Urine protein

Several test strips or dipsticks are commercially available and are commonly used to assess proteinuria, but there are several limitations to their use. Highly alkaline or buffered urines give false positive protein reactions, and the test strips are primarily sensitive to changes in albumin rather than globulin fractions (Evans and Parsons 

Allowances should be made for the urine volume and concentration when interpreting test strip results. The quantitative measurement of urine protein is being used more frequently in preclinical toxicological studies (see Chapter 4). 

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All dose levels increased elimination of sodium, potassium, chloride, and urine protein interference with creatinine clearance at 200 mg/kg BW and higher (Santa Maria et al. 1986)... 

Fig. 12. Summary of sequential investigations carried out on a patient with Bence Jones myelomatosis. Note the high blood urea, high proteinuria, and the early elevated pokeweed mitogen (PWM) response instead of elevated phytohemagglutinin (PHA) response. Urine protein , blood urea O, PWM PHA ratio o, IgM,, IgA X,IgG.

Pharmacokinetics These agents are metabolized and excreted primarily through the urine. Protein binding of these agents exceeds 90%. Furosemide is metabolized approximately 30% to 40%, and its urinary excretion is 60% to 70%. Oral administration of bumetanide revealed that 81% was excreted in urine, 45% of it as unchanged drug. Torsemide is cleared from the circulation by both hepatic metabolism (approximately 80% of total clearance) and excretion into the urine (approximately 20% of total clearance). ... 

Drug/Lab test interactions Because false-positive readings were reported with the Ames N-Muitistix SG dipstick test for urinary protein when gabapentin was added to other antiepileptic drugs, the more specific sulfosalicylic acid precipitation procedure is recommended to determine the presence of urine protein. 

Drug/Lab test interactions False-positive tests for urobilinogen may occur during nizatidine therapy. False-positive tests for urine protein with Multistix may occur during ranitidine therapy testing with sulfosalicylic acid is recommended. 

Figure 10.1 Home pregnancy testing devices, like the one seen here, utilize biotechnology techniques. This test uses paired monoclonal antibodies and colored beads to indicate increased human gonadotropin in urine. The second round well is a control, indicating the device is working properly by trapping a common urine protein.

Renal function, urinalysis (especially serum creatinine and urine protein prior to each dose), and blood chemistry (to include serum uric acid, phosphate, and bicarbonate), white counts with differential during intravenous therapy... 

Mechanism of Action Abisphosphonate that binds to bone hydroxyapatite (part of the mineral matrix of bone) and inhibits osteoclast activity. Therapeutic Effect Reduces rate of bone f urnover and bone resorption, resulting in a net gain in bone mass. Pharmacokinetics Absorbed in the upper GI tract. Extent of absorption impaired by food or beverages (ofher than plain water). Rapidly binds to bone. Unabsorbed portion is eliminated in urine. Protein binding 90%. Half-life 10-60 hr. 

Intravenous cidofovir is effective for the treatment of CMV retinitis and is used experimentally to treat adenovirus infections. Intravenous cidofovir must be administered with high-dose probenecid (2 g at 3 hours before the infusion and 1 g at 2 and 8 hours after), which blocks active tubular secretion and decreases nephrotoxicity. Cidofovir dosage must be adjusted for alterations in the calculated creatinine clearance or for the presence of urine protein before each infusion, and aggressive adjunctive hydration is required. Initiation of cidofovir therapy is contraindicated in patients with existing renal insufficiency. Direct intravitreal administration of cidofovir is not recommended because of ocular toxicity. 

Moreover, Cellis et al. have been working on identifying protein markers that may be valuable for diagnosis and follow-up of bladder cancer patients. To achieve this goal, they have focused on the establishment of a comprehensive 2D gel database of urine proteins. 

The active metabolite 4-methyl-amino-antipyrine reaches peak plasma concentrations 1.2 to 2 h after oral administration and is further metabolised with a mean elimination half-life of 2.6 to 3.5 h. Of the four main metabolites about 60% are excreted in the urine. Protein binding of these metabolites is less than 60% (Levy et al. 1995). 

Urine proteins Prevents precipitation of calcium oxalate ... 

In multiple myeloma, the neoplastic plasma cells secrete monoclonal proteins such as either IgG or IgA. Generally, either k or A. light chains are secreted. These M (monoclonal) proteins can be detected by serum and urine protein zone and immunofixation electrophoretic techniques, the latter providing better discrimination. The immunoglobulin levels exceed 25 g/L. Quantitation of immunoglobulins can be performed by rate nephelometry. 

Urine protein excretion should be measured on timed overnight specimens collected at intervals from 3 d to 3 wk from individual mice in metabolism cages and is assayed by the sulphosalicylic method. 

The dipstick test uses the bromphenol blue method for protein that is most sensitive for albumin and is optimized for protein levels/urine pH common in humans (Newman and Price 1999) False positives are thus common in animals because of their higher urine pH and background urine protein (Finco 1997 Loeb and Quimby 1999). A positive result with a urine dipstick test must therefore be followed by a more detailed quantitative and qualitative assessment of the increase in protein excretion in order to determine the site and nature of the renal injury present. 

The combination of qualitative and quantitative assessment of the normally-excreted urine protein (see... 

Increased albumin usually indicates glomerular injury, although it is not a specific marker for any one nephron site (Guder and Hofmann 1992 Price et al. 1996 Finn and Porter 1998). High levels of albumin in urine are invariably the result of glomerular malfunction. Low level increases in urine albumin, especially in circumstances where total urine protein excretion is not elevated ( microalbuminuria ) can result either from increased glomerular filtration or decreased tubular reabsorption, and albumin values... 

Urinary enzyme activity provides a means to determine the presence and location of renal tubular injury as opposed to an index to the functional status of the nephron. Urine enzymes provide several advantages over urine protein for the assessment of tubular injury (Stonard et al. 1987 Vanderlinde et al. 1981 Price 1982 Plummer et al. 1986 Clemo 1998 Dubach et al. 1988 Westhuyzen et al. 2003) ... 

Ind avenous cidofovir is well tolerated. The major deatment-limidng toxicity of this drug is irreversible nephrotoxicity (Plosker and Noble, 1999). Ind avenous pre-hydradon with normal saline and aclminisdadon of oral probenecid must be used with each cidofovir infusion to lessen the effects on the kidney. Serum creadnine and urine protein must be monitored with each infusion and adjusted accordingly. Other adverse effects associated with its use are neudopenia and peripheral neuropathy (Plosker and Noble, 1999). 

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