% trypsin; 0.02% EDTA; 0.05% glucose in PBS) for trypsinization.
Why I get a white clump after centrifuging the trypsinized mesenchymal stem cells?? is there a way to get rid of it?Following
- Ashaq husssain Najar added an answer:Neurons obtained from Human Neural Stem Cells and grown for ~ 45 days failed to fire when patched. Could anybody advise how to solve the problem?
I have generated NSCs from many human pluripotent stem cells (Human ES and iPS lines). I am trying to differentiate these NSCs into pan neuronal populations in Neurobasal medium supplemented with B27 (with Vitamin A) and Glutamax. On day 6-7 of differentiation, I add cAMP for 3 days. Then cells are grown in the above differentiation medium for upto 45 days till the cells show fine neuronal morphology. These cells get somewhat stressed over time. They stain positive for early and mature neuronal markers but when patched, fail to fire. I use PDL/laminin-coated glass cover slips for growing the cells on. Are these cells not mature enough to fire? what could be the other reason/s for not getting functional neurons?
Thanks a lot Adrian. I am NOT using either of the factors BDNF /GDNF. Just basal medium, B27 supplement and cAMP. You are right in saying that electrophysiology of these cells is very much dependent on the type of media used.Following
- Roberto Ensenat-Waser added an answer:What is the best and the most simple protocol for Embryonic stem cells karyotyping?
I'm doing karyotyping in mouse embryonic stem cells,but it is really difficult to count chromosome number accurately, requiring a long time to find good metaphases.
I would like to know if someone could help me with a better way to spread chromosomes, and provide some tips to facilitate counting.
Thanks a lot!
As Saleh said it helps adding colcemid or colchine, but normaly with mESC growing at their normal rate you should get plenty metaphases. In my hands the critical steps was the height and even more aiming properly the drop on the coverslip. use the position of your hand in respect to your head as reference. you will need a couple of tries to get the proper one, then measure it andn write it down.
another trick, put the coverslips on dry ice to ensure they're really cold.
For the counting you have to be really patient and be realistic with the acceptable n, I was doing fusion between ESC and SSC and we realised that at least 15 are a must but between 20 and 40 should do the job.
Finally check if you have a medical faculty or hospital around, if big enough they have Karyotyping facilities and setting the software to count mouse chromosomes won't be an issue. They may ask you, though, to have the cells ready and fixed.
- Saleh Alkarim added an answer:Is there any chemokine that responds only to stem cells?
Are there any chemokine receptors found only on stem cells and not on mature leukocytes?
I agree with all researchers , see the links here i hop help you
- Tomo Saric added an answer:Has anyone had any problems while using dispase to split iPSCs?
We are been having trouble lately when using dispase for more than three minutes. Our feeder cells are coming out with our colonies in the wash step as a one layered mess. When we re-plate our cells to expand, there are this ugly strings of MEF cells all over the plate. We thought it was mycoplasm but our culture is negative for it. We also tried to dilute our dispase (StemCell @ 5U/ml) and change the incubation time from 5 minutes to 3 minutes but with no luck. Could it be the gelatin we use when plating the MEFs? We have looked at the MEF plates before using to plate our iPSCs and it look fine. Any thoughts?
We haven't use dispase for splitting our human iPSCs but have very good experience with EDTA (i.e. Versene) for splitting iPSCs grown on vitronectin-coated plates and cultured in E8 medium. This is a gentle, enzyme-free and time-saving procedure that allows both the stable passaging of iPSCs adapted to feeder-free conditions and their efficient cryopreservation. If you continue having problems with dispase you may consider switching to EDTA procedure because it will also reduce your costs associated with generation or purchase of MEFs, which itself may unnecessarily introduce variability in your iPSC cultures.Following
- Wen Li added an answer:Does anyone have good experience to convert human ESC to naive state by 3iL(Ng) or 4i(Hanna)?I m suffering a little trouble ...?
I used two cell lines hESC cutured in E8 medium feeder-free condition.When I convert into naive state use protocal by 3iL or NHSM media,I find the colonies shows continuous apoptosis and cannot passage even though forming a little dense colonies as picture.First I think the high concentration of every inhibitor harms to cells in consideration of individual cell line,but when I reduce the dose,it does not work.
Does anyone have similar experience or can give me advices?
Only some perspective according to current knowlegde. I have no experience on coverting primed hESCs to their naive state. If primed hESCs represent epibalst stage, depending on TGFb/FGF2 signaling to maintain their self-renewal, while naive hESCs rely on 4I or 3i, representing earlier stage compared with epiblast stage. It might not so easy to convert the later stage cells into early stage by just changing the culture condition. The success report on that simple way might be some remained naive stage cells within the primed culture, which can survived in the 4I or 3i environment and be enriched because primed cells die out just like what you observed. I remember that some pluripotent gene, KLF4or KLF2, when ectopically enhanced in primed hESCs, is sufficient to push them back to the naive state, by both X activation and TGFb/FGF2 independent.Following
- Juan Uriel Mascotte Cruz added an answer:Does anyone have any experience with in vitro differentiation of neural stem cells at various plating densities?
Anyone have any experience with in vitro differentiation of neural stem cells at various plating densities? I have found that plating at densities within the usual recommended range (50-100,000 cells/cm2) does not give an adequate amount of RNA from TRIzol extraction.
However, from what I understand, too high of a density may inhibit differentiation. I am planning on trying 100-500,000 cells/cm2. What upper limit have you found, if any, where neural stem cells are unable to differentiate as effectively?
As Pavel Ostasov said, I commonly seed 300,000 cells/cm^2 and they grow well, but if you want an extraction, You can wait until the first 4-5 days. And what was your medium? Because you can add different concentration of FBS and this is going to modified your final concentration of your cells for the extraction. All in a flask of 75cm^2! good luck!Following
- Jaya Aseervatham added an answer:Can I loose the protein of interest from a stable clone?
Iam facing a weird problem after transfection. I am using C3H10 meschencymal cell line which is a stable clone expressing a protein which is GFP tagged. Iam using this cell line to transfect another protein having a red tag. both the protein has G418 resistance. After a month, I have few colonies. But when I see it under the fluorescent microscope the resistant cells neither have GFP or red tag.
1 . How is this possible, when I have used a stable clone with a GFP protein ( I did check the cell for fluorescence before the experiment.) for transfection.
2. Do the cells loose the protein for any reason.
Suggestions are welcome
Thank you Patel. I will discuss it with my PIFollowing
- Jessica Bowman added an answer:Is anyone able to help with immunocytochemistry before plastic embedding?
I'm currently trying to optimize a protocol for plastic embedding and sectioning human embryoid bodies (EBs) from H9 stem cells. Since I am trying to show that our labs way of developing embryoid bodies is potentially more organized in shape and growth compared to other previous methods for making EBs, I wish to show the 3 germ layer formation, ideally through ICC before embedding and sectioning.
I am looking at this kit from R&D http://www.rndsystems.com/Products/sc022/
but I know there are some varying levels of success with antibodies and plastic embedding...
Has anyone previously used the antibodies that come with this kit, or the kit itself with plastic embedding? If so, what were the downfalls? Better success with ICC before or after embedding?
Basically, any info on these antibodies with use in plastic embedding would be much appreciated!
Hi all, thank-you for your answers. There's a bit more confidence added to how I will go about this.Following
- Budd A Tucker added an answer:Does anyone have experience with amaxa 4D system for nucleofection of human neural stem cell?
I have to nucleofect 2 cell types. I have access to amaxa 4D system. Standard transfection with lipofectamine 3000 and Mirus Lt-1, I get approximately 30-40 efficiency, but most of thetransfected cells die.
1) iPS cells
2) iPS derived neural stem cells.
Does anyone have experience with amaxa 4D system? Conditions, cell number, plasmid quantity and program to use?
Thanks a lot!
We have used the 4D system quit a bit for hIPSCs, we use the P3 kit with program CB150 in either 25ul strips or 100ul snap top cuvettes. The key is to plate the cells back post-transfection at a rather high density, i.e. ~1x10^6 cells per well of a 24 well culture plate. George Church has a good paper describing the technique in detail for CRISPR work, DOI: 10.1002/0471142727.mb3101s107.
As for human neural stem cells we have done photoreceptor precursor cells with similar methods, there is a rather useful optimization program that is built into the 4D system that would help you optimize your protocol. For human photoreceptor precursor cells the P2 kit and program DS150 works well (~70% efficiency).
Hope this helps.
- Hasan Serdar Mutlu added an answer:CM-Dil Cell Tracking for HSCI tried to stain Hematopoietic Stem Cells with Cm-Dil fluorescent carbocyanite according to the providers manual for cells in suspension. I stained 3 min at 37°C with the working solution (1µM) and further stained at 4°C for 15 min. Then centrifuged, washed in PBS 1x and resuspended in media again. The staining did not work :-)
The cells were not freshly isolated but already 5 days cultured in StemSpan media....
Has anybody experience with HSC in this context?
What color did you see CM DiI in your sections?. I labeled cells with CM-DiI 1µM concentrations 5 min. at 37 C and 15 min. 4 C. And then injected in vivo. After 5 days from injection, I saw greenish florescent in formalin fixed paraffin embedded sections. Is it correct ????Following
- André Luiz Lourenço added an answer:How can I measure HUVEC express P-selectin and a derivative/P-selectin interaction?
I'm starting to work with HUVEC and several works do this assay with HUVEC, but the majority induces in different manners.
I would seriously recommend using fluorescence for the detection of P-selectin expression. BioLegend provides a plethora of anti-human CD62P (P-selectin) with fluorophores. You can use the common FITC or AlexaFluor647-antihuman CD62P antibodies to mark P-selectin in live cells and quantitate the signal using flow citometry or confocal microscopy.
Alternatively you could coat microplates with collagen or fibrinogen (purchase a Maxsorp 96-well flat bottom microplate, add 50 microliters of a collagen/fibrinogen concentrate and incubate overnight at -4C (adding a surplux of BSA is advised). In the next day you should have a coated microplate with collagen or fibrinogen located at the bottom. From here you could add platelets (isolated or directly from PRP)...wait for 15 minutes and perform washing steps. After the washing procedure you'll be able to quatiate platelets/HUVECS that are still bind to the coating-cell network in each well through FITC-anti-CD62P antibody.
If antibodies are not available and you need quick results, you can always try -FITC-phalloidin. And if phalloidin is also hard to find for any reason, you can stick to the traditional approach by using Giemsa staining (Check publication attached below).
I'm adding a thesis from Andreas Eriksson which covers a lot about ways to assess platelet adhesion and function using highthroughput microplate assays, which may also work with HUVECs if you choose the right matrix.
Hope that helps.
- Maja Diana Neely added an answer:Can anyone help with neuron attachment on glass coverslips?Been differentiating ES/IPS cells into neurons. I need to culture them on glass coverslips for downstream microscopy. I find that neurons don't attach well to coverslips coated with Poly-Lysine, PL/Laminin and PL/LM/Fibronectin combinations. LM alone, coating looks OK except that the attachment is not strong! So, whenever I change medium invariably some cells come off the surface and by the end of incubation period over a couple of weeks many of the cells are gone. Any ideas to get a more firm attachment of neurons to glass coverslips?
When you read Gary Bankers book "Culturing Nerve Cells", he mentions there that the glass you use is of utmost importance; he gives company names and glass type to use.Following
- Amna Abdalla Mohammed Khalid added an answer:How can I dissolve EGTAI need to prepare 5mM but it's too difficult to dissolve the EGTA
In PBS. I'm Use it for some types of stem cells just for dissociate the cells
Thank you, it helps me tooFollowing
- Katherine Carvalho added an answer:Could anyone suggest proliferation markers of hMSCs?
I am working on human bone marrow-derived mesenchymal stem cells.
Could you please suggest me about the proliferation markers of hMSCs?
Is there any gene that indicate the self-renewal ability of hMSCs?
With Ki67 or BrdU by cytometric analysis.Following
- Katherine Carvalho added an answer:How can I improve thawing efficiency of human iPSC?
Hi everybody. I've bought human CD34+ derived iPSC line from Life Technologies. In the initial recovery as soon as I got the cells, it worked great. However when I cryopreserved the cells with E8 medium with 10% DMSO and thaw them, I found massive cell death.
Here are the details:
Day 1. Thaw cells as fast as possible. Culture them with E8 medium + ROCK inhibitor.
Day 2. Most of the cells are viable. Change the medium, with ROCK inhibitor.
Day 3. Start to see modest cell death. There're still some decent looking colonies. Change the medium, with ROCK inhibitor.
Day 4. Massive cell death. Although there're still some cells left (but not quite look like colonies) adherent in the dish (vitronectin coated), I am worry that eventually all the cell will die.
So is that normal or I did something wrong with the culture? I will definitely try longer culture.
Dear Sihan Wu,
I believe that your Protocol was correct. Maybe you need to pay attention in your trypsine-time that you use in your IpSc colonies and damage you adhesion molecules protein like, then after seeded they died.Following
- Henry E Young added an answer:Would you rather use knockout or heat inactivated serum to expand MSCs?
I am trying to decide what serum to use to expand canine mesenchymal stem cells and/or mesenchymal stem cell progenitor cells without losing stemness aka. avoiding spontaneous differentiation. Thanks.
Alternatively, Atlas Biologicals in Fort Collins CO make a heat inactivated serum that works wonders. Previously, I was attempting to explain trouble-shooting. If you just want a serum that will do the job at a reasonable cost and forget about trouble-shooting your cultures then the heat-inactivated serum from Atlas is superb.Following
- Richard Josephson added an answer:Is there anyone with experience in using and successfully differentiating the Rat Fetal Neural Stem Cells from Invitrogen into Oligodendrocytes?
I managed to get the cells to reach confluence, and I fixed and applied primary Antibodies of CNPase and MBP about 8-9 days after the initial addition of the Differentiation Media, however when I imaged them, there as no positive staining for either CNPase or MBP. I was wondering if there are any tips or tricks about how long to wait before going in to characterize, or any antibodies that have worked well.
I was also interested in whether anyone has been able to succesfully re-thaw P1 generation cells that were frozen down in DMSO and kep in liquid nitrogen. I seem to be having problems with the cells clumping together after thawing them again, and also very low viability. Any tips or tricks for this issue?
What is the Differentiation Medium that you are using? Are you differentiating just by FGF2 withdrawal, or adding other growth factors? Many people induce oligo differentiation with 1 uM T3, and I find that BDNF and CNTF help keep the oligos alive.Following
- Kenneth Ka-Ho Lee added an answer:Has anyone tried to repeat the Hou et al.,2013 Science 341:651-651 experiment of using only seven small molecules to produce ciPS cells?
It is now 2 years since the publication of this very important study by Hongkui Deng. Has anyone managed to reproduce it?
"Pluripotent Stem Cells Induced from Mouse Somatic Cells by Small-Molecule Compounds"
Pingping Hou, Yanqin Li, Xu Zhang, Chun Liu, Jingyang Guan, Honggang Li, Ting Zhao, Junqing Ye, Weifeng Yang, Kang Liu, Jian Ge, Jun Xu, Qiang Zhang, Yang Zhao, Hongkui Deng, Science (2013)
Maybe you should consider publishing you negative results. Journals like F1000Research will publish it - probably not to the liking of Science.
- Monica Yiyun Jiang added an answer:Can I put 2 promoters together and hope both of them will function?
As my problem, I am working with ES cell lines and want to induce them into neurons. in this process we want to observe it as GFP+ cells. but seems the promoter (i.e ef1a) express high in es cell didn't working well in neurons, and neuron specific promoter didn't working in ES cells.
So I was thinking make a plasmid, has 2 promoter. like this:
neuron promoter-es cell promoter-GFP-polyA.
So that in es cell stage, the es cell promoter can working, and in neurons, the neuron specific promoter can working. but I didn't see any plasmid like this.
Does anyone do this before?
Ok seems all of reply said need two promoter with two protein, and Paritosh's idea is great, so that I can see the process from ES cell to neurons. Thanks all of yours!Following
- Indumati Sharma added an answer:How can I successfully transduct mouse adipose tissue-derived mesenchymal stem cells lentivirus ?
I want to transduct mouse Adipose Tissue-Derived Mesenchymal Stem Cells with lentiviral that expression GFP buttransduction don't succeed, GFP expression is not detectable .
I use working concentration for polybrene is 8 to 10 μg/ ml.microgram/ml) for transduced For 12 to 14 hours.
How effective is RetroNectin?Following
About Stem Cell Biology
All about stem cell biology! Stem Cell Protocols and Methods.