Science topic

Drug Resistance - Science topic

Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.
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A549 cells were attempted to be drug-resistant by exposure to drug treatments for a total of 5 months. After the applications, the cells were tried to be removed by trypsinization but could not be removed. Below are the trypsinization processes tried.
Trypsinization was performed classically by incubating 0.25% 1x trypsin for 3 min in a 37 degree incubator containing 5% CO2. But the cells could not be removed.
When the cells could not be removed, the process was tried again for 5 min and 10 min.
The amount of trypsin was increased (3 ml in a T25 flask) and incubated for 5 and 10 minutes, respectively.
A new, unused trypsin was applied to cells that still did not removed. The newly applied trypsin was also tried to be activated with high volume, 5 and 10 min incubator applications.
The trypsin concentration was increased. Trypsin at 10X concentration was applied in 2 ml volume. It was kept for 5 and 10 min, but the cells could not be removed again.
Finally, the trypsin in the cells was inactivated and the cells were taken back to fresh medium.
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You can also try washing your cells with a PBS/EDTA mixture to help prime the cells for detachment. Don´t be afraid to tap the flask hard to encourage the cells to detach as well once they´ve had trypsin on them.
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Anyone who can help me in obtaining a protocol to detect mutation in pfdhfr and pfdhps genes using Real-time PCR.
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Hello dear Ali
PCR for detection
and
q-PCR for gene expression rate.
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From the perspective of Plant Population Ecology, what are the causes of drug-resistant plants and how to effectively manage drug-resistant plant species.
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Hello Yanice; Perhaps you are referring to examples like Johnson Grass' resistance to the herbicide Roundup in sorgum fields. As Zaal suggests, you can find many citations. I'd suggest using Google Scholar as a handy first resource. Best regards, Jim Des Lauriers
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why i am not getting good quantity of DNA from drug resistant bacteria ?
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Thank you for your answer.
But, I face the difficulty only with the case of resistant bacteria..
I get bucket load of DNA and good quality of DNA from sensitive samples.
The procedure I am performing at the same time and with same amount of CFU for both the type of samples.
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Should I start with IC75 or IC90 concentration to get rid of all the sensitive cells at the initial stage and then gradually work on the increasing concentration from Ic10 until IC90 to get a new IC50.
or Start with the lowest dose and gradually increase to higher cytotoxic concentrations.
Which approach will work better
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Starting concentration should be below IC50 level then gradually increase
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Dears
What are the tradeoffs of using traditional medicines? Would traditional medicines have a bright features in light of the increasingly drug resistance encountered conventional medicines?
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Currently usual doses of antifungal drugs are ineffective in most of the fungal infections. We prescribe usually double/triple drugs in higher doses for fungal infections to cure it.
In tuberculosis, there are MDR and XDR tuberculosis. When tuberculosis is resistant to at least two of the most powerful first-line anti-TB drugs isoniazid and rifampin, it is multidrug-resistant tuberculosis (MDR-TB). When tuberculosis is resistant to isoniazid and rifampin plus any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin), it is extensively drug-resistant TB (XDR TB).
When should we label fungal infections as drug resistant infections?
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Developing a new molecular entity (drug) is very expensive, cumbersome and risky with little expectation of success. Therefore a more safer and less expensive alternative with high possibility of success is needed to mitigate the problem of drug resistance, tolerance and most importantly to manage emerging diseases like COVID-19
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The reason drug repositioning rarely occurs is that drugs are optimized for their targets, so they usually have poor efficacy against other targets. Trying to use a higher concentration of the drug to make up for the lower effectiveness leads to higher toxicity.
(An example: P-glycoprotein is a multidrug transporter that is overexpressed by some cancer cells, making them resistant to multiple chemotherapy drugs by keeping them from accumulating inside the cells. Early on, it was discovered that P-glycoprotein was inhibited by verapamil, which is a drug used to treat certain heart conditions by blocking calcium channels. Trying to use verapamil to block the action of P-glycoprotein was not successful because the high concentration needed can't be tolerated by the patient.)
Having said that, occasionally, an unexpected side effect of a drug turns out to point to another therapeutic application. Sildenafil is a famous case of that.
There is a commercial downside to repurposing an old drug: lack of exclusivity because the patent has expired. Since nobody can own the exclusive right to the composition-of-matter (i.e. the chemical), anyone can make it and sell it, reducing the commercial incentive to spend a ton of money to conduct the necessary clinical trials to get regulatory approval for the new therapeutic indication. For rare diseases, however, it is still possible to get exclusivity in the US.
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Hi.
We have some carbon nanoparticles and want to check antibacterial activity against drug-resistant bacteria. Before working on drug-tolerant bacteria, Are there any protocols or parameters for checking nanoparticles whether have the antibacterial capability on drug-resistant bacteria?.
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Follow
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Hi.
I have prepared hetero-atom-doped carbon dots (Nitrogen with sulfur, boron, phosphorous) for the eradication of biofilm of drug-resistant bacteria. But, I did not see any bacterial death at low concentrations when I am using doped carbon dots. Should I change any parameters or something else?
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Dear Saravanan Arumugam thanks for sharing this very interesting technical question with the RG community. Personally I'm not an exert in this field of reserach (we are inorganic / organometallic chemists) and I was not even aware of the fact that hetero-atom-doped carbon dots have antibacterial properties. However, there are various reports in the literature in which this effect has been demonstrated. For example, please have a look at the following potentially useful articles which migth help you in your analysis:
Applications of N-Doped Carbon Dots as Antimicrobial Agents, Antibiotic Carriers, and Selective Fluorescent Probes for Nitro Explosives
and
Antibacterial Activity of Nitrogen-Doped Carbon Dots Enhanced by
Atomic Dispersion of Copper
The first article is freely available as public full text, while the second has been published Open Access (please see attached pdf file). Apparently it might be worth a try using the hetero-atom-doped carbon dots in combination with copper or silver nanoparticles for enhanced antibacterial activity.
Good luck with your work!
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We got a colistin resistance Klebsiella pneumoniae which induced in vitro by serial passages in media containing increasing colistin concentrations.
1、By Re-sequencing, we found that there was no gene mutation(including gene insertion, gene deletion and point mutation) in the known drug resistance genes(phoP/Q,mgrB,pmrA/B,crrB).
2、Through RNA-seq, we found that mgrB gene expression was down-regulated and PhoQ / P gene expression was up-regulated。
3、We detected the LPS of drug-resistant bacteria by MS and found that the LPS of drug-resistant bacteria was modified by L-Ara4N rather than modified by pEtN. This result is consistent with the result of RNA-seq.
4、This Cositin resistance can be stably inherited, that is, when we remove cositin, this strain still has Cosition resistance(MIC=16-32).
5、How can I explain this phenomenon?Or what methods do I need to find the cause of stable genetic resistance?
6、In fact, this phenomenon has been reported in some papers(DOI:10.2807/1560-7917;DOI:10.1016/j.ijantimicag.2014.07.020;DOI:10.1128/JCM.01017-15;DOI:10.3389/fmicb.2017.02262;DOI:10.1128/CMR.00064-16), but most of them are in clinical strains, and no further research has been done。
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Detection of colistin resistance currently relies on MIC determinations using broth microdilution (BMD), a slow process that, despite being the gold standard for polymyxin susceptibility testing, has been subject to reliability and standardization problems
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I am comparing the global prevalence in intestinal carriage of drug resistant E. coli between community and healthcare settings. I found that the global pooled prevalence in feacal ESBL E.coli carriage in healthcare settings as 21.1% ( 95%CI, 19.1-23.2%) while the prevalence in the community was 17.6% (95%CI, 15.3-19.8%). Can we say the prevalence in healthcare settings was higher than in the community? Note, the 95%CI s ovelap!
If not how shall I compare/describe these
two findings?
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I don’t think it can, because it may exist selection bias.These are 2 samples with different attributes.I suggest you consider DID analysis.
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Currently, I am looking for a solution to develop chemotherapeutic drug resistance in a primary cancer cell line. But after a quick look at the literature, it is indicated that the management of acquirement of drug resistance takes plenty of time, more than eight months! Is there any convenient method to subculture chemoresistant cell lines in a short time? Or any other suggestions rather than eight months interval with an increasing dose of chemotherapeutic agent?
Best regards.
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Dear researchers, thank you all for your contributions. Dear Mohana Krishna Gopisetty, the method you have suggested is time-efficient and problem-solving, I appreciated that. However, the cancer type we are working with is a little bit struggling. Our drug of interest is one of the members of the chemotherapy regimen which consists of other different drugs (we can say that it is given as a cocktail). Also, the relative survival rate of patients is low, diagnosis with specific drug chemoresistance takes time. (but we know that chemoresistance happens - under investigation)
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I did some population analysis profiling test for examining bacterial heteroresistance, but I'm not sure how to interpret the result.
It's turns out that as the start inoculum level increases the output survivor rate increases too.
(attached file : Colony counting for 1. bacteria-K.pneumoniae with 10 fold dilution, 2. start inoculum-1.5*10^6 CFU per 15ml LB agar with antibiotics, 3. AB-Cefotaxime with root 2 fold dilution)
I guess it's because of inoculum effect that the mass resistance increases as the concentration increases.
How do you deal with this problem in hospitals or research centers for antibiotic resistance?
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I would like to recommend this chapter. I hope it helps out.
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I have been working on Cancer chemotherapy and Drug resistant cancer cell lines. Presently, I have developed two drug resistant cell lines. However, I need more cell lines to check the drug resistant reversal activity of my compounds. I would be happy if anyone of you agree to provide me the resistant cell line or provide me the address from where I can get the resistant cell lines in India. I will duly acknowledge their support and provide the authorship as well. Thank you.
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You should make your own resistant lines. These are something not available in cell repositories or shared by other scientists. Of course this is a costly, time consuming and tricky process.
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I need some specific cancer tissue samples' slides for IHC which is resistant and sensitive to specific cancer drugs, especially for prostate, lung, and breast cancer. Is it possible to buy or collect from some organization? If anyone has the information of proper source as well as if anyone has some sample, I would like to request you all to help me with this issue.
Thanks in advance.
Regards,
Mamun
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Gürhan Abuhanoğlu Dear Professor, Thank you for your kind information. However, I do not need any cell line, I have so many cancer and normal cell lines. I am just searching for a cancer drug-resistant tissue array for the immuno-histochemistry experiment.
Regards,
Mamun
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I have some questions about the main principles in drug resistant cell models development.
After determination of IC50 whatever cytotoxic assay is used. I knew there are 2 schools; those who prefer to do a dose-escalation of anti-cancer drug concentrations, and this consumed a lot of time to develop (increase the drug concentration gradually.)
The second, those who prefer to start with a high dose (higher than IC50) and then keep changing the media (drug-free) every week/ 2 weeks.
So how can the one be sure in these weeks (while putting a drug-free media), all cells won't lose the resistance they develop or in other words, why we didn't keep putting drug to cells every week? In order not to kill them all or just mimics what happened in the clinic?
In drug resistant models development, Is there transient vs stable phenotype of drug resistance? How can we really distinguish?
And also there are any methods except for what I said?
Thank you!
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I think these two methods are designed to do two different things.
In the first method, in which the cytotoxic drug concentration is gradually increased from a level that permits substantial cell survival, the purpose is to allow time for resistance mutations to occur, and even to accumulate, during the course of the treatment. An example might be the gradual amplification of the gene for a multidrug resistance transporter.
In the second method, in which the cells are treated for a short time with a high concentration of the cytotoxic drug that kills nearly all the cells, then grown in medium without the drug, the purpose is to select for a rare, stable, preexisting mutation in the cell population that confers high-level resistance. An example might be a mutation in the drug target (such as topoisomerase) that reduces the binding affinity of the drug.
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Which teacher knows how to detect the fidelity of drug-resistant strains by high-throughput sequencing? What are the references?Thank you very much!
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The question does not make any sense the way it is formulated. Bacteria are not fidel to anything, anyway.
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The efficacy of antibiotic therapy for Helicobacter pylori is highly variable in the world. It depends on bacteriological, environmental and host factors. First- line antibiotic drug-resistance is increasingly seen in some regions of the world. Every time the introduction of new therapeutic schemas are necessary for overcome this problem. According to your personal experience what is the best antibiotic therapy schema in you practice and what is your protocol for confirming eradication? Best regards to everybody
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Dear Prof Diego García-Compeán , given the low virulence of Helicobacter pylori and the high prevalence of its infection worldwide, it might be the time to regard it as a commensal organism, not treat it a pathogen:
The medicines used for the eradication of H. pylori will inevitably kill other commensal organisms in the human microbiome, which might have adverse effect on our health.
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Tuberculosis is a deadly infectious disease. In 2018, there were more than 10 million cases of active TB which resulted in 1.5 million deaths ("Global Tuberculosis Report" (PDF). WHO. WHO. 2019. Retrieved 24 March 2020). Tuberculosis control programs are mandatory to save lives. I assume due to the COVID-19 pandemic, tuberculosis control programs are getting less attention. Qiao Liu et al. in the attached article opined that the Covid-19 pandemic may impede global tuberculosis elimination goals. In Jiangsu Province, China, tuberculosis notifications dropped 52% in 2020 compared to 2015-2019. Treatment completion and screening for drug resistance decreased continuously in 2020. Urgent attention must be paid to tuberculosis control efforts during and after the Covid-19 pandemic. In this context, in your opinion what could be the possible impacts of COVID-19 on tuberculosis?
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Use of alcohol antiseptic sanitizers during COVID-19 pandemic and fear of drug resistance bacteria.
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No fear at all. As physicians we do it 40 - 80 times a day without any concern.
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I have a HNSCC cell line resistant to a drug (2 different clones) showing different morphology than the parental cell line. Attached are phase contrast images of these cells. There are black dot like structures visible, within the cytoplasm (probably aggregates, but of what?). Anyone seen anything like this in their experiments. I suspect this maybe the reason for unusual results in my subsequent experiments. Can this be eliminated in anyway? How can i know what it is exactly? Any thoughts and inputs will be highly appreciated. Thanks in advance.
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My CDDP resistance cells also present these aggregates. I also wonder what this could be...
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Is it possible that the RND-type efflux pump, which is most common on gram-negatives, contribute also to the repulsion of non-drug chemicals (like dyes) trying to enter the cell?
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Interesting question with great insights. Looking forward to the discussion!
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DNA Replication and its components are common targets in discovering new drugs as antimicrobial therapeutic agents especially while dealing with antibiotic-resistant species and other diseases that are related with the disfunction in DNA Replication. Are there any methods or interventions to identify changes in DNA Replication Complex as a result of drug exposure ? Are there isolated total DNA Replication Complex to see consequences of interaction of drugs with the its components in big picture?
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Great points. Thanks
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We all know that poor hygiene within dense populations is a breeding ground for diseases. On the other hand, we know that some kind of medium level of exposure to infectious agents on a daily basis is strengthening immunity and keeps it alert.
The big question is what happens when we start to use sanitizers en masse within whole populations?
Hospitals have special procedures aiming at the rotation of chemically-based sanitizers to avoid the rise and promotion of drug-resistant bacteria and viruses.
How is this problem addressed within whole populations? This seems to be important to know right now during the COVID19 outbreak.
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Dear Jiri,
you posted an intriguing question. Although preventing drug-resistance is reasonable and scientifically accurate, this very moment is delicate and we have to fully enforce hand sanitizing. Whole world population is now in a real dangerous time; scientific community has to promote public hygiene as hard as possible. In my opinion, sanitizers rotation is a very clever way to manage this emergency, and it should be encouraged.
Good luck with your work,
Dave
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I’m trying to compose a timeline that projects threats and problems that cause uncertainty to health over the next century.
I’m interested in all long-term health issues including drug resistance, global warming impacts, the impact of technology, biological warfare and terrorism etc.
The closer these events are, the better we can predict when and if they’ll make an impact, but I'm interested in the lot (and the fuzzy logic of when and how big).
I've asked a similar question recently and I got a single good answer - but surely there's more than just one forward thinking researcher out there!
1. Have you heard of any major risks to health over the next 100 years?
2. When are these risks expected and why then?
3. Any predictions on impact size?
4. Do you have any references? They don’t need to be academic, but academic Is better.
5. Any other thoughts?
6. Do you want to receive this data once I’ve compiled it?
Thanks
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There are many emerging and re-emerging zoonoses, such as SARS, Bird flu, Swine flu, Hanta virus, West Nile fever, Dengue fever, Nipah virus, Rift Valley fever etc. are significant cause of morbidity and mortality in developing as well as developed nations.Further research should be conducted on molecular epidemiology, chemotherapy and vaccinology.
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Hi dears
Anybody know the percentage of MRSA and MSSA of S.aureus in the differen population? or totally in the world?
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Article Methicillin Resistant Staphylococcus aureus (MRSA) Nasal Car...
Article Comparison of chromogenic agar medium and diffusion disk tes...
Article Detection of methicillin resistant Staphylococcus aureus (MR...
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I have found a few questions here for this issue but I am not sure about the current admitted idea.
I want to make a drug treatment for establishing a resistant line and I will use a nucleoside analog. So, should I make my cell population synchronic before treatment? Of course, I will make cell viability and cytotoxicity tests on them.
Some researchers said the starvation or serum deprivation is not proper for making the cells synchronic, while some assumed this method is working. If I try this manner, how can I sure about its trustworthiness? And if it is working, how much durable is it? E.g; for the next passage after the synchronization, should I do it again and again?
Thank you!
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Hello Gülşah,
To your question:" So, should I make my cell population synchronic before treatment? ", the short answer is: No.
You can do this but I don't think it's necessary, or even very useful. Your cells will not immediately be resistant to the drug and you don't want them to die too much, so you are going to start with low, sub lethal doses. The cells not in S phase will eventually "run" into it and then incorporate your analogue.
Another tip: Work with at least two dishes/flasks at the same time, one with a higher one with a lower concentration of the drug. If you then, in the course of your resistance trial, "loose" the cells with the higher concentration (i.e. to massive cell death or senescence) You will have the backup with the lower conc. to go ahead with.
Hope that helps.
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Could you please suggest me some papers, textbooks and basic tools for learning in silico methods? Primarily, I want to research about cancer metabolism, drug resistance, and epigenetics. For example, how can I work on and understand "possible" protein-protein interactions, non-coding RNA targets and cell to cell communication?
Thank you in advance
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Dear Abhijeet Singh thank you for your answer but actually I had tried to explain why I want to learn. I am researching on cancer drug resistance and this resistance can be due to epigenetics changes in cell. Hence, these topics are relatively close to each other as to me. I have written all them down because I thought maybe there could be specific tools or databases which I do not know about these. Wish you good work!
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I am working on Acute myeloid leukemia (AML) bone marrow derived Mesenchymal stem cells and will be studying their interactions with AML cells. For standardization process i need to work with drug resistant cell lines. Can anyone help me or suggest me Drug resistant AML cell lines for my study.
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Hi Manasi,
What is the nature of your drugs? Are they well-characterized in the literature, and if so, there may be drug resistant cell lines already published by other groups that you can contact.
If these drugs have known molecular targets, you may want to consider knockdown or knockout of those targets in your cell line of choice to generate a "resistant" clone.
If these are novel drugs with no clear molecular targets or no such cell lines are available, you could consider generating your own resistant clones. Generally, this involves first calculating a dose response curve measuring viability or proliferation of your AML cells (e.g. HL60) with increasing drug concentration at multiple timepoints.
Then you'd culture your cells at a low drug concentration (for instance, enough to kill ~10% of your cells) for an extended period such as 7-10 doublings. You would continue escalating the drug concentration and continue passasing your cells. After about two months, you hopefully have a resistant population.
Some things to consider:
1) Do you know the stability of your drug in media? You may have to replenish the media depending on how fast the drug gets depleted or inactivated.
2) You may want to consider deriving clonal populations from your resistant cells (for instance 2-3 clones) to make sure your interactions are consistent across clones.
3) You may want to culture a non-drug selection flask in paralell with your drug selection flask so you can partly control for passaging numbers. That way, you should have by the end of selection both a drug senstive and drug resistance culture of similar passage.
I hope that clarifies your question.
Thanks,
Barry
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I want to check the effect of chemotherapeutic dug on breast cancer cell line, which possible tests can I perform to check either cells are showing resistant to the drug or not?
Thank you
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BIOPSY - MRI SCAN / CANCER MARKER IN BLOOD after applying Chemothepeutic Agents .
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I am interested to explore the Genetics of Complex Human Diseases (infectious diseases and cancer). Aiming to evaluate the transcriptional and proteomics regulation of genes/ proteins involved in disease progression and proliferation, Molecular insight of Host-pathogens interaction, genetic variation and drug-resistance mechanisms, molecular diagnostic, prognostic and predictive Biomarker of the diseases.
Being an early career researcher I have submitted several projects for funding based on molecular biology but no successful results yet. I am still trying very hard to get funds and collaborate with national and international researcher.
I have an expertise at OMICs level (DNA/RNA/Proteins techniques), if you have any related interest, you are welcomed for collaboration, we can share the present resources or can wright a joint research projects, submit somewhere for funding....
Hope to work together for the betterment of our coming generation...
Best Regards
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Dear @Najeeb Ullah Khan
Thanks for the wishes.
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There have been many different pathogens isolated in PJI, but does this mix differ between countries, and if so in what way? Could it be the genus or species, or maybe the pattern of drug resistance? Could studying this improve our understanding of this devastating complication and help us treat it in the future?
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following
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Alarming surge in drug-resistant HIV uncovered. Honduras is one of the first according to survey. The drug-resistant form of the virus has been detected at unacceptable levels across Africa, Asia and the Americas. But if the application of these medicines has been going on for years, why is this known so far? Is there no follow-up of cases in each country?
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Dear many countries may not monitor the response because microorganisms are known with mutations and other strategies to thwart the effectiveness of chemotherapy.
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To identify exact factor of resistance of drugs
To take measure on drugs cost
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The development of drug resistance in bacteria is a natural process that can't be stopped. However, it can be slowed. Resistance is currently developing at an alarming rate because of inappropriate and unnecessary antibiotic use.
Inappropriate use in healthcare settings includes using antibiotics when they are not needed for treatment, prescribing the wrong type of antibiotic for treatment, and prescribing antibiotics for an inappropriate duration.
According to the CDC, an antibiotic prescription is inappropriate half the time. For instance, antibiotics do not resolve viral infections such as the common cold, influenza (flu), most bronchitis, most sore throats, and the majority of sinus infections. However, unnecessary antibiotic use for these viral infections is still widespread.
In food animals, antibiotics are sometimes added to livestock food and water to promote growth and prevent disease. More than half of antibiotics currently made are used to enhance livestock growth. This contributes to bacteria becoming resistant to drugs important for human health.
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Due to my curiosity, I've done some light research about how people are going about managing Naegleria fowleri and treating patients who have the amoeba in their system. However, some articles have stated that the use of the drug, miltefosine, kills naegleria fowleri--and therefore, have used the drug on patients infected. My concern is that if people continue to use the drug to combat Naegleria fowleri, wouldn't the amoeba gain resistance to miltefosine over time and prove to be ineffective as treatment?
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Theoretically it is possible. The use if miltefosine extends beyond that if Naegleria - it is the only approved oral agent for the treatment of Leishmaniasis, and is used (rarely) to treat metronidazole-resistant Trichomonas, refractory Chaga's disease, other free-living amoeba like Balamuthia and Acanthamoeba. It has also been found to effective against more hardly strains of Candida species and Plasmodium falciparum - so its use is broad-spectrum, anti-amoebic, anti-protozoal, anti-fungal.. Leishmaniasis is the more common indication - it is endemic in nearly 100 countries, has an incidence of over 1 million cases every year, and 350 million people at risk of the disease. Its potential use therefore is actually pretty significant. Miltefosine is unfortunately, not excluded from the development of resistance. In recent years there has been an increasing trend in treatment failures and relapses in patients with Leishmaniasis and the mechanism of resistance has been found to be altered aminophospholipid/miltefosine transporter (MT), so inward translocation of the drug is defective.
There are several possibilities for resistance development:
(i) environmental exposure due to the increased use to the drug
(ii) genetically transferable antibiotic resistance: cross-species genetic transfer by way of capsids (or a similar model)
(iii) the inherent symbiont nature of amoeba of facilitating genetic transfer between bacteria could be a risk factor - amoeba are the genetic "melting pots" after all
(iv) the gene-switching ability of amoeba by utilisation of the genetic material of endosymbiotic bacteria
(v) increased habitat availability with rising temperatures
(vi) dilution of the salinity of sea water by melting glaciers again increases potential habits
(vii) flagellate-empty hypothesis: Naegleria thrives when competition posed by thermosensitive fauna is eliminated, so thermal pollution, again contributes to its abundance by removing resource competitor
(viii) other animals have also been found to be susceptible to Naegleria, including rodents, sheep, cattle and tapirs. These could serve as potential reservoirs, and the thermostability may allow for their survival of cooking and be acquired from consumption of infected meat as well (sheep/goat brain is commonly eaten in some regions).
(ix) The advent of multi-drug resistant superbugs and the role they could play in horizontal gene transfer needs to be considered
(x) Changing trends in infectious disease epidemiology - there is a change in the infection patterns globally, with previously rare diseases becoming more frequently seen - these "Emerging Infectious Diseases" are an excellent model to study the effect of the ecological changes we have set in motion. This group of diseases includes Zika, Ebola, SARS, Chikungunya. The environmental changes that have taken place and are continuing to take place favour the thermophilic amoeba - it very well could become an emerging infectious disease.
Of course these are mostly theoretical, but drug resistance itself was a theory until the first cases of penicillinase producing bacteria were discovered hardly a decade after the introduction of penicillin..
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Have there been any screen about the Prion in all kinds of Cancers? In my opinion, it would be a good explanation for all the characteristics of Cancers, such as Histogenesis\Metastasis\Relapse\Drug resistence\Stemness and so on, that Cancers derive from Prion.
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Biological agents (viruses, insects, bacteria, etc) can become resistant to countermeasures (engineered host resistance, drugs, pesticides, etc), but the resistance often comes with a cost. In the absence of the countermeasure, resistant mutants are often less fit and less competitive than wild-type counterparts.
Consequently, I'm wondering if there are any real-world examples of a previously resistant organism becoming susceptible over time in the absence of the countermeasure.
For instance, an insect pest that develops resistance to a pesticide but then loses resistance when that pesticide isn't used for several years.
Or, a chronic infection that is initially treated with a drug, develops resistance, but then becomes susceptible to that drug after a prolonged period of no treatment.
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The best example is the acquired resistance of insects to insecticides. When there is selection of pressure on a population of a pest insect through the continued application of the same insecticidal molecule with the same mode of action, more than 80% of the population acquires resistance in a few generations, but if the insecticide is no longer applied, the populations will become susceptible again in a few generations.
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Similar social determinants impacting the prevalence of the currently identified and listed 17 NTDs contribute to H.pylroi infections worldwide including inadequate drinking water and sanitation, crowded living conditions, environmental impacts on food and water, behavioral and socioeconomic factors, ethnicity and poverty! Drug resistance to commonly used drugs is emerging and change in the approach of management of H.pylori infections is also being recommended too! So, Is it time to include Helicobacter pylori in the lists of NTDs?
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Good . It possible to combine the current data about H. pyelori supporting this Idea
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There are many MSSA Biofilm producing strains such as Rosenbach and ATCC 35556 strains. But I am interested to work on strong Biofilm producing MRSA lab strains. Please share the names of these strains. Thank you.
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Try mrsa 33591
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Cell to cell cta
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Your question is much too broad to be able to answer. What are you trying to learn from your experiments, in other words what is the question you are trying to answer.
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There are several pathogenic bacteria/ fungus acquired already or are in the process of acquiring drug resistance against antibiotics/anti-fungal drugs available. My question is that, what are those factors/components which communicate/ interface to these bacteria / fungi (intracellular/ extracellular) for developing resistance against the drugs used to combat them?.
Up to what level we got success in this concern or still we are looking ahead?
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Following
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Hello everyone, I am working on drug resistance studies and I need to extract cell membrane proteins specifically ATP binding cassette proteins(ABC family). I tried sonication and freez-thaw cycles using liq. N2 for extraction but I am not getting the protein content and even I get its very poor.....I am willing to purchase membrane protein extraction kit but I am not sure if it can work in my case. So can somebody suggest me some way to extract the membrane proteins??????
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Extracting the protein from the membrane requires the use of a detergent. Here is an example, for P-glycoprotein, which discusses a little about the effect of different detergents:
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Hi colleagues,
I am currently working on sequencing drug resistant genes in M. tuberculosis complex. Sizes of the PCR products varies from 450 bp to 1300 bp. I was wondering should I change cycling conditions for large fragment ( <1 kb)?
Normally I'm setting the following conditions:
96C/1 min, 25 cycles of (96C/10s, 55C/5s, 60C/4m) and hold at 4C.
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Firts see how much DNA yield you have available, then you can try increasing primer concentration to double. Nest, yes Increase the cycles to 30. I tried all and helps.!
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Genxpert and Line probe assay both are molecular/genotypic methods of drug-susceptibility testing. It is said to me that for the diagnosis of MDR-TB only one of them is carried out. So, if genexpert have been performed to diagnoses only RIF resistance does culture is done for detecting second line DST?
Can anyone suggest a workflow starting from AFB staining followed by genexpert, line probe assay, and culture DST.
Thank you!
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LPA is a genotypic test which is limited to INH and RIF for first line and then the fluoroquinolones and aminoglycosides for second line. Culture takes care of all first and second line drugs. Culture considers viable organisms whereas LPA concentrates on the DNA. So when the bacilli is dead, culture result will be negative while LPA will be positive because the DNA of the dead bacilli may still be present in the system. This why Culure is taken to be the gold standard.
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I am looking for the exact mechanism of developing drug resistance and miRNA in prostate cancer patient who treated with Abiraterone acetate or Zytiga .
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Not yet.
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Hi all,
I want to make a drug resistant cell line. What will be the easiest but effective way to make a cell line drug resistant. (IC 50 of my compound is 0.2uM)
Thank you in advance for your answers.
Thanks,
Utsav
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Hi Utsav
It depends on how long you cell line takes to grow, if it grows quickly then you can easily create a drug resistant line in a few weeks, if they take long you may need a few months.
First determine your baseline MIC value of your cell line. Then you can start by growing them in medium containing 0.1 uM of your compound, in the next passage take the survivors and grow them at 0.2uM, then 0.3uM, then 0.4, till you reach the concentration you would like. Check the resistant MIC now, there should be a 2- 4 fold difference. Then you have a resistant line.
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I need to know if there is a colon cancer cell line with cisplatin drug resistance. Also is there any other drug which colon cancer cell lines developed drug resistance against to it ?  
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Hi Muzaffer ,
Try HT-29 and HCT-15 (KRAS and BRAF mutated respectively). also you can try HCT-116. But yes HT-29 will show better drug resistance than the others (as my lab result).
Thanks,
Utsav
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Hi,
I trying to establish an ovarian cancer cell line resistant to the drug cisplatin. What is the best method to do so?
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From
PLoS One. 2013; 8(1): e54193. Published online 2013 Jan 17. doi:  10.1371/journal.pone.0054193PMCID: PMC3547914PMID: 23349823
Generation and Characterisation of Cisplatin-Resistant Non-Small Cell Lung Cancer Cell Lines Displaying a Stem-Like Signature
Martin P. Barr, 1 , * Steven G. Gray, 1 Andreas C. Hoffmann, 2 Ralf A. Hilger, 2 Juergen Thomale, 3 John D. O’Flaherty, 1 Dean A. Fennell, 4 Derek Richard, 5 John J. O’Leary, 6 and Kenneth J. O’Byrne 1 Pan-Chyr Yang, Editor
"Cisplatin-resistant (CisR) variants of each cell line were derived from each original parental (PT) cell line by continuous exposure to cisplatin (Sigma-Aldrich, UK) following initial dose-response studies of cisplatin (0.1 µM–100 µM) over 72 h from which IC50 values were obtained. Initially, each CisR subline was treated with cisplatin (IC50) for 72 h. The media was removed and cells were allowed to recover for a further 72 h. This development period was carried out for approximately 6 months, after which time IC50 concentrations were re-assessed in each resistant cell line. Cells were then maintained continuously in the presence of cisplatin at these new IC50 concentrations for a further 6 months. While A549 cells were initially treated with IC50 concentrations of cisplatin, cells were sensitive to treatment at this concentration resulting in cell senescence and delayed growth. For this reason, the cisplatin concentration was reduced (IC25) until such time as cells demonstrated sensitivity to cisplatin at the appropriate IC50 concentration. "
Good luck!
rolando
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Is the Mycobaterial gDNA extracted using genolyse extraction kit (provided for LPA) good enough for the amplification of katG, rpoB and inhA genes that would be further sequenced. since I m planning to characterize drug resistant genes, i m in a dilemma whether to save time and resource using the already extracted DNA or begin for sub culturing and extraction of DNA from fresh isolates. plase throw in your valuable comments
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well I guess I can use it. found an article that worked on it . it was a good read.
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After 50 days of exposure to sub-lethal concentration of Malachite green, tilapia showed some oxidative stress effects. However on day 60, no more stress was observed between the control and treatment group. Is it due to the multixenobiotic drug resistance in fish? Or any role played by the P glycoproteins? Please share with me your opinion.
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That’s a very interesting question. I am presently working on the photocatalytic decomposition of malachite green oxalate dissolved in H2O (5 ppm concentration) and it appears that MG spontaneously disappears slowly even without ZnO catalyst films. Parameters such as light irradiation intensity have an influence on the discoloration kinetics and temperature may also play a role (not checked yet). Could some external factors modify the amount of MG ingested by your fishes depending on particular days? Did you check the concentration of MG in the aquarium after e.g. 24h before the daily water/toxicant renewal?
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Viruses that cause human disease often become resistant to the drugs that we treat them with.
In contrast, plant viruses seem to overcome countermeasures (such as resistance genes incorporated into host genotypes either through conventional breeding or genetic engineering) less often.
Of course, you can take issue with this characterization. I'd welcome literature that either supports or opposes it. However, in scanning the literature, it seems to be true. Viral resistance genes in plants seem to be more durable than anti-viral drugs used to treat viral infections in animals.
My question is: Why?
Is it something to do with the generally different way we treat viruses in plants (incorporating resistance genes into the genome) vs viruses in people (drugs, vaccines, etc)? Or something else?
I welcome speculation. I especially welcome papers.
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I'm not completely sure why, but my educated guess is that animal viruses spread faster, so the virus goes through more generations more quickly. Animals usually move so they can expose others more quickly than a plant can. More viral replication generations means more opportunities for the selection of traits that can cause resistance.
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I have fresh dried blood spots that i need to extract Plasmodium falciparum parasite DNA for analysis of Antimalarial drugs Resistance markers.I will sequence the DNA thus i required high quality DNA.How do i go about the very first step ?
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I think the link above has comprehensive information to answer your question
best,
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Hi there!! I want to do quality check some Sanger sequence reads and realized that the reads contain some odd letters (N, K, Y, B etc) different from the normal 4 DNA base letters (ATGC). What can i do to edit away these strange nucleotides represented by the strange letters?
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These are not strange nucleotides, but they represent ambiguous peaks at those positions, and polymorphism. Each of these letter specific combinations of signals and are defined in the IUPAC list of ambiguous nucleotides. You need to check these positions in your sequence electrpherograms and confirm. If you have peaks of comparable intensity, you may retain these letters while submitting your sequences to the GenBank. GenBank accept sequences with IUPAC codes. Fllow the link while revising your sequences:
SD
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I have 9 VCF files for individuals i need some publications or tools to know more about:-
- Disease risk calculations.
- Disease identification.
- Drug response.
- Antibiotic resistance.
- Dealing with novel SNPs
- Fitness and Nutrition genes
Also if sample contain gene related to specific disease Is this means that this person suffer from this disease or this person suspected to be patient in the future. (How to know if gene is active or not?)
Waiting your replies with publications, tools and recommendations
Thanks
elsayed
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Hi,
From your question, I understand that you might not be very comfortable with linux and command line based tools. I would suggest you to visit wAnnovar (http://wannovar.wglab.org/). Make sure you provide same genome build and gene definition as used for NGS analysis. Another good option is Variant Effect Predictor (https://asia.ensembl.org/info/docs/tools/vep/index.html). Both are very comprehensive variant annotation tools.
I hope this suggestion helps you with your analysis.
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Microbials, kept subjected to several under-doses (mostly) and over-doses from herbal medicine use, are likely to develop resistance to particular drug molecules, which could also be the principle active compounds in some conventional antimicrobials. How far could this be true? Is the future any good? What interventions can be put in place. Please let me know your views
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More research is being carried out to determine the efficacies of several herbal preparations. In line with answer provided by Mushtaq Ahmad , the optimal doses and side effects for each preparation need to be determined
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Dear Professor and colleagues:
inflammation and cell proliferation induced via activation of nFKappaB leading to an increase in the transcription of pro-inflammatory cytokines (IL-1β, TNF-α, and IL-6...)
in case of abnormal metabolism, cancer cells need inflammation to growth and to form a new blood vessels "neoangiogenesis" which will supply cancer cells by nutrients and oxygen... thus, to the spread of tumors to other organs which we call "Metastasis".
In the other hand, Sugar supports this mechanism, but how? I mean what are the specific signaling pathways that lead to increasing Glucose metabolism during aerobic glycosis (Warburg effect)!!!??
Could anybody help me to know what are the most signaling pathways involved in the metabolic pathways...
Thank you very much for you valuable answers,
Sincerely,
Fouzia
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GSK3beta is negatively downregulated signalling moleculue. That means, when GSK3beta is phosphorylated at serine 9 in presence of signals like Akt/PI3K/PKA/Wnt , they participate in metabolic syndromes.
As you have mention' GSK3beta induces inflammation and cell proliferation via activation of nFKappaB leading to an increase in the transcription of pro-inflammatory cytokines (IL-1β, TNF-α, and IL-6) '
''it means all these sequences are happening when GSK-3beta is unhpshorylatd/activated, so we need to phosphorylate/deactivate GSK-3beta in order to avchive anti-inflamatory effects which is prequisite in metabolic syndrome. Additionally GSK-3beta has shown to mitigate insulin resistance, which again confirm that inactivation/phophorylation of GSK-3beta is prerquisite for acting against metabolic syndrome.
GSK-3beta act by phosphorylation/deactivation of GSK-3beta at ser9 domain.
in brief, Akt/PI3K/PKA/Wnt and as mentioned by John Patrick Alao, mTOR pathways should be considered
You may refer to : Song WJ, Song EA, Jung MS, Choi SH, Baik HH, Jin BK, Kim JH, Chung SH. Phosphorylation and Inactivation of GSK3β by Dual-Specificity Tyrosine (Y)-Phosphorylation-Regulated Kinase 1A (Dyrk1A). Journal of Biological Chemistry. 2014 Dec 4:jbc-M114.
regards,
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Any feedback, ideas, suggestions
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Interesting question and looking forward to read answers
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Dear Friends,
Recently we have got approved our Concept Note on Therapeutics interventions for the treatment of various disease conditions caused by AMR bacteria under NAHEP Programme of ICAR funded by World Bank. 
The concept theme is based on our recent research on Synergistic Interactions of herbal antimicrobials with each other and with antibiotics with the aim to develop Herbibiotics (synergistic combination of Herbal antimicrobials) and Combiotics (synergistic combinations of Antibiotics and herbal components).
Under the programme, we are searching for international collaboration specifically for faculty and Student exchange programme to further the research and keep the hope against emerging drug resistance through trained human resource to deal with the problem. In recent years we have identified feasible synergism between important antibiotics and herbal antimicrobials, useful synergism between two or more herbal antimicrobials and identified the utility of some herbal components as effective antimicrobials. Besides, we are able to locate and identify genes responsible for herbal antimicrobial resistance and synergism.
Your Early response is anticipated as we need to give the names of collaborators within next two weeks.
Thanking you with regards and with anticipation for participation.
Sincerely yours
BR Singh
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We manufacture magnetic Nano particles with Silver attached to the particles. These particles have a minimum 5 log reduction value against a broad spectrum of microbes. I would suggest using these reusable particles of attaching your herbal chemistries to these particles for sterilization
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I am looking for the software or API like predicting quantitative parameters(e.g.IC50) expressing drug resistance of various HIV sequences?
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Hi Ryosaku,
what you need is at least two things: The 'wildtype' IC50 and a fold resistance.
1) there are various tools for genotype to phenotype mapping (this is probably what you are looking for). What this predicts from your sequence is a fold resistance (fold increase in IC50) for each available drug.
there is also a 'rule-based'/expert curated tool at Stanford, but it's predictive power is less than the tool above.
2) 'Wildtype' IC50 values can be found in e.g. Shen et al (2008). Nat Med 14(7), pages 762ff...check the tables in the supplementary material. These parameters were measured in primary human PBM cells. That is pretty useful. But be aware of a detail: some compounds tested are highly protein bound and in the assay they used 50% human serum only. So, one needs to correct for protein binding to obtain a good in vivo estimate. That can easily be done, but please tell if you do not know how.
3) Be aware that all these tools oversimplify. E.g. epistasis will not be accounted for. So the result cannot be assumed to be accurate/absolutely quantitative.
Hope that helps a bit...
Max
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Hi.
I want to start experiments in a few months, but i want to cover every single detail before starting with such time consuming protocols.
To give a little bit of context, i aim to develop resistance to antiandrogens in breast cancer cell lines.
I´m already considering getting an incubator specifically for this task and working with several replicates.
Could you provide any recommendations in this regard? Anything from very specific to general, either way it will be highly appreciated.
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Mauricio:
Before you start, consider that cancer is not a two-dimensional disease. You may be mislead by assuming that cell lines in 2D are relevant to cancer.
Good luck!
CS
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Are hospital susfaces devices reservoirs for drug resistant pathogens , how long?
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Table 1. Persistence of clinically relevant organisms on dry inanimate surfaces.2 Organism duration of persistence (range) Acinetobacter spp. 3 days - 5 months Clostridium dicile (spores) 5 months Escherichia coli 1.5 hours - 16 months Enterococcus spp, including VRE 5 days - 4 months Inuenza virus 1 – 2 days Norovirus and feline calici virus 8 hours – 7 days Staphylococcus aureus, including MRSA 7 days – 7 months Adapted from: Kramer A, Scwebke I, Kampf G. How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infectious Diseases 2006;6:130.
The above table is published in url: https://www.barbicide.com/wp-content/uploads/sites/5/2013/05/nosocomial_pathogen_survival.pdf. Very instructive paper.
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I had established a cisplatin-resistant cell line from an OSCC cells and was wondering if there is any gene markers that I can used to confirmed the resistance development?
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Please refer to the following paper-
BMC Cancer 2006 6:224. DOI. 10.1186/1471-2407-6-224
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Actually sorafenib is less used in treatment of hepatocellular carcinoma for its drug resistance. However my research interest is focused on it. Now I am going to spread a new scientific project and evaluating whether it is good to continute the sorafenib research.
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I think still it is a field of research interest specially for elucidating the drug resistance mechanisms
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Dear All,
I have a very basic question but I could not find the answer from any papers. I am trying to establish resistant cell lines in the lab by treating the cells with increasing concentration of drugs. However, there is a suggestion that FBS should be added in the media during developing resistant cell lines. I normally do not add FBS during drug incubation. What is the general protocol everyone using? What are your recommendations? Thank you very much.
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...correct. At least this is my experience for cell lines from solid tumors and platin resistance.
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My Student has identified two genes recently for Herbal Antimicrobial Drug Resistance (Carvacrol Resistance) in Pseudomonas aeruginosa.
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Dear Dr. Singh,
This theme has basically been explored by your group. But I think it's a new topic to be thought of, I'll talk to my group that works with genome analysis to analyze these bacteria.
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The isolate from glacier stream and water showed high resistance profile, what are the possible reasons? Any paper or study that may be useful to explain this?
Thanks.
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I'm working on horizontal gene transfer among two aforementioned bacteria and need to isolate M. tuberculosis after conjugal gene transfer. i can ensure successful transformation of m. smegmatis bacteria by drug resistance gene placed on plasmid but i don't know how i can select m. tuberculosis bacteria to further evaluation on successful conjugation!
although drug sensitivity-based selection is of most convenient way to select colonies but i don't think these bacteria have different drug sensitivity/resistance patterns...
thanks for your kind help
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I agree with Morad. However, in order to complement those identification test, you can incorporate Para-nitro benzoic acid (PNB) in your culture media. M. tuberculosis is sensitive to PNB and should not growth on it. I am attaching my publication for your reference
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We know that most of the major drugs and antibiotics resistance are due to the poor treatment practices. Thus, we search for new drug targets and new drugs. If the similar trend follows we run out of all the possible drug targets sooner or later. Then what? Instead of investing huge amount of money in research which will become useless after the resistance has occurred, shouldn't we focus on educating people first? 
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Hypothetically speaking we do run out of targets; which was thought to be a distant reality and now is a pressing issue. We will have to resort to pro-drug systems where a universally toxic compound is converted to a nontoxic precursor which can be processed by an enzyme only present in target organism cytosolic proteome. This method is very effective and is the basis of activity of some of the most successful and long standing antibiotics (Isoniazid, artemisinin). However such compounds are difficult to design because of lack of information on xenobiotic modifying enzymes of various organisms. Also, it adds a dual exponential degree of resistance frequency in both target and prodrug activating enzyme. Some highly essential enzymes like isoprenoid, amino acid or nucleotide synthesis/salvage can be exploited to activate designer prodrugs releasing highly potent toxins inside the target organism. As far as educating people is concerned there is a huge controversy on whether incomplete course of antibiotics is the main cause of resistance. Please see article and news in following links:
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Recently, I read several papers about developing sensitive methods for viable MTB identification and the results indicated that PMA-qPCR or EMA-qPCR was high of sensitivity in drug resistance test. I'm wondering why the method has not adopted as standard method in clinical drug resistance test? Is there any concern needed to be considered such as standard protocols? Would the kind one get me out of the confusion? Thanks a lot.
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Hi,
I have been treating my A549 cells with loads of drugs such as geftininb, erlotinib,metformin among others. Although only the cells that are in the 96 well plate are treated, but not the ones in cell culture flasks.
I believe that my cells have become drug resistant. The ic50 after 72 hours treatment were as follows:
Erlotninb (100 um)
geftininb (30 um)
Imatininb (30 um)
metformin (20 um)
Please let me know how can I see if they are indeed drug resistant apart from MTT assay for cell viability?
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Drug-treated A549 cells should exhibit a highly enlarged morphology, due to the onset of senescence as well as polyploidy and multinucleation. It is becoming increasingly evident that moderate, clinically relevant concentrations of virtually all genotoxic agents do not kill the majority of cancer cells (solid tumors, such as A540 cells treated with 10 uM cisplatin). Instead, in response to such treatments, cancer cells become highly enlarged and exhibit the ability to convert MTT to its water insoluble formazan metabolite at a rate ~10 times higher than untreated cells. As you might be aware, such giant cancer cells give rise to cancer-repopulating progeny. If you are interested to know the details of these observations, please search the PubMed for my name "Mirzayans R" and you will find a number of recent open access papers. Alternatively, please feel free to send me an email (razmik.mirzayans@ahs.ca).
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Does anybody know in current clinical practice, what is the therapeutic option for EGFR mutation NSCLC patients who develop acquired resistance to first-line EGFR inhibitor but do not have T790M mutation? Are chemo, radiation, or even surgery still feasible? Thank you.
 
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Dear Sir, 
according to his symptoms and number and sites of progressive lesions.
If he is asymptomatic or he has symptoms with single lesion, you can add local therapy like radiotherapy plus to continue on EGFR inhibitors.
if he is symptomatic with multiple lesions, you have to give systemic chemotherapy plus or minus immunotherapy according to PD-L1 status.
Thanks
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The New study revealed that Antimicrobial Drug Resistance and Herbal Drug Resistance in Bacteria may go Hand in Hand. What Next?
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The work on biochemical investigation of medicinal herbs and seeds with a focus on antibacterial activity was extensively conducted when I was in Government College University Lahore (1967-1993). A number of articles have been published and are being manually added to RG List.. This article is of interest to me because a different methodology for determination of antibacterial activity has been applied and spectrum of effect on different microorganisms interpreted statistically. Resumption with collaboration of my old students involved in different research activities wish for my guidance . We will welcome   collaboration of experts on the platform of Research gate.. Rest I shall say after reading the text.   
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I am planning to do a SNP analysis to determine the presence of drug resistance signatures in Plasmodium falciparum. Is someone having the scripts which i can use do for my variant calling?
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hi see this link can help  you https://www.ncbi.nlm.nih.gov/pubmed/10697834
also this article
 Out of Africa: origins and evolution of the human malaria parasites
Plasmodium falciparum and Plasmodium vivax
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we are already facing multi drug resistant bacteria and people are dying everyday. why there is little research happening on this field all over the world ovbsly leaving Russia, poland etc. Why only they see the potential of this type of therapy?
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ContraFect's (Yonkers, NY) bacteriophage-derived lysin CF-301 for the treatment of Staphylococcus aureus bacteremia has already completed a Phase 1 clinical trial.
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Dear all researchers
I've read several publications that contained keywords are consisting of bacteria, drug resistance, mutation, SNP, outbreak and whole genome sequencing. Then I saw this word "fitness cost" or "fitness cost of mutation" throughout the papers and I do not understand its meaning. Could you please give me some explanation of that term or any related to the term.
Thank you
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Let's say you have an antibiotic which targets an important biological pathway. Mutations that confer antibiotic resistance often involve modification of the target enzyme to prevent antibiotic binding. These mutations often make enzyme suboptimal compared to evolutionary optimized "wild-type" version. This can reduce fitness, manifesting as decreased virulence, transmission, and growth rate. However, despite being less fit under normal growth conditions, this mutant can survive under conditions of antibiotic treatment. So this a trade off also known as fitness cost. 
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Simple protocol for developing a drug resistant cancer cell line against 5FU or any chemotherapeutic agents.
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Nothing to add to the really excellent article by Yoshida