Serum beta 2-microglobulin concentrations were determined in 21 untreated hyperthyroid patients (12 with Graves' disease, and nine with toxic nodular adenoma) and in 20 healthy controls. All subjects ...had normal serum creatinine concentrations and urine analysis. Both total and free thyroid hormones were significantly higher in the hyperthyroid groups than in controls. Beta 2-microglobulin concentrations were significantly increased in both groups of hyperthyroid patients compared with controls. No difference was found in the thyroid hormone and beta 2-microglobulin concentrations between both sets of patients. The beta 2-microglobulin and thyroid hormone concentrations were not correlated. These data show that hyperthyroidism is another cause of increased beta 2-microglobulin production along with viral infections, immunologically mediated diseases, and malignant neoplasms. The increased serum beta 2-microglobulin concentration in thyroid hyperfunction is probably related to metabolic rate, even if autoimmunity might contribute to its overproduction.
NKF-DOQI guidelines suggest a Kt/V value of 2.1 and a creatinine clearance (CRCL) value of 63 L/1.73 m2 of body surface area per week as minimum targets in continuous cycling peritoneal dialysis ...(CCPD). Those targets are obtained by adapting the CAPD guidelines. The aim of our study was to verify the possibility of reaching the suggested targets with continuous tidal peritoneal dialysis (CTPD) and to check target modification in this automated treatment. Eight anuric patients underwent four consecutive CTPD sessions with increasing total prescribed volumes (17 L, 22 L, 27 L, and 32 L; night 9 h; fill 2.2 L; tidal 75%, day 2 dwells). The Kt/V increase was significant (P = 0.012), unlike that of CRCL, with larger volumes. Two patients did not reach target Kt/V, and four did not reach target CRCL. The volume normalized for 1.73 m2 corresponding to DOQI targets was 19.6 +/- 2.6 L for Kt/V and 20.2 +/- 2.4 for CRCL. The overall Kt/V was 2.29 +/- 0.66 and CRCL was 57.3 +/- 16.5 L/1.73 m2. CRCL/Kt/V overall ratio was 25.6 +/- 4.7 and significantly different from the target ratio (63/2.1 = 30, P < 0.001). The CRCL/Kt/V ratio showed a significant decrease with larger volumes (P = 0.001, linear trend P < 0.001). Adequacy targets can be reached only in some patients on CTPD even with high dialysis volumes. The changes in the CRCL/Kt/V ratio in relation to dialysis volume can be considered for adaptation and evaluation of adequacy targets in automated treatments.
PD ADEQUEST software (Baxter Healthcare, Deerfield, IL, U.S.A.) is used in peritoneal dialysis for calculating the indices of dialysis efficiency and for the mathematical simulation of the results of ...various dialysis regimens. The aim of our study was to quantify the modeling errors and find the methods which give best results.
Nonrandomized, repeated measurement, clinical validation study.
The study included 78 patients on continuous ambulatory peritoneal dialysis (PD), daytime ambulatory PD, and automated PD.
We used 207 collections of dialysate and urine associated with peritoneal equilibration tests (PETs) performed with different glucose concentrations (1.36%, 2.27%, 3.86%). The measured urea Kt/V, creatinine clearance (CRCL) and ultrafiltration (UF) were compared with the same data simulated mathematically using the PD ADEQUEST software version 1.4.
The Kt/V, CRCL, and UF measured values were significantly correlated and in agreement with modeled data concordance correlation (rc) was 0.849, 0.839, 0.625 respectively. The errors (modeled - measured) were: Kt/V = -0.04 +/- 0.27 (p = ns), CRCL = 2.1 +/- 7.7 L (p < 0.001), UF = -121 +/- 711 mL (p = 0.016). Applying ANOVA to both the peritoneal transport data calculated by PD ADEQUEST (mass transfer area coefficient of the solutes, fluid reabsorption, and hydraulic permeability) and the modeling errors, significant differences were found in relation to the PET glucose concentrations.
PD ADEQUEST proves to be a useful instrument in peritoneal dialysis, although there is undoubtedly still room for improvement in its prediction efficacy, which is influenced by the glucose concentration used in the PET.
Serum bone GLA-protein, a modern and sensitive marker of bone turnover, was measured in 15 patients with primary hyperparathyroidism, 18 patients with hypercalcemia of malignancy, 41 patients with ...bone metastasis without hypercalcemia, and 29 healthy subjects. Serum bone GLA-protein was increased in primary hyperparathyroidism (17.6 +/- 3.9 ng/ml) and normal in hypercalcemia of malignancy (5.2 +/- 2.8 ng/ml; p less than 0.001 vs hyperparathyroidism) and in normocalcemic patients with bone metastases. In primary hyperparathyroidism parathyroid hormone correlated positively with urinary calcium excretion (p less than 0.05) and with urinary hydroxyproline excretion (p less than 0.001). The sensitivity of serum bone GLA-protein measurements in differentiating between primary hyperparathyroidism and hypercalcemia of malignancy was 91% and the specificity 84%. Thus this marker appears to be a useful tool for the differential diagnosis of hypercalcemias.
Poor compliance in peritoneal dialysis (PD) is a significant cause of dropout and morbidity. PD Adequest software, which, through a mathematical model, predicts the effect of the dialysis ...prescription on the basis of the peritoneal transport, may be used to identify the noncompliant patient. Fifty patients from two dialysis centers, aged 65.9 +/- 1.5 years and on PD for 28.6 +/- 4.7 months, were studied. A peritoneal equilibration test (PET) was carried out and 24-hour urine and dialysate were collected. Total weekly creatinine clearance (CrCl, L/week/1.73 m2) was calculated, as well as the glomerular filtration rate (GFR), mL/min, mean CrCl and urea nitrogen clearance (UNCI). The dialytic schedules used were then introduced into the program and the parameters were recalculated using the software model. Nine patients considered noncompliant from their case histories were used to assess the differences of reference between expected and measured values. The control group was significantly different from the noncompliant group in the percentage of the CrCl and the serum creatinine (sCR) differences. The noncompliance threshold value was calculated from the mean of the lower 95% confidence interval of the compliant group and the higher one of the noncompliant group (-5.3%) for CrCl and vice versa for sCR (+10%), which behaved to the contrary. Reassessing the patients, 11 (22%) were identified as probably noncompliant.
The aim of this study was to examine the possibility of increasing sodium and water removal with peritoneal dialysis. Ten patients aged 67.3 +/- 6.2 years, on continuous ambulatory peritoneal ...dialysis (CAPD) for 28.1 +/- 13.9 months, with no episodes of peritonitis for at least 2 months and clinically normohydrated, gave their informed consent to undergo two consecutive peritoneal equilibration tests (PETs) with dialysis solution at a sodium concentration of 126 mEq/L (low sodium) and 132 mEq/L (normal sodium), both with 2.5% glucose. Net ultrafiltration and sodium mass transfer were 319.4 +/- 178.5 and 443.2 +/- 234.4 mL (p = 0.0346) and 27.7 +/- 24.5 and 28.2 +/- 27.1 mEq (p = NS), respectively. There were no variations in natremia or the transport indices of the studied solutes or in the arterial pressure or heart rate. All patients showed drowsiness or torpor during the low sodium PET and one had cramps. The 126 mEq/L sodium dialysis solution showed no advantages compared to the more common solution, 132 mEq/L. However, further study is necessary to check the potentiality of solutions with different sodium and glucose compositions for both acute and chronic use.
Creatinine measurements in peritoneal dialysis fluids using the Jaffé method have poor specificity due to interfering substances. We have checked to see if calcium lactate, in addition to glucose, ...interferes with the Jaffé kinetic measurement. Eight samples were prepared with increasing concentrations of glucose (960-3890 mg/dL) and eight were prepared with the same glucose content plus 7 mg/dL of calcium lactate, all without creatinine; in addition, 96 samples with increasing concentrations of glucose (1500-4000 mg/dL), calcium lactate (3-7.5 mg/dL), and creatinine (0.75-4.5 mg/dL) were prepared. There was a 0.31 +/- 0.13 mg/dL glucose interference on the Jaffé kinetic measurement in the first series, with an exponential trend. Interference was greater with calcium lactate and glucose: 0.50 +/- 0.16 mg/dL with the same trend. Data from the second series confirm the overestimation: 0.54 +/- 0.05 mg/dL (32.6%) with an exponential trend. The interference of glucose, creatinine, and calcium lactate on the Jaffé kinetic measurement was obtained by multi-variate regression. The single effects of glucose2 and glucose are predominant, but both creatinine and calcium lactate have a significant effect. Our study highlights the nonlinear glucose interference on creatinine measurement with the Jaffé kinetic method and the linear interference of both calcium lactate and creatinine.
To assess treatment adequacy by calculating total clearance (CL) in patients on peritoneal dialysis (PD), fluids must be collected over 24 hours, a laborious procedure and prone to inaccuracy. CL ...calculation from the plasma disappearance curve of an injected tracer has none of the above inconveniences. We therefore compared creatinine clearance CR-CL with CL calculated from the plasma disappearance curve of 125I-iothalamate (IO) injected in a single intravenous bolus. Twelve patients aged 63 (44-80) years and on PD for four (1-44) months were studied in hospital. Nine plasma samples were taken for IO-CL after a bolus of 21 kBq/kg of tracer. The least-squares biexponential fitting according to Gauss-Newton-Raphson was then carried out: Aexp(-at) + Bexp(-bt), and clearance was calculated by the formula, IO-CL = dose/AUC, where AUC = A/a + B/b. Both CLs were normalized for 1.73 m2 of body surface. Agreement (r = 0.746, p = 0.005) for the CR-CL (6.8 +/- 1.9 mL/min) and IO-CL (7.6 +/- 1.9 mL/min) was good, with a difference of 0.9 +/- 1.4 mL/min (t = 2.182, p = 0.052). Extracellular volume (ECV), calculated from the IO plasma disappearance curve with the formula, ECV = dose/ bAUC, and including the endoperitoneal fluid, was 19.8 +/- 2.9 L (29.5 +/- 6.2% body weight).
Overestimation of creatinine measurement using the Jaffé kinetic method in peritoneal dialysis solutions, due to glucose interference, has been quantified and corrected through the elaboration of ...linear formulas obtained from 110 recovery and 301 biological tests. The added pure powdered creatinine and enzymatic method were considered as references after proven accuracy. Considering creatinine as well as glucose concentration interference, we obtained correction formulas from multiple regression application. All the computed formulas gave satisfactory corrections but different accuracy levels. The best model in biological samples was: Corrected CR = K1JafféCr + K2Glucose (all values in mg/dl) where K1 = 0.973 and K2 = -0.00035 (Rsq = 0.987, F ratio = 10,945, p = 0.00001). Applying formulas to biological samples there was a drop in accuracy, possibly explained by the presence of numerous unidentified substances in peritoneal dialysis biological samples that can amplify scatter. Every laboratory can reduce the error of the Jaffé kinetic assay by calculating their own correction formula in relation to the method and instrument used, because Jaffé kinetic assay gives different results with different kinetic windows. So, especially when applied to peritoneal dialysis fluid measurements, if a creatinine assay reference method is not available, the correction formula can be applied directly as given. Otherwise the method we have described can be followed with a well-structured creatinine recovery fest to identify and quantify assay interferences.
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