Diagnostic Assays : Other assays

Diagnostic Assays Portfolios


Predicting Glucoregulatory Dysfunction

UW–Madison researchers have developed a method based on blood lipid chemistry to identify a subject at risk for glucoregulatory dysfunction. The method involves obtaining a biosample from the subject, separating the diacylglycerol fatty acids and determining if the concentration is above or below a control range.

Colorimetric Presumptive Illicit Drug Detection

Researchers at the University of Wisconsin – Platteville have developed a rapid, inexpensive color test for the presumptive identification of multiple classes of controlled substances including synthetic cathinones, cannabinoids, opiates and stimulants including cocaine. This novel, aqueous reagent test can be delivered in an industry-accepted plastic test pouch containing an ampoule of chemical reagents necessary for preliminary testing of controlled substances. Test reagents can be tailored to detect specific target compounds of interest and as new derivatives are developed.

One-Step DNA Extraction from Dried Blood Spots for Newborn Screening

A Wisconsin researcher has developed a one-step method for eluting DNA from a blood sample. The method involves using a DNA elution solution and agitating the blood sample in the solution with heat. The purified DNA is suitable for use in techniques such as enzymatic DNA amplification and real-time PCR.

Measuring the Activity of a Specific Fraction of Albumin for Early Diagnosis of COPD or Sepsis

UW-Madison researchers have developed a sensitive and rapid high throughput assay that can be used for early detection of COPD or sepsis. This assay measures the functional activity of a specific fraction of albumin (SFA) in serum or plasma.

The assay uses a liposome that contains a fluorescently labeled fatty acid and a negatively charged phospholipid as a substrate. The liposome is mixed with phospholipase A2 (PLA2), an enzyme that plays a key role in inflammation, and a biological sample from a patient. The SFA in the sample then acts to remove the labeled fatty acid from the liposome, causing a detectable change in fluorescence intensity. This change can be used to determine SFA activity.

The measured SFA activity then can be compared to a normal range of SFA activity or to a baseline measurement from the patient to determine if it is decreasing, abnormally low or normal. A decrease or low measurement of SFA activity can indicate inflammation. If the patient is a tobacco smoker, a decrease in activity as compared to an earlier measurement from the patient suggests the patient has developed or will soon develop COPD. If a patient has recently undergone surgery, a decrease in SFA activity can indicate infection and the possibility of sepsis. On the other hand, a return of SFA activity to normal levels may indicate that the patient has recovered.

Non-Invasive Diagnosis and Evaluation of Disease

UW-Madison researchers have developed a non-invasive method for rapidly measuring early onset or progression of disease by identifying specific biomarkers in a biological sample. This method allows for “fingerprinting” the dynamic changes of disease progression and aids in evaluating the disease process.

A biological sample, such as blood or plasma, is taken from a subject undergoing testing for a disease, and one or more biomarkers are measured. The measurements then are compared to a standard biomarker profile that describes how the biomarkers change as a result of the specific disease. Because the profile changes as the disease progresses, measuring a biological sample at a single point in time provides information on whether or not an individual has the disease, the type (e.g., bacterial or viral) and the stage of the disease (e.g., early or late). 

Synthetic Cofactor Analogs of S-Adenosylmethionine as Ligatable Probes of Biological Methylation

UW-Madison researchers have developed compounds and methods for specifically labeling the substrates of SAM-dependent methyltransferases. The methods use SAM analogs that have been modified at the C5` position so the analog is transferred by the methyltransferase to a methylation site in a substrate, such as a peptide or nucleic acid. Once anchored to the substrate, these cofactor analogs allow for the addition of a detectable and/or isolable label. The label may contain various moieties that aid in determining the methylation state of the substrate. The SAM analogs can also be used with nucleic acid methyltransferases to allow for the rapid identification of specific DNA or RNA residues that are typically methylated.

Identification of Disease Characteristics Using Isotope Ratios in Breath

The researchers now have developed a method of using isotope changes in breath to distinguish bacterial infections from viral infections in humans and other animals. A cavity ringdown spectrometer is used to collect and analyze the isotopes in breath samples taken from a subject over time. A change in the ratio of one stable isotope to another within several hours of exposure to an infectious agent indicates a bacterial infection. On the other hand, a delayed change in isotope ratios, followed by periodic alterations in the ratios, indicates a viral infection.

Method to Diagnose and Treat Degenerative Joint Disease

UW-Madison researchers have developed methods for detecting and treating joint disease, particularly in joints containing a functionally important intra-articular ligament or tendon. To diagnose joint or ligament degeneration, a sample is taken from a joint or ligament and tested for the expression of cathepsin K, cathepsin S, or tartrate-resistant acid phosphatase (TRAP). Because these enzymes are up-regulated during the development of inflammatory arthritis or ligament degeneration, increased levels indicate the presence of disease. Treatment of joint or ligament disease would involve inhibiting the activity of cathepsin K, cathepsin S, or TRAP.

Using Environmental and Genetic Factors to Assess Predisposition to Depression in Humans

UW-Madison researchers have identified a combination of environmental and genetic factors that predicts whether a person is likely to develop depression.  They discovered that adults with an s allele for the 5HTT gene have a significant risk of becoming depressed when they encounter trauma or other stressful life events.  In addition, children with an s allele are at high risk of developing depression when they are maltreated.  On the other hand, l/l individuals seem to be resistant to depression. 

White Blood Cell Assay for Determining Risk of Sepsis and Other Inflammatory Disorders

UW-Madison researchers have developed a method of rapidly assaying P2X7 pore activity in white blood cells within a sample of whole blood. The white blood cells are labeled and then depolarized in an isotonic depolarizing solution. Next, the cells are mixed with a dye and a P2X7 agonist to activate the pore activity of P2X7. Finally, the cells are mixed with a divalent cation to deactivate P2X7’s pore activity. To quantify P2X7 pore activity, the amount of dye taken up by the labeled cells is compared to the dye uptake in control cells without the P2X7 agonist. The amount of activity may help indicate prognosis and suggest a treatment plan for patients at risk for sepsis or other inflammatory disorders.

Phospholipase Activity Provides a Simple Test for Systemic Inflammation in Acute and Chronic Disease

UW-Madison researchers have developed a fluorescence assay for measuring phospholipase activity, including secretory PLA2 (sPLA2) activity.  This assay provides a simple, rapid and highly reproducible blood test that can be used to monitor systemic inflammation over an extended period and evaluate the effectiveness of anti-inflammatory therapies.

The assay uses a unique, fluorescently labeled liposome.  When a sample containing a phospholipase is added to the liposome, the phospholipase hydrolyzes the phospholipid components of the liposome, causing a detectable change in fluorescence intensity.  The degree of change indicates the activity of the phospholipase.

The sample can be compared to a control to determine if an individual has elevated PLA2 activity, which may indicate a disorder associated with systemic inflammation, such as sepsis, heart disease, cystic fibrosis or chronic obstructive pulmonary disease.  The assay also can be used to identify agents capable of altering phospholipase activity. 

Because the activity of sPLA2 in serum is a critical marker for monitoring the onset and severity of systemic inflammation in patients with sepsis or heart disease, this assay also could be used to create a portable, bedside device for early detection of hyper-inflammation.  Such a device could provide accurate, real-time monitoring of changes in fluorescence intensity resulting from changes in sPLA2 activity and may enable early interventions for the prevention of multi-organ failure.

DNA Encoding a DNA Repair Protein

UW-Madison researchers had developed an isolated and purified DNA molecule encoding p95, a DNA repair protein. p95 is a product of the NBS1 gene, the defective gene in the disorder NBS. It also is an integral member of the double strand break repair complex, the function of which is impaired in cells from NBS patients.

Among other uses, this discovery provides an assay in which agents that increase or decrease the activity of p95 can be identified by first expressing p95 in a cell line. Some of the cells are then exposed to the agent, and the amount of p95 is measured relative to that of the control cells.

Screening Assays Based on Stearoyl-CoA Desaturase for Diseases Related to Serum Levels of Triglycerides and VLDL

UW–Madison researchers have developed screening assays using human stearoyl-CoA desaturase 1 (hSCD1).  The researchers discovered that a number of human diseases and conditions are the result of aberrant hSCD1 biological activity.  They also found that hSCD1 is directly related to serum levels of triglycerides and VLDL. 

The assays are based on the role of hSCD1 in disorders relating to serum levels of triglycerides, VLDL, HDL, LDL or total cholesterol or production of secretions from mucous membranes, monounsaturated fatty acids or wax esters.  They may be used for identifying therapeutic agents that modulate the biological activity or expression of hSCD1 and thus may be useful in the treatment of diseases such as atherosclerosis, diabetes or cancer.

Novel Assay for Measuring Stress-Induced CREB Phosphorylation

UW-Madison researchers have developed a phospho-specific antibody that can be used to monitor stress-induced phosphorylation of the CREB transcription factor. CREB is phosphorylated in response to a wide variety of cell stresses that result in oxidative or radiation damage to cellular DNA. The researchers identified three sites on CREB that are phosphorylated by the ATM kinase. This affinity-purified, rabbit polyclonal antibody specifically recognizes one of these sites after phosphorylation has occurred. The antibody can be used to determine if ATM has phosphorylated CREB.