Bayesian parameter estimation for phosphate dynamics during hemodialysis

Hyperphosphatemia in patients with renal failure is associated with increased vascular calcification and mortality. Hemodialysis is a conventional treatment for patients with hyperphosphatemia. Phosphate kinetics during hemodialysis may be described by a diffusion process and modeled by ordinary differential equations. We propose a Bayesian model approach for estimating patient-specific parameters for phosphate kinetics during hemodialysis. The Bayesian approach allows us to both analyze the full parameter space using uncertainty quantification and to compare two types of hemodialysis treatments, the conventional single-pass and the novel multiple-pass treatment. We validate and test our models on synthetic and real data. The results show limited identifiability of the model parameters when only single-pass data are available, and that the Bayesian model greatly reduces the relative standard deviation compared to existing estimates. Moreover, the analysis of the Bayesian models reveal improved estimates with reduced uncertainty when considering consecutive sessions and multiple-pass treatment compared to single-pass treatment.

THE ROLE OF OXIDATIVE STRESS IN PATIENTS WITH CHRONIC KIDNEY DISEASE

OBJECTIVE

The aim: To study the role of oxidative stress in patients with chronic kidney disease.

PATIENTS AND METHODS

Materials and methods: By evaluating MDA and GSH in the serum, we tried to find out how oxidative stress affects CKD patients with end-stage renal dysfunction (ESRD). The study included 90 patients with ESRD disease whom were under hemodialysis treatment, and 30 healthy control people.

RESULTS

Results: Urea, creatinine, and MDA levels were noticeably greater in ESRD patients compared to controls, but GSH levels were noticeably lower. In conclusion, oxidative stress can cause more problems to these patients by its involvement in the appearance of metabolic and cardiovascular diseases.

CONCLUSION

Conclusions: Furthermore, GSH was reduced significantly in ESRD patients and associated negatively with the level of MDA. This indicates the strong involve¬ment of antioxidants, especially GSH, in the development of oxidative stress in ESRD patients.

[Discriminant analysis for prognosis of thrombophilia development in patients with stage VD CKD]

OBJECTIVE

Introduction: Chronic kidney disease (CKD) is a critical medical and social problem. Every year 7& of such patients require renal replacement therapy associated with one of the most life threatening complications - disturbed hemostasis and development of thrombophilic conditions which are typical of complicated comorbid diseases. Prediction of potential thrombogenesis in that category of patients requires multidimensional approach, including comprehensive laboratory investigation of hemostasis on the one hand, and creation of mathematical model based on thrombophilia predictors on the other. The aim: To create the prognostic model of thrombophilia development in patients with stage VD CKD, treated by long term hemodialysis, using discriminant function analysis and biochemical variables of hemostasis.

PATIENTS AND METHODS

Materials and methods: Of 12 hemostatic parameters (factors of influence), studied in 85 patients with stage VD CKD, two groups of variables were formed - pre-thrombosis (soluble fibrin (sF), D-dimer (D-d), protein C (PC)) and post-thrombosis (D-d, H (maximal end turbidity of plasma clot) and pC).

RESULTS

Results: Linear discriminant functions (two models), based on two groups of variables, demonstrated rather high coincidence rate (92.2÷93.5&) in group distribution. The patients referred to those with thrombotic complications, 100& matched the prospective (for a year) study.

CONCLUSION

Conclusions: By the results of correlation analysis, the most significant molecular biochemical hemostatic parameters (sF, D-d, pC, H) were determined. Using definite biochemical parameters, discriminant models complementing each other and having high prediction (р <0.0001) of thrombophilic states in 92.2-93.5& of cases, were developed for patients with stage VD CKD, treated by long term hemodialysis.

[Toxic alcohol poisonings]

Accidental or intentional poisonings with ethylene glycol or methanol constitute a serious toxicological problem in many countries. Both alcohols are quickly metabolized by alcohol dehydrogenase to toxic metabolites responsible for high anion gap severe metabolic acidosis and profound neurological, cardiopulmonary, renal disturbances and death. In the early period, the competing inhibition the alcohol dehydrogenase with ethanol or fomepizol may successfully prevent the formation of the toxic metabolites. Once severe acidosis develops an emergency hemodialysis is required.