Beta 2-microglobulin Serum Levels during Dialysis: Effect of Cuprophan and Serum Osmolality Changes

New cuprophan dialysers were used in twenty, re-used dialysers in twelve dialyses and new dialysers in ten sequential ultrafiltrations. Serum beta 2-microglobulin (β2m) concentration was measured before and after all these procedures. Serum osmolality changes were compared with changes in serum β2m concentrations. These concentrations rose in dialyses with new and re-used dialysers, but remained unchanged during sequential ultrafiltration. β2m increased with serum hypo-osmolality, decreased with serum hyperosmolality and did not change during iso-osmolar dialysis. These results indicate that cuprophan membrane does not raise β2m concentration during dialysis. It is hypo-osmolality that is responsible for the increment of β2m in serum.

Comparison of Different Techniques of Hemodialysis Vascular Access Flow Evaluation

Measurement of vascular access flow (QVA) has been suggested as a method of choice for vascular access quality (VAQ) monitoring. Besides traditional duplex Doppler, a number of bedside methods based mostly on the Krivitski principle of QVA evaluation from recirculation at reversed needles (RX), have been developed. This work compares ultrasonic dilution (UD), taken as a reference, HD01, Transonic Systems; duplex Doppler (DD); thermodilution (TD), BTM, Fresenius; optodilutional RX measurement (ORX), Critline III, R-mode, HemaMetrics; direct optodilutional QVA evaluation from jumpwise changes in ultrafiltration rate at both normal and reversed needles connection (OABF), Critline III, ABF-mode; and direct transcutaneous optodilutional QVA evaluation (TQA), Critline III TQA.

Firstly, reproducibility of each method was assessed by duplicate measurement at unchanged conditions. This was followed by paired measurement with each method performed at controlled change in relevant measurement condition (two different extracorporeal blood flows in UD and TD, changed sensor position in TQA). Finally paired measurements by each method and the reference method performed at identical conditions were evaluated to assess accuracy of each method. The simple Krivitski formula QVA= QB(1-RX)/RX was used wherever manual QVA calculation was needed.

Very high reproducibility was seen in UD, both for measurement at the same extra corporeal blood flow (QB) (correlation coefficient of duplicate measurement r= 0.9702, n= 58) and for measurement at two different QB (r= 0.9735, n= 24), justifying its current status of a reference method in QVA evaluation. Slightly lower reproducibility of TD measurement at the same QB (r= 0.9197, n= 40) and at two different QB (r= 0.8508, n= 168) can be easily overcome by duplicate measurement with averaging. High correlation of TD vs. UD (r= 0.9543, n= 54) makes TD a viable clinical alternative in QVA evaluation. Consistently different QVA obtained at two different QB should prompt closer investigation of anatomical conditions of the access. Use of the simple Krivitski formula in TD (which measures total recirculation, i.e. sum of access recirculation and cardiopulmonary recirculation) brings about underestimation of QVA, which progressively increases from QVA of about 600 ml/min up. Good correlation, although with significant scatter (r= 0.8691, n= 27) was found between the DD- and UD-based QVA. By far the worst reproducibility at the same QB from among the investigated methods was found in ORX (0.6430, n= 23). Also the correlation of ORX vs. UD was lower than in other methods (r= 0.702, n=33) and general overestimation of QVA by about 25% was noted. Correlation of OABF vs. UD (r= 0.6957, n= 26) was slightly better than that of ORX and it gave less overestimated values. The TQA method showed very high reproducibility (r= 0.9712, n= 85), however only for unchanged sensor position. Correlation of QVA measured at two different sensor positions was much worse (r= 0.7255, n= 22). Correspondence of TQA vs. UD was satisfactory (r= 0.8077, n= 36). Skilled and experienced operators are a must with this method.

CONTINUOUS BLOOD VOLUME MONITORING AND “DRY WEIGHT” ASSESSMENT

There are two distinct facets of adequate fluid balance control in haemodialysis patients--estimation of dry weight (DW) as the target and adequate ultrafiltration (UF) strategy, i.e. the way to reach the target in a possibly symptom-free way. The article reviews the continuous blood volume monitoring (CBVM) based procedures to deal with the former facet-DW determination. The existing approaches are divided in three groups--methods defining certain alert value of relative blood volume (RBV) reduction, methods working with RBV response to constant UF rate, and methods evaluating dynamics of RBV response to UF pulse or chain of UF pulses. While the first and the third approaches are relatively easy to automate, the second group of methods are suitable mainly for observational evaluations only. All the discussed methods, without exception, need large-scale verification, as they all were evaluated in the majority by their authors only and on small patient cohorts.

The correlation of serum prolactin level and psychic stress in women undergoing a chronic hemodialysis programme

Altogether eight women undergoing a chronic hemodialysis treatment were studied for five months. Four of them were in the premenopause and four in the postmenopause. Once a month levels of prolactin, FSH, LH, estradiol and progesterone were measured, Lüscher colour test was performed, from which the screamer index as an indicator of psychic stress was calculated and the levels of urea, creatinine and hematocrite were assessed to inform us of the adequacy of dialysis. We tested the hypothesis, whether there exists a correlation between psychic stress and the prolactin level in these women. For statistic evaluation we used linear regression under the use of dummy variables to intercept the interindividual differences in the Lüscher test. We found that the fluctuation of the prolactin level and of the value of the screamer index of the Lüscher test are parallel (p less than 0.05). These results bear witness of a participation of psychic stress in the onset and level of hyperprolactinemia in women being in a chronic hemodialysis treatment.

Increase of nocturnal melatonin levels in hemodialyzed patients after parathyroidectomy: a pilot study

In hemodialyzed patients hormonal disturbances are known to occur. However, melatonin levels have not been completely studied. The aim of the study was to find whether changes in calcaemia affect melatonin secretion. For this reason we followed the nocturnal serum concentrations of melatonin and parathyroid hormone (PTH) in 9 hemodialyzed patients (6 women and 3 men, aged 37-65 years) both before and 1-3 months after parathyroidectomy at 6 p.m., 9 p.m., 11 p.m., 2 a.m., 5 a.m. and 7 a.m. At 6 p.m. blood samples to evaluate the levels of calcium and phosphate were also collected. Parathyroidectomy resulted in an increase in nocturnal melatonin levels. As expected, the parathyroidectomy was followed by considerable PTH decrease. PTH showed no nocturnal variation before or after parathyroidectomy. Calcium levels significantly decreased after the operation while phosphate levels increased. In summary, in hemodialyzed patients with hyperparathyroidism, parathyroidectomy significantly increases the nocturnal secretion of melatonin. Relationships between the pineal gland and parathyroid glands have yet to be elucidated.

Plasma ghrelin levels in patients with end-stage renal disease

Ghrelin is an acylated peptide stimulating secretion of the growth hormone (GH). It was originally isolated from the rat stomach as an endogenous ligand for the growth hormone secretagogue receptor. Although being predominantly produced by endocrine cells of the gastric fundus, its secretion has been found in various tissues including the kidney. To study the influence of renal failure on plasma ghrelin levels we examined 16 patients with end-stage renal disease (ESRD) receiving hemodialysis (8 men and 8 women) and 19 controls (10 men and 9 women). Both groups were comparable in age and BMI. In all subjects we assessed plasma levels of ghrelin, leptin, soluble leptin receptor, insulin, IGF-I, IGFBP-1, IGFBP-3 and IGFBP-6. Ghrelin levels were significantly higher in the group of dialyzed patients (4.49+/-0.74 vs. 1.79+/-0.15 ng/ml; p<0.001). These patients had significantly higher levels of GH, IGFBP-1, IGFBP-6, leptin and percentage of body fat (p<0.05). In the group of patients with ESRD plasma ghrelin levels positively correlated with IGFBP-1 (p<0.01). In the control group, ghrelin positively correlated with GH concentrations (p<0.01) and negatively correlated with the levels of insulin and creatinine (p<0.05). In conclusion, patients with ESRD have higher ghrelin concentrations, which might be caused by a decreased excretion/metabolism of ghrelin in the kidney during renal failure.

Plasma ghrelin levels in patients with end-stage renal disease

Ghrelin is an acylated peptide stimulating secretion of the growth hormone (GH). It was originally isolated from the rat stomach as an endogenous ligand for the growth hormone secretagogue receptor. Although being predominantly produced by endocrine cells of the gastric fundus, its secretion has been found in various tissues including the kidney. To study the influence of renal failure on plasma ghrelin levels we examined 16 patients with end-stage renal disease (ESRD) receiving hemodialysis (8 men and 8 women) and 19 controls (10 men and 9 women). Both groups were comparable in age and BMI. In all subjects we assessed plasma levels of ghrelin, leptin, soluble leptin receptor, insulin, IGF-I, IGFBP-1, IGFBP-3 and IGFBP-6. Ghrelin levels were significantly higher in the group of dialyzed patients (4.49±0.74 vs. 1.79±0.15 ng/ml; p<0.001). These patients had significantly higher levels of GH, IGFBP-1, IGFBP-6, leptin and percentage of body fat (p<0.05). In the group of patients with ESRD plasma ghrelin levels positively correlated with IGFBP-1 (p<0.01). In the control group, ghrelin positively correlated with GH concentrations (p<0.01) and negatively correlated with the levels of insulin and creatinine (p<0.05). In conclusion, patients with ESRD have higher ghrelin concentrations, which might be caused by a decreased excretion/metabolism of ghrelin in the kidney during renal failure.

Increased Levels of Pregnancy-Associated Plasma Protein A Are Associated with Mortality in Hemodialysis Patients: Preliminary Results

Pregnancy-associated plasma protein A (PAPP-A) is a new prognostic indicator of acute coronary syndrome. This protein is elevated in hemodialysis (HD) patients and is closely related to inflammation and oxidative stress. The aim of our pilot study was to find out whether PAPP-A is related to mortality in HD patients. 40 HD patients in a stable clinical state (20 men and 20 women, mean age 69 +/- 12 years) were enrolled in the study and followed up for 20 months. PAPP-A was assessed immunochemically (TRACE method) in serum samples (before the HD session) at the beginning of the observation period. During the follow-up, 22 patients died, 15 of them due to cardiovascular events. PAPP-A levels were significantly higher in the patients who died, compared to living HD patients: 26.8 (21.6-36.8) vs. 20 (14.9-26.6) mU/l, p = 0.034. PAPP-A could also be a new prognostic marker in hemodialysis patients, probably due to its close association with cardiovascular risk. More extensive studies are required to confirm this hypothesis.

[An importance of vitamin D metabolites assessment in patients with impaired renal function]

The goal of this prospective multicentric study was to assess concentrations of vitamin D metabolites in patients with renal insufficiency and to monitor response of calcium phosphate metabolism parameters to a focused individualised therapy. The sample consisted of 184 patients, 66 of them were undergoing regular dialysis (Ccreat 0.11 +/- 0.05 ml/sec., age 57.6 +/- 16.6) and 118 patients were dispensed for renal insufficiency (Ccreat 0.42 +/- 0.23 ml/sec., age 60.8 +/- 11.0). After an assessment of basic parameters of bone metabolism (Ca, Pi, ALP) and parameters of acidobasic balance, calcidiol, calcitriol, and parathormon were assessed by radiation immunisation and than the used treatment was evaluated and adjusted according to results of the assessment. Two month later laboratory tests were done. Entry concentrations of calcidiol were in 73% of patients in reference area. However, according to clinical recommendations the bottom value of the reference area had to be reevaluated towards higher values. Such more strict criteria suited only 20% of patients. Calcitriol levels in reference area were found in 30% of patients, after treatment adjustment in 49% of patients. Treatment with vitamin D pharmaceuticals was often limited by hyperphosphataemia, low PTH or hypercalinemia. Input levels of calcitriol in nondialised patients significantly correlated with input calcidiol, 1alpha-hydroxylasis in kidneys could be stimulated in them via calcidiol administration. Attention deserve especially low calcidiol and calcitriol levels in patients with renal failure because timely, individualised and controllable supplementation of vitamin D metabolites in renal insufficiency serves as a prevention of later advanced forms of bone metabolism impairment in a period of dialysis treatment.

Comparison of different techniques of hemodialysis vascular access flow evaluation

Measurement of vascular access flow (QVA) has been suggested as a method of choice for vascular access quality (VAQ) monitoring. Besides traditional duplex Doppler, a number of bedside methods based mostly on the Krivitski principle of QVA evaluation from recirculation at reversed needles (RX), have been developed. This work compares ultrasonic dilution (UD), taken as a reference, HD01, Transonic Systems; duplex Doppler (DD); thermodilution (TD), BTM, Fresenius; optodilutional RX measurement (ORX), Critline III, R-mode, HemaMetrics; direct optodilutional QVA evaluation from jumpwise changes in ultrafiltration rate at both normal and reversed needles connection (OABF), Critline III, ABF-mode; and direct transcutaneous optodilutional QVA evaluation (TQA), Critline III TQA. Firstly, reproducibility of each method was assessed by duplicate measurement at unchanged conditions. This was followed by paired measurement with each method performed at controlled change in relevant measurement condition (two different extracorporeal blood flows in UD and TD, changed sensor position in TQA). Finally paired measurements by each method and the reference method performed at identical conditions were evaluated to assess accuracy of each method. The simple Krivitski formula QVA=QB(1-RX)/RX was used wherever manual QVA calculation was needed. Very high reproducibility was seen in UD, both for measurement at the same extra corporeal blood flow (QB) (correlation coefficient of duplicate measurement r=0.9702, n=58) and for measurement at two different QB (r=0.9735, n=24), justifying its current status of a reference method in QVA evaluation. Slightly lower reproducibility of TD measurement at the same QB (r=0.9197, n=40) and at two different QB (r=0.8508, n=168) can be easily overcome by duplicate measurement with averaging. High correlation of TD vs. UD (r=0.9543, n=54) makes TD a viable clinical alternative in QVA evaluation. Consistently different QVA obtained at two different QB should prompt closer investigation of anatomical conditions of the access. Use of the simple Krivitski formula in TD (which measures total recirculation, i.e. sum of access recirculation and cardiopulmonary recirculation) brings about underestimation of QVA, which progressively increases from QVA of about 600 mL/min up. Good correlation, although with significant scatter (r=0.8691, n=27) was found between the DD- and UD-based QVA. By far the worst reproducibility at the same QB from among the investigated methods was found in ORX (0.6430, n 23). Also the correlation of ORX vs. UD was lower than in other methods (r=0.702, n=33) and general overestimation of QVA by about 25% was noted. Correlation of OABF vs. UD (r=0.6957, n=26) was slightly better than that of ORX and it gave less overestimated values. The TQA method showed very high reproducibility (r=0.9712, n=85), however only for unchanged sensor position. Correlation of QVA measured at two different sensor positions was much worse (r=0.7255, n=22). Correspondence of TQA vs. UD was satisfactory (r=0.8077, n=36). Skilled and experienced operators are a must with this method.

Soluble leptin receptor levels in patients with chronic renal failure

Soluble leptin receptor (SLR) is the extracellular part of the leptin receptor. This protein is released into circulation and constitutes the main circulating leptin-binding protein. The aim of our study was to measure SLR concentrations in patients with chronic renal failure (CRF) and healthy subjects and to explore the relationship of SLR to other hormones and cytokines. The patients with CRF had significantly higher serum leptin, TNF-alpha and insulin levels than healthy subjects (25.1+/-23.5 vs. 9.4+/-7.6 ng.ml(-1) (S.D.); 14.2+/-4.2 vs. 4.55+/-2.5 ng.ml(-1); 39.8+/-36.1 vs. 20.3+/-11.1 mU.l(-1)). Serum soluble leptin receptor levels did not differ between these groups (19.1+/-11.3 vs. 19.6+/-6.1 U.ml(-1)). An inverse relationship between serum SLR and leptin levels was found in both groups. In patients with CRF the inverse relationship between SLR and insulin, body fat content and total protein levels were also found, while in healthy subjects only inverse relationship of SLR with insulin and albumin concentrations were detected. We conclude that soluble leptin receptor levels in patients with chronic renal failure do not differ from those of healthy subjects despite higher serum leptin levels in CRF patients. The physiological consequences of this finding require further investigation.

Advanced Glycation End Products in Clinical Nephrology

As a result of oxidative and carbonyl stress, advanced glycation end products (AGEs) are involved in the pathogenesis of severe and frequent diseases and their fatal vascular/cardiovascular complications, i.e. diabetes mellitus and its complications (nephropathy, angiopathy, neuropathy and retinopathy, renal failure and uremic and dialysis-associated complications), atherosclerosis and dialysis-related amyloidosis, neurodegenerative diseases, and rheumatoid arthritis. They are formed via non-enzymatic glycation which is specifically enhanced through the presence of oxidative and carbonyl stress, and their ability to form glycoxidation products in peptide and protein structures finally modulating or inducing biological reactivity. Food can be another source of AGEs; however, high serum AGEs in hemodialysis patients might reflect nutritional status better. Several methods of renal replacement therapy have been studied in connection with the AGE removal, but unfortunately the possibilities are still unsatisfactory even if high flux dialysis, hemofiltration, or hemodiafiltration give better results than conventional low flux dialysis. AGEs are currently being studied in the patients on peritoneal dialysis as their precursors can be formed in the dialysis fluid. AGEs can cause damage to the peritoneum and so a loss of ultrafiltration capacity. Many compounds give promising results in AGE inhibition (inhibition of formation of AGEs, inhibition of their action or degradation of AGEs), are tested for these properties, and eventually undergo clinical studies (e.g. aminoguanidine, OPB-9195, pyridoxamine, antioxidants, N-phenacylthiazolium bromide, antihypertensive drugs, angiotensin-converting enzyme inhibitors and angiotensin II receptor-1 antagonists).

Relationship of pregnancy-associated plasma protein-a to renal function and dialysis modalities

BACKGROUND

The aim of the study was to determine pregnancy-associated plasma protein-A (PAPP-A), which was recently described as a new marker of cardiovascular events, in patients with chronic renal insufficiency/failure and to find out its relationship to renal function and to prominent markers of oxidative stress (advanced oxidation protein products--AOPP) and inflammation (C-reactive protein--CRP).

METHODS

The studied group consisted of 36 chronic hemodialysis patients (HD), 10 patients treated with continuous ambulatory peritoneal dialysis (CAPD) and 38 patients with chronic renal insufficiency (CHRI) not yet dialyzed. PAPP-A was measured by Time Resolved Amplified Cryptate Emission technology. Determination of AOPP is based on a spectrophotometric method.

RESULTS

PAPP-A levels are statistically significantly elevated in the both groups of dialyzed patients in comparison with healthy subjects (27.0 +/- 16.5 mIU/l in HD and 14.07 +/- 6.73 mIU/l in CAPD vs. 8.22 +/- 2.7 mIU/l in the control group, p < 0.0001 and p < 0.001, respectively, p < 0.05 HD vs. CAPD). The mean serum PAPP-A levels in the CHRI patients not yet dialyzed were not significantly higher in comparison with the control group (9.72 +/-4.44 vs. 8.22 +/- 2.7 mIU/l, n.s.). In the CHRI not dialyzed patients, we found a significant positive correlation between serum creatinine and PAPP-A levels (r = 0.68, p < 0.05). In comparison with controls, AOPP and CRP levels were significantly higher in HD patients [AOPP 155.0 +/- 37.9 micromol/l, p < 0.0001 vs. controls, CRP 10.0 (4.6- 26.9) mg/l (median, interquartile range), p < 0.0001 vs. controls], CAPD patients [AOPP 118.5 +/- 25.8 micromol/l, p < 0.0001 vs. controls, CRP 7.7 (2.0-18.8) mg/l, p < 0.01 vs. controls] and AOPP levels in chronic renal failure patients not yet dialyzed (98.5 +/- 43.24 micromol/l, p < 0.01 vs. controls). The correlations between PAPP-A and AOPP (r = 0.49, p < 0.05) and PAPP-A and CRP (r = 0.48, p < 0.05) serum concentration were statistically significant in HD patients. In CAPD patients, neither a correlation between PAPP-A and AOPP nor a correlation between PAPP-A and CRP were found.

CONCLUSION

We can conclude that serum PAPP-A levels sensitively reflect the changes in renal function, depend on dialysis modality, and may represent a novel marker associated with inflammation and oxidative stress in chronic renal failure patients.

[Junctions of hepatology and nephrology]

The liver and the kidney jointly or in a complementary manner play an important role in maintaining homeostasis of the internal environment, mainly regarding detoxification, excretion and regulation. Hepatorenal syndrome can develop under pathological circumstances due to severe hepatic impairment, when the metabolism of both organs is affected by various xenobiotics, when they are damaged by genetic defects as in renal polycystosis, glycogenoses, alpha-1 antitrypsin deficiency or in hereditary amyloidosis. In primary hyperoxaluria or familiar thrombotic microangiopathy renal impairment develops due to the metabolic defect in the liver. Both organs may be impaired also in some hemolytic anemias, viral hepatitis, AIDS, leptospirosis, in circulatory failure, intoxications, and after the bone marrow or solid organ transplantation. In the dialysis units, prevention of viral hepatitis and HIV infection is of the basic importance; its principles are discussed in more detail.

[Tuberculosis in patients with chronic kidney failure]

BACKGROUND

In a retrospective study we analysed the incidence of tuberculosis (tb) in end-stage renal disease patients undergoing dialysis treatment at the Department of Medicine Strahov, General University Hospital, 1st Medical Faculty, Charles University, Prague. Study included patients who died and were autopsied from 1991 till 2000.

METHODS AND RESULTS

Active tb was found in 11 cases (4 men and 7 women, age 56 to 84 years) from the total of 275 patients, i.e. in 4%. The results confirmed the increased risk of tb in our group as compared to general population. Tuberculosis was diagnosed of in 2 patients before they died and in 3 patients there was a suspicion of tb before the death. In 6 cases tb was found during autopsy. Unlike the non-dialysed population, where pulmonary tb has the highest incidence (in Czech republic 75%), in the studied group extrapulmonary forms of tb were predominant (9 patients, i.e. 81.8% had some form of extrapulmonary tb). Miliary tb was found in 8 cases (72.7%). Because the symptoms of tb are unspecific and they are not pathognomonic, they were masked by other, already known diseases in patients with multiple co-morbidities. The low number of cases of tb diagnosed before death represents a serious problem. Obviously, it is difficult to prove tb unambiguously, even when such possibility is taken into account.

CONCLUSIONS

In differential diagnosis, we always have to bear in mind the possibility of the patient having tb. In examination algorithm we have to concentrate on both pulmonary and extra-pulmonary forms of tb.

[Diabetes mellitus and chronic renal insufficiency]

In the nineties of the 20th century diabetic nephropathy has become the leading cause of regular dialysis treatment (RDT) in developed countries. In particular type 2 diabetics are involved. A similar trend can be observed also in the Czech Republic which holds in this respect the first place among countries of the former eastern block (33% patients with RDT) suffer from diabetes. The cause of the increase of patients with diabetic nephropathy and renal failure caused by diabetes is not only the rising prevalence and incidence of type 2 diabetes in the population but in particular the better care provided to patients with type 2 diabetes which enables them to survive macro- and microvascular complications incl. diabetic nephropathy. It is estimated that diabetic nephropathy affects 4-8% patients attending diabetic clinics. With regard to the increasing number of diabetics in RDT, moreover associated with their high polymorbidity, this is a serious medical and economic problem. The main factors which influence in the diabetic patients the risk of development of diabetic nephropathy are long-term control of glycaemia, genetic (ethnic) factors, age and sex. The decisive factor influencing in patients with diabetic nephropathy the progression of chronic renal insufficiency is control of the blood pressure. Including diabetics in RDT is not associated only with medical problems but also with socio-economic issues. The quality of life of diabetics is much lower and the survival of diabetics treated within the framework of RDT is still almost half as compared with the survival of non-diabetic patients. Decision on the selection of the dialysis method is not easy. Medical differences are well defined but should not be considered absolute. It is important to consider also which method is preferred by the patient. Optimally the decision is taken during the period of dispensarization. Both dialyzation methods have comparable results and survival although for diabetics under 50 years of age a more favourable prognosis of peritoneal dialysis is reported. However, the risk of "failure of the method" is in general higher in peritoneal dialysis.

[Epidemiology of functional disorders of the kidneys]

The new classification K/DOQI of chronic renal disease differentiates five stages according to the grade of glomerular filtration. In the fifth, most severe grade (= renal failure) dialyzation/transplantation treatment is indicated. For dialyzation/transplantation activities in developed countries relatively accurate epidemiological data exist (national and supranational registers of dialyzation and transplantation programmes). The number of patients increases year by year, in particular in the more advanced age groups. The predominating diagnosis is renal failure is diabetes. Although treatment by one of the methods substituting renal function involves less than 0.1% of the population the economic costs amount to as much as 6 = of the total expenditure on health services (Medicare data, USA). On the other hand the prevalence of chronic renal disease in less advanced stages is not exactly known. It is estimated that chronic kidney disease may be present in some 10% of the population. If the disease were detected in time and the patient was given professional care which can retard the disease, it would be not only of medical but also of socio-economic benefit.

[Renal bone disease]

Renal bone disease is a serious complication associated with chronic renal failure. The pathogenetic mechanisms are very complicated. The disorder develops as a result of hypophosphataemia, hypocalcaemia and calcitrol deficiency already during the period when renal functions decline below 50%. Formerly the form with an excessive bone turnover predominated, nowadays we encounter ever more frequently so-called a dynamic bone disease. A serious manifestation are extraosseous calcifications. In treatment phosphate binding substances in the gastrointestinal tract are involved (along with other provisions, correcting hypophosphataemia), supplementation of calcium in case of hypocalcaemia correction of metabolic acidosis and administration of the active vitamin D metabolite (continuously as supplementation in deficient endogenous production, in a pulsatile pattern with the aim to suppress the activity of parathyroid bodies). In case of "resistant" hyperparathyroidism surgery is indicated (parathyroidectomy). Treatment of the dynamic form is not known, prevention of suppression of excessive parathyroid activity is important. New trends in the treatment of renal bone disease are non-calcium phosphate binding substances in the gastrointestinal tract, vitamin D analogues (with a lower hypercalcaemic potential) and calcium mimetics.

Age-related extracellular to total body water volume ratio (Ecv/TBW)--can it be used for "dry weight" determination in dialysis patients? Application of multifrequency bioimpedance measurement

The article suggests a novel method for quantitative determination of optimal dry weight in dialysis patient based on their extracellular volume (ECV) to total body water (TBW) ratio and its relation to age. Values of ECV and TBW are evaluated by means of whole body multifrequency bioimpedometry. In an effort to find a suitable marker of hydration status in an individual from bioimpedance data, significant correlation has been found between ECV/TBW ratio and age in health. Assuming that all excess fluid in dialysis patients is stored exclusively in ECV and that distribution of their TBW at the state of optimal dry weight corresponds to that of a healthy person of the same age, the pre-dialysis ECV/TBW could be used for quantitative determination of optimal dry weight and/or of the ultrafiltration to reach this weight. Practical bioimpedance measurement of ECV/TBW in a group of dialysis patients both pre- and post-dialysis confirmed both above assumptions, i.e. nearly exclusively extracellular origin of ultrafiltration as well as normalisation of the ECV/TBW ratio towards the end of dialysis. Supporting evidence of increasing ECV/TBW value with age was also found in literature. Although the suggested method needs detailed analysis of possible disturbing factors (ethnic "specificity" of the reference ECV/TBW vs. age characteristics in health, possible difference in "biological" and "physical" age of dialysis patient and others), the article is published at this early stage to enable wider testing of the proposed novel method by different investigators.

[Parameters of bone metabolism in patients with various degrees of kidney function damage]

BACKGROUND

Patients with renal failure frequently have their calcium and phosphate metabolism seriously disrupted. It may result in a skeletal malady--the renal osteopathy. Late forms of this syndrome are difficult to cure. The aim of this comparative study is to follow the relation between parameters of the bone metabolism (calcitriol, calcidiol, parathormone, calcitonin, osteocalcin, Pi, Ca--total or ionised, and others) and the degree of deterioration of the kidney function.

METHODS AND RESULTS

Three groups of patients were included into the study: A-hemodialyzed patients with chronic renal failure (Ccreat = 0.07 +/- 0.02 ml/s, n = 21, age 71.0 +/- 10.6 years); B--not dialyzed patients with decreased renal function (Ccreat = 0.33 +/- 0.05 ml/s, n = 19, age 65.0 +/- 9.6 years); C--patients with normal renal function (Ccreat = 1.45 +/- 0.12 ml/s, n = 16, age 85.2 +/- 4.7 years). Calcidiol concentration [microgram/l] did not differ in individual groups (A: 11.3 +/- 4.7, B: 10.7 +/- 8.2, C: 11.7 +/- 5.7, reference limits RM: 8.9-46.7). In contrast, calcitriol concentration [ng/l] was statistically different in all studied groups (A: 1.7 +/- 2.8, B: 17.6 +/- 12.4, C: 30.6 +/- 9.1, p < 0.001, RM: 19.9-67.0) and it correlated with the degree of renal function deterioration (calcitriol vs. creatinine, r = -0.76, p < 0.001). In PTH levels (pmol/l) the group C differed significantly from groups A and B (A: 27.4 +/- 32.0, B: 23.7 +/- 16.5, C: 6.2 +/- 2.4, C vs. A, p < 0.01, C vs. B, p < 0.001, RM: 1.0-6.8). PTH concentrations correlated with osteocalcine and HCO3 (r = 0.74, r = -0.56, p < 0.001).

CONCLUSIONS

Results of the tested parameters have shown that abnormalities in the bone metabolism significantly correlate with the degree of renal deterioration. It demonstrates the requirements for vitamin D metabolites supplementation for patients is needed already in the pre-dialysis stage.

[Evaluation of the severity of vascular impairment in the lower extremities in patients with chronic kidney failure]

BACKGROUND

Arterial ischemic disease represents highly serious complication for patients undergoing chronic haemodialysis. The aim of the study was to examine peripheral arteries in the group of haemodialysed patients and to estimate the incidence and seriousness of pathological findings.

METHODS AND RESULTS

Total 82 sonographic examinations of arteries in lower extremities using Multi Dopplex II set with graphic registration of dopplex curves was done in 53 dialysed patients. Blood pressure values of four peripheral arteries at legs together with blood pressure values at the brachial artery were evaluated as the ankle-arm index (API). Character of changes of dopplex curves was classified as SO index (obliteration index). Also with normal API, changes in SO were identified. SO index was significantly higher (p = 0.034) in patients of the peritoneal dialysis program in comparison with haemodialysed patients, in persons with diabetes the value was only marginally higher. Patients who died later (of the cardiovascular complications), the SO index was significantly higher then in others (p < 0.0001), though the API values were not different. Repeated testing in 29 patients after 6 months brought about worsening of the SO index (p < 0.00001) in those patients where no changes of API were seen. No relation with any of the followed biochemical parameters was found.

CONCLUSIONS

To estimate most accurately the conditions of the peripheral arteries in dialysed patients ankle-arm index was used together with evaluation of the shape of dopplex curves (index SO). Such detailed Doppler examination has proved identifiable changes of arteries in 73 out of 82 cases.

[Gastrointestinal hemorrhage and endoscopic findings in patients with chronic kidney failure]

Case-control study comparing 81 patients with chronic renal failure (CRF) with 58 patients without renal disease who were evaluated by endoscopy of upper and/or lower gastrointestinal tract (GIT) for gastrointestinal bleeding or dyspepsia. The success of endoscopic examinations was the same in both groups. Patients with CRF more often underwent endoscopic examination because of gastrointestinal bleeding and they presented more often by hematochezia. Patients with CRF were more often found to have hemorrhagic gastropathy or duodenopathy and angiodysplasia of upper and lower GIT. However, duodenal ulcer was significantly more common in the control group without renal disease. Incidence of Helicobacter Pylori infection was low in both groups.

[Sleep disorders in patients treated with continuous ambulatory peritoneal dialysis]

BACKGROUND

A lot of patients with end stage renal disease with the necessity of renal replacement therapy have some sleep problems. The aim of this study was to get basic information about the sleep of patients treated with continuous ambulatory peritoneal dialysis (CAPD), mainly their subjective view on their sleep, including comparison with hemodialyzed patients (HD).

METHODS

All patients treated with continuous ambulatory peritoneal dialysis in two dialysis centres were given a simple questionnary containing 20 questions concerning sleep. It was filled in by all these patients--25 patients (mean age 58.1 years)--12 men and 13 women. Data obtained from 103 hemodialyzed patients from the same two-dialysis centres were used for comparison (mean age 60.4 years)--61 men and 42 women (the same questionnary).

RESULTS

40% of CAPD patients regard their sleep as bad. Thirty six percent of patients have problems with falling asleep, 32% awake three times or more during the night and 28% snore or have some breath problems. CAPD patients feel more frequently tired after the night (32% vs. 18.4% HD), more patients sleep during the day (64% vs. 5.15% HD) and fewer patients feel restlessness of legs (36% vs. 45.6% HD). These differences are not statistically significant.

CONCLUSION

Occurrence of sleep disorders and their characteristics in patients on CAPD is similar to that in hemodialyzed patients.

[The calciphylaxis syndrome as a complication of chronic kidney failure. 6 case reports and literature review]

Calciphylaxis is a rate complication of unknown pathogenesis in patients with end stage renal disease. It is characterized by calcification of tunica media of small arteries associated with intimal fibrosis and thrombus formation which leads to the development of skin and subcutaneous tissue necrosis. Superinfection of skin lesions is a common consequence of this syndrome which may lead to the sepsis. The prognosis of this condition in serious. We performed a retrospective study of 6 subjects (4 men and 2 women) in the age of 35 to 59 years. We followed the parameters of calcium-phosphate metabolism, presence of calciphylaxis risk factors and the effect of parathyreoidectomy. Five patients were on hemodialysis, one had a kidney transplant. Skin and subcutaneous tissue necrosis were present in all subjects. The serum levels of parathormone were either high, normal or low, levels of calcium were normal or slightly elevated and phosphate levels were high or normal. Calcium was substituted before calciphylaxis development in 5 patients, calcitriole in 3 of therm. Five patients underwent parathyroidectomy. Three patients died (all of sepsis), one patient had the lower into amputation for infected lesions and the remaining two achieved regression. Our findings do support the hypothesis that calcium and calcitriole administration participates in development of calciphylaxis. Fatal prognosis of the once infections skin lesions was also proved.