Questions related to Clinical Biochemistry
Most of the dissolution tests use 900 mL of medium. How was this volume defined? Is there any correlation with the volume of gastric fluid in humans?
Imagine, you have no problem choosing one of the following disciplines.
Which of these disciplines do you choose? Be sure to state the reason for your choice.
Thanks a lot
I have approached various companies but they aren't dealing with an Elisa kit which can measure corticosterone level in brain tissue homogenate. Can anyone suggest me such kit? Is it possible( considering sensitivity) to use a kit for brain tissue homogenate which is marketed for plasma, serum, urine, milk etc?
Biological techniques are methods or procedures that are used to study living things. They include experimental and computational methods, approaches, protocols and tools for biological research.
looking for some best ref. books on Viva in Clinical Biochemistry / Biochemical Analysis / Biochemistry PDF ??
Any journals associated with biochemistry or clinical biochemistry indexed in scopus and clarivate in the same time.
We are trying to collect a sample before and after exercise. Plasma Dihydroxyphenylalanine (DOPA) is a precursor of urine free dopamine. If one collects the urine sample then what is the time frame to match your urine dopamine concentration to plasma?
Good day to everyone.
Can somebody provide me please, to get the answer to this question?
What is the reason for the number of wells in Microtiter plate that uses in Elisa technique is 96 wells or its multiples in some cases? Nor more neither less of that.
Thank you! I appreciate the help.
I'm trying to measure the heme content of plasma with and without the hemoglobin depleted to better understand heme trafficking. I've looked into Hemoglobind but the price is prohibitive given the number of samples I would like to run. Does anyone have a chemical method for removing Hemoglobin?
Soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) are not only observed in serum and plasma in preeclampsia. Both are biomarkers of angiogenesis and cardiovascular risk in the metabolic syndrome.
"Placental growth factor is a vascular endothelial growth factor involved in angiogenesis, vascular inflammation and plaque formation. Soluble Fms-like tyrosine kinase 1 is a decoy receptor for placental growth factor, reducing its activity. " (Theilade S, and col. in Diabet Med. 2012 Mar;29(3):337-44)
In my lectin haemaglutination assay by doing 2-fold serial dilution I have to add 50ul of trypsinized rabbit erythrocytes instead of normal rabbit erythrocytes and also I have heard that the wells need to be coated with EDTA. Can we do the EDTA coating ourselves? Please explain. Thank you. Also can we use direct human blood for the assay. If yes then how to store it till we do the assay?
I have an in vitro dissolution profile, and I would like to predict the plasmatic concentration or the absorbed percentaje, for a bioequivalence study.
The dissolution test results for a particular product have a high variability and are very high. What is the upper limit for the amount of drug released in dissolution testing?
Parameters to be analyze : Glucose, Triglyceride,ALT,AST,ALP,Calcium,T.Protein,Urea,T.Bil , Phosphorous,GGT,LDH ,Creatinine ,Cholesterol .
Analysis to be processed immediately after sample separation.
I need the protocol of Vitamin B9 quantification to determine the Vit B9 level in liver of fishes treated with increasing concentrations of this vitamin for a long period.
I am looking for the information on the normal concentration of butyrylcholinesterase in the blood serum of a healthy horse in µg/mL.
Metabolites to be extracted from blood plasma and urine samples
I want to know what different methods exsist to determine the gene polymorphisms of the CYP2C9 and VKORC1, which are inportant in warfarin therapy.
What are the straightness and weaknesses of each method? Which one is the "gold standard"? Which was the first one?
Does the final price of the test relates to the method that test is based on? How?
it would be very helpfull if you can back up your answers with references.
I have some incomplete data regarding creatinine in mouse urine that I would like to use to evaluate proteinuria. I would like to know what is the usual quantity of creatinine found in 24h urine to compare it to my results, does anyone know it?
I am planning to do a drug discrimination task in rats with Isoproterenol hydrochloride. As the risk of heart faillur is very high with that drug, I wanted to be aware of any precautions I should take to prepare the drug in 0.9% Saline.
I just want to determine the TNF-α levels in human blood plasma and what is the most reliable, recent method for this?
Hi there, I want to measure the 15d-PGJ2 titer in endothelial cell culture medium supernatant and therefore I extracted it using solid phase extraction. I eluted the samples in ethyl acetate and stored them temporarily until I evaporated the solvent using a speed vac. I tried to reconstitute the dried residues in assay buffer for subsequent ELISA. In contrast to my anticipation, only part of it dissolved. Neither increase of the buffer volume nor repeated vortexing could make a difference. Now my question is: does this precipitate hint to an incorrectly performed SPE/evaporation or is it a common co-observation, that should be ignored.
Thanks for your help
LDL cholesterol (LDL-C) is the main culprit for the CHD, sometimes is called "bad" cholesterol. This is because it carries cholesterol to tissues, including heart arteries. A high LDL cholesterol level raises the risk of CHD potentially.
Since 1972 the LDL-C has been estimated using this Formula called Friedewald. LDL-c = TC-HDL-c- TG/5 (in mg/dl)
But the limitation of Friedewald Formula is as follows:
1)Inability to measure LDL-C in samples containing chylomicrons.
2)Erroneously high results in patient with Type III hyperlipoproteinemia.
3)Only applicable with plasma TG concentration <400mg/dL.
Moreover, studies showed that FW formula significantly overestimated LDL-C values at TG <100mg/dL, while increasingly underestimated at >200mg/dL.
Global attempts are taken to overcome the problem:
1. Several LDL-C assays; expensive, labor-intensive and time consuming
2. New formulas and modification of FW formula
None of them could satisfy the degree of accuracy compared to expensive direct measurement.
I have developed a new formula that overcome all limitations associated with LDL-C estimation. Implication of this formula will save the time and money and reduce burden of CHD management
Interleukins can be very unstable and their degradation is related to temperature as well. I'm looking for a protocol who can give a reliable measurement of interleukins in patient with chylothorax or pleural effusion. In detail I would like to understand:
1. How collect the sample? Usually we can not define for how long the fluid remain in the chest cavity or in the chest drain before collection.
2. How prepare the sample, I know have been seen to be collected in heparin container and put in ice and centrifuged and frozen -80. Is there any preparation protocol for how centrifugate and store the sample?
I need to perform the measurement of ATP in cardiac extracellular milieu without disaggregating the organ to prevent not to release intracellular ATP. How can I perfuse it?
(ATP colorimetric/fluorometric assay kit- Sigma Aldrich)
Most of the literature refers to increased troponin in serum as a biomarker but I am interested in knowing if decreased levels in the heart indicates disease.
How clinical biochemistry analyzers remove effects of some interference by measuring absorbence at two different wave lengths. E.g serum calcium 650 nm & 700 nm.
We use GFP (Green fluorescent protein) to ensure implantation of mesenchymal stem cells injected into the vein.
I want to know in the intratumoral injection of mesenchymal stem cells, use of the GFP is necessary ?
Some say 24 hours (UK Minimum retesting interval), whereas others say 48 hours (Waldron JL, et al. An automated minimum retest interval rejection rule reduces repeat CRP workload and expenditure, and influences clinician-requesting behaviour. J Clin Pathol. 2014 Aug;67(8):731-3.).
Who is right?
I want to perform some biochemical experiments(cancer effect of ibuprofen on the liver) on ibuprofen, but these experiments require dissolve ibuprofen in a solvent for injection it to the rats. The ibuprofen not dissolved in water, 0.9%NaCl, DMSO, but dissolve in ethanol. Is ethanol a suitable solvent for injection?
Dragendorff’s reagent is used for visualization of alkaloids. Its modifications (e.g. Munier-Macheboeuf) with alkaloids and other compounds are unclear.
What is that modification, can someone elaborate the details please?
Is supersaturation relative to Ca oxalate, for example, defined relative to the saturation value in pure water at a given T and pH, or relative to empirically measured or calculated saturations in actual urine with its host of Ca binding ligands?
I need your help to get some good protocol for extracting metabolites (volatile and non volatile both) from urine and serum samples. Generally I have found through literature surveys that people are using methanol to extract metabolites from serum. Can anybody suggest some good protocols for metabolite extraction from urine and serum. I would be using LC-MS & GC-MS for my studies.
We have a patient with raised (6x the upper limit) urine normetanephrine. However, this patient had noradrenaline 5 days previous. The half-life of noradrenaline is very short (minutes)- but is metabolised to normetanephrine which is what we measure in our assay. Could this just be the drug?
I am conducting an RCT for my PhD measuring Oxytocin Levels in mothers and their babies. After my previous post I have decided to do this with Urine samples as it feels more ethical than Saliva samples as then baby and mother can still eat. I need to cost the analysis of these samples and I was wondering if anyone else has done this analysis, particularly in England, GB? Does anyone know the cost of having the samples analysed? I am surmising that the kits are not DIY as all the research talks about centrifugal force in the lab? Any advice, recommendations would be gratefully received.
i want to estimate total antioxidant(with FRAP test) in the liver tissue homogenate but the frap test usually done in serum or plasma.whats difference between method of meassuring FRAP in serum and tissue homogenate?
I see most people running urinary steroid hormone and oxytocin assays are publishing that SPE is required as sample prep, but I have been unable to replicate results reliably. I can use a commercially available EIA kit that does not require SPE prior to running, but I'm looking for good resources on how to know what sample prep is appropriate for your sample matrix and testing method as well as how to choose the correct SPE column. There are multiple types in the literature that are used. For example, oxytocin extractions interchangeably report using Phenomenex StrataX, Waters Oasis HLB, and Sep Pak C18,
Hi, I want to find out change in concentration of six different proteins due aging in muscle tissue. I am performing western blot right now. Is there another technique available to get accurate protein concentration? I don't have purified proteins to use as standers so can't perform ELISA.
In general lipase protocol-
Lipase activity assay
Determination of liberated free fatty acid was measured by colorimetry method (Kwon and Rhee, 1986) using olive oil as substrate. The reaction mixture, consisting of 1 ml crude enzyme (culture filtrate), 2.5 ml olive oil emulsion (properly mixed of an equal volume olive oil with 50 mM sodium phosphate buffer, pH 7.0) and 0.02 ml of 20 mM CaCl2, was incubated in a water bath shaker for 30 min at 50°C under 200 rpm agitation. The enzyme reaction in the emulsion system was stopped by adding 6 M HCl (1 ml) and isooctane (5 ml), followed by mixing for 1 min. The upper isooctane layer (4 ml) containing the free fatty acid was transferred to a test tube and properly mixed with 1 ml copper reagent.
The reagent was prepared by adjusting the solution of 5% (w/v) copper (II) acetate-1-hydrate to pH 6.1 with pyridine. The free fatty acid dissolved in isooctane was determined by measuring the absorbance of the upper layer at 715 nm after mixture settlement. Lipase activity was determined by measuring the amount of free fatty acid released based on the standard curve of oleic acid (0-50.0 µmole) in isooctane. One unit of lipase activity was defined as 1.0 μmol of free fatty acid liberated min−1 and reported as Uml−1.
I would like to know if same can be done using palm oil as substrate.
On our high throughput hospital clinical chemistry analysers we measure haemolysis, icterus and lipaemia using simple spectrophotometric indices. This is to avoid analysing tests where these interference are know to lead to factitious results.
We have recently observed that some patients with persistent raised triglycerides have high haemolysis indices and there is a relatively strong correlation!
Has anyone else seen this? I am not sure if this represents increased invitro haemolysis in lipaemic samples or a direct analytical interference. The strong correlation suggests the later to me?
All help gratefully received.
I am going to measure this activity but I don't know the exact protocol (quantity and concentration of PA or buffer...)
It is possible that the absorption of fat soluble vitamins have not affected? What happens with their plasmatic transport if the truncated form causes that plasma concentration of LDL is very low?
Free radicals and mitochondrial dysfunction are proportionally correlated.
Newly discovered hormones or markers, that have relation with fertility and some glands cancers.
Often we find markedly lipemic serum in which biochemical analyzes suffer from strong interference, including the concentration of the analytes in "free water". What could be the pretreatment in order to analyze them properly avoiding the positive interference that produce the turbidity and the effect of the volume due to chylomicrons usually present?
Some recent studies have demonstrated a strong reduction of the cLDL with diverse molecules that have this activity. But does someone know about studies directed to the cardiovascular effect of the inhibiting PCSK9? What do you think about possible collateral effects?
In some recent studies there seems to be a greater occurrence of diabetes in patients treated with high doses of statins. Do you think that it is an artifact or actually exists, and if so, why?
In general sense, all the drugs have an expiry date (shelf life). After the expiry date the drug is recommended not to use as it may produce toxic effects in biological system and/or lose its potency in lesser or greater extent i.e. deviation from the optimum specification is seen. My question is what will be happened in case of a toxicant (toxin)? Is there any recommendation for toxiants' using? What will be there toxicological efficacy after expiry?
In our laboratory, we tried to measure iodine levels by ion selective electrodes. However, our direct assays were subject to interferences from other anions like fluorine, bromine. We would like to use a resin and solvent extraction to discard the interference molecules.
As you know chylomicrons or vldls take apo E from hdl in the blood during circulation. Does anyone know its mechanism? Is there any molecule or whatever else that provides this transfer between lipoproteins?
I am interested in the microparticles' functions in blood. I want to determine the levels of some microRNAs included microparticles by real-time qPCR. As the level of microparticles in blood is limited, I want to know if the level of the included microRNA is sufficient to be detected?