Monitoring Of Therapy In Patients Research Articles

Calcium metabolism in cancer.Studies using calcium isotopes and immunoassays for parathyroid hormone and calcitonin

Studies of calcium metabolism in 38 patients with cancer indicated that: 1) intestinal absorption of calcium was reduced in patients with skeletal metastases and in those with hypercalcemia; 2) calcium-47 space (a measurement of bone turnover rate) was high in the patients with skeletal metastases; 3) hypercalcemic patients had higher urinary and endogenous fecal excretion of calcium than those who were normocalcemic; 4) levels of plasma immunoreactive parathyroid hormone were similar in normo- and hypercalcemic patients, but the levels for a given serum calcium in malignant disease were lower than those in primary hyperparathyroidism; and 5) some patients had elevated calcitonin levels. Hypercalcemia complicating malignant disease is therefore not due to hyperabsorption or diminished excretion of calcium, and a low calcium diet is unlikely to benefit these patients. Measurement of 47Ca space could be of use in monitoring therapy of patients with skeletal metastases, and measurement of plasma parathyroid hormone could be useful in the differential diagnosis of hypercalcemia.

Determination of Serum Gentamicin Sulfate Levels

Determination of serum gentamicin levels (SGLs) is helpful in monitoring therapy in patients receiving this drug because there is a narrow therapeutic margin and serum levels may vary greatly between patients receiving similar doses. During a ten-month period, definite indications for obtaining SGL determinations were present for 189 of 212 serum samples (89.2%) submitted to the laboratory. However, 110 samples (51.9%) were improperly drawn and results of 85 samples (40.1%) were ignored. Only 26 of the 62 correctly drawn and not ignored samples (41.9%) were appropriately acted on. At most, 42 of the 212 samples (19.8%) were appropriately used in making patient-care decisions. Thus, in this study, an inordinatley large number of SGLs were incorrectly drawn, apparently ignored, or inappropriately used in making patient-care decisions.

Urinary fibrinogen derivative excretion and intraglomerular fibrin deposition in glomerulonephritis.

The relations between glomerular fibrin deposition, urinary excretion of fibrinogen derivatives (F.D.), and proteinuria were explored in 81 patients with glomerulonephritis. A positive correlation existed between proteinuria and F.D. excretion even when no fibrin could be detected in the glomerulus. In two patients with tubular proteinuria F.D. excretion was also raised, suggesting that tubular reabsorption or catabolism of F.D. or both normally occur.Disproportionately high titres of F.D. were observed when fibrin was deposited in an extracapillary site, but mesangial fibrin deposition was not accompanied by a higher excretion of F.D. than that observed in patients in whom intraglomerular fibrin was not detected. These observations suggest that the immunofluorescent findings on renal biopsies should be the major criteria on which a trial of anticoagulants in proliferative glomerulonephritis might be instituted and that measurement of urinary F.D. is likely to be of value in monitoring therapy in patients with extracapillary fibrin deposition.