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Serum C-reactive protein (CRP) levels were measured by nephelometry in 30 healthy subjects (controls) and in 99 patients with uncomplicated terminal uremia on conservative therapy (group 1, n = 30) or chronic hemodialysis (group 2, n = 69). Whereas there was no difference between controls and group 1, both the mean concentration of CRP and the incidence of elevated levels were significantly higher in group 2 in comparison with both controls and group 1. Moreover, the degree of increase in these patients was directly correlated with the duration of hemodialysis. The abnormality, therefore, is somehow related to chronic hemodialysis per se. From a practical standpoint, we concluded that this test cannot be recommended as an acute-phase reactant in this clinical setting.

To evaluate the relative contribution that dialyzer membrane composition and geometry make to hemodialysis-associated platelet loss, the effect of a single dialysis with three different types of dialyzers on platelet count was examined on a cross-over basis in 19 uremic patients on maintenance hemodialysis. Also, the plasma levels of antithrombin-iii before and after dialysis were measured, but no significant variations were found regardless of which dialyzer was in use. Our patients suffered significant platelet loss during cuprophan dialysis, but not polyacrylonitrile dialysis. More than 99% of initial circulating platelets were recovered at the end of polyacrylonitrile dialysis, whereas cuprophan dialysis did leave a significantly lower percentage of circulating platelets (p less than 0.05). The internal comparison of results obtained with the two cuprophan dialyzers used shows no difference as to the dialyzer geometry (flat plate or hollow fiber). This indicates that the membrane composition is the major factor influencing hemodialysis-associated platelet loss. We suggest that patients with low platelet count and/or with risk of bleeding may benefit from polyacrylonitrile dialysis.

The possible relationship between platelet dysfunction and secondary hyperparathyroidism (HPT) in chronic renal failure was examined in 23 uremic patients on conservative therapy (group I) and in 27 patients on maintenance hemodialysis (group II). Platelet function was assessed by measuring the degree of aggregation in response to various concentrations of adenosine diphosphate. Secondary HPT was evaluated by means of serum biochemistry (parathyroid hormone, calcium, phosphorus, and alkaline phosphatase) and radiographic examinations (x-ray films of the hand skeleton). This study showed impaired platelet aggregation in group I patients, compared to either group II patients or controls. There were no significant differences when group II patients were compared to controls. No significant correlations between platelet aggregation and the hematochemical changes associated with secondary HPT were found. No differences in platelet aggregation were found with regard to the activity (alkaline phosphatase) and the severity (x-ray findings) of secondary HPT. Effective treatment of secondary HPT with 1,25-dihydroxycholecalciferol in both group I and group II patients was not associated with consequent changes in platelet aggregation. It is concluded that secondary HPT is probably not a major factor in the pathogenesis of platelet dysfunction in chronic renal failure.

To evaluate the role, if any, of alpha-1-ag in the pathogenesis of dislipidemia in hemodialysis patients, serum alpha-1-ag levels were measured in 31 patients during maintenance hemodialysis. The mean serum alpha-1-ag concentration was higher in the dialysis patients (117.58 +/- 36.65) than in controls (98.32 +/- 19.5) (p greater than 0.05), with an unexplained significant difference between males and females (p less than 0.01). Serum alpha-1-ag levels were above normal in 6 patients (19.3%) and below normal in no one. A further significant increase in the mean alpha-1-ag concentration was observed following a single dialysis (132.19 +/- 37.12) (p less than 0.001). No correlation with dialytic age or underlying nephropathy was noted. Serum alpha-1-ag levels did not correlate with serum triglycerides, nor was there any difference between normotriglyceridemic and hypertriglyceridemic patients. Therefore it seems unlikely that a deficit in alpha-1-ag due to uremia per se or secondary to dialysis may have a role in pathogenesis of dislipidemia in uremic patients during maintenance hemodyalysis.

The possible relationship between erythrocyte (RBC) function and secondary hyperparathyroidism (HPT) was examined in 35 uremic patients on maintenance hemodialysis. Mechanical tests (i.e., osmotic fragility and deformability) were used to assess RBC function. Secondary HPT was evaluated by means of serum biochemistry (parathyroid hormone, calcium, phosphorus, and alkaline phosphatase) and radiographic examinations (X-ray films of the hand skeleton). Sixteen sex and age-matched normal volunteers acted as controls. This study shows that the mechanical properties of RBC were indeed markedly altered in hemodialysis patients when compared with controls. No significant correlations between either the osmotic fragility or the deformability of RBC and the hematochemical changes associated with secondary HPT were found. No differences in RBC function tests were found as far as the activity (alkaline phosphatase) or the severity (X-ray findings) of secondary HPT are concerned. Effective treatment of secondary HPT by either pharmacological means (1,25-dihydroxycholecalciferol) or surgical removal was not associated with consequent improvement in RBC function. These findings clearly speak against secondary HPT as a major cause of RBC dysfunction in uremic patients on maintenance hemodialysis.

Serum concentrations of monoclonal antibody-defined tumor markers CA 19-9 and CA 50 were measured in 64 uncomplicated hemodialysis patients (Group 1) and in 8 hemodialysis patients with cancer (Group 2) in comparison with corresponding CEA determinations. From our results in Group 1 patients it appears that both CA 19-9 and CA 50 maintained an excellent specificity in these patients. As to the sensitivity of these tests, our findings in Group 2 patients are comparable with those reported in patients with cancer and normal renal function. It is concluded that, unlike CEA, these new tumor markers maintain their clinical value in chronic renal failure.

The effects of different dialyzer membranes on serum concentration of angiotension-converting enzyme (ACE) and white blood cells during hemodialysis were examined on a cross-over basis in 20 chronically uremic patients. Hemodialysis with cuprophane membranes was associated with a significant (p less than 0.001) fall in the mean leukocyte count during the 1st hour of treatment. The use of polymethylmethacrylate membranes resulted in a more attenuated form of leukopenia and with polyacrylonitrile membranes no change was observed during hemodialysis. Hemodialysis with each membrane caused a comparable, significant (p less than 0.005) increase in serum ACE, independent of the degree of leukopenia but significantly (p less than 0.001) correlated with the increases in serum proteins. We conclude that this increase in serum ACE concentration after hemodialysis does not reflect acute damage of the pulmonary vascular endothelium during treatment and most probably is a result of hemoconcentration. Therefore, serum ACE analysis is not an indicator of dialyzer membrane biocompatibility.

Red blood cell volume distribution width (RDW) was obtained with the Coulter counter in 60 haemodialysis patients and 55 normal individuals. RDW tended to be higher in the former and the degree of increase was to some extent correlated with the underlying nephropathy. Although RDW failed to correlate with conventional tests of iron status, it was observed that iron administration could produce a decrease toward normal in RDW and a parallel increase in haemoglobin when the initial RDW was increased. In contrast, the response to iron was negligible in the patients with normal RDW basally. It was concluded that high RDW is an acceptable indicator of iron deficiency in haemodialysis patients.