Biomedical subjects
Publications and source records attributed to D B Lee.
Eight cases of nontraumatic renal allograft rupture were identified in 237 renal transplants performed at UCLA Medical Center. Careful clinicopathologic studies in these patients suggest three principal underlying causes: major graft vessel occlusion, hyperacute or accelerated rejection, and acute rejection. The clinical and pathologic features of these various categories are compared and contrasted.
Hypercalcemia is most commonly seen in normal infants as the result of normal rapid bone growth. The most common causative diseases are malignant disease and hyperparathyroidism. A variety of pharmacologic agents, especially vitamin D and its metabolites and thiazide diuretics, can elevate serum calcium levels. Hypersensitivity to vitamin D appears to be a cause of hypercalcemia in infants and in patients with granulomatous disease, such as sarcoidosis. Ingestion of escessive amounts of calcium, especially with alkali, may also cause hypercalcemia, as may prolonged immobilization, particularly under conditions of rapid bone turnover.
Hypercalcemia calls first for supportive measures, eg, adequate hydration, movement or mobilization of the patient to the greatest amount tolerated, and reevaluation of drugs being taken. When immediate lowering of the serum calcium level is not clinically mandatory, oral administration of furosemide, corticosteroid, or phosphorus should be considered. In acute emergencies, saline loading and parenteral furosemide therapy should be tried first, except in a patient with renal failure and congestive heart failure, in whom peritoneal dialysis or hemodialysis should be used instead. Calcitonin can be given for the first 12 to 24 hours to lower serum calcium concentration until a definitive management plan is formulated. Corticosteroid, if not contraindicated, should be started as soon as possible. In severe primary hyperparathyroidism with hypophosphatemia, phosphorus can be given intravenously until oral phosphate therapy can be established. Surgery, of course, should be performed as soon as possible. In most cases of neoplasia, mithramycin given according to a recommended schedule is safe and frequently effective. In desperate cases, additional use of prostaglandin synthesis inhibitors probably now is justified by empirical observations. All of these therapeutic measures are used only to stabilize electrolyte balance so that the primary cause of the hypercalcemia can be treated.
Intestinal calcium (Ca) hyperabsorption is a well-documented feature of experimental phosphorus depletion (PD). To further evaluate the effect of PD on Ca absorption we studied metabolic balance and in vitro everted duodenal sac uptake of Ca and phosphorus (P) in weanling male rats. Animals were assigned to three dietary groups: normal, 0.3% P ad libitum (NP); low, 0.03% P ad libitum (LP); and normal, 0.3% P but pair-fed with assigned LP mates (NP-PF). Results indicate that although PD led to an early but unsustained increase in 45Ca uptake by the everted duodenal sac in vitro, net intestinal Ca retention is consistently decreased in rats on the LP diet compared with rats eating either the NP or NP-PF diet. The reduction in net intestinal Ca absorption is reflected by an increase in fecal Ca, both in absolute quantities and in proportion to dietary Ca intake. The initial negative P balance after the initiation of the LP diet was promptly, albeit precariously, corrected. This was associated with a sustained increase in duodenal 32P uptake in vitro and virtual cessation of growth. Because the biosynthesis of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and its accumulation in intestinal mucosa have been reported to increase with PD, our study represents an example in which the physiological interrelationship between the activity of 1,25(OH)2D3 and intestinal Ca absorption may be dissociated.
We studied weanling rats fed 0.06% (group 1) and 0.10% (group II) magnesium (Mg) during phosphate depletion (PD) in order to evaluate the role of Mg in the bone, soft tissue, and serum changes of PD. The following results were obtained: 1) serum Mg remained stable in the face of a negative Mg balance; 2) the hypercalcemic and hypercalciuric response to PD was the same in both groups; 3) bone Mg content was decreased with PD in both groups and was associated with a significant decrease in bone calcium and phosphorus. We conclude that: 1) the hypomagnesemia of PD is dependent mainly on the dietary intake of Mg; 2) the hypercalcemia and hypercalciuria of PD are not caused by primary changes in Mg homeostasis; 3) low-dietary Mg during PD may cause a defect in soft tissue utilization of P in the growing rat.
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FOR THE PURPOSES OF THIS REVIEW, THE VAST AND INCREASINGLY COMPLEX SUBJECT OF HYPERCALCEMIC DISORDERS CAN BE BROKEN DOWN INTO THE FOLLOWING CATEGORIES: (1) Physiochemical state of calcium in circulation. (2) Pathophysiological basis of hypercalcemia. (3) Causes of hypercalcemia encountered in clinical practice: causes indicated by experience at the University of California, Los Angeles; neoplasia; hyperparathyroidism; nonparathyroid endocrinopathies; pharmacological agents; possible increased sensitivity to vitamin D; miscellaneous causes. (4) Clinical manifestations and diagnostic considerations of hypercalcemic disorders. (5) The management of hypercalcemic disorders: general measures; measures for lowering serum calcium concentration; measures for correcting primary causes-the management of asymptomatic hyperparathyroidism.
Forty-seven SLE patients with severe renal disease characterized by renal biopsy documentation of diffuse proliferative or membranous glomerulonephritis or the nephrotic syndrome have been treated with azathioprine and prednisone in combination and followed for up to 12 years. Survivorship was 82% +/- 6% for five years and 74% +/- 8% for 10 years. There have been eight deaths and two patients have gone on hemodialysis. Five of the eight deaths are attributable to superinfection. Improvement in creatinine clearance was documented in 21 and decreased proteinuria in 35 of the patients. A therapeutic program, which included high dose corticosteroids initially, the combinations of azathioprine with corticosteroids chronically, and the rapid reduction in corticosteroid dosage to an alternate day schedule, appears to contribute to improved survivorship.
In a nineteen-year-old male in whom severe and protracted hypertension developed after a successful renal transplantation, the removal of the diseased kidneys resulted in restoration of normal blood pressure. Prenephrectomy blood samples obtained from the venous drainage of all three renal veins demonstrated no evidence for excessive renin secretion, nor was a significant difference in renin activity found between any two kidneys. It is postulated that the patient may be a clinical variant of the experimental form of renal hypertension with normoreninemia. Alternatively, the remnant kidneys may be implicated to produce a nonrenin pressor substance.
One month following a cadaver renal transplant for obstructive uropathy, a 27-year-old man developed diabetes mellitus. Two years later, marked proteinuria and decreased renal function were detected. Eight months later, a second decline in function occurred. Light microscopy of graft biopsy specimens obtained after each decline in renal function showed increased mesangial cells and matrix, thickening of Bowman capsule, and tubular atrophy with basement membrane thickening. Vascular changes, interstitial infiltrate, and fibrosis were not prominent. Electron microscopic studies of the second biopsy specimen confirmed the light microscopic changes; subepithelial dense deposits were also detected. Immunofluorescent studies of both biopsy specimens demonstrated linear staining of glomerular and tubular basement membranes and Bowman capsule for IgG and albumin. Antikidney antibodies were not detected in the patient's serum. These observations suggest development of the diffuse form of diabetic nephropathy in a renal homograft following steroid-induced diabetes mellitus.
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Maintenance hemodialysis and chemotherapeutic agents were used in the treatment of seven patients with end-stage myeloma kidney disease. Results indicate that with the use of such therapy life can be prolonged substantially. It appears that patients with myeloma-with or without serious extrarenal complications-are suitable candidates for maintenance hemodialysis and should not be denied the treatment even in the face of systemic neoplasm.
A fourth kindred displaying the triad of hereditary nephritis, deafness and thrombocytopenia with giant platelets is described. Renal involvement, a common cause of death amongst afflicted subjects, appears to have a better prognosis in the affected members of this family. Although the electron microscopic appearance of the megakaryocytes in the present case appears similar to that in previously reported cases, we suggest that the "giant" platelets may result from a degenerative process of megakaryocytes leading to nuclear regression and cytoplasmic fragmentation, rather than the usual blebbing process.
Eleven patients with chronic renal failure and presumed secondary hyperparathyroidism developed a syndrome of medial calcinosis of the arteries and painful ischemic ulcers of the fingers, legs, or thighs, or any combination of the three. Five patients required maintenance hemodialysis; six had functioning renal homografts. Severe hyperphosphatemia had existed in each; seven showed roentgenographic evidence of subperiosteal resorption. Similarities are evident between the lesions and experimentally produced calciphylaxix. The lesions demonstrated a relentless, progressive course, with serious morbidity and mortality. Hyperplastic or adenomatours parathyroid tissue was removed from ten of 11 patients unergoing surgical procedures; healing followed in seven patients. Treatment with phosphate-binding antacids to lower serum phosphorus levels may prevent this syndrome. Total or subtotal parathyroidectomy should be considered when ischemic skin lesions appear in uremic patients or in renal transplant recipients.
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