CHAPTER 11 Amino Acids and Proteins Urine Protein Methods Rapid, easy to use; un
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CHAPTER 11 Amino Acids and Proteins Urine Protein Methods Rapid, easy to use; unequal methods (sulfosal Proteins are precipitated as fine trichloroacetic acid,particles; turbidity is measured sensitivity for individual protein acid, uem chloride) spectrophotometrically Proteins are concentrated by precipita- tion, redissolved in alkali, then reacted with Cu: Cu forms colored complex with peptide bonds. Initial biuret reaction; axidation of tyro- sine, tryptophan, and histidine residues by Folin phenol reagent (mixture of phosphotungstic and acids)c measurement of resultant blue color Accurate Very sensitive Limited linearity: unequal sensitivity pinding (Coomassie blue.Protein binds to dye, causes shift in for individual proteins absorption maximum ELISA. RIA, and zone immunoelectrophoresis. Table 11.8 the various methods for measurement of Control Patient Control Patient rinary total protein. The reference values or intervals for urinary pro- xins are highly method dependent, ranging from 100 250 mg every 24 hours, Turbidimetric procedures most frequently used today because of their ease of speed, and sensitivity. Immunochemical, chromato- gaphic, and liquid chromatography-mass spectrometry nethods for quantifying urine albumin are also being used. Even a fluorescence resonance energy transfer assay ir point-of-care testing of urinary albumin has been developed. SPE UPE CASE STUDY 11.5 A male patient aged 47 years came to the clinic after nchod a minor work accident. He works as a painter and had eafillem off a 12-foot scaffold and hurt his ankle. He had a inhalg corpicated medical history that included severe diabetes. dagnosed a decade earlier, with peripheral neuropathy nd retinopathys chronic renal insufficiency; hyperten ion for the past 20 years; and hyperlipidemia. At this clinic vist, the patient was noted to have mild hepatomegaly The patient's blood showed a normochromic normocytic nemia. An SPE with immunofixation demonstrated a UPE Immunofixation Bonoclonal IgGk of less than 100 mg/dL. Urine protein (UPE) with immuno negative Questions rlight chains (Bence Jones protein). Although his ankle 1. What does the presence of the monoclonal lgGk band as not sprained, the patient continued to have breathing ptublems over the next several months and returned to the indicate? da often Among many other tests, a follow-up SPE and 2. What further information is obtained from the UPE UPE with immunofixation were performed. The results re shown below 3. Was this patient's SPE finding consistent with his com plicated medical history?Explanation / Answer
1. Protein electrophoresis are used for the detection of specific proteins or presence of any abnormal type or level of certain proteins. Serum protein electrophoresis (SPE) reveals the level of specific serum proteins, which in turn reflect any disease or abnormalities (like infections, tumours, or malignancies) in a patient. Immunofixation process, conducted during electrophoresis, detects the presence of a type of immunoglobulin in the serum.
The presence of high amount of an antibody, indicates higher immune response. While, presence of high levels of monoclonal antibodies, reflects gammopathies. This depict, that clone of a specific type of protein (in this case IgG ) are derived from single type or few types of plasma cells (B-cells).
High level of IgG indicate that the patient may have conditions like malignancies, multiple myeloma, lymphoma.
2. Usually, protein should be in trace amount in urine. Damage or loss of function of renal glomeruli, cause leakage of proteins in urine. Urine protein electrophoresis (UPE), is used to detect the presence of proteins like albumins or globulins in urine.
The UPE of the patient, exhibited the presence of multiple bands in the Gamma globulin (IgG) region, this may indicate multiple myeloma in the patient.
3. The patient has a history of diabetes, hypertension, hyperlipidaemia, chronic renal insufficiency, retinopathy and peripheral neuropathy. Monoclonal gammopathies may be associated with polyneuropathies. This may be due to the association of monoclonal proteins and nerve damage. Presence of monoclonal IgG may thus be related to neuropathies. Such history of neuropathies, along with presence of monoclonal IgG, may indicate the presence of malignancies.