Chondrosarcoma of the larynx. Diagnosis with magnetic resonance imaging and computed tomography.

Chondrosarcomas are the most common sarcomas of the larynx. They are generally slow-growing lesions with insidious onset of symptoms. We are presenting a case of chondrosarcoma that recurred 10 years after excision of a presumed chondroma. Computed tomographic and magnetic resonance imaging (MRI) scans were performed. Both studies delineated the lesion nicely. To the best of our knowledge, this is the first report on MRI characteristics of chondrosarcoma of the larynx. A review of the literature regarding the use of computed tomography in the management of chondrosarcoma is presented. The MRI characteristics are discussed and the two scanning modalities are compared. Computed tomography is an excellent study in its ability to demonstrate the extent of the lesion within the laryngeal skeleton. Furthermore, it is more highly sensitive than plain roentgenograms in the detection of calcifications that are highly suggestive of chondrosarcoma. Alternatively, MRI can also demonstrate the lesion within the larynx but it has the added advantage of superior contrast resolution of the tumor and paralaryngeal tissues. When the three-dimensional imaging capacity of MRI is considered as well, MRI seems to be the superior study.

Intraocular pressures during high-flux hemodialysis.

The intraocular pressures of 16 patients with end stage renal failure treated with high-flux dialysis were measured before and during a high-flux dialysis treatment. The patients were selected so as not to have glaucoma or history of glaucoma. Intraocular pressures did not change significantly in any patients during or following a high-flux hemodialysis treatment. These data suggest that high-flux hemodialysis does not result in increases in intraocular pressure nor does it precipitate acute glaucoma in well-dialyzed patients undergoing intermittent in-center hemodialysis.

The role of aluminum in the pathogenesis of anemia in an outpatient hemodialysis population.

Anemia is a well-defined complication of aluminum overload in chronic dialysis patients which may be present before other manifestations of aluminum toxicity are obvious. Causes of anemia in chronic renal failure are multiple, and at the present time there is no marker for aluminum-induced anemia. Deferoxamine (DFO) treatment can correct aluminum-related anemia and microcytosis, but may be associated with side effects. Because of the possible role of aluminum in red blood cells in causing the anemia associated with aluminum overload, we attempted to test red blood cell (RBC) aluminum as a marker for aluminum-associated anemia and to assess the prevalence of aluminum-associated anemia in an outpatient dialysis population. Both random plasma aluminum and RBC aluminum correlated well with the increase in plasma aluminum seen following DFO challenge. However, RBC aluminum was affected less by changes in oral aluminum intake than plasma aluminum. There were strong correlations of RBC and plasma aluminum to corpuscular volume (MCV) in our patients. Moreover, patients within the highest quartile of RBC aluminum had a lower mean MCV (82.1 +/- 1.7 vs 89.6 +/- 1.7, p less than .01) and hematocrit (HCT) (24.3 +/- 4 vs 28.2 +/- 1.5, p less than .05) than those within the lowest quartile. These data suggest that aluminum toxicity is an important cause of microcytic anemia in outpatient hemodialysis patients. Prospective long-term studies are needed to further define the usefulness of RBC aluminum in diagnosing and following hemodialysis patients with aluminum-induced anemia.

Intravenous streptokinase for thrombolysis of occluded arteriovenous access. Its use in patients undergoing hemodialysis.

Thrombosis of arteriovenous access is a major cause of morbidity in the patient population undergoing hemodialysis. This investigation utilized the technique of infusing streptokinase directly into the afferent limb of an occluded graft or fistula to restore patency. A total of seven patients was studied, one patient on two separate occasions nine months apart. Total clot lysis was observed in five of eight infusions. Partial clot lysis was seen in two of eight infusions, although one of these patients required thrombectomy to ensure persistent functioning of the fistula. One of the eight episodes was unsuccessful. A postinfusion fistulogram was performed on seven of eight occasions and demonstrated partial clot lysis in two patients or a stenotic lesion requiring surgical revision in two other cases. In conclusion, streptokinase infusion into the thrombosed vascular access appears to be a safe and efficacious technique for this patient population.

The anemia of chronic renal failure: in vitro response of bone marrow to erythropoietin.

Bone marrow cells of patients with chronic renal failure were studied in short-term in vitro cultures to determine erythropietin responsiveness. Seven normals and fourtheen patients on hemodialysis were studied. Bone marrow cells of normal subjects and of patients with chronic renal failure responded similarly to erythropoietin. Total heme synthesis was significantly lower in cultures prepared with uremic serum than normal serum. We conclude that there is a substance in the serum of uremic patients which suppresses general heme synthesis and that this "uremic toxin" may be responsible, in part, for the clinically severe anemia seen in these patients.