PubMed Health⌕ Search

Biomedical subjects

T Tsobanelis

Publications and source records attributed to T Tsobanelis.

10 recordsLinked to original sources
PubMed1995

Differences in calcium kinetic pattern between CAPD and HD patients.

To assess the effect of different dialysis modalities on calcium turnover, we studied 57 patients on maintenance hemodialysis treatment (HD) and 38 patients on continuous ambulatory peritoneal dialysis (CAPD) with tracer kinetic studies using two calcium isotopes (45Ca by mouth and 47Ca intravenously). The two groups were comparable in age, sex and prevalence of diabetes. The groups did not differ in their serum concentrations of intact parathyroid hormone (iPTH), calcium, inorganic phosphate and 1,25-dihydroxyvitamin D. 25-hydroxy-vitamin D and alkaline phosphatase were found to be significantly higher in HD patients. Despite these similarities, CAPD patients showed a significantly lower calcium kinetic response as measured by calcium retention and plasma calcium efflux than HD patients. Mean calcium retention was 39.5% in HD patients compared to 31.2% in the CAPD group (p < 0.05). Plasma calcium efflux was significantly lower in the CAPD group (2.7 vs 3.2 respectively; p < 0.01). iPTH correlated with calcium retention and plasma calcium efflux in HD patients (r = 0.69 and r = 0.67 respectively). In CAPD patients, the correlation coefficient between iPTH and calcium retention was markedly lower (r = 0.54), whereas no correlation was found between iPTH and plasma calcium efflux (r = 0.08). In addition, the slope of the correlation curve were higher in HD patients (p < 0.01 and p < 0.001, respectively), indicating a better response of this patient group to the action of parathyroid hormone. Our data are in accordance with recently published results showing that the dialysis modality has a major impact on bone turnover and on the progression of uremic bone disease. It has been shown that CAPD is an independent risk factor for the development of the adynamic form of renal bone disease. This finding may be explained by the lower response of calcium turnover to the action of PTH as shown here with tracer kinetic studies.

Adult↗
PubMed1993

Decrease in peritonitis rate by integrated disconnect system in patients on continuous ambulatory peritoneal dialysis.

The prevention of peritonitis is of major concern for successful long-term continuous ambulatory peritoneal dialysis (CAPD) treatment. The effect of a Y-system on peritonitis incidence and patient morbidity was observed in a comparative, retrospective single-center analysis over a period of 5 years. The integrated disconnect system prolonged the peritonitis-free period from 1:11 patient-months, observed with the conventional system, to greater than 1:50 patient-months. The rate of hospitalization was reduced by 45%.

Humans↗
PubMed1992

Effect of recombinant human erythropoietin on iron balance in maintenance hemodialysis: theoretical considerations, clinical experience and consequences.

Iron deficiency is the main reason for insufficient response to rEPO therapy. Serum ferritin and transferrin saturation give valuable information on storage iron and iron transport. Iron demand for correction of anemia can easily be estimated after HCT (vol%) x average blood volume (dl) = mg iron. Inadequate iron supply of the bone marrow in the presence of sufficient storage iron in the RES develops frequently under rEPO, possibly explaining the improvement of bone marrow response to rEPO by concomitant intravenous iron supply. The reasons of functional iron deficiency are still speculative.

Anemia↗
PubMed1986

Cancer in renal transplant recipients.

The incidence of cutaneous malignancies and non-Hodgkin lymphomas is higher in transplant recipients than in the general population. From 1968 to 1984, 200 kidney grafts were transplanted to 180 patients with end-stage renal disease. All patients were on azathioprine (Aza) and prednisolone. In selected cases ALG and/or small doses of CsA were added. Six patients developed malignant tumors (two Kaposi sarcoma, one squamous cell and one squamous plus basal cell skin cancers, one reticulosarcoma, and one glioma). Mean age of patients was 43 years (range 35-53 years), and mean time of appearance of the tumor after transplantation was 62 months (range 24-98 months). Treatment consisted of reduction of the dosage of Aza, surgical removal or local irradiation of the tumor, and chemotherapy in case of systemic involvement (two cases). Three patients died (one Kaposi sarcoma, one reticulosarcoma, and one glioma) 3 to 6 months after diagnosis, and all three had previously been on high doses of Aza. The remaining three cases (one Kaposi) were cured by stopping or decreasing Aza, by excision, and/or local irradiation of the tumor. It seems that late diagnosis and Aza in high dosage are the main factors leading to the rapid dissemination of the initially localized tumor.

Adult↗
PubMedDate not supplied

Altered pattern of calcium kinetics in hemodialysis patients after parathyroidectomy.

Six HD patients with severe secondary hyperparathyroidism (sHPT) underwent studies of calcium kinetics prior to and after parathyroidectomy (PTX) with autotransplantation. Postoperatively, patients received vitamin D and calcium supplementation. Before PTX, a markedly elevated bone turnover was found, with increased fluxes of calcium from plasma into the exchangeable calcium pool. This pool was three times larger than normal, indicating a high risk of extraosseous calcifications. Despite a marked fall in parathyroid hormone (iPTH) levels after PTX, bone cell activity was maintained, as indicated by elevated values for Ca retention. Although Ca efflux from plasma into other compartments of the exchangeable pools remained above normal, the size of the total exchangeable calcium pool markedly decreased after PTX, indicating that PTX with autotransplantation, followed by vitamin D therapy, can normalize bone turnover and shift the balance of calcium flux towards mineralized bone. Reduction in the exchangeable calcium pool may explain the clinical finding that extraosseous calcifications regress in some patients after PTX.

Adult↗
PubMedDate not supplied

Calcium kinetic studies in patients on CAPD: improvement of secondary hyperparathyroidism without concomitant improvement of calcium turnover.

OBJECTIVE: An association between the development of low turnover osteopathy and the form of dialysis treatment, that is, continuous ambulatory peritoneal dialysis (CAPD), has been described. To examine the effect of a year-long CAPD treatment on calcium (Ca) turnover, 12 patients were studied prior to and one year after initiation of CAPD treatment with a dialysate calcium of 1.75 mmol/L. DESIGN: A prospective analysis. SETTING: Academic teaching hospital dialysis unit. PATIENTS: Twelve patients with an average age of 54.8 years (range: 23-76 years) at commencement of dialysis and after 13 months of CAPD treatment. MEASUREMENTS: Calcium kinetic studies were performed using two calcium isotopes: 45Ca as an oral tracer and 47Ca as an intravenous tracer. Measurements of plasma and whole body activities were performed over a four-week period. From these measurements, kinetic parameters describing calcium turnover in different compartments were studied. These measurements were repeated after a mean time of 13.4 months. Patients were not treated with vitamin D, but received aluminum- and calcium-containing phosphate binders, in order to keep inorganic phosphate below 2.0 mmol/L and calcium within the normal range. RESULTS: After one year on CAPD, serum levels of calcium increased from 2.2 mmol/L to 2.35 mmol/L. Inorganic phosphate also increased from 1.4 mmol/L to 1.9 mmol/L, despite increased use of oral phosphate binders. Serum levels of intact parathyroid hormone (IPTH) decreased from 51.2 pmol/L to 28.3 pmol/L. Alkaline phosphatase did not change, nor did serum levels of vitamin D. Despite improvement of serum IPTH levels and better control of serum calcium, the kinetic parameters describing calcium turnover in the different calcium pools did not improve. In addition, the calcium retention of bone remained below normal range and did not rise. Perhaps more importantly, the relationship between Ca efflux and Ca retention did not change. While Ca retention remained low, plasma Ca efflux was normal. This imbalance was seen at the beginning of CAPD and did not change under CAPD. CONCLUSION: These data demonstrate that, after one year of CAPD treatment without vitamin D treatment, calcium turnover did not improve, despite a significant fall in serum IPTH levels. Studies on a larger number of patients are warranted to verify these results.

Adult↗