Diagnostics - Science topic

(too late of an answer, but in case anyone ever has the same question). Very easy to use! It does both primary and secondary antibody binding, blocking and washes "automatically", it takes about 2.5h-3h. Time and energy saver!

Hi Tom,

Apart from the data of the low concentrations, blank injections are also needed to calculate to S/N and LOD of an established analytical method.

As I am working in environmental chemistry, common we prefer to use method detection limit (MDL) to describe these things, and you can visit "https://www.epa.gov/cwa-methods/method-detection-limit-frequent-questions" for more information.

Plasmids should not be CpG sensitive. Perhaps dam methylation, if grown in E. coli

Correlation coefficients

The Fn (Francisella novicida) Cas9 Editor Linked Uniform Detection Assay (#FELUDA) which uses the FnCas9 protein and a lateral flow paper-based strip is now awaiting approvals to be used for detecting #COVID19. Read more: https://www.biobulletins.com/post/snp-diagnostics-the-feluda-way

good proposition

—Here researcher wants to know about the root causes of the problem. He describes the factors responsible for the problematic situation. It is a problem solving research design that consists mainly:

Guanghui Zhu Thank you for the suggestion. Could you please elaborate it? I'm not sure how I can infer the separatrix position from radiation distribution or temperature and density profiles. In both cases, I think that I'd have to make some additional assumption, such as "upstream separatrix temperature is 70 eV" supported by the two-point model.

"Should and always" in the above answer poses high doubt in the efficiency and accuracy of the dye based qPCR assays. In the case of off target detection, I would say it is not primarily a method based problem, it is a primer based problem. If you are going for diagnostics, you should be well aware of sure about the primer specificity before you are really using it as diagnostic purpose. I am not opposing probe based assays. By that diagnostics assay can be multiplexed but at a higher initial cost. If people dealing with it are not experienced, it is possibility that they are not taking advantage of the probe based assay.

In my opinion, one should be well aware of the pros and cons, but which is better, probes or primer based assay, this can only be answered after analyzing the nuts and bolts of the project.

Hi Robert,

We are covalently binding the antibodies on the surface. Thus, probability of displacement is fairly low. Our buffer is mostly BSA, PBS and sometimes Tween-20.

Our assay is a sandwich immunoassay. Do you think non-specific binding can be the sole reason here?

If you are using the TaqMan probe chemistry then, there might be a chance of cross-contamination of you NTC.

Following suggestions might solve your problem.

1) You can give 50 cycles, and check if your NTC is having a proper curve or not. Sometimes you may not have actual amplification but just a signal noise.

2) You can gel check you NTC after the run completes.

No, Ion torrent PGM cannot be used for Whole Genome Sequencing, you can perform targeted gene sequencing in PGM but for whole genome sequencing ion torrent Proton is recommended.

Dear Fritz,

I am not talking specifically of electrical impedance tomography (EIT). EIT is just an application where the electrical conductivity distribution of an object is imaged using four-electrode impedance technique. Regardless of the application (e.g., EIT, BIA, MF-BIA, BIS, EIM, EIS), excitation signal (e.g., sinewave, broadband signal) or signal processing (e.g., frequency-difference, time-difference, or sensitivity method used in EIT), the norm IEC-60601 regulates the amount of injected current that can be applied by the device for its use in people. Further, these limits will change with the frequency depending on the type of contact.

Going back to your question, that is the one of the applications of impedance techniques, namely to evaluate the status/condition of fluids, tissues or organs. This has been scientifically validated in many applications such as impedance cardiography or body impedance.

Hope this makes sense

Benjamin

Can you define how a visible spectrophotometer instrument is different from a colorimeter?

Regular (aka "end-point") PCR is good at "presence, absence" tests. Like "does the patient have [whatever pathogen] present in their body?". It is not useful for telling the amount of the pathogen. Many labs instead rely on ELISA assays (for both detection and quantification).

PCR can sometimes be useful for detecting disease-associated alleles, IF there is a difference in allele sizes. But genetic mutations/disease-associated alleles are normally only diagnosed by DNA sequencing.

Do a literature search for the disease/pathogen you are interested in and what diagnostic tools already exist. Good luck!

can you do liver function tests

I think there is something odd going on here. If both HindIII and EcoRI are supposed to cut only one time, then the band should be the same size, which they are not in your gel. (I assume you mean the top band from the pair and not the much fainter band that is above your MW marker). One guess is that you have a DNA prep with a mixture of plasmids of somewhat different sizes. But as Debasish suggests, you might also just have partial digestion where the one band is linearized and the other is uncut supercoiled plasmid.

hi

https://www.qualtrics.com/blog/determining-sample-size

Hi Fahmi,

The diagnostic platform that is accepted as the gold standard varies by application; you have not provided enough information. In some cases, an experimental design can be utilized that uses a combination of reference tests when there is not a perfect gold standard in order to minimize biases of a suboptimal "gold" standard. Calculation of of sensitivity, specificity, positive- and negative predictive values are straightforward when 1) there is an accepted gold standard and 2) the gold standard performs as well as or better than the test method. However, innovative diagnostic tests often perform better than the accepted "gold standard." There are a number of publications that address the appropriate research design when there is or is not an accepted gold standard. Here are some publications that you may find useful:

Best regards,

Marcus

Clinician with profound experience, in a world with unlimited resources (and unlimited clinicians with profound experience). In the real world, I believe that a sonographers/physician team approach could be reasonable for basic echocardiography.

Dear Muhammad Zeeshan Zafar

Thank you very much for your contribution, I share a publication, I hope it helps.

 

hi see this article 

https://www.ncbi.nlm.nih.gov › NCBI › Literature 

You are welcome

Houda

Thank you sir @Jon_Ashley

The link was really helpful but the concern is international certificates like FDA approval ,etc.  It seems Aptagen co. provides some services just with conventional guarantee.

14

thanks , but question is not about what you have replied?

Hi, 

Please. What is the molecular mechanism of statins in Pathological Erythrocytosis of Height?

Dear Nasar,

May I see the photos?

Best wishes

Anna

Thank you very much for your input, I already registered it in ClinicalTrials.gov.

Thanks for your help.

The bond breaking at specific pH and temperatures. 

hello dear ..false found other 

It's based on my own clinical observations which will be published soon.  These articles may help:

Cheung S-H, Legge GE.  Functional and cortical adaptations to central vision loss.   Vis Neurosci. 2005 ; 22(2): 187–201.

Riss-Jayle M, Giorgi R, Barthes A. La mise en place de Zone Rétinienne Préferentielle. Partie II: Quand? Ou? Pourquoi s’installe-t-elle? J Fr Ophtalmol, 2008; 31 (4): 379-385.

leaves of P. guajava are been used locally by native to treat ailments in birds, Hence the work was to check antiviral (NDV) activities of the leaf extracts. our findings shows antiviral potentials against NDV.

Get the article to read more. 

Hi Anna Streisand

In medical diagnosis, test sensitivity is the ability of a test to correctly identify those with the disease (true positive rate), whereas test specificity is the ability of the test to correctly identify those without the disease (true negative rate). Sensitivity and specificity are prevalence-independent test characteristics, as their values are intrinsic to the test and do not depend on the disease prevalence in the population of interest- For any test, there is usually a trade-off between the measures, and I will suggest you refer to Bayesian clinical diagnostic model which describes this concepts graphically.

I hope this was helpful.

Dear Naheed,

Ag85B is found in most pathogenic mycobacterial species, including opportunistic pathogens such as M. avium, as well as the BCG vaccine, although expression by BCG seems to be quite low. Ag85B is strongly immunogenic in multiple species, including humans and is included in many different TB vaccines currently under development: in animal models it shows quite good efficacy against bacterial replication.

It has also been tested as a diagnostic antigen, both under its own name and under the alternate name of 32kDa antigen. However, the specificity of the antigen is low, and reactivity mirrors very closely that of the TST. Studies comparing Ag85B with non-infected TST+ controls have repeatedly shown that they cannot reliably seperate the two groups. It has therefore largely been abandoned as a potential diagnostic.

Sulfa drugs are well tolerated by guinea pigs even with compromised renal function. Probiotics are doing similar work.

Paper based sensor circuit firstly provide an inexpensive substrate, which is foldable and lightweight.

But it is a challenging technology, considering its porous structure, and is prone to attach by humidity.

One has to carefully select the quality of the paper.

For example when we tried some initial experiments, we found the paper used for producing currency notes is very reliable. Because everyday we use currency notes, and handle them very roughly in our pockets, taking them in and out.

there are many varieties of paper, so one has to carefully select the paper.

Next for sensing technology where kinds of layers related to beio sensing etc have to be deposited on the paper.

So it slowly boils down to technological problems, but if good results are achieved, then paper based sensor circuits/cards will offer a cheap inexpensive disposable platform. 

k. Sreenivas

We developed a test for heart transplant patients to measure their reactivity in vitro: Transplantation 18; 409; 1974. It is available on my site if you are interested. It is old,but it may have some ideas for you.

You are welcome. 

thank you sir sending a wonderful paper on cystatin c. it obviously give me a great help.

with warm regard

dr kamal kachhawa

i believe it depends on a lot of factors, definition of abnormal EEG, age, timing, preceding clinical status, usage of augmenting procedures and others. For example in elderly population, the general yield is around 40%.

You might try "maternal role attainment", which is not quite what you're looking for but does focus on non-clinical populations.

The phrase, 'Find disease' encompasses almost every human illness.

If you could elaborate what disease you are referring to, if it is a specific one.

Please let me know what is your interest in serum and perhaps we can go further.

Are you referring to diseases that do not elicit an immunologic response?

Please respond.

Hi Jae-Ho Jung!

Good day!

I would be referring you to one of our experts in the field of protozoology.

you can email him concerning your question.

have a most pleasant week ahead!

Dear Marcelo!

Thank you very much for sending me these papers! I read them and I found many interesting information in these articles!

Best regards,

Dubravka

Do you have any test results to go with these symptoms?  I wouldn't rule out an infectious etiology unrelated to the dumpster, weeds, or couch.

Let's identify some of the probabilities associated with this case:

P that mother was exposed to real rabies: moderate

P that she will develop rabies given real exposure: low to very very low (depending on PEP procedures)

P that she will shed virus without developing disease: zero

P that she will shed virus in the milk given clinical rabies: very very low (some weak evidence suggests it might be possible)

P that she will shed virus in her saliva given clinical rabies: probable

P that baby can contract rabies given viral shedding by mother: probable (although never recorded)

P that baby will receive protective antibodies through milk: very likely

Adding all these up I would say that the risk for the baby is low but can be mitigated by allowing it to breastfeed.

Prof Beals as suggested above is an excelent expert opinion in the field. However if all you want is testing, as a reference, clinically available genetic tests can be searched on Orphanet (www.orpha.net).

Besides the problems mentioned above, you might also have a faulty actuator in the pressure line. We recently had a similar problem and an Agilent technician replaced the faulty actuator that regulates the pressure. You can try to get a replacement or have a third-party to come in for repair. 

Most textbook discussions, it seems to me, do say that perfect discrimination is only rarely (if ever) achieved in the real world.  One reason for that is that diagnostic tests are typically used when there is diagnostic uncertainty.  And in that situation, the distributions for those with and without the disease/condition have considerable overlap--so false positives and false negatives will both occur with some frequency.

In your case, I wonder how the subjects were selected.  Are they a random sample from some population where there is diagnostic uncertainty?  Or did you select a sample of folks who clearly have the disease and another sample of healthy controls who clearly do not have it?  If you did the latter, then your study suffers from spectrum bias (see link below), and overestimates the sensitivity & specificity if the test is to be used when there is diagnostic uncertainty. 

HTH.

If you need more sources than mentioned by Jan, we can provide several. Just search here http://www.linscottsdirectory.com/search/antibodies for 4HNE and follow the "More Info" links to the suppliers' data pages.

Good luck!

Yes, it has been used for that purpose.  My original statement should have been clarified to mean unweighted kappa.  There is literature that is critical of the application of weighted kappa to both the ordinal and other situations and its use at this point must be considered to be controversial.  It is also more difficult to explain to reviewers. 

We have a headache-specific QOL questionnaire, called CHQQ (Comprehensive Headache-Related Quality of life Questionnaire) that we validated in migraine and tension-type headache and found it to be responsive to the effects of treatment in a group of patients with medication overuse headache. Validation in other languages is underway, with very promising results. If you are interested, we can share the English version, just write me.  

the most specific blood test for pancreatitis is trypsin or trypsinogen.  Amylase and lipase can increase from many other acute or chronic conditions in the absence of pancreatitis.  There is a guideline: a lipase that is increased more than 3 times the upper limit for the lab, is consistent with pancreatitis, but proof comes from elevated trypsin levels.  

Non-invasive imaging can be misleading.  it is possible to have a negative ct/mri/us with/without contrast using dynamic sequencing on a pancreas protocol with mild disease.  Enzyme levels do not correlate all that well with disease severity by imaging in the individual patient. If the imaging is consistent with pancreatitis, it doesn't matter what the blood enzyme levels are. The opposite is not consistent correct however.

Aza= associated pancreatitis does occur but it is pretty uncommon. I have managed thousands of patients in GI, Hepatology, and Transplant over the past couple decades and the rate in that experience is less than 0.1% (based on ruling out all other causes, and re-challanging patients (before Cellcept came along).  Those that get pancreatitis on Aza will very likely have recurrant acute panreatitis (RAP) if the drug is restarted.  

If there was ever some reason to think Aza was essential to a patient who gets RAP on the drug,  there should be a comprehensive eval of the panc to rule out any other cause (insect bites, other meds, social (tobacco, alc, otc/rec drugs/herbals, snake handlers, etc), imaging, eus, +/-ercp, genetics) before restarting the drug..

My personal bias is that prednisone does not cause pancreatitis. At least in my experience and the larger institutions I have worked in,  there has been no case I am aware of that had RAP on steroids after ruling out all other causes as best possible for the time.

Confocal is suitable for manytypes of  nevi and melanomas but is not appropriate here for 2 reasons: its field of view is narrow at most 8x8mm especially compared to the surface of a giant congenital nevi, and its depth is 200 to 300 microns while it is suspected that giant congenital nevi degenerate in their depth part.

what are the pros and cons of hosting data outside one's country?

Like all isothermal techniques, RPA has its advantages and disadvantages. In our experience it has had very fast amplification and is a much more simple assay to design than LAMP. However, it seems to be more sensitive to contaminants and off-target nucleic acid contamination (Mathew, perhaps you have some suggestions for us to improve this?)

Hi, I don't know if there is an oxidizing agent that specifically targets Fe+2 and does not oxidize other molecules.

I have seen in the literature that many use serum albumin to preserve a reducing environment. Bear in mind though, that serum albumin has one free -SH group. This free -SH of albumin is a major contributor to the reducing environment of plasma.

Many commercial preparations of albumin have oxidized -SH groups or the -SH as a dithiol with glutathione.  Without a free -SH group, albumin is less effective at maintaining the redox of plasma. 

There are more than ten companies (probably about 30) producing spectral-domain OCT devices:

The most common to my knowledge are:

I do not get the problem> Are you saying that someone published an article in your name? If that is right, I would suggest you write to the editor of the journal so they can publish an ERRATUM in the journal to correct the problem. It could very well be that the correct authors have raised the problem, that is if my understanding is correct.

Dear Fernando,

With respect but it is because we can use spotting robots , automate and use pattern recognition software that we are using MALDI - Tof mass spectrometry as new faster and cheaper methods in haematology and clinical chemistry. Microbiology is being revolutionised by MALDI-Tof direct identification of bacteria - this is the future.

In the first week , PCR is the test of choice for diagnosis of leptospirosis . Culture is the gold standard , but the results come late to help clinical diagnosis . Culture is valuable for sero-epidemiological purposes to identify the serovars . In the second week , MAT is the gold standard serological test , but is complicated & not easily available in developing countries , where leptospirosis is common . Elisa IgM is a simple , sensitive & specific test , which can be used for rapid diagnosis . Rapid tests such as Latex agglutination test , Lepto dipstick , lepto tek lateral flow & lepto tek dri-dot tests are available . 

 Therefore, in the first week , PCR followed by Elisa IgM & MAT  in the second week , if available would be ideal . In developing countries , non availability of these tests , would require development of simple ,sensitive & specific rapid tests , which is urgently needed . Leptospirosis is under diagnosed in developing countries , because of non availability of simple diagnostic tests .

 The recent diagnostic tests are PCR & Rapid diagnostic tests , while culture & MAT are gold standard tests & are older tests .

We have experience/accreditation in routine food testing using qPCR and experience with BioRad's QX100 and now the QX200 for absolute quantification of DNA reference materials.

The adaptation appears reasonable in most items, though all the n/a's excepting perhaps #11, may need a bit of explanation to understand why, and probably depends on other design details that are not apparent.  Fundamentally, I think most reviewers will respect the attempt to use something of an emergent standard, and with clear explanation of the need to adapt, and will probably be more than understanding.  Best of luck.

Do you think that it is worth to report it ?

Hi, 

The answer by dr. McIver is very interesting, but nevertheless is not exactly what is the present "guidelines" view, based on outcome driven evidence. Nevertheless I like his idea of correcting endocardial function for wall thickness. 

What however is underpinned by the same idea but is better validated, is the analysis of midwall function according to Shimuzu. This was shown to be independently predictive of events in the LiFE study and still its additional value over and above LV mass and BP. 

I put enclosed a lecture given last week at the ESC. I carefully reproduced in these slides what is written in the coming Recommendations for the echo evaluation of the patient with hypertension (JASE and EJCVI to be in press soon). 

Dear Naser,

I added the German manual of the SCL-90(r)-S on Researchgate. You could detect psychological distress, if the T-score is T>=60. You could prove the "Case Definition", 2 T-scores and/or T(GSI) >=63. It is usual to compare the individual score with normative data. Sincerly yours, GHF

This is such an interesting and important question. I believe that it is a combination of both – lack of appropriate technology/method and interest (or more precisely financial interest). On the other hand, there is more research out there than you probably realize due to a lack of common language. This research can sometimes fall under non-local healing, prayer effects, shamanism, energy healing, healing touch, qi gong, Traditional Chinese Medicine, Reiki, etc. These studies may or may not specifically address measured frequencies but they certainly do address the existence, use and effects of the human bio-field. There are also studies that attempt to understand the bio-field through triangulation using physiological bio-markers.

As for prominent researchers, I would definitely recommend checking out Beverly Rubik. There is a profile on her and discussion of research in this area here: http://www.faim.org/energymedicine/measurement-human-biofield.html

Here are links to a couple articles as well:

You might do a search for dissertations on the subject as this would, ideally, provide some current research and a thorough literature review.

I think like all microscopic parasites of blood, you need firstly to make a blood culture and after the PCR technic with the specific primers. You can look at this article for example: http://jcm.asm.org/content/35/6/1353.full.pdf

I hope it will help you

Hi Christian,

I tend to think of surfing as having three elements that are suitable for performance testing in a lab or on dry land.

First, balance on the board. There are quite a few systems avaialbe to test standing balance on two feet. An example is the "Wobbegong" balance board. (Try searching using the terms Wobbegong and Balance). These systems give you a reading from movements of an inclinometer attached to an unstable board, as people try to keep if still. So it is similar to measuring sway on a force plate, except that the surface is unstable, so it matches surfing better. This would give you a 20-second test of balance stability on an unstable surface, which replicates that skill required to control a surf-board.

Second, arm fitness to paddle in to the breaking wave. Perhaps the Wingate crank test (a form of hand cycle, to explain it simply). This has been used a lot with swimmers. I'm not sure if surfers need arm endurance or sprint power. You would have to do a bit of motion analysis of surfers catching waves to see how long they paddle for, as well as the work they do to get back out beyond the break each time. Then you could treat them as a power swimmer or an endurance swimmer, depending on what you want to find out.

Third, jumping up onto the board. They do a powerful push-up and then spring to their feet. Perhaps you could use a force plate under their hands, and do a "clapping" push-up, to see how much sinlge-repetition force they can apply to launch themselves upwards. However, the most compatible test would also include a pwerful tucking up of the legs under them, so it is more like a "burpee" movement. Perhaps a power test for squat-tuck movement slike this would be more compatible (e.g. 10 seconds, maximum repetitions)?

I have not seen any evidence of these sorts of dry-land performance tests for surfers, so you would be doing something new. As a result you might have toestablish validity and relibility for any new versions of these tests that you create. (Still, that is what research is for...something new.)

Good luck.

Jeremy

The following articles describe the terms mentioned:

Hello Tam,

You should take into consideration both the route of administration and volume of injection. Subcutaneous and intraperitoneal routes are most commonly used and are equally good. As you said that you are using Freund's adjuvant, if it is CFA (complete FA) then it must be limited to the initial immunizing dose. All subsequent boosters should use IFA (incomplete FA) as an adjuvant. The FA:antigen emulsified mixture of 1:1 is commonly used. Please note that intravenous (IV) administration of antigen with CFA is prohibited in mice.

Hope this will help you.

Flag this if it is really worthful.

What Khaled is correct, the AQ-10 is actually an abridged version of the AQ, with slightly different psychometrics (again, see the article I referenced, above).

That's exactly what happened. Hematuria was significant enough to cause clot retention. Patient was stable through out the episode. Angiography was performed and showed no abnormality or cause for bleeding.

This question is very similar to that of Omar J BenMarzouk-Hidalgo posted Sept 3, 13. You might check the 39 answers given there.

Best wishes!

Do you get the sequence of the virus? And are you sure the sample is infected by the virus? Before the RNA extracting, did you detected the sample whether it was infected? If you answers are "Yes", you can get a result by Northern Blot as David Gilmer said.

I find a paper said that they get a RNA virus genome band after the RNA extraction. The vRNA is protect by coat protien. So if I face this question, I will freeze and thaw my sample in PBS firstly to smash the sample and the cells. And then treat this homogenate with RNase by 37 degree for 30 min. And then extract the vRNA by Trizol. By this way, the RNA will be all from the RNA virus.

Dear Azad,

Viruses and bacteria are always present. In many hosts they do no damage, but as soon as a monoculture is started, be it agricultural crops or aquaculture species, the chance of an infection occurring increases substantially.

Aquaculture is a relatively new field for raising food for consumption when compared to beef., chicken etc So the history of the disease that affect the different cultured species is not as long. If shrimp were carrying WSSV prior to being cultured, (in the wild) no one would be aware of a shrimp dieing in the open sea, but once you put an infected shrimp into a monoculture, the disease will spread like wildfire. Diagnostics have improved, but a new bacteria or virus (EMS is a good example now) will always pop up and have to be characterized