Objective To evaluate the efficacy and safety of 7.5% icodextrin peritoneal dialysis solution for once-daily long dwell exchange in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Methods A prospective, multicenter, randomized, double blind, parallel controlled study was conducted for 5 weeks in 201 CAPD patients (96 male, 105 female) with mean age (56.1±13.7) years old. These patients were from 7 centers with 98 allocated to the icodextrin group and 103 to the dextrose group randomly. Patients in the icodextrin group were given 7.5% icodextrin and those in the dextrose group were given 2.5% Dianeal?誖PD-2 or PD-4 for the nocturnal long dwell exchange while the diurnal dialysis remained unchanged. During the 4- week treatment, patients were tested every other week for net ultrafiltration, peritoneal creatinine and urea nitrogen clearance after the long dwell. Other laboratory tests and adverse events were recorded. Results Compared to the dextrose group, the net ultrafiltration was up-regulated more significantly from the baseline in the icodextrin group [(342.53±25.79) ml vs (73.59±24.09) ml, P<0.01]. Episodes of net ultrafiltration less than 0 ml in the icodextrin group were much less than those in the dextrose group. Similarly, the mean difference between groups for change from baseline for peritoneal creatinine and urea nitrogen clearance was much higher[（428.02±53.14） ml/12 h vs （－99.79±50.19） ml/12 h， P<0.01； （306.43±53.31） ml/12 h vs (－116.02±51.05） ml/12 h， P<0.01， respectively] in the icodextrin group. In the icodextrin group, there was a decrease in serum sodium and chloride compared with baseline (P<0.01). Serum amylase activity decreased from (87.04±48.01) U/L to (21.59±13.58) U/L(P<0.01). Cholesterol in the icodextrin group was lower than baseline (P<0.05). There was no significant difference between two groups for the incidence and severity of adverse events. Conclusion 7.5% icodextrin is a safe and effective peritoneal dialysis solution for once-daily long dwell exchange in CAPD patients.

Objective To observe the influence of daily protein intake (DPI)（0.8≤DPI≤1.0 g&#8226;kg-1&#8226;d-1 or 1.0<DPI≤1.2 g&#8226;kg-1&#8226;d-1） on early nutritional status in peritoneal dialysis (PD) patients. Methods New PD patients from June 2004 to June 2005 with DPI level between 0.8 g&#8226;kg-1&#8226;d-1 and 1.2 g&#8226;kg-1&#8226;d-1 on the first month of peritoneal dialysis were enrolled in the study. Nutritional status and nutrition-related factors were assessed on the month 1，3 and 6 after PD. Hemoglobin(Hb), serum albumin(Alb), urea nitrogen (BUN) and serum creatinine (Scr), direct anthropometry [arm circumference(AC), triceps skin-fold thickness(TSF), arm muscle ciucumference(AMC)] and lean body mass(LBM) were examined as nutritional indices. Nutrition-related factors including DPI and daily energy intake (DEI), dialysis adequacy (total and renal Kt/V, total and renal Ccr), metabolic acidosis(CO2CP), inflammation (serum CRP), volume status [extracellular water(ECW), intracellular water(ICW), total body water(TBW), calculated ECW/TBW and normalized ECW] were analyzed respectively. Results Eighty-two PD patients were included in the study. Thirty-nine patients were 0.8 g&#8226;kg-1&#8226;d-1≤DPI≤1.0 g&#8226;kg-1&#8226;d-1 and the other 43 patients were 1.0 g&#8226;kg-1&#8226;d-1<DPI≤1.2 g&#8226;kg-1&#8226;d-1. There were significant differences of baseline DPI and DEI levels, DPI on the 3rd month, DPI and DEI on the 6th month between two groups (P<0.05). The average tKt/V, rKt/V, tCcr, rCcr, CRP, CO2CP, ECW/TBW and nECW were not significantly different between two groups during the six months of PD（P>0.05）. All the patients maintained good nutritional status. Serum levels of Alb, BUN, Scr, Hb, AC, AMC, TSF and LBM in patients on the 1st, 3rd and 6th month of PD were not significantly different between two groups（P>0.05）. Conclusions New PD patients can maintain good nutrition on the early stage of dialysis whether their DPI levels are 0.8 g&#8226;kg-1&#8226;d-1≤DPI≤1.0 g&#8226;kg-1&#8226;d-1 or 1.0 g&#8226;kg-1&#8226;d-1<DPI≤1.2 g&#8226;kg-1&#8226;d-1. All nutritional indices are not significantly different between two groups in the first six months.

Objective To explore the change of angiotensinⅡ(AngⅡ) and renin and its role in peritoneal fibrosis of continuous ambulatory peritoneal dialysis (CAPD) patients. Methods The levels of AngⅡ and renin in effluent and serum of CAPD patients were investigated by radioimmunoassay. A reproducible model for culture of rat peritoneal mesothelial cell was established by isolating from rat omenta by enzymatic disaggregation. Levels of mRNA expression of angiotensinⅡ type 1 receptor (AT1) and angiotensin-converting enzyme(ACE) in rat peritoneal mesothelial cells (RPMC) were detected with real-time PCR when stimulated by different concentration of D-glucose or mannitol. Concentration of AngⅡ in supernatant of RPMC was tested at the same time by radioimmunoassay. Levels of mRNA and protein expression of transtorming growth factor β1(TGF-β1) and connective tissue growth factor (CTGF) in RPMC after the stimulation by different concentrations of AngⅡwere examined with real-time PCR and Western blot respectively, then TGF-β1 in supernatant was detected by ELISA. Results No renin was detected in effluent of CAPD patients. AngⅡ levels in the effluent of patients with peritonitis and long time dialysis patients(≥6 months) were (151.99±114.00) pmol/L and (14.17±41.50) pmol/L, which were 19 times and 6.5 times of normal CAPD [(7.98±12.69） pmol/L] and short time dialysis(＜6 months) [(2.18±5.62) pmol/L)] patients respectively（P<0.01, P<0.05）. Serum renin and AngⅡ concentration were (4.30±8.48) and (54.19±34.43) pmol/L,which were 4.06 times and 1.21 times of basal level respectively after 4 hours exposure to high glucose dialysis fluid(2.5%), while the base levels of renin and AngⅡ concentration were (1.06±6.0) pmol/L and (44.72±19.19) pmol/L respectively（P<0.01）. High D-glucose(2.5%) enhanced the expression of AT1, ACE mRNA in RPMC and AngⅡ protein in supernatant of RPMC, which were 2.61, 2.62 and 2.01 times of that of low D-glucose（0.3%）（P<0.05）. AngⅡenhanced TGF-β1 and CTGF expression of RPMC both in mRNA and protein levels. 100 nmol/L AngⅡ induced the expression of TGF-β1 mRNA and protein, which were 2.8 and 2.19 times of the control group（P<0.05）. 1000 nmol/L AngⅡ up-regulated the CTGF mRNA and protein expression, which were 4.48 and 2.82 times of the control group（P<0.05）. Conclusions Long time peritoneal dialysis and peritonitis activate renin angiotensin system (RAS) in CAPD patients. Peritoneal mesothelial cells play an important role in the activation of RAS. AngⅡ participates in the process of peritoneal fibrosis by up-regulating the expression of prefibrosis factors such as TGF-β1 and CTGF. RAS antagonist may be new target for prevention and treatment of peritoneal fibrosis.

Objective To explore the hemodynamic mechanism in the relation between volume status and blood pressure in peritoneal dialysis patients. Methods Fifty-one peritoneal dialysis patients were enrolled in this study. ECW, ICW and TBW were assessed by bioimpedance analysis and NECW was calculated after individual height in meters was taken into account. The mean value of NECW in each gender was used to define normal volume (NV:≤mean value) or high volume status (HV:＞mean value). All patients were thus divided into four groups: normotension with NV (NT-NV), normotension with HV (NT-HV), hypertension with NV (HT-NV) and hypertension with HV(HT-HV). The stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were measured through echocardiograms and their respective indices(SI, CI and TPRI) were calculated. Results The ECW, ICW and TBW in the NT-HV group and HT-HV group were higher as compared to the NT-NV and HT-NV groups (P<0.01). The TPR[（219.4±47.4） Pa&#8226;s&#8226;cm-3] and TPRI[（148.8±29.5） Pa&#8226;s&#8226;cm-1] in the HT-NV group were also significantly higher as compared to the other three groups. The SV, SI, CO and CI in the NT-HV group were not significantly different from those of the NT-NV group and HT-NV group. However, the SV and CO in the HT-NV group were significantly lower than those of the HT-HV group [SV:(58.3±8.4) ml vs (75.6±21.9) ml; CO: (4.03±0.70) ml/m2 vs (5.18±1.46) ml/m2, both P<0.05 ]. Conclusions The overlap in volume status between normotensive and hypertensive peritoneal dialysis patients is related to the significant difference in TPR and TPRI, but not in SV, SI, CO and CI. The normotensive patients with high volume status are characterized by lower TPR or TPRI, while the hypertensive patients with normal volume status are characterized by higher TPR or TPRI.

Objective To investigate the effects of variation and polymorphism of gene ACTN4 on primary focal segmental glomerulosclerosis (FSGS). Methods Eighty-two patients with primary FSGS were enrolled in the study, including 43 males and 39 females, ranging from 12 to 76 years old. Among these patients, 55 were diagnosed as nephrotic syndrome (NS). Seventy healthy volunteers were as control group. Genomic DNA was extracted from peripheral blood cells of primary FSGS patients and from hair of their parents. ACTN4 variation was analyzed by PCR and direct sequencing. Variation was matched with GenBank. Hair DNA of the parents with novel mutation was sequenced and alpha-actinin-4 expression in kidney tissue of the patients was examined by immunofluorescence. With single nucleotide polymorphism(SNP) loci, after Hardy-Weinberg equilibrium test, allele association and the frequencies of genotypes were analyzed, then genotypes and phenotypes were analyzed, including urine protein, serum albumin, blood pressure and serum creatinine. Results In this study, one heterozygous variation 184T>A with amino-acid substitution (Ser 62Thr) and one 5’UTR mutation 1-34C>T were detected, and both patients were diagnosed as non-NS FSGS. The above variation were not found in the control group. Matched with genbank, 1-34C>T and 184T>A might affect the transcription and translation of ACTN4 gene as well as alpha-actinin-4. No above variation were found in their parents’DNA and alpha-actinin-4 expression reduced significantly in patients’ kidney tissue(P<0.01). Additional 17 variation or SNP were also screened, including 6 novel variation, 2 novel SNP and 9 genbank reported SNP, without amino-acid substitution. Novel SNP 484+87C>G was associated with FSGS (Hardy-Weinberg equilibrium test, P>0.05; G frequence 0.085 vs 0.029, P<0.05), and there was significant difference in urinary protein excretion between wild genotype and mutated genotype (7.90±1.60 g/24 h vs 4.50±0.46 g/24 h, P<0.01). Conclusion Two heterozygous variation are found in exon 2 and 5’UTR in primary patients with FSGS, these variation may affect the ACTN4 transcription and alpha-actinin-4 translation. One SNP associated with FSGS is found. The ACTN4 variation may play an importent role in the pathogenesis of primary FSGS.

Objective To analyze the clinical characteristics of patients with type 2 diabetic nephropathy(DN) in Tibet area. Method Clinical data of 306 patients with type 2 diabetes mellitus (DM) in our hospital from may 2001 to october 2006 were retrospectively analyzed. Results Above 306 patients included 151 cases of DN and 155 cases of non-DN ,then the DN patients were divided into microalbuminuria group (n=30), clinical albuminuria group (n=84) and renal insufficiency group (n=37) by the urinary albumin level. As compared to non-DN group, urinary albumin, Scr, β2 microglobulin(MG) increased significantly in DN group（P<0.01）. Urinary albumin was positively correlated with both systolic pressure and blood β2 -MG（r=0.187, P<0.05; r=0.297, P<0.01）, but negatively correlated to glomerular filtration rate(GFR)（r=－0.287, P<0.01）. Patients in DN group had higher incidence of hypertension (60.27％）and higher blood pressure compared with non-DN patients（P<0.01）. In DN patients, 14 cases（9.27%） were suffered from uremia; 8 cases（5.30％） were dead among whom 5 died of uremia; 20 patients (13.25%) were complicated with diabetic retinopathy and 6 (3.97%) with cardiocerebrovascular diseases. Conclusions Significant increment of urinary albumin, blood pressure and β2-MG of blood and urine can be found in early stage of type 2 DN patients in Tibet area, meanwhile the GFR decreases obviously and complications are quite common and severe in late stage of DN.

Objective To investigate the expression and function of organic anion transporter(OAT) 1 and 3 after ischemia reperfusion injury（IRI） in rat kidney. Methods Rat renal ischemia reperfusion injury models were established and were sacrificed at day 1, 2, 4, 6 after injury. Renal OAT1 as well as OAT3 expression were analyzed by immunohistochemistry and Western blotting. P-aminohippurate (PAH) excretion was detected by capillary electrophoresis and net secretion of PAH was calculated. Results IRI operation resulted in severe renal tubules damage on day 1 with significantly increased serum creatinine level [(278.9±51.8) vs (41.4±4.6) μmol/L， P<0.01]. Compared with sham-operated rats, there was a significant increment in the expression of OAT1 and OAT3 in renal cortex homogenates and basolateral membranes on day 1 after IRI. While on day 2 and 4 after IRI, the expression of OAT1 and OAT3 in renal cortex homogenates and basolateral membranes decreased gradually but were still significantly higher than that of the sham-operated rats. The excretion rate of PAH was significantly decreased on day 1 compared with that of sham-operated rats [(0.53±0.15) vs (4.00±0.67) ml/min, P<0.01] and returned to normal when the tubular injury recovered. Renal tubular basolateral membrane Na+-K+-ATPase activity decreased significantly on day 1 [(9.33±1.37) vs (15.07±0.15) μmol Pi&#8226;(mg pro)-1&#8226;h-1, P<0.01]but gradually increased on day 2, 4 and 6 in IRI rats. On day 6 after IRI, renal tubular injury recovered to normal state. Consistently, the Na+-K+-ATPase activity was regulated to the level comparable to that in sham-operated rats. Conclusion IRI is reversible and the expression levels of OAT1 and OAT3 are elevated in the early stage of IRI while OAT-mediated PAH excretion is markedly decreased, which may be due to diminished activity of the Na+-K+-ATPase.

Objective To investigate the influence of high glucose and shear strees on the expression of albumin receptor megalin and cubilin in renal proximal tubules of streptozotocin(STZ)-induced diabetic rats and its significance. Methods Diabetic rats were induced by STZ. Proteinuria was measured and the expression of megalin and cubilin was detected by immunohistochemistry at week 2, 4, 6 respectively. Cultured NRK-52E cells were divided into high glucose group, mannitol group and control group. These groups were exposed to shear stress of 0.5 Pa and 1.0 Pa for 1, 3 and 6 h respectively. Megalin and cubilin mRNA expressions were examined by RT-PCR. Results Compared with control group, the expression of megalin and cubilin was significantly decreased in STZ-induced diabetic rats(P<0.05). Levels of megalin and cubilin in diabetic rat kidney were negatively correlated with urine albumin excretion respectively(P<0.05). Compared to the control group, the mRNA expression of megalin and cubilin was significantly decreased in high glucose group (P<0.05). Shear stress significantly down-regulated the mRNA expression of megalin and cubilin in a magnitude- and time-dependent manner (P<0.05). Conclusion Increased tubular flow shear stress and high glucose down-regulate the expression of megalin and cubilin, and decrease albumin absorption in renal proximal tubular cells, which may play a role in trigering microalbuminuria in the early-stage of DN.

Objective To investigate the influences of Epstein-Barr virus transformation on the expression of IgA1 molecular glycosylation associated gene ST6GALNAC2 and the alteration of its encoded protein 2,6-sialyltransferase. Methods Two patients with IgA nephropathy, 2 patients with IgA multiple myeloma and 3 healthy controls were enrolled in the study. Peripheral blood samples from participants were used for B lymphocytes enrichment by CD19+ immunomagnetic beads and for EBV transformation. The expression of gene ST6GALNAC2 was detected by real-time RT-PCR and the level of sialic acid in IgA1 molecule was observed by ELISA. Results The expression level of gene ST6GALNAC2 in B lymphocytes after EBV transformation was lower than that enriched from fresh peripheral blood. The level of sialic acid in IgA1 molecule secreted from B lymphocyte was down-regulated after EBV transformation. Conclusion In the investigations on the expression of IgA1 molecular glycosylation associated genes and the effect of its encoded enzymes, B lymphocytes enriched from fresh peripheral blood can not be entirely replaced by B lymphocyte transformed by EBV.