Adenine reutilization as a cause of increased ATP concentration in erythrocytes of patients with chronic renal failure

Abnormalities of adenine nucleotide metabolism are observed in erythrocytes of patients with chronic renal failure (CRF) and the elevated ATP concentration is the most impressive one. In humans, adenine and/or adenosine reutilization is the only source of purine moiety used to erythrocyte adenine nucleotide synthesis. In the present study we have focused on the role of adenine as a substrate for the intraerythrocyte ATP production. 10 patients with CRF and 10 healthy volunteers (control group) were included into the study. Using HPLC, the measurements were performed in plasma and erythrocyte extracts. We observed a few fold higher adenine concentration in both plasma and erythrocytes of patients with CRF when compared with control group. There was also elevated an intraerythrocyte ATP concentration in the studied group of patients. Moreover, we have found a positive correlations between a) plasma creatinine concentration and plasma adenine concentration, b) plasma creatinine concentration and erythrocyte adenine concentration, c) plasma adenine concentration and intraerythrocyte ATP concentration. It appears that increased adenine reutilization could be a principle reason of the increased ATP synthesis in erythrocytes of patients with CRF.     

Renal replacement therapy results in correction of plasma and erythrocyte adenine nucleotide abnormalities in patients with chronic renal failure

High concentration of intraerythrocyte ATP is a common phenomenon in patients with chronic renal failure (CRF). It is likely that this is a result of increased plasma concentration of adenine--one of purine moiety donors which is necessary for ATP synthesis. In the present study we monitored changes of both adenine and intraerythrocyte ATP concentration during renal replacement therapy. We have also estimated the influence of erythropoietin treatment. 4 groups of patients were included into the study: 22 patients with CRF, 22 patients on maintenance hemodialysis treatment (11 patients with EPO therapy), 19 patients after kidney transplantation (7 patients with insufficiency of transplanted kidney) and 26 healthy volunteers served as a control group. The measurements were performed in plasma and erythrocyte extracts using HPLC. Significant decrease of high plasma adenine concentration was observed after both HD session and successful kidney transplantation, however the achieved values were still higher than in healthy volunteers. Kidney transplantation resulted in a permanent decrease of plasma adenine concentration, but along with the deterioration of transplanted kidney function, the plasma adenine concentration reincreased. Also, it started to increase right after HD session had ended. On the other hand, the intraerythrocyte concentration of adenine and ATP after successful kidney transplantation and single HD session came back to normal values. Also in this case, along with the deterioration of transplanted kidney function, both studied parameters reincreased. We have not observed any significant influence of erythropoietin treatment on studied adenine nucleotide concentration in hemodialysis patients. The present study confirms the strong interrelationship between the adenine nucleotide metabolism abnormalities and the advancement of renal failure. The abnormalities intensify along with the disease progression and the renal replacement therapy results in partial their correction.     

Gender differences in rat neuropathic pain sensitivity is dependent on strain

It is well recognized that gender differences play a major role in pain sensitivity, pain report, analgesic efficacy and prevalence of certain chronic pain disorders. In the present study we sought to determine whether male or female rats of two different outbred strains (Sprague-Dawley and Holtzman) experienced differential pain sensitivity after the same mononeuropathy lesion. Following baseline mechanical allodynia testing, rats of each sex and strain underwent an L5 spinal nerve transection. Mechanical allodynia using 2 and 12 g von Frey filaments was assessed at days 1, 3, 5, 7, and 10 post surgery. There were no statistically significant differences in allodynia between gender in the Holtzman strain or between strains. However, mechanical allodynia was significantly greater in female Sprague-Dawley rats as compared with males following a spinal nerve transection. These data suggest that the choice of rat gender and strain should be considered in experimental neuropathic pain studies, especially in the assessment of potential analgesics.     

Neurologic complications in Wegener's granulomatosis

Nervous system involvement is relatively frequent in Wegener's granulomatosis (WG). It may be difficult to differentiate between the primary central nervous system involvement and complications secondary to concomitant arterial hypertension, renal insufficiency and iatrogenic effects of immunosuppressive therapy. The crucial role in the assessment of intracranial pathology may be ascribed to the diagnostic imaging techniques: magnetic resonance imaging (MRI), computed tomography (CT) and cerebral blood flow imaging utilising the single photon emission computed tomography (SPECT). SPECT may prove superior sensitivity to MRI. It may be especially useful in differentiating central nervous system involvement in WG with secondary changes of other origin.     

Analysis of a rapid, simple, and inexpensive technique used to obtain platelet-rich plasma for use in clinical practice

The use of platelet-rich plasma (PRP) has become more generally accepted, and implant dentists are using PRP more frequently to promote the healing of oral surgical and/or periodontal wounds. Critical elements of PRP are thought to be growth factors contained within the concentrated platelets. These growth factors are known to promote soft-tissue healing, angiogenesis and osteogenesis. We present a rapid, simple, and inexpensive methodology for preparing PRP using the Cliniseal centrifuge method. This study demonstrates that platelets are concentrated approximately 6-fold without altering platelet morphology. Further we demonstrate that key growth factors, platelet-derived growth factor BB (PDGF-BB), transforming growth factor B (TGF-B1), vasculature endothelial growth factor (VEGF), and epidermal growth factor (EGF) are present in comparable or higher concentrations than those reported with the use of other techniques. Prolonged bench set time (>3 hours) after centrifugation resulted in decreased concentration of TGF-B1 but not decreased concentration of PDGF-BB, VEGF, or EGF. This study confirms the molecular aspects of PRP obtained using this inexpensive and efficient methodology.     

Treatment of End-Stage Renal Disease in Central and Eastern Europe: Overview of Current Status and Future Needs

The situation of end-stage renal disease (ESRD) patients in central and eastern Europe was very poor for many years during the so called socialistic era. Economical and political liberation resulted in the significant growth of renal replacement facilities in this region. The number of hemodialysis units increased significantly (56%) during the period 1990–1996, and the number of patients treated with this modality has risen by 75%. More dramatic progress was achieved in peritoneal dialysis. The number of units performing this method of renal replacement therapy (RTT) increased by 277% and the number of patients by more than 300%. Not only quantitative but also qualitative changes were observed. More modern hemodialysis machines installed in the vast majority of units allow for the performance of bicarbonate dialysis, controlled ultrafiltration, and sodium profile modeling. Also, a wider choice of biocompatible dialyzers has become available during the last few years. The number of centers performing renal transplantation has increased significantly, but the number of renal transplants has not followed this progress. Despite all the progress, further development of all RRT methods is necessary to achieve acceptance rates comparable to those observed in developed countries.     

Effectiveness of antihypertensive treatment in patients with chronic kidney disease.

OBJECTIVE: Hypertension is closely associated with chronic kidney disease (CKD) and is one of the main factors of progression of CKD. Early detection of CKD allows introducing a therapy that slows the progression of CKD. SETTING: A prevalence of hypertension and effectiveness of its treatment were assessed during the accomplishment of the Program for Early Detection of CKD in Poland (PolNef). RESULTS: In 456 of a total of 2476 participants of PolNef program (269 females, 187 males), CKD was recognized. Diagnosis of CKD was made according to classification proposed by K/DOQI and KDIGO. Estimated glomerular filtration rate (eGFR) from serum creatinine, albuminuria and ultrasound examination were the main diagnostic tools. Hypertension was defined on the basis of actual antihypertensive treatment or on the basis of medium value (> or = 140 and/or > or = 90) of three separate measurements of blood pressure. Frequency of hypertension and effectiveness of its treatment, frequency of overweight and obesity, microalbuminuria, and abnormalities in ultrasound examination of urinary system were studied. CONCLUSION: Of the CKD population, 68% were hypertensive, 21% remained without antihypertensive medication, and 22% on medication were effectively treated. Kidney insufficiency with eGFR below 60 ml/min/1.73 m2 was recognized in 9% of CKD population. Also, 63% of women and 39% of men without hypertension had normal body mass compared to 19% of people with CKD and hypertension. Microalbuminuria was found in 51% of women and 66% of men with CKD and hypertension. Increased echogenicity of kidney and simple cysts were detected significantly more often in hypertensive patients.     

Algorithm to manage highly sensitized kidney transplant recipients in Poland

Objective

Programs for immunized transplant recipients are essential to achieve graft survivals comparable to those of non-immunized recipients. The threshold in Poland is a PRA by the complement-dependent cytotoxicity (CDC) method greater than 50%, which includes approximately 3.8% of the patients. At the same time the United Network for Organ Sharing there recipients represent approximately 16% of the waiting list in the United Network for Organ Sharing (UNOS). The underestimation of the immunized group in Poland may be due to differences in laboratory techniques to assess alloantibodies.

Materials and methods

This study investigated 55 potential recipients with a PRA by CDC > 50%. We used the following algorithm to assess their immunization: Luminex screening test for an HLA antibody; specificity assessed with Luminex Single Antigen, vPRA (evaluation of immunization of the patient); and analysis of acceptable HLA incompatibilities (HLAMatchmaker).

Results

All recipients were positive class I anti-HLA antibodies and 94.5% were positive for class II. For the groups of subjects with PRA-CDC from 50% to 79% versus those greater than 80%, the average values of PRA-CDC were 62.2% and 89.5%, respectively. The virtual PRA results for these groups were 95.7% and 97.2%, respectively. In addition, anti-HLA-Cw, anti-DQ and anti-DP antibodies were detected in 77%, 84%, and 51% of recipients, respectively. Immunized recipients reported to the next transplant were characterized by the antibodies against mismatch only in 68%. For all potential recipients, additional acceptable non-compliance was determined with HLAMatchmaker: 152 specificity for locus A and 252 for locus B.

Conclusions

Evaluation of immunization status of recipient candidates should be routinely performed using tests to assess class and specificity as well as level of alloantibodies to enable determination of a safe potential donor. As a routine test, PRA-CDC underestimates the number of highly immunized patients. Exclusion from the list of patients with repeated non-compliance is a simplification, which reduces their chance for transplantation.