Concentrations of thyroxine-binding globulin in sera and peritoneal dialysates in patients on chronic peritoneal ambulatory dialysis

Losses in thyroxine-binding globulin (TBG) in peritoneal dialysate and thyroid function were evaluated in patients undergoing continuous ambulatory peritoneal dialysis (CAPD), in comparison to patients on hemodialysis (HD) without TBG loss in the dialysate. The TBG concentration in the peritoneal dialysate was 0.26 +/- 0.09 microgram/ml (mean +/- SD, n = 24), with a daily loss of 2.47 +/- 0.94 mg. The serum TBG level in CAPD patients was 21.0 +/- 4.71 micrograms/ml (n = 24), which was not significantly different from that in HD patients (20.0 +/- 5.72 micrograms/ml, n = 24) or in healthy Japanese subjects. The serum TBG level correlated positively with the TBG loss and TBG level in the peritoneal dialysate (p less than 0.001). The serum T4 level in CAPD patients (4.93 +/- 1.38 microgram/dl, n = 24) was significantly greater than in HD patients (4.08 +/- 1.30 microgram/dl, n = 24, p less than 0.05).     

Serum erythropoietin levels and hematocrit in end-stage renal disease: influence of the mode of dialysis

Serum erythropoietin (Ep) levels were measured by radioimmunoassay in 70 patients with end-stage renal disease (ESRD) to evaluate the influence of the mode of dialysis on the relationship between serum Ep levels and the severity of anemia. Thirty-five patients were on hemodialysis (HD), seven were on intermittent peritoneal dialysis (IPD), and 28 were on continuous ambulatory peritoneal dialysis (CAPD). Compared to HD, CAPD patients had higher serum Ep (CAPD), 46.1 +/- 13.4 v HD, 16.9 +/- 2.2 mU/mL) and hematocrit (CAPD, 33.9 +/- 2.5 v HD, 24.8 +/- 1.4%; P less than 0.05). The Ep and Hct values for IPD patients were intermediate between the other two groups. Serum Ep levels were higher in CAPD patients in the first 4 weeks of initiation of CAPD (144 +/- 35 mU/mL, n = 6) than later (39 +/- 6.4 mU/mL, n = 24). A significant fluctuation in serum Ep and Hct values was noted in patients on all three modes of dialysis, when multiple samples were obtained at different time intervals. There was a weak correlation between serum Ep and Hct in the three groups of dialysis patients; r = 0.36, P less than 0.005. The data suggest that CAPD provides a better biochemical milieu for Ep production and responsiveness than HD treatment of ESRD.     

Plasma level of lipoprotein Lp(a) is high in predialysis or hemodialysis, but not in CAPD.

Plasma Lp(a) lipoprotein level was determined in chronic renal failure (CRF) patients, 24 before initiation of dialysis, 18 undergoing hemodialysis, and 24 on continuous ambulatory peritoneal dialysis (CAPD). Eighteen healthy subjects were studied as controls. Median of Lp(a) level in both predialysis and dialysis patients was significantly increased: 23.5 mg/dl (range: 0 to 109) and 24.0 mg/dl (range: 1.4 to 90), respectively, as compared to healthy controls: 4.7 mg/dl (range: 1.8 to 27; P less than 0.001). By contrast, the median Lp(a) level in CAPD patients, 2.4 mg/dl (range: 0 to 39.5), was similar to the control group. Whether the CAPD procedure reduces the Lp(a) level in CRF patients has to be established in a prospective study.     

Superoxide Dismutase and Catalase Activities in Patients Undergoing Hemodialysis and Continuous Ambulatory Peritoneal Dialysis

In this study, superoxide dismutase (SOD) and catalase activities were determinated in the erythrocytes (RBC) from patients with chronic renal failure. The study included healthy subjects (n = 7), patients on hemodialysis (HD) using polyacrylonitrile-type dialysis membrane (before and after HD) (n = 10), patients on HD using cuprophane-type dialysis membrane (before and after HD) (n = 6), and patients on continuous ambulatory peritoneal dialysis (CAPD) (n = 11). A significant decrease in SOD activity was found in HD groups using polyacrylonitrile- or cuprophane-type dialysis membrane. SOD activity was found to increase in patients undergoing CAPD. We have found that CAT activity is higher in all the CRF groups in respect to the control: with polyacrylonitrile-type dialysis membrane, with cuprophane-type dialysis membrane, and in CAPD treatment.     

High serum lipoprotein(a) concentrations in uremic patients treated with continuous ambulatory peritoneal dialysis.

We measured serum lipoprotein(a) [Lp (a)] concentrations in 50 uremic patients treated on continuous ambulatory peritoneal dialysis (CAPD) and compared them with those in 29 uremic patients on hemodialysis (HD) and those in 62 normal controls. The median values were 47.9 mg/dl in CAPD patients, 25.2 mg/dl in HD patients, and 11.7 mg/dl in controls, respectively. These differences were statistically significant when assessed by Kruskal-Wallis test (p < 0.0001). Thirty-five out of 50 patients on CAPD (70%) and 12 out of 29 patients on HD (41%) had Lp(a) concentrations above 30 mg/dl, whereas these high values were observed in only 15% of normal controls. This difference in prevalence of high Lp(a) was also significant by 2 x 3 chi-square test (p < 0.01). There was a significant positive correlation between Lp(a) and apolipoprotein B (r = 0.517, p < 0.0001). In CAPD patients, 9 with ischemic heart disease had a significantly higher median Lp(a) than those without it (67.4 vs 40.9 mg/dl, p < 0.01 by Mann-Whitney U-test). These results suggest that high levels of serum Lp(a) might contribute to an increased risk for ischemic heart disease in CAPD patients, and that there may be a relationship between Lp(a) and apolipoprotein B metabolism in CAPD patients.     

Serum beta 2-microglobulin concentration and its removal in patients treated with continuous ambulatory peritoneal dialysis

This study was performed to clarify serum beta-2 microglobulin (beta 2-M) level and its change in 50 CAPD and 56 HD patients. There was significant correlation between duration of dialysis and serum beta 2-M level in CAPD and HD patients treated under 12 months, but no correlation in those treated over 12 months. Serum beta 2-M level was 33.5 +/- 9.1 mg/l in 45 CAPD patients treated over 12 months, and 46.2 +/- 21.1 mg/l in 35 HD patients. In 26 CAPD patients treated over 12 months, clearance and removal of beta 2-M were 1.0 +/- 0.3 ml/min and 43.0 +/- 17.8 mg/day. There was significant correlation between dwell time and beta 2-M removal (p less than 0.01), and these results suggested beta 2-M was removed by diffusion. Because CAPD treatment can lower serum beta 2-M level compared to HD, there is possibility that CAPD is useful at prevention of dialysis associated amyloidosis.     

The Effect of Renal Replacement Therapies on Serum Gastrointestinal System Hormones

Background. The kidney is a major site for the inactivation, degradation, and clearance of a variety of peptide hormones. It has been shown that the uremia increases or decreases gastrointestinal system (GIS) hormones. Moreover, studies investigating the serum GIS hormones levels in chronic renal failure (CRF) were conducted mainly in a particular period of the renal replacement therapy, and the changes caused by continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) could not be fully demonstrated. In this study, we investigated the effect of CAPD and HD on serum GIS hormones (amylase, lipase, trypsinogen, and gastrin) levels in CRF patients who were diagnosed for the first time. Methods. Serum amylase, lipase, trypsinogen, and gastrin levels were measured in 36 patients who were just diagnosed with CRF, 22 patients with CAPD and 14 patients with HD. GIS hormones of these patients were measured before treatment and three months from the beginning of CAPD and HD treatment. As the control group, 20 normal healthy cases with well-matched age and gender were used. Results. The mean serum amylase, lipase, secretin, and gastrin levels were found meaningfully decreased according to the beginning values at third months of the CAPD and HD treatment. However, they were higher than control group. Conclusion. In patients receiving CAPD or HD as renal replacement therapy, GIS hormone levels were found to be lower, albeit higher than the healthy control group.     

Low prevalence of hyperphosphatemia independent of residual renal function in peritoneal dialysis patients.

OBJECTIVE: Our objective was to evaluate serum phosphorus control in patients undergoing continuous ambulatory peritoneal dialysis, with and without residual renal function, by investigating the metabolic balance of phosphorus. METHODS: We assessed serum phosphorus levels in 205 patients undergoing continuous ambulatory peritoneal dialysis (CAPD). The clinical factors related to serum phosphorus were also examined, including dietary phosphate intake, dietary protein intake (DPI), phosphate removal through urine and dialysate, doses of phosphorus binder and vitamin D, and serum intact parathyroid hormone (PTH) levels. Nutritional indexes, including serum albumin (Alb), lean body mass (LBM), hand-grip strength (HGS), and subjective global assessment (SGA), were also assessed. Dialysis adequacy and residual renal function (RRF) were calculated by a standard technique. Patients with RRF <2 mL/min were viewed as having no significant RRF. Hyperphosphatemia was diagnosed in patients with serum phosphorus levels >1.78 mmol/L. RESULTS: The mean serum phosphorus level of all patients was 1.6 +/- 0.5 mmol/L (mean +/- SD). Only 58 of 205 patients (28%) had hyperphosphatemia. The average DPI was 0.8 +/- 0.3 g/kg/d, whereas the average dietary phosphorus intake was 691 +/- 201 mg/d. There were no differences in mean serum phosphorus levels or incidents of hyperphosphatemia between patients with and without RRF (1.6 +/- 0.4 mmol/L vs. 1.7 +/- 0.5 mmol/L, P = .256; 22% vs. 31%, P = .336). Although total phosphorus removal through urine and dialysate was lower in the 115 patients without RRF than in the 90 patients with RRF (270 +/- 106 mg vs. 333 +/- 129 mg, P = .000), they simultaneously had a lower dietary phosphorus intake (656 +/- 191 mg vs. 713 +/- 215 mg, P = .046). In addition, patients without RRF had significantly lower DPI, Alb, LBM, and right HGS levels than patients with RRF (P < .01-.05). In those without RRF, the 79 patients without hyperphosphatemia had significantly lower DPI, LBM, and HGS levels, and a higher prevalence of malnutrition diagnosed by SGA, than the 36 patients with hyperphosphatemia (P < .001-.05). However, in patients with RRF, there was no difference in nutritional index between patients with and without hyperphosphatemia (P > .05). CONCLUSION: A relatively lower prevalence of hyperphosphatemia existed in CAPD patients both with and without RRF, which may be associated with incremental dialysis, the correct administration of phosphorus binder, and a lower protein and phosphorus intake. However, patients without RRF, especially those without hyperphosphatemia, ran the risk of malnutrition, despite a well-controlled phosphorus intake.     

Leptin in CAPD patients: serum concentrations and peritoneal loss.

BACKGROUND: To determine whether serum leptin concentrations in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) are influenced by peritoneal loss of leptin and to compare serum leptin levels of normal subjects with those of patients receiving renal replacement therapy such as haemodialysis (HD), CAPD, or kidney transplantation. SUBJECTS AND METHODS: Eighty-four individuals were investigated: six females and 14 males on standard CAPD; 13 females and 13 males on chronic HD; 10 female and eight male kidney transplant recipients, and 10 female and 10 male subjects as controls. Morning serum, 8-h and 24-h samples of peritoneal fluid concentrated to 6-20-fold by Centricon 3 (cutoff 3000 daltons), and 24-h urinary concentrations of leptin were measured with commercial RIA (Linco Research, Inc., USA). Venous blood and peritoneal fluid samples of albumin, beta2-microglobulin, glucose, urea, and creatinine were determined by standard laboratory techniques. Serum insulin levels were measured by radioimmunoassay. RESULTS: Patients (men and women) on CAPD and after kidney transplantation exhibited significantly higher serum concentrations of leptin and leptin/BMI ratios than control subjects. These increased values did not reach statistical significance in HD patients. Serum leptin concentrations were correlated very significantly with BMI in all cases (r=0.380, P<0.001). Moreover, in CAPD patients (r=0.630, P<0.007) and in HD patients (r=0.668, P<0.005), but not in kidney transplant recipients or control subjects, significant correlations were observed between serum leptin and insulin concentrations. Residual renal function (RRF) in the range 0-12.8 ml/min and serum beta2-microglobulin levels in the range 7.9-47.1 mg/l did not influence serum leptin levels in CAPD and HD patients. As expected, leptin was detected in the peritoneal fluid of CAPD patients. Twenty-four-hour peritoneal loss (30.95+/-21.05 ng/min) and 24-h peritoneal clearance (0.01+/-0.01 ml/kg/min) of leptin account for only 3.9% of estimated whole-body leptin production rate and 0.7% of leptin clearance from plasma respectively. Twenty-four-hour urinary losses of leptin in CAPD patients were negligible, accounting for 5.6+/-1.8% (range 0.3-15.2%) of total (peritoneal and urinary) loss of this hormone. CONCLUSIONS: These findings suggest that serum leptin levels are not affected by continuous peritoneal loss of leptin during CAPD and that insulin resistance and hyperinsulinaemia contribute to elevated serum leptin concentrations in CAPD and HD patients. The aetiology of increased serum leptin levels in kidney transplant recipients is probably different from that in dialysis patients.     

Plasma levels of pancreatic secretory trypsin inhibitor in relation to amylase and lipase in patients with acute and chronic renal failure

Plasma levels of pancreatic secretory trypsin inhibitor (PSTI), lipase and amylase were measured in patients with chronic renal failure (CRF), patients undergoing regular hemodialysis treatment (RDT) or continuous ambulatory peritoneal dialysis (CAPD), patients with acute renal failure (ARF) and patients following successful cadaveric kidney transplantation. Plasma PSTI values were 9.2 +/- 0.8 ng/ml in controls (CO), 156.9 +/- 16.2 ng/ml in CRF patients, 257.6 +/- 22.3 ng/ml in RDT patients, 376.8 +/- 57.5 ng/ml in CAPD patients and 2,300 +/- 276.9 ng/ml in patients with posttraumatic ARF. RDT patients with malignant diseases displayed significantly higher PSTI values (1,014 +/- 148.7 ng/ml; p less than 0.01) than RDT patients without malignancy. Transplant patients with normal kidney function (creatinine 1.25 +/- 0.1 mg/dl) showed significantly lower PSTI values (16.7 +/- 2.1 ng/ml) than transplant patients with impaired renal function (creatinine 4.7 +/- 0.5 mg/dl; PSTI 72.8 +/- 11.8 ng/ml; p less than 0.01). Daily urinary excretion of PSTI increased from 26.7 +/- 3.1 micrograms (CO) to 551.8 +/- 54.8 micrograms in CRF patients. In CAPD patients, daily peritoneal loss of PSTI was 164.3 +/- 58.4 micrograms. Plasma PSTI values increased during hemodialysis with dialyzers made of cuprophan (317.0 +/- 32.6 vs. 422.0 +/- 46.2 ng/ml; p less than 0.05) and decreased with polysulfone dialyzers (226.6 +/- 19.9 vs. 86.6 +/- 18.1 ng/ml). There was no correlation between PSTI and urea, creatinine, lipase or amylase in each tested group. Our results document markedly elevated plasma PSTI values in all forms of renal insufficiency, suggesting extrapancreatic PSTI production and/or reduced renal elimination.     

Study on the assay of uremic protein-binding inhibitors: furan compound and hippuric acid]

Plasma levels of 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (FA) and hippuric acid (HA) were studied in healthy subjects, uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD). Analysis of FA and HA in the plasma were performed by gas chromatography with capillary column. The mean value of FA in HD patients (16.7 +/- 6.1 micrograms/ml) was significantly higher than these in healthy subjects (3.6 +/- 1.0 micrograms/ml) and in patients on CAPD (4.1 +/- 3.7 micrograms/ml) (p less than 0.01). HA levels in CAPD and HD groups were higher than those in healthy controls (2.4 +/- 0.8 micrograms/ml). In addition, the values in HD patients (46.7 +/- 53.5 micrograms/ml) were more increased than those in CAPD (18.5 +/- 16.5 micrograms/ml) (p less than 0.05). Approximately 95% of total FA and 25% of HA were bound to the plasma protein. However, the plasma level of HA was significantly reduced by HD therapy, whereas that of FA was not altered. In the previous study, it was described that no effect of HD on the percent of the binding of acid drugs to the plasma protein in the uremic plasma was observed. Therefore it is supposed that FA is more involved in the binding of drugs to the plasma protein in comparison with HA. The peritoneal losses of FA and HA in CAPD were 2.3 +/- 1.3 mg/day and 276 +/- 40 mg/day, respectively. As the duration of HD became longer, plasma concentrations of FA in HD patients were more increased. In general, they were maintained to be comparatively low in patients on CAPD.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of renal replacement therapies on serum gastrointestinal system hormones

BACKGROUND: The kidney is a major site for the inactivation, degradation, and clearance of a variety of peptide hormones. It has been shown that the uremia increases or decreases gastrointestinal system (GIS) hormones. Moreover, studies investigating the serum GIS hormones levels in chronic renal failure (CRF) were conducted mainly in a particular period of the renal replacement therapy, and the changes caused by continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) could not be fully demonstrated. In this study, we investigated the effect of CAPD and HD on serum GIS hormones (amylase, lipase, trypsinogen, and gastrin) levels in CRF patients who were diagnosed for the first time. METHODS: Serum amylase, lipase, trypsinogen, and gastrin levels were measured in 36 patients who were just diagnosed with CRF, 22 patients with CAPD and 14 patients with HD. GIS hormones of these patients were measured before treatment and three months from the beginning of CAPD and HD treatment. As the control group, 20 normal healthy cases with well-matched age and gender were used. RESULTS: The mean serum amylase, lipase, secretin, and gastrin levels were found meaningfully decreased according to the beginning values at third months of the CAPD and HD treatment. However, they were higher than control group. CONCLUSION: In patients receiving CAPD or HD as renal replacement therapy, GIS hormone levels were found to be lower, albeit higher than the healthy control group.     

Endothelin in renal failure

Endothelin is a 21-residue peptide vasoconstrictor produced by endothelium. Using a radioimmunoassay, endothelin values were measured in four groups of individuals: normal controls (0.54 +/- 0.12 pmol/l, n = 20); undialysed patients with chronic renal failure (CRF) (0.82 +/- 0.13 pmol/l, n = 38); chronic renal failure patients on continuous ambulatory peritoneal dialysis (CAPD) (2.81 +/- 0.63 pmol/l, n = 20); and patients with CRF on haemodialysis (HD) (4.52 +/- 1.21 pmol/l, n = 14). The endothelin values were significantly greater in undialysed patients with CRF when compared with controls (P less than 0.001) and significantly greater in both dialysis groups when compared with controls and the undialysed CRF group (P much less than 0.001). The difference between the two dialysis groups was not significant (P = 0.07). There was no correlation between endothelin and serum creatinine, mean arterial pressure, presence of chronic hypertension and/or diabetes, use of calcium-channel blockers and/or ACE inhibitors, or primary renal diagnostic category. A single haemodialysis session had no significant effect on endothelin values in the ten patients in whom this was assessed. Fast protein liquid chromatography (FPLC) appeared to confirm that the molecular species found in chronic renal failure were the same as those found in diabetic patients.     

Effects of dialysis and transplantation on red cell Na pump function in renal failure

Ion pumping by the erythrocyte Na, K-ATPase has been measured using ouabain-sensitive 86Rb flux in 11 non-dialysed patients with chronic renal failure (CRF), 13 patients on haemodialysis (HD), 13 patients on peritoneal dialysis (CAPD) and 15 patients with functional transplants (FT). Flux measurements were performed in plasma and simultaneous estimates of specific 3H-ouabain binding were made. The results indicate that, compared to normal controls, Na,K pump flux was reduced by 21% in CRF (p less than 0.01), 30% in HD (p less than 0.01), 15% in CAPD (p less than 0.02), and was normal in FT. Mean specific ouabain binding sites per cell (+/- SEM) were; controls 366 +/- 16; CRF, 290 +/- 16; HD, 344 +/- 17; CAPD, 321 +/- 18; FT, 345 +/- 26. Calculation of mean turnover rate per pump site indicated that patients on HD showed a 30% reduction compared to controls (influx 55 K ions/s versus 79 K ions/s, p less than 0.01). Cross-incubation experiments suggest that the lowered pump flux seen in the CRF and HD groups was due to plasma factors. This work shows that erythrocyte Na,K pump number is reduced in CRF, while patients on maintenance HD have normal pump numbers per erythrocyte but reduced pump turnover.     

Serum free carnitine, carnitine esters and lipids in patients on peritoneal dialysis and hemodialysis

Serum free and esterified carnitine levels as well as lipids were investigated in patients undergoing regular hemodialysis (HD) treatment before and during 12 weeks of treatment with L-carnitine (1 g i.v.) at the end of each HD. The results were compared with those obtained in patients on continuous ambulatory peritoneal dialysis (CAPD; n = 15) or intermittent peritoneal dialysis (IPD; n = 3) and healthy controls (CO; n = 20). In HD patients (n = 23) total carnitine (TC) was 49.9 +/- 3.9 (CO: 46.0 +/- 2.5; NS), free carnitine (FC) was 31.6 +/- 2.8 (CO: 37.4 +/- 1.3; p less than 0.05), short-chain acylcarnitine (SCC) was 17.0 +/- 1.8 (CO: 7.2 +/- 0.9; p less than 0.0001) and long-chain acylcarnitine (LCC) was 1.2 +/- 0.2 mumol/l (CO: 0.6 +/- 0.1; p less than 0.05). FC was in the normal range in CAPD (35.6 +/- 3.2) and IPD (44.5 +/- 8.0 mumol/l) patients, whereas SCC (30.1 +/- 3.5) and LCC (2.9 +/- 0.2) levels were maximal elevated in IPD patients (11.8 +/- 0.8 and 1.5 +/- 0.2 on CAPD). Therefore, TC was higher in IPD than in CAPD patients (77.5 +/- 5.0 vs. 49.0 +/- 3.5 mumol/l). 12 weeks after L-carnitine supplementation in HD patients, TC was 313.9 +/- 22.6, FC was 207.7 +/- 12.4, SCC was 99.6 +/- 12.1 and LCC was 7.1 +/- 0.6 mumol/l. TC and FC were significantly lower in females compared with males. Total cholesterol and ketone bodies were normal, HDL cholesterol was significantly decreased before and after L-carnitine supplementation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the humoral markers of bone turnover and bone mineral density in patients on haemodialysis and continuous ambulatory peritoneal dialysis

Renal osteodystrophy is an important complication in patients with end-stage renal disease on maintenance dialysis. The aim of this study was to compare the biochemical markers of bone formation (serum collagen type I C-terminal propeptide) and resorption (serum deoxypyridinoline - DPD - and pyridinoline - PYR) with the bone mineral density (BMD) at lumbar spine, femoral neck, and forearm in patients with end-stage renal disease on haemodialysis (HD) versus continuous ambulatory peritoneal dialysis (CAPD). Fifty-nine adult patients, 45 on CAPD (18 females, 27 males) and 14 on HD (2 females, 12 males), were studied. The mean age was 44 +/- SEM 1.6 and 54.4 +/- 4.8 years, respectively. No significant differences in serum calcium, phosphorus, creatinine, and parathyroid hormone were found between patients on HD and CAPD in predialysis samples. Serum urea was significantly lower (p = 0.02) in the CAPD group. Serum PYR (nmol/l) and DPD (nmol/l) were significantly higher in patients on HD as compared with those on CAPD: 105 +/- 23.3 versus 43.7 +/- 3.47 (p = 0.007) and 31.0 +/- 2.4 versus 24.4 +/- 1.4 (p = 0.027), respectively. The results were still significantly higher in the HD patients following correction for serum creatinine and body mass index. There was a close correlation between dialysate DPD and creatinine in both dialysis modalities (HD r = 0.9, CAPD r = 0.76). The clearance of DPD did not differ significantly between the CAPD membrane and the HD membrane (p = 0.22). Serum collagen type I C-terminal propeptide was not significantly different between the HD and CAPD patients. The results were unaffected following correction for age and gender. The BMD was measured in 38 (65%) of the patients (HD n = 8, CAPD n = 30) by dual-energy X-ray absorptiometry and expressed as 'Z' scores. This was reduced at all sites in the patients with end-stage renal disease. The BMD was significantly lower at the ultradistal forearm (mostly trabecular bone) in HD patients as compared with CAPD patients (n = 0.02). A similar trend was observed at the lumbar spine, although the results failed to reach significance. In the whole population (n = 38), linear regression analysis revealed a significant negative correlation between BMD at the ultradistal forearm and serum PYR (r = -0.35, p = 0.04) and DPD (r = -0.33, p = 0.049). Combined measurements of BMD and biochemical markers of bone resorption may have potential in the identification of patients at high risk of bone loss who may require further evaluation of bone remodeling by bone histomorphometry.     

Thyroid function tests in patients undergoing maintenance dialysis: characterization of the 'low-T4 syndrome' in subjects on regular hemodialysis and continuous ambulatory peritoneal dialysis

Thyroid function tests were evaluated in 38 patients on regular hemodialysis (HD), in 36 on continuous ambulatory peritoneal dialysis (CAPD) and in 39 healthy controls. A significant reduction in total thyroxine (TT4), total triiodothyronine (TT3), reverse (rT3), and free T4 (fT4) mean levels and normal TSH, free T3, TBG and albumin concentrations was found in both HD and CAPD patients. A 'low-T4 syndrome' (serum T4 less than 5 micrograms/dl) was found in 9 CAPD (25%) and 20 HD (53%) patients, but none of them had fT4 levels below the normal laboratory range. The only striking difference between low-T4 HD and low-T4 CAPD patients was the significantly lower TBG and albumin serum levels in CAPD group. Low-T4 HD displayed normal TBG levels but enhanced fT4/TT4 and fT4/TT4 X TBG ratios. We concluded that: the abnormalities in thyroid function tests in patients on long-term dialysis (HD and CAPD) do not express the existence of a true hypothyroidism; a different pathogenesis of the low-T4 syndrome in the CAPD and HD groups may be hypothesized: in the former it could be attributed to a reduction in serum-binding capacity for thyroid hormones, in the latter the relative increase in fT4 percentage despite normal TBG levels suggests either the presence of T4-TBG-binding inhibitor(s), or structural abnormalities of thyroid-hormone-binding proteins.     

Apolipoprotein B-containing lipoproteins in renal failure: the relation to mode of dialysis

BACKGROUND: The aim of this study was to establish whether there is a differential effect of mode of dialysis, hemodialysis (HD), or continuous ambulatory peritoneal dialysis (CAPD) on the dyslipidemia of renal failure. METHODS: The lipoprotein profile was determined in 61 non-diabetic patients on chronic HD (N = 30) and CAPD treatment (N = 31), and in a control group of 27 healthy subjects. The analysis included the measurement of individual apolipoprotein (apo) A- and apo B-containing lipoproteins (LPs) separated by sequential immunoaffinity chromatography. Apo A-containing lipoproteins include lipoprotein A-I with apo A-I and lipoprotein A-I:A-II with apo A-I and apo A-II as the main protein constituents, whereas apo B-containing lipoproteins comprise simple cholesterol-rich lipoprotein B (LP-B), with apo B as the only protein moiety and complex triglyceride (TG)-rich lipoprotein B complex (LP-Bc) particles with apo B, apo A-II, apo C, and/or apo E as the protein constituents. RESULTS: CAPD patients had significantly higher concentrations of total cholesterol (6.8 vs. 5.1 mmol/liter), low-density lipoprotein (LDL) cholesterol (4.6 vs. 3.2 mmol/liter), TG (2.3 vs. 1.5 mmol/liter), apo B (155.3 vs. 105.7 mg/dl), LP-B (136.0 vs. 91.9 mg/dl), and LP-Bc (19.3 vs. 13.8 mg/dl) than HD patients. Both HD and CAPD patients had significantly higher TG, VLDL cholesterol, apo C-III, and apo E and significantly lower high-density lipoprotein cholesterol, apo A-II, and lipoprotein A-I:A-II levels than control subjects. The distribution of apo C-III in high-density lipoprotein and VLDL-LDL was altered in CAPD patients in comparison with control subjects. This suggests that the removal of TG-rich lipoproteins is less efficient in patients on CAPD. Normotriglyceridemic (NTG; TG < or = 1.7 mmol/liter, 150 mg/dl) CAPD patients had significantly higher levels of TC, LDL cholesterol, apo B, and LP-B than NTG-HD patients. There was little difference in the LP-Bc levels between NTG-CAPD, NTG-HD, and controls. Similarly, hypertriglyceridemic (HTG) CAPD patients had significantly higher TC, LDL cholesterol, apo B, and LP-B levels than HTG-HD patients. The LP-Bc levels were significantly increased in HTG-HD and HTG-CAPD patients compared with controls, but the slightly higher levels in the CAPD patients did not differ significantly from the HD group. CONCLUSION: CAPD and HD patients have a lipoprotein profile characteristic of renal failure. Patients on long-term CAPD have higher levels of cholesterol-rich apo B-containing lipoproteins unrelated to TG levels. Many patients on CAPD also have a substantial elevation of the plasma concentrations of TG-rich LPs. The clinical significance of increased levels of potentially atherogenic LP-B during CAPD remains to be investigated.     

The immune status of uraemic children/adolescents with chronic renal failure and renal replacement therapy

In adults with chronic renal failure (CRF) and/or renal replacement therapy (RRT) various immunological abnormalities have been described, but few data are available for the paediatric age group. We performed basic in vitro immunological studies in 26 patients 10 months–19 years of age with advanced renal failure, 11 with CRF (creatinine clearance 16.8±5.2 ml/min per 1.73 m²), 15 on RRT with haemodialysis (HD;n=9) and continuous ambulatory peritoneal dialysis (CAPD;n=6) as well as in 16 healthy controls. None had clinical evidence of deranged immune function. No significant differences were found in the percentages of B- and T-cells, T-cell subsets CD3, CD4, CD8 and mitogenic responses to phytohaemagglutinin and concanavalin A (Con A) between RRT patients (HD=CAPD) and control children. Most parameters in CRF patients were also normal, although they had a low percentage of B-cells (12.1±4.1; RRT: 19.7±6.5; controls: 18.5±7.1;P<0.01), relatively low levels of serum immunoglobulin G (948.4±209.4 mg/dl; HD: 1374.7±235.2 mg/dl;P<0.01; CAPD: 966.3±430.2 mg/dl, NS) and a high normal response to Con A (34.3±13.6 cpm ×10^–3; RRT: 34.5±11.3 cpm ×10^–3; controls: 23.4±9.9 cpm ×10^–3,P<0.01). All these values were, however, well within the normal accepted range. These data indicate that children/adolescents with CRF and/or RRT have no significant basic in vitro immunological defects. This study did not test the functional immune status of the young uraemic patients.