Proteinuria high-molecular weight

High-molecular weight proteinuria Low-molecular weight proteinuria... 

The appearance in the urine of serum proteins with a molecular weight (Mr) in excess of 40,000 to 50,000 daltons is an early marker of glomerular damage. The commonly measured high molecular weight proteinuria includes albumin (Mr 69,000), transferrin (Mr 77,000) and IgG (Mr 146,000) (Table 6). 

Cadmium is effectively accumulated in the kidneys. When the cadmium concentration exceeds 200 gg/g in the kidney cortex, tubular damage will occur in 10% of the population, and proteins begin to leak into urine (proteinuria). When the concentration of cadmium in the kidney cortex exceeds 300 pg/g, the effect is seen in 50% of the exposed population. Typically, excretion of low-molecular weight proteins, such as beta-microglobulin, is increased, due to dysfunction of proximal tubular cells of the kidney. The existence of albumin or other high-molecular weight proteins in the urine indicates that a glomerular injury has also taken place. The excretion of protein-bound cadmium will also be increased. 

The following combination of tests could be useful for detecting renal dysfunction in occupationally exposed workers examination of urine with reagent strips for the presence of glucosuria and proteinuria and quantitative determination of at least two proteins, one of the high molecular weight for... 

A 72-year-old man was treated with ceftriaxone (2 g bd) and gentamicin (80 mg tds) for a severe urinary tract infection (75). On day 5 his serum potassium concentration was 3 mmol/1 with a normal serum creatinine and urine examination. Despite treatment with oral potassium chloride plus a high potassium diet, his serum potassium fell to 2.3 mmol/1 4 days later, accompanied by inappropriate kaliuresis, hypouricemia with inappropriate uri-cosuria, and hypophosphatemia with inappropriate phosphaturia. There was no bicarbonate wasting, but there was proteinuria 1.2 g/day, with a predominance of low molecular weight proteins in contrast, serum creatinine was normal and creatinine clearance was 78 ml/minute. The aminoglycoside was withdrawn with subsequent progressive improvement in renal proximal tubular function, which normalized 9 days later. 

---