Peritoneal dialysis patient survival: a comparison between a Swedish and a Korean centre.

BACKGROUND: Dialysis patient mortality remains high, and this high mortality may be due to many factors. In peritoneal dialysis (PD) patients, old age, co-morbid diseases, malnutrition, low residual renal function (RRF) and a high peritoneal transport rate have been shown to influence survival, but the relative importance of these factors may differ between different patient populations. Besides, centre practice patterns may differ between centres and may influence patient survival. In addition, the literature suggests that dialysis patient survival may be better in Asian than in Caucasian patients. METHODS: The influence of centre and patient characteristics on patient survival was investigated in 132 Korean and 106 Swedish incident PD patients, who underwent initial biochemical measurements and assessment of adequacy of dialysis, nutritional status, RRF and peritoneal transport characteristics. RESULTS: At the start of PD, Korean patients had a higher prevalence of diabetes, peritoneal Kt/V(urea), peritoneal creatinine clearance and peritoneal fluid removal, and lower body mass index, RRF and dialysate to plasma creatinine concentration ratio (D/P Cr) compared with Swedish patients. Significantly more patients from Korea were placed on temporary haemodialysis before PD (100 out of 132) when compared with Swedish patients (21 out of 106). During the follow-up, there was a significantly higher rate of transfer to other units in Korea and a significantly higher rate of kidney transplantation in Sweden. On Kaplan-Meier analysis, overall patient survival did not differ and relative risk for death was also not different between the two centres even after adjustment for age, diabetes, cardiovascular disease, RRF and D/P Cr. On Cox proportional hazards multivariate analysis, age, diabetes, RRF and D/P Cr were found to be independent predictors of mortality in the combined cohort of patients. While age, diabetes and D/P Cr were independent predictors of mortality in Korean patients, age and RRF independently predicted mortality in Swedish patients. CONCLUSION: Although there were significant differences in centre and patient characteristics, we were unable to confirm a survival advantage for Korean over Swedish PD patients. The results of this study suggest that the reported difference in survival between Asian and Caucasian dialysis patients may have been due, in part, to differences in centre and patient characteristics rather than to race as such. The genetic influence on patient characteristics remains, however, to be elucidated.     

Femoral component fixation with and without intramedullary plug A 6-year follow-up

A total of 113 patients underwent a cemented total hip replacement (THR) operation involving femoral component fixation either without the use of a distal intramedullary plug (n = 57, group 1) or with the plug (n =56, group 2). We studied the femoral component fixation radiographically at on average 6 years after THR. The cement coating was assessed as technically good in 86% and 95% of groups 1 and 2, respectively. There was radiographically diagnosable loosening of the femoral component at the follow-up in 25 cases in which stems were inserted without the intramedullary plug, and in 6 cases in those with the plug (P < 0.0008), and the mean subsidence of the femoral component was 5 mm in group 1 and 1.5 mm (P < 0.0003) in group 2, respectively. Osteolytic changes around the femoral component were noticed in both groups in equal numbers and with no statistical difference. The use of a distal intramedullary plug in the cementation of the femoral stem results in a better cement coating, reduces femoral component subsidence and ameliorates the loosening rates.     

Leg length inequality after total hip arthroplasty

Leg length inequality (LLI) in 55 patients with cemented total hip arthroplasty (THA) was measured from weight-bearing anteroposterior (AP) hip radiographs. The mean radiologic LLI was 8.7 mm in unilateral and 11.6 mm in bilateral THA, differing significantly from the clinically measured values (2.8 mm and 4.2 mm, respectively). LLI as a cause of aseptic loosening and unexplained pain warrants investigation in THA patients.     

Human fetal dopamine neurons grafted into the striatum in two patients with severe Parkinson's disease. A detailed account of methodology and a 6-month follow-up

By using stereotaxic surgical techniques, ventral mesencephalic tissues from aborted human fetuses of 8 to 10 weeks' gestational age were implanted unilaterally into the striata in two patients with advanced Parkinson's disease. The patients were treated with a cyclosporine, azathioprine, and steroid regimen to minimize the risk for graft rejection. They were examined for 6 months preoperatively and 6 months postoperatively and continued to receive the same doses of antiparkinsonian medication. There were no significant postoperative complications. No major therapeutic effect from the operation was observed. However, in the clinical tests, both patients showed small but significant increases of movement speed for repeated pronation-supination, fist clenching, and foot lifting. The rate of walking also increased in the one patient tested. For both patients, there was an initial worsening postoperatively, followed by improvement vs preoperative performance at 1 to 3 months. Both patients also showed significant improvement in the magnitude of response to a single dose of levodopa (L-dopa), but there was no increase in the duration of drug action. The motor readiness potential increased in both patients postoperatively, primarily over the operated hemisphere. Neurophysiological measurements also showed a more rapid performance of simple and complex arm and hand movements on the side contralateral to transplantation in one patient at 5 months postoperatively. Positron emission tomography demonstrated no increased uptake of 6-L-(18F)-fluorodopa in the transplanted striatum at 5 and 6 months. Taken together, these results suggest that the fetal nigral implants may have provided a modest improvement in motor function, consistent with the presence of small surviving grafts. Although our results support further scientific experimentation with transplantation in Parkinson's disease, widespread clinical trials with this procedure are probably not warranted at this time.     

Cyclosporin A in Fat Emulsion Carriers: Experimental Studies on Pharmacokinetics and Tissue Distribution

Abstract: In the commercially available intravenous formulation of Cyclosporin A (Sandimmun®), polyoxyethylated castor oil (Cremophor®EL) is used as a solubilizing agent. We have recently reported that the acute nephrotoxic effect of this preparation was alleviated by replacing Cremophor®EL with a soybean oil-based fat emulsion in a rat model. To further explore the potential of fat emulsions as carriers for cyclosporin A, data on the in vivo pharmacokinetics and tissue distribution are required. In this study in pigs, the pharmacokinetics of soybean oil-cyclosporin A was compared to that of Sandimmun®. The two formulations seemed bioequivalent, as there were no significant differences in the systemic clearances, volumes of distribution or elimination half-lives. Moreover, the tissue distributions of soybean oil-cyclosporin A and Sandimmun® were compared in rats. These studies also included two additional lipid-based carriers: one based on iodized ester of poppy seed oil and the other on a liposomal preparation. The tissue distributions were found to be similar regardless of the carriers used. Fat emulsion carriers seem to offer possibilities for preparing better tolerated intravenous formulations of cyclosporin A while maintaining the same characteristics concerning pharmacokinetics and tissue distribution.     

Stabilization of an inserted tricalcium phosphate spacer enhances the healing of a segmental tibial defect in sheep

The effect of inserting a tricalcium phosphate (TCP) spacer stabilized by a rigid or non-rigid fixation technique on the healing of segmental tibial defects of critical size was established. The osteotomized tibiae, 11 with and 8 without TCP spacers, were fixed by an external circular device in 11 mature sheep and by plates in 8 mature sheep, respectively. Healing was evaluated roentgenographically 16 weeks after the operation. Compared with the defects without TCP spacers, enhanced stability and healing were observed in the defects with TCP spacers under an identical external fixation. Furthermore, a significantly higher incidence of healing was obtained with plate fixation than with external device fixation in the TCP-implanted defects (P < 0.04). An abundant bridging callus was roentgenograpically demonstrated in most of the healed defects, but none in the unhealed defects. The TCP spacer with its mechanical integrity enhances the stability of external fixation, and the stable immobilization provided by rigid fixation is essential for osteoconduction of an inserted TCP spacer in the healing of segmental diaphyseal defects in sheep.     

Response of bone marrow stroma cells to demineralized cortical bone matrix in experimental spinal fusion in rabbits

The effect of autogeneic bone marrow (BM) cells and allogeneic demineralized bone matrix (DBM), alone or combined, as transplantation materials was studied in an experimental posterior thoracic spinal fusion model in rabbits. Transplantation of composite grafts composed of BM and DBM showed the first signs of fusion between two spinal segments after four weeks, reaching 86% after 20 weeks. Late fusion results achieved with DBM alone were similar. The capacity of BM per se to build up a spinal fusion was insignificant. Calcified tissue, documented roentgenographically, was shown to develop locally with time, and the earliest bridging of an interspace was noted after four weeks. Histologically, formation of new bone and cartilage was observed after two weeks, showing mature lamellar bone formation between thoracic segments after 20 weeks. Furthermore, increased 45Ca activity was still observed in the fused tissues after 20 weeks. Although, with grafting materials used, this model for experimental spinal fusion gave promising results, further investigations with other fusion techniques could give still better effects.