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Background: Glucose-free dialysis solutions may be more biocompatible owing to the physiological pH and the lack of glucose degradation products, and the effects can be reflected by the changes in some markers of peritoneal mesothelial cells (PMC). Method: Peritoneal effluents were collected in 17 CAPD patients after one daily exchange of glucose-containing dialysate to Nutrineal (1.1% amino acid-based PDF), and human PMC were cultured from peritoneal effluent and treated with various peritoneal dialysis (PD) solutions. Results: The level of cancer antigen 125 (CA125) in peritoneal effluent increased significantly after using Nutrineal® for 3 months (p = 0.045), whereas that of procollagen I peptide (PICP) remained unaltered. Production of CA125 by human PMC showed a time-responsive increase after stimulation with Nutrineal and Extraneal (icodextran-based PDF). An increased expression of CA125 was observed in cultured human PMC treated with various PD solutions, and the increase induced by Nutrineal was lower than that induced by 4.25% Dianeal® and Extraneal®. A lower increase was also observed for lactate dehydrogenase (LDH). The levels of heat shock protein 70 (HSP70), however, were not altered. Conclusion: Nutrineal is more biocompatible to the peritoneal membrane than the conventional PD solutions tested herein, reflected by both the in vivo and in vitro response of CA125.

Integrin is the major adhesion molecule for the attachment of podocytes to the glomerular basement membrane, and integrins have been shown to play a major role in the regulation of cell survival. In this study, the authors investigated the apoptosis and its related signal pathways to integrin in cultured rat podocytes. Apoptosis was detected with the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique. Cytochrome c was examined by immunohistochemical stain, and Fas, Fas ligand, Bax, Bcl-2, and ERK activation (p-ERK/ERK) were analyzed by Western blotting analysis. The results demonstrated that the integrin antagonist, Gly-Arg-Gly-Asp (GRGD), increased the percentage of cells with apoptosis (from 0.9+/-0.5% to 27.2+/-9.9%, P0.01). Inhibition of protein tyrosine kinase with genistein also caused apoptosis of podocytes (from 0.9+/-0.5% to 26.0+/-8.7%, P0.01). In GRGD-treated cells, cytochrome c was found released into cytoplasm by immunohistochemical study and the Bax expression was upregulated, whereas Bcl-2 expression was not changed. Fas was not expressed in both control and GRGD-treated podocytes, although Fas ligand was upregulated in GRGD-treated cells. ERK activation was also found to be increased in GRGD-treated cells. The results indicated that alpha3beta1integrin is necessary for the prevention of the apoptosis of cultured rat podocytes, and that the signaling involves the Bax, Bcl-2, and cytochrome c pathways.

Integrins attach cells to extracellular matrix (ECM) and mediate signals from ECM to cells or from cells to ECM. They regulate cell functions, including adhesion, migration, cell cycle regulation, and differentiation. Podocytes may detach from the glomerular basement membrane (GBM) and be excreted in the urine, and proteinuria is found in patients with primary focal segmental glomerulosclerosis (FSGS); both may be associated with loss of alpha3beta1integrins. In this study, we have examined the podocyte number in patients with primary FSGS and normal controls, and the alpha3- and beta1-integrin subunits expression of podocytes in patients with primary FSGS and chronic puromycin aminonucleoside (PAN)-treated rats by the morphometric, immunoperoxidase histochemical, and immunoelectron microscopic examination. We also measured their expression serially in rats that received repeated PAN injection. The results showed that the podocyte number was significantly decreased in patients with primary FSGS than in normal control (P0.05). The immunostaining score showed that both alpha3- and beta1-integrin subunits on podocytes in patients with primary FSGS were significantly lower than in normal controls (both P0.01). The number of immuno-gold particles of alpha3- and beta1-integrins at the effaced foot process area of patients with primary FSGS were also significantly decreased than that of normal controls (both P0.05). The immunostaining score of both alpha3- and beta1-integrin subunits was negatively correlated with the degree of glomerular sclerosing score and the amount of daily protein loss, and they were positively correlated with the number of podocytes. Chronic 12-week PAN-treated rats showed similar findings with decreased immunostaining expression and immuno-gold particles of alpha3-integrin on podocytes than in normal control (both P0.05). The chronic PAN-treated rats also showed a trend toward gradually decreased immunostaining expression of alpha3-integrin subunit on podocyte during the progress from normal to FSGS state. These studies indicate that podocyte expression of alpha3- and beta1-integrin subunits is significantly reduced in humans with primary FSGS and chronic PAN-treated rats, before the morphological changes of FSGS are observed. The decreased podocyte expression of alpha3beta1 integrins is closely related with podocyte depletion, glomerular sclerosis, and daily protein loss in patients with primary FSGS.

Adrenomedullin (AM) immunostaining and gene expression have seldom been measured in human kidneys. Because previous studies have shown that AM exerts antiproliferative effects on rat mesangial cells in vitro and that urine AM levels are decreased in patients with chronic glomerulonephritis, we measured glomerular AM and its gene expression in patients with primary IgA nephropathy (IgAN). Glomerular AM was measured by immunohistochemical staining, and glomerular AM mRNA was measured by in situ hybridization. Plasma and urine AM were measured by radioimmunoassay. The results showed that both the intensity of immunostaining for glomerular AM and the glomerular expression of AM mRNA were significantly decreased in IgAN patients compared with normal controls (both P.05). Similar results were not observed in patients with non-IgA MsPGN. Glomerular AM immunostaining and glomerular AM mRNA expression were significantly correlated ( P.001), and both were negatively correlated with the number of glomerular cells ( P.05 and.01, respectively). Both glomerular AM immunostaining and glomerular AM mRNA expression were correlated with urine AM levels (both P.001), but not with plasma AM levels. The urine AM level was significantly lower in IgAN patients than in normal controls ( P.01), whereas the plasma level was not different between the 2 groups. Our findings indicate that glomerular production of AM was decreased in patients with IgA nephropathy and that this lack of glomerular AM may be related to the pathogenesis of this mesangial disease.

To investigate the status and role of glutathione peroxidase (GPX) in diabetic nephropathy, we measured GPX in the plasma and urine of 14 patients with diabetic glomerulosclerosis (DGS) and measured glomerular GPX immunostaining in these patients and in rats with streptozotocin-induced diabetes of varying duration. Plasma GPX levels were significantly lower in DGS patients than in diabetic patients without nephropathy (P.05) or normal controls (P.01). Urinary GPX concentrations were also significantly lower in DGS patients than in diabetic patients without nephropathy or normal controls (both P.05). Immunostaining of glomerular GPX was significantly less in DGS patients than in normal controls (P.05) and was negatively correlated with the glomerular sclerosis score and the index of mesangial expansion. Serial examination of glomerular GPX in diabetic rats showed that immunostaining scores for glomerular GPX in rats were significantly lower than those in normal control rats after 1 and 3 months' duration of diabetes, and staining scores were also significantly lower in rats killed after 3 months of diabetes than in those killed after 1 week. In conclusion, our study demonstrates that GPX concentrations in plasma, urine, and glomeruli are decreased in individuals with DGS and that the immunostaining of glomerular GPX decreases progressively.

San-Huang-Xie-Xin-Tang (SHXT) is a traditional Chinese medicinal formula containing Coptidis rhizoma, Scutellariae radix and Rhei rhizoma. The present study aimed to determine the preventive effects of standardized SHXT on lipopolysaccharides (LPS)-induced arterial hypotension, protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), cytokines formation and prostaglandin E2 (PGE2) production. LPS-induced activation of iNOS has been recognized to increase cytokines and nitric oxide, some of them play predominant roles in sepsis. Intravenous injection of LPS (10 mg/kg) caused a marked decrease of the mean arterial pressure in normotensive rats. However, the LPS-induced arterial hypotension was inhibited by SHXT (0.01 and 0.03 g/kg), when it was given 30 min before LPS. Moreover, plasma level of cytokines and PGE2 were lowered by SHXT. In RAW 264.7 cells, SHXT (20-200 microg/ml) dose-dependently inhibited LPS (1 microg/ml)-induced iNOS and COX-2 expression, and it also significantly decreased LPS-induced cytokines in a dose-dependent manner. In conclusion, our data suggest that SHXT prevented LPS-induced arterial hypotension, which might be mediated through its inhibition activities on the expression of iNOS and COX-2, cytokines formation and PGE2 production. Therefore, its protection activity against LPS-induced arterial hypotension and inflammatory mediators release might be beneficial in the treatment of endotoxin shock and/or associated inflammation.

Our previous work demonstrated that liriodenine, an isoquinoline alkaloid isolated from plant species of many genera, exhibits a potent cytotoxic effect on various types of human cancer cells. In this study, we investigated the effect of liriodenine on the growth and viability of human lung cancer cells and addressed the underlying mechanism of action. We found that liriodenine suppressed proliferation of A549 human lung adenocarcinoma cells in a dose- and time-dependent manner. Flow cytometric analysis showed that liriodenine blocked cell cycle progression at the G2/M phase. Induction of G2/M arrest by liriodenine was accompanied by reduction of G1 cyclin (D1) and accumulation of G2 cyclin (B1). In vitro kinase activity assay demonstrated that the enzymatic activity of the cyclin B1/cyclin-dependent kinase 1 complex was reduced in liriodenine-treated cells. More importantly, incubation with liriodenine led to activation of caspases and apoptosis in A549 cells. The apoptosis-inducing activity of liriodenine was more apparent when cells were cultured under serum-free conditions. Our results indicate that liriodenine exerts potent anti-proliferative and apoptosis-inducing effects on human lung cancer cells.

Glutathione peroxidase (GPX) is an important antioxidant that effectively scavenges hydrogen peroxide. Recent studies have revealed that plasma GPX activity is decreased in patients with chronic kidney failure. However, there have been no reports on renal and urinary GPX levels in patients with kidney disorders. Therefore in this study we have measured the plasma and urinary GPX levels and glomerular GPX immunostaining in patients with focal segmental glomerulosclerosis (FSGS) and normal kidney function as compared with those in patients with minimal change disease (MCD) and those in normal control subjects. Rats with puromycin aminonucleoside-induced FSGS were also studied. The results showed that the plasma GPX level was significantly lower in FSGS patients than in either MCD patients or normal control subjects (both P

Insulin and heparin suppress superoxide production in diabetic rat glomeruli stimulated with low-density lipoprotein. Patients with diabetic nephropathy frequently show increased levels of circulating low-density lipoprotein (LDL) and oxidized LDL, which have been reported to be related to the generation of oxygen-free radicals. In the present study, we evaluated the effects of insulin and heparin on the superoxide production of glomeruli, which were isolated from rats with streptozotocin-induced diabetes for one week, one month, and three months, respectively, and the glomeruli were stimulated with native and oxidized LDL. LDL was isolated from normal subjects with normolipidemia, and the superoxide was measured by using a spectrophotometer. The results demonstrated that the poorly controlled diabetic rat glomeruli showed a significantly higher production of superoxide than normal glomeruli under basal status and after stimulation, and this production increased further with the progression of diabetes. Insulin suppressed both the basal and stimulated production of superoxide in diabetic glomeruli, but not in normal glomeruli. Heparin suppressed superoxide production of diabetic glomeruli stimulated by either native or oxidized LDL, and it also partly suppressed superoxide production of normal glomeruli stimulated by oxidized LDL. Our results suggest that glomerular injury in diabetics with hyperlipidemia may be mediated through enhanced generation of oxygen-free radicals, which can be partially attenuated by insulin and heparin.

Background: IgA nephropathy (IgAN) is characterized by predominant deposition of IgA in the glomerular mesangium. Serum IgA is often elevated in patients with IgAN, and it has been postulated that it is responsible for the mesangial lesions. However, the direct effect of circulating IgA on mesangial cells is not clear. Methods: We investigated the effects of sera and IgA which were isolated from patients with IgAN on thymidine uptake, superoxide and fibronectin production and fibronectin mRNA expression of cultured rat mesangial cells, and we compared the findings to the effects of IgA isolated from patients with non-IgA mesangial proliferative glomerulonephritis (MsPGN) and normal controls. IgA was isolated with affinity chromatography using cyanogen bromide activated Sepharose 4B coupled to sheep antihuman IgA antiserum. Results: Our results demonstrated that both sera and IgA from patients with IgAN dose-dependently increased mitogenesis of mesangial cells as measured by 3H-labeled thymidine uptake. The thymidine uptake by sera and IgA isolated from patients with IgAN was significantly higher than that of sera and IgA isolated from patients with MsPGN and normal controls. Sera and IgA from patients with IgAN significantly enhanced superoxide and fibronectin production and fibronectin mRNA expression of mesangial cells. The superoxide and fibronectin production was also significantly higher as compared with patients with MsPGN and normal controls. Conclusions: Our results indicate that circulating IgA isolated from patients with IgAN is different from that of patients with MsPGN and normal controls and may potentially induce oxidative injury and production of extracellular matrix of glomerular mesangial cells in IgAN.

Advanced glycation end-product (AGE) is important in the pathogenesis of diabetic nephropathy (DN), and captopril (an angiotensin converting enzyme inhibitor) is effective in treating this disorder. We have shown that the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) cascade is responsible for AGE-induced mitogenesis in NRK-49F (normal rat kidney fibroblast) cells, but its role in renal fibrosis in DN remains unknown. Therefore, we have sought to determine whether JAK/STAT is involved in AGE-regulated collagen production in NRK-49F cells. We found that AGE time (1–7 days) and dose (10–200 μg/ml)-dependently increased collagen production in these cells. Additionally, AGE increased RAGE (receptor for AGE) protein expression. AGE-induced RAGE expression was dose-dependently inhibited by antisense RAGE oligodeoxynucleotide (ODN) and captopril. AGE-induced type I collagen production and JAK2-STAT1/STAT3 activation were decreased by AG-490 (a specific JAK2 inhibitor), antisense RAGE ODN and captopril. Meanwhile, STAT1 and STAT3 decoy ODNs also suppressed the induction of collagen by AGE. We concluded that RAGE and the JAK2-STAT1/STAT3 pathway were involved in AGE-induced collagen production in NRK-49F cells. Furthermore, captopril was found to reverse AGE-induced collagen production, probably by attenuating RAGE expression and JAK2-STAT1/STAT3 activities. J. Cell. Biochem. 81:102–113, 2001. © 2001 Wiley-Liss, Inc.

Background/Aims: Hemodialysis (HD) patients are prone to developing peptic ulcers. However, of all the risk factors associated with peptic ulcers, none have been shown to be more prevalent in HD patients than in the general population. However, salivary epidermal growth factor (EGF) may play a role in peptic ulcer diseases. Methods: Salivary EGF levels and bioactivities were assayed in 47 maintenance HD patients and 30 normal controls, and the molecular weights of EGF were assessed using high-performance liquid chromatography (HPLC). Results: Salivary EGF levels were not different between both groups of subjects (4.2 ± 0.34 vs. 5 ± 0.54 ng/mg protein, NS), and HPLC revealed that salivary EGF in both groups had similar molecular weights. However, salivary EGF bioactivity was significantly depressed in the HD patients as compared to the normal controls (0.59 ± 0.08 vs. 1.55 ± 0.15 ng/mg protein, p < 0.01). Stepwise multiple regression showed that the low salivary EGF levels were associated with female gender (p < 0.05), while low salivary EGF bioactivity was associated with HD per se (p < 0.05). In the 22 HD patients who underwent gastric endoscopy, salivary EGF bioactivity was significantly lower in those with peptic ulcers than in those without (0.38 ± 0.08 vs. 0.69 ± 0.08 ng/mg protein, p < 0.05). Conclusion: Decreased salivary EGF bioactivity may contribute to peptic ulcer disease among maintenance HD patients.

The adhesion molecule integrin alpha3beta1 is the major receptor of podocyte to the glomerular capillary basement membrane (GBM). Since progressive alteration of the glomerular extracellular matrix (ECM) compartment leading to GBM thickening is common in diabetic nephropathy, we investigated the cellular distribution of alpha3beta1 integrin in podocytes of patients with diabetic nephropathy and streptozotocin-induced diabetic rats, and we evaluated the effects of high glucose on the cultured rat podocytes. Both human and rat kidneys were stained using the immunoelectron microscopy and immunoperoxidase technique with mouse monoclonal antibodies to human integrin alpha3 subunit. The results showed that both the number of immunogold particles and the staining of integrin alpha3 subunit on podocytes were weaker in patients with diabetic nephropathy than those of control kidneys. The staining of alpha3 on podocytes in the poorly-controlled diabetic rats was also weaker after one and three months of hyperglycemia. However, the staining was identical to controls in rats with only one week of hyperglycemia. High glucose (25 mM) but not streptozotocin in vitro suppressed the alpha3 expression of cultured rat podocytes. Our results demonstrated that the expression of integrin alpha3beta1 on podocytes was suppressed in both human and rats with diabetes, possibly due to the effects of hyperglycemia, and the suppression became more severe with the duration of diabetes.

To investigate the role of renal endothelin-1 (ET-1) synthesis in water-sodium homeostasis, we measured mRNA expressions, protein levels, enzyme activity, and receptor binding of the renal ET-1 system in a DOCA- and salt-treated rat model. Male Wistar rats were divided into control and DOCA- and salt-treated (DOCA-Salt) groups. The DOCA-Salt group received 25 mg/kg body wt DOCA and was maintained on 1% NaCl drinking water. Rats were killed on days 1, 2, 4, and 10 of the experiment. Urinary ET-1-like immunoreactivity significantly increased from the second day in the DOCA-Salt group and correlated well with the urinary sodium excretion rate ( r = 0.81, P < 0.001). Renal endothelin-converting enzyme (ECE) activity, ET-1, and ECE-1 mRNA expressions were significantly increased in the renal medullary area of DOCA-Salt rats. In situ hybridization and immunohistochemical studies showed that the increase in ET-1 synthesis was mainly localized in the inner medullary collecting ducts. The maximum binding of endothelin B receptor also increased from the second day in the renal medulla of the DOCA-Salt group. Our results suggest that renal medullary synthesized ET-1 may be a natriuretic factor and may participate in the intrarenal regulation of water and salt homeostasis in prehypertensive DOCA-and salt-treated rats.

Clinical outcome of dialysis patients after eating star fruit ( Averrhoa carambola ) varies, but it may be fatal. In the past 10 years, 20 such patients were treated in our hospital when they developed clinical symptoms after eating the fruit or drinking star fruit juice. Their initial presentations included sudden-onset limb numbness, muscle weakness, intractable hiccups, consciousness disturbance of various degrees, and seizure. No other major events that might be responsible for these symptoms could be identified. Eight patients died, including one patient with a serum creatinine level of 6.4 mg/dL who had not yet begun dialysis. The clinical manifestations of the survivors were similar to those who died except for consciousness disturbance and seizure. Death occurred within 5 days despite emergent hemodialysis and intensive medical care. The survivors' symptoms usually became less severe after supportive treatment, and these patients subsequently recovered without obvious sequelae. The purpose of this article is to report that patients with renal failure who ingest star fruit may develop neurological symptoms and also run the risk for death in severe cases. Mortality may also occur in patients with chronic renal failure not yet undergoing dialysis.

Advanced glycation end product (AGE) is important in the pathogenesis of diabetic nephropathy, which is characterized by cellular hypertrophy/hyperplasia leading to renal fibrosis. However, the signal transduction pathways of AGE remain poorly understood. The Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway has been associated with cellular proliferation in some extra-renal cells. Because interstitial fibroblast proliferation might be important in renal fibrosis, we studied the role of the JAK/STAT pathway in NRK-49F (normal rat kidney fibroblast) cells cultured in AGE/BSA and non-glycated BSA. We showed that AGE dose-dependently (10-200 microgram/ml) increased cellular mitogenesis in NRK-49F cells at 5 and 7 days. However, cellular mitogenesis was unaffected by the simultaneous presence of BSA. Regarding the JAK/STAT pathway, AGE (100 microgram/ml) induced tyrosine phosphorylation of JAK2 (but not JAK1, JAK3 or TYK2) at 15-60 min; it also induced the tyrosine phosphorylation of STAT1 and STAT3 at 1-2 h and 0.5-4 h respectively. Being a transcription factor, AGE also increased the DNA-binding activities of STAT1 and STAT3 AG-490 (a specific JAK2 inhibitor) (5 microM) inhibited tyrosine phosphorylation of JAK2 and the DNA-binding activities of STAT1 and STAT3. The same results were obtained by using specific 'decoy' oligodeoxynucleotides (ODNs) that prevented STAT1 and STAT3 from binding to DNA. Meanwhile, the STAT1 or STAT3 decoy ODN and AG-490 were effective in reversing AGE-induced cellular mitogenesis. We concluded that the JAK2-STAT1/STAT3 signal transduction pathway is necessary for AGE-induced cellular mitogenesis in NRK-49F cells.

Recombinant human erythropoietin enhances superoxide production by FMLP-stimulated polymorphonuclear leukocytes in hemodialysis patients. Recombinant human erythropoietin (rHuEPO) is a hematopoietic growth factor that has a broad spectrum of action. We have observed the in vivo and in vitro effects of rHuEPO on the superoxide production of circulating polymorphonuclear leukocytes (PMNs) in hemodialysis patients. The PMNs were separated from heparinized blood after dextran sedimentation and Ficoll-Conray centrifugation and stimulated with formyl-methionyl-leucyl-phenylalanine (FMLP), serum-treated zymosan (STZ), or phorbol myristate acetate (PMA). The in vivo study showed that rHuEPO therapy for 12 weeks enhanced the superoxide production by FMLP-stimulated PMNs (P < 0.01). However, no significant changes on superoxide production was found in either STZ- or PMA-stimulated PMNs. Simultaneous measurement of PGE2 production by PMNs in response to all three stimulants did not show any significant changes after rHuEPO therapy. The direct in vitro effect of rHuEPO on PMNs showed that rHuEPO does not enhance the superoxide production by non-stimulated PMNs. However, preincubation of rHuEPO enhanced superoxide production from FMLP- and STZ-stimulated PMNs. Our results indicate that rHuEPO enhanced FMLP-stimulated superoxide production of PMNs both in vivo and in vitro in hemodialysis patients, which may be responsible for the increased oxidant stress in hemodialysis patients after rHuEPO therapy.

We have shown that epidermal growth factor (EGF) may be important in diabetic renal hypertrophy. Since EGF is the most potent mitogen for the proximal tubule, it may be relevant to the cellular hyperp

Role of lipid control in diabetic nephropathy. Patients with diabetic nephropathy are known to be associated with many lipoprotein abnormalities, including higher plasma levels of very low-density lipoprotein, low-density lipoprotein and triglycerides, and lower levels of high-density lipoprotein. Many studies have reported that lipids may induce both glomerular and tubulointerstitial injury through mediators such as cytokines, reactive oxygen species, chemokines, and through hemodynamic changes. Clinical studies in patients with diabetic nephropathy showed that lipid control can be associated with an additional effect of reduction in proteinuria. Experimental studies demonstrated that lipid-lowering agents exerted a certain degree of renoprotection, through both indirect effects from lipid lowering and a direct effect on cell protection. Therefore, lipid control appears to be important in the prevention and treatment of diabetic nephropathy. Diabetic nephropathy has become the leading cause of end-stage renal failure in many countries, including Taiwan. One of the major risk factors for the development and progression of diabetic nephropathy is dyslipidemia. In this paper we will review the role of lipid in mediating renal injury and the beneficial effects of lipid control in diabetic nephropathy.

A simple and reliable sampling method for measuring post-dialysis blood urea nitrogen (C2) has not been well established. Therefore, the effects of different methods of sampling C2 on calculating urea kinetic modeling (UKM) derived parameters were studied in patients on hemodialysis. At first, C2 values were sampled at the end of hemodialysis at a blood flow rate of 300 ml per min (blood flow rate (Qb) 300 ml per min). They were then divided into two groups. In group 1 (n = 11), C2 samples were taken after slowing down Qb to 100 ml per min for 3 min (C2-100); the blood pump was then stopped for 1 min, and C2 was again sampled (C2-100-stop). Finally, C2 was sampled with Qb restored to 100 ml per min and the venous line clamped for another 12 sec (C2-100-clamp). In group 2 (n = 11), C2 samples were collected after Qb was slowed down to 50 ml per min for 3 min (C2-50), and C2-50-stop was then measured. Finally, C2-50-clamp was measured. Using C2-clamp as a reference standard, UKM parameters were calculated using a variable volume, single pool UKM. The authors found that Kt/V calculated by C2-300, C2-100, and C2-50 overestimated the reference Kt/V by 8.4-9.1%, 5.1%, and 3%, respectively. In contrast, protein catabolic rate and time-averaged BUN were affected only minimally. Therefore, a low flow technique with a Qb of 50 ml per min for 3 min can be used for the routine estimation of C2 and UKM-derived parameters with reasonable accuracy.

The effects of recombinant human erythropoietin (rHuEPO) treatment on parathyroid function in patients on maintenance hemodialysis (HD) with secondary hyperparathyroidism (HPT) is poorly understood. We compared the levels of serum intact parathyroid hormone (PTH) and the suppressibility of PTH by intravenous calcium infusion before and after 12 weeks of rHuEPO treatment in 8 HD patients with secondary HPT. The suppressibility of PTH by calcium infusion in HD patients was also compared with that of normal subjects. After rHuEPO treatment, in HD patients hematocrit and hemoglobin levels increased significantly from 20.1 +/- 1.3% and 6.65 +/- 0.46 g/dl to 28.7 +/- 1.0% and 9.68 +/- 0.39 g/dl, respectively. The serum intact PTH levels did not change significantly (541.9 +/- 65.3 pg/ml before versus 572.9 +/- 75.3 pg/ml after rHuEPO treatment), nor did serum ionized calcium, phosphate, magnesium, aluminum, alkaline phosphatase, and 1.25(OH)2D levels. Calcium infusion significantly increased serum ionized calcium and suppressed serum PTH levels. However, the increment in serum calcium levels and the percent decrement of serum PTH showed no significant differences before and after rHuEPO treatment in HD patients. Elevations in serum calcium levels during calcium infusions were not significantly different between normal subjects and HD patients. However, the percent maximal decrement in serum PTH level was less in HD patients both before and after rHuEPO treatment than in normal subjects (-75.4 +/- 3.9 and -76.4 +/- 4.1% versus -91.4 +/- 1.4%). We conclude that rHuEPO treatment has no influence on parathyroid function in maintenance HD patients with secondary HPT. In addition, PTH secretion is less suppressed by calcium infusion in the same group of patients.

To investigate the intrarenal endothelin 1 (ET-1) synthesis in streptozocin (STZ) diabetic rats with moderate hyperglycemia, we measured plasma ET-1, renal ET-1 mRNA, and renal tissue ET-1 levels. The renal ET-1 mRNA expression progressively decreased from the 2nd to the 6th week after induction of diabetes by STZ. The renal ET-1 mRNA expression and the renal tissue ET-1 content were significantly reduced in 8 diabetic rats with a mean blood glucose level of 21.0 +/- 0.4 mM as compared with 7 normal rats sacrificed at the 6th week after STZ or citric buffer injection. The reduction of renal ET-1 and mRNA levels was ameliorated in 9 diabetic rats with a mean blood glucose level of 6.9 +/- 0.7 mM after strict glycemic control by insulin treatment. Kidney weight and glomerular filtration rate in moderately hyperglycemic rats were significantly increased as compared with normal rats at the 6th week after STZ injection. The mean plasma ET-1 levels in moderately hyperglycemic diabetic rats were not different from those of the other two groups. This study demonstrates that moderate hyperglycemia in diabetic rats is associated with a reduction in renal ET-1 synthesis. Whether decreased renal ET-1 synthesis is an adaptive phenomenon of a renal hemodynamic change during the early stage of diabetes is worthy of further investigation.

Induction of heparin-binding epidermal growth factor-like growth factor mRNA by protein kinase C activators. Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a potent smooth muscle cell mitogen of macrophage origin. To determine whether the HB-EGF gene is transcribed and regulated in mesangial cells, we measured HB-EGF mRNA levels in cultured rat mesangial cells by RNA blot analysis. A 2.5-kb HB-EGF mRNA was detected in unstimulated mesangial cells. The protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA) increased HB-EGF mRNA levels by 15-fold in mesangial cells, and this induction of HB-EGF mRNA by TPA was both time- and dose-dependent. HB-EGF mRNA could also be stimulated by 10% fetal calf serum, ionomycin, thrombin, and endothelin-1. Staurosporine, a protein kinase C inhibitor, abolished the induction of HB-EGF mRNA by TPA and serum. To determine whether HB-EGF is mitogenic for mesangial cells, we transfected COS cells with HB-EGF expression plasmids. Culture medium from COS cells transfected with these plasmids increased 3 H-thymidine incorporation in mesangial cells in a dose-dependent manner. To our knowledge, this is the first report that HB-EGF is expressed in renal cells. This inducible transcription of HB-EGF suggests that it may have an autocrine role in mesangial cell proliferation in kidney disease.

Because aluminum hydroxide, as a phosphate binder, lowered intestinal zinc absorption, we studied the effects of calcium carbonate (CaCO3) and calcium acetate (CaAc), two other phosphate binders, on intestinal Zn absorption in nine patients on hemodialysis and in 11 controls by measuring 1- and 2-hour serum Zn levels after oral administration of 50 mg of elemental Zn as Zn gluconate with or without concomitant administration of 2 g CaCO3 (800 mg elemental Ca) or 3 g CaAc (750 mg elemental Ca). Fasting serum Zn levels were not different between patients and controls (14.0 +/- 2.3 v 14.1 +/- 1.2 mumol/L [91.8 +/- 14.9 v 92.3 +/- 8.0 micrograms/dL]), but the area under the curve of serum Zn increment (AUC) 2 hours after an oral Zn challenge without or with either of two of phosphate binders used was significantly smaller in patients than in controls (P less than 0.05). The AUC after concomitant administration of Zn with CaCO3 did not differ from that of Zn alone in either patients or controls, but it was significantly less in Zn with CaAc than in Zn alone or in Zn with CaCO3 in both groups. The results demonstrate that intestinal Zn absorption after an oral Zn challenge decreased in patients on hemodialysis and concomitant administration of CaAc, but CaCO3 did not decrease intestinal Zn absorption in either group.

ObjectiveWe examined whether amino acid–based peritoneal dialysate that contains 85 mg/dL L-methionine affects homocysteine (Hcy) metabolism.DesignThe study enrolled 17 adult CAPD patients (11 men, 6 women) who had been receiving CAPD for at least 6 months and who had low serum albumin levels (ResultsAfter use of Nutrineal, serum albumin was unchanged, but blood urea nitrogen (BUN) and total protein were increased. Before the study began, 1 patient had a very high Hcy level (256 μmol/L); his data were excluded from the analysis. In the remaining 16 patients, baseline Hcy was 24.4 ± 7.0 μmol/L. Levels of Hcy progressively increased with the use of Nutrineal: 28.1 ± 6.2 μmol/L in week 2, 28.4 ± 7.1 μmol/L in week 4, 29.1 ± 7.6 μmol/L in week 6, 29.3 ± 9.0 μmol/L in week 8, 27.5±9.7 μmol/L in week 10, and 30.3 ± 8.2 μmol/L in week 12.ConclusionsNutrineal might help to replenish daily protein loss, but it also increased formation of Hcy and, therefore, the potential risk of cardiovascular illness. Further studies will be needed to examine the effect of folic acid and vitamin B12supplementation in the rescue of that Hcy increase, and also a possible correlation with methylenetetrahydrofolate reductase gene polymorphism.

Previously, we showed that Janus kinase 2 (JAK2) is important in advanced glycation end-product (AGE)-induced effects in renal interstitial (NRK-49F) fibroblasts. Leptin is a JAK2-activating cytokine via the long form leptin receptor (Ob-Rb). Leptin and connective tissue growth factor (CTGF) may be involved in renal fibrosis. However, the relationship between leptin and CTGF in terms of AGE-induced effects remains unknown. Thus, the effects of AGE (150 μg/ml) and leptin on mitogenesis, CTGF and collagen expression in NRK-49F cells were determined. We found that leptin and AGE increased mitogenesis and type I collagen protein expression at 3 and 7 days, respectively. AGE increased leptin mRNA and protein expression at 2–3 days. AGE increased CTGF mRNA and protein expression at 3–5 days. AG-490 (JAK2 inhibitor) abrogated AGE-induced leptin mRNA and protein expression at 2–3 days. AG-490 and Ob-Rb anti-sense oligodeoxynucleotides (ODN) abrogated AGE-induced CTGF mRNA and protein expression at 3–5 days. AG-490 and CTGF anti-sense ODN abrogated AGE-induced mitogenesis and collagen protein expression at 7 days. Additionally, leptin dose (0.2–1 μg/ml) and time (1–2 days)-dependently increased CTGF protein expression. AG-490 abrogated leptin (1 μg/ml)-induced CTGF protein expression at 2 days. AG-490 and CTGF anti-sense ODN abrogated leptin-induced mitogenesis and collagen protein expression at 3 days. We concluded that AGE induced JAK2 to increase leptin while leptin induced JAK2 to increase CTGF-induced mitogenesis and type I collagen protein expression in NRK-49F cells. Additionally, AGE-induced mitogenesis and type I collagen protein expression were dependent on leptin-induced CTGF. © 2004 Wiley-Liss, Inc.

Elevated plasma homocysteine, arterial stiffness, and increased pulse pressure (PP) are independently associated with higher cardiovascular risk in patients with end-stage renal disease. The aim of this study is to investigate the influence of plasma homocysteine on arterial stiffness and PP in hemodialysis (HD) patients. One hundred and nine HD patients were stratified into three groups by plasma homocysteine levels: low (11.2-20.8 micromol/L), middle (21.2-25.1 micromol/L), and high tertiles of plasma homocysteine (Hcy) group (25.2-43.9 micromol/L). Using a computerized oscillometry, we measured the arterial stiffness index (ASI) and blood pressure (BP) hemodynamic parameters in the brachial artery. The high Hcy group exhibited a higher ASI (110.4+/-129.5 versus 46.2+/-17.5, mean+/-S.E., P

The expression of inducible nitric oxide synthase (iNOS) expression and release of nitric oxide (NO) from macrophages are markedly increased in granulomatous infections. Activation of macrophages 1alpha-hydroxylase results in an increase of 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)]. However, the significance of this increased production is not completely understood. In this study, we analyzed 1,25(OH)(2)D(3) and NO production in patients with tuberculosis infection and hypercalcemia and used lipopolysaccharide (LPS) to stimulate RAW 264.7 cells in an attempt to assess iNOS expression and gaseous NO production regulated by 1,25(OH)(2)D(3). Peroxynitrite (OONO(-)) production and lactate dehydrogenase activity were also examined. Without additional stimulation, peripheral-blood mononuclear cells (PBMCs) from patients with tuberculosis converted more 25-hydroxyvitamin D(3) to 1,25(OH)(2)D(3) than did those from normal controls. These PBMCs released less NO than did those from control subjects, at baseline and in the stimulated state. We found that 1,25(OH)(2)D(3) dose-dependently inhibited iNOS messenger RNA expression of the LPS-stimulated RAW 264.7 cells and also significantly reduced the gaseous NO release and OONO(-) production. Paralleling the 1,25(OH)(2)D(3)-induced inhibition of NO release were reductions in OONO(-) and LDH production. In conclusion, 1,25(OH)(2)D(3) inhibited iNOS expression and reduced NO production by LPS-stimulated macrophages in the range of physiological doses. Inhibition of the NO surge was coupled with a reduction in OONO(-) and LDH production. Increased 1,25(OH)(2)D(3) production and decreased release of NO from the PBMCs of patients with tuberculosis and hypercalcemia were also noted. We propose that 1,25(OH)(2)D(3) production by macrophages may protect themselves against oxidative injuries caused by the NO burst. In the case of tuberculosis infection, increased 1,25(OH)(2)D(3) synthesis may further contribute to the development of an unwanted phenomenon-hypercalcemia.

The possible association between the risk of death from renal failure (RF) and the levels of calcium in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Characteristics for all eligible RF-related deaths (2469 cases) among Taiwan residents from 1991 through 2000 were compared with those of people who died from other causes (2469 controls). The levels of calcium in the drinking water of these residents were determined from data obtained from the Taiwan Water Supply Corporation (TWSC). The controls were pair-matched to the RF-related cases by year of birth and death. The adjusted odds ratios (ORs) (95% confidence interval, CI) for RF-related deaths were 1.21 (1.03-1.43) for the group with water calcium levels between 25.1 and 43.0 mg/L and 1.34 (1.12-1.60) for the group with calcium levels of 43.3 mg/L or more. There was a significant trend for increased risk of death from RF with higher calcium levels in drinking water.

Decreased renal Na-K ATPase activity in ureteral obstruction contributes to tubular sodium reabsorption defect in obstructive nephropathy. The integrated changes on the enzyme activity, protein number, and mRNA level of renal cortical Na-K ATPase, in response to bilateral or unilateral ureteral obstruction (BUOUUO), were studied in rabbits. Ouabain-sensitive Na-K ATPase activities of renal cortex were significantly decreased at 24 h after BUO and further decreased at 48 h. The unobstructed contra-lateral kidney had significantly higher Na-K ATPase activity compared to the obstructed side. Immunoblots of Na-K ATPase alpha and beta subunits protein were both decreased at 24 h of BUO and further decreased at 48 h. The levels of Na-K ATPase beta subunit mRNA showed to be significantly decreased at 12 h after obstruction and further decreased at 24 and 48 h. However, the levels of alpha subunit mRNA were not changed as that of beta subunit throughout the study period. This study also used a newly developed method for release of obstruction. All the parameters studied above recovered to variable extents after release of the ureteral obstruction. In summary, decreases in Na-K ATPase activity, protein, and mRNA in obstructed kidney are specific cellular responses to ureteral obstruction. The degree of down-regulation is related to the duration of obstruction. The reduced activity of Na-K ATPase can be explained by decreased enzyme protein. However, the discordant findings in Na-K ATPase subunits protein amounts and mRNA changes suggest that renal Na-K ATPase subunits have different cellular regulatory processes to obstruction, in which transcriptional, translational and even intra-cytoplasmic processing may be involved.

Relative hypoparathyroidism (parathyroid hormone [PTH] < or = 200 pg/mL) is prevalent in hemodialysis (HD) patients, with unknown pathogenesis and prognosis. Thus, to clarify risk factors and prognosis of time-dependent relative hypoparathyroidism in HD patients, a retrospective cohort study was performed for 126 HD patients with four or more PTH determinations and no previous total or subtotal parathyroidectomy. Values for intact PTH, ionized calcium, phosphate, magnesium, albumin, creatinine, urea reduction ratio (URR), glucose, hemoglobin A1c (HbA1c), aluminum, and 1,25(OH)2D were obtained at enrollment and at some time during follow-up. The prevalence of relative hypoparathyroidism at entry was 76 of 126 patients (60.3%). Univariate analysis showed that patients with hypoparathyroidism were older, more likely to have diabetes, and had greater ionized calcium levels and lower phosphate, albumin, blood urea nitrogen (BUN), and creatinine levels. Patients with diabetes were older and had a shorter duration of dialysis therapy and lower PTH, phosphate, albumin, BUN, and creatinine levels and URRs. Conversely, multivariate analysis showed that PTH levels at entry were associated directly with creatinine levels and inversely with age and ionized calcium levels (but not diabetes). During follow-up, PTH levels fluctuated concomitantly with ionized calcium and phosphate levels over time in all patients. Time-dependent PTH levels were associated directly with duration of dialysis therapy and use of vitamin D and phosphate and albumin levels, but inversely with age and ionized calcium and magnesium levels (but not glucose or HbA1c levels). Interestingly, time-dependent PTH levels were independently associated with survival after adjusting for traditional risk factors (diabetes, age, albumin and creatinine levels, and URR) and duration of dialysis therapy. We conclude that in HD patients, relative hypoparathyroidism was not associated with diabetes per se. Time-dependent PTH levels were associated with age, duration of dialysis, and levels of ionized calcium, phosphate, albumin, and magnesium. Moreover, relative hypoparathyroidism at entry and lower time-dependent PTH levels predict mortality.

Pravastatin is a potent inhibitor of HMG-CoA reductase and is effective in lowering serum lipid levels. Recent studies have shown that pravastatin also reduces the oxidative modification of low-density lipoprotein (LDL). To determine whether pravastatin has a direct effect on glomerular mesangial cells, we have measured the effects of pravastatin on the production of superoxide and fibronectin of glomerular mesangial cells stimulated by LDL. Our results demonstrated that the superoxide production of mesangial cells increased after LDL stimulation (100 µg/ml for 4 h) and that the superoxide production was significantly suppressed by either superoxide dismutase (SOD; 500 U/ml for 36 h; p < 0.01) or pravastatin (80 µM for 36 h; p < 0.05). The production of fibronectin was also increased after LDL stimulation which was also significantly suppressed by either SOD (p < 0.01) or pravastatin (p < 0.01). SOD or pravastatin alone had no effect on the unstimulated cells. Our results indicate that pravastatin may have a direct effect as an antioxidant and suppresses the fibronectin synthesis of glomerular mesangial cells independent of its hypolipidemic effect.

Pravastatin is a potent inhibitor of HMG-CoA reductase and is effective in lowering serum lipid levels. Recent studies have shown that pravastatin also reduces oxidative modification of LDL and decreases albuminuria in patients with diabetes. To determine the possible benefit of pravastatin on the diabetic kidney, we have measured the effects of pravastatin on the proliferation and the production of superoxide and fibronectin, and the expression of fibronectin mRNA of glomerular mesangial cells stimulated by oxidized-LDL and high glucose. Our results demonstrated that the [ 3 H]-labeled thymidine uptake of mesangial cells decreased after oxidized-LDL stimulation (50 μg/ml, 6 h) and increased after high glucose stimulation (25 mM, 48 h). The production of superoxide and fibronectin and the expression of fibronectin mRNA of glomerular mesangial cells were all significantly increased after stimulation with either oxidized-LDL or high glucose, or the combination of oxidized-LDL and high glucose. Pravastatin (100 μM, 48 h) alone had no effect on unstimulated cells. However, pravastatin significantly reversed thymidine uptake, inhibited the production of superoxide and fibronectin, and inhibited the expression of fibronectin mRNA of glomerular mesangial cells after stimulation with either oxidized-LDL or high glucose. Our results indicate that pravastatin may effect as an antioxidant and may suppress fibronectin synthesis of glomerular mesangial cells in diabetic patients with hyperlipidemia.

Advanced glycation end products (AGEs) are important in the pathogenesis of diabetic nephropathy, which leads to renal fibrosis. Previously, we found that the janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling pathway is necessary for AGE-induced cellular proliferation in normal rat kidney interstitial fibroblast (NRK-49F) cells. However, a direct link between JAK/STAT and cell-cycle progression has not been well established. In this regard, STAT5 has been found to induce cyclin D1 and proliferation in hematopoietic cells. Therefore, we examined effects of AGE on STAT5 and cell-cycle-dependent mitogenesis in NRK-49F cells. We found that AGE increased cyclin D1 expression and cyclin-dependent kinase (cdk)4 activity while decreasing p21(WAF1/CIP1) expression. We also found that AGE (100 microg/mL) induced STAT5 tyrosine phosphorylation. Meanwhile, AGE induced STAT5 protein-DNA binding activity, which was reversed by AG-490 (a specific JAK2 inhibitor) and STAT5 decoy oligodeoxynucleotide (ODN). In addition, STAT5 decoy ODN reversed AGE-induced cell-cycle-dependent cellular proliferation and cyclin D1 protein expression. We concluded that AGE induced cell-cycle-dependent cellular proliferation by inducing the JAK2-STAT5-cyclin D1 and cdk4 pathways in NRK-49F cells.

Both reactive oxygen species (ROS) and endothelin-1 (ET-1) have been implicated in the pathophysiology of diabetic nephropathy. The interrelationship between them, however, has not been documented in this disease. To determine whether ROS regulates ET-1 production in diabetic kidneys, we examined the in vitro and in vivo effects of ROS donors and scavengers on ET-1 production of diabetic rat glomeruli. For in vitro study, the glomeruli were isolated with a sieving method from streptozotocin-induced diabetic rats and killed at 1 week, 1 month, and 3 months, respectively. Superoxide was measured by a spectrophotometer, and ET-1 was measured by radioimmunoassay. The results demonstrated that the basal production levels of superoxide and ET-1 were higher in diabetic glomeruli than in normal glomeruli in vitro. There was a positive correlation between the production of superoxide and ET-1 in diabetic glomeruli. The basal ET-1 production was markedly attenuated by ROS scavengers including superoxide dismutase, catalase, dimethyl sulf- oxide, and deferoxamine in diabetic glomeruli. Exogenous ROS generated by xanthine/xanthine oxidase significantly enhanced ET-1 generation by both diabetic and normal glomeruli. A high glucose concentration (500 mg/dL) in vitro increased ET-1 production by normal glomeruli but not diabetic glomeruli, and insulin partly suppressed ET-1 production by diabetic glomeruli. The in vivo study demonstrated that when diabetic rats were injected daily with superoxide dismutase or catalase after diabetes was induced, the basal production of ET-1 was markedly attenuated after 1 week and 1 month, respectively. These results indicate that exogenously or endogenously derived ROS can enhance ET-1 production by diabetic rat glomeruli and that ROS scavengers suppress ET-1 production both in vitro and in vivo. The effects of ROS on ET-1 production of diabetic glomeruli may be partly caused by the effect of hyperglycemia or insulin deficiency. (J Lab Clin Med 2000;135:309-15)

Oxygen free radicals have been implicated in mediating diabetic complications, and patients with diabetic nephropathy frequently show increased levels of circulating and oxidized low–density lipoproteins (LDL). In the present study, we measured the superoxide production of glomeruli isolated from poorly controlled diabetic (streptozotocin) rats sacrificed 1 week and 1, and 3 months after the induction of diabetes. The animals were stimulated with native and oxidized LDL isolated from normal humans with normolipidemia. The superoxide ion was measured by using a spectrophotometer. The results demonstrated that the poorly controlled diabetic rat glomeruli showed a significantly higher production of superoxide than normal glomeruli under basal conditions, and this production increased further with the progression of diabetes. Stimulation with either LDL or oxidized LDL enhanced superoxide production by diabetic glomeruli, with oxidized LDL being more potent than LDL. Our results suggest that oxidized LDL may play important roles in the pathogenesis of diabetic nephropathy through enhanced generation of oxygen free radicals.

Induction of heat shock protein 70 protects mesangial cells against oxidative injury. The heat shock response is an immediate cellular response to elevated temperatures and other types of injury that consists of the synthesis of so-called heat shock protein (hsp). This study was designed to investigate the production and the protective role of the 70kDa hsp (hsp70) in cultured rat mesangial cells. When mesangial cells undergo thermal (45°C, 15 min) stimulation, they express hsp70 mRNA expression and increased hsp70 protein production. Following this, Northern blots show an enhanced gene expression of hsp70 at one hour that reached a maximum by 12 hours after heat shock. The hsp70 protein production, estimated by Western blots, was detectable 12 hours after heat shock and reached a maximum by 36 hours. Oxidative injury generated by xanthine and xanthine oxidase inhibited cell survival and cellular proliferation, as measured by trypan blue exclusion and [ 3 H]-labeled thymidine uptake. It did not affect hsp70 mRNA expression. Furthermore, when mesangial cells were preconditioned by heat shock, subsequent oxidative injury caused less inhibition of cell survival and cellular proliferation. Pretreatment of cells with quercetin, a transcription inhibitor, abolished the protective effect of heat shock on subsequent oxidative injury. We conclude that heat shock, not oxidative injury, induces hsp70 in mesangial cells, and this induction of hsp70 protects mesangial cells against subsequent oxidative injury.

The value of serum transaminases (ST) in evaluating hepatitis B (HBV) and C (HCV) infection was studied in 217 hemodialysis (HD) patients and 804 normal controls. Mean serum aspartate aminotransferase (AST) was 22.3 (22.0-22.7) and 22.6 (21.6-23.6) IU/l or 0.371 (0.366-0.378) and 0.376 (0.36-0.393) mu kat/l in controls and HD patients, respectively (nonsignificant), while mean serum alanine aminotransferase (ALT) was 20.3 (19.9-20.7) and 16.3 (15.3-17.3) IU/l or 0.338 (0.331-0.345) and 0.271 (0.255-0.288) mu kat/l in these two groups (p < 0.001). However, both AST and ALT became significantly depressed in HD patients after adjusting for age, gender, HBV surface antigen (HBsAg) and anti-HCV. The usual practice of regarding AST and ALT as being 'abnormal' in evaluating viral hepatitis when they exceeded the upper reference range (40 and 46 IU/l or 0.666 and 0.766 mu kat/l in our laboratory) was then critically assessed by the receiver operating characteristic (ROC) curve. ROC analysis showed that ST was useless in detecting HBsAg, while the best cutoff point for detecting the presence of anti-HCV was 18 IU/l (0.3 mu kat/l) for AST and 16 IU/l (0.266 mu kat/l) for ALT in HD patients, respectively. These are considerably lower than the conventional criteria for an 'abnormal' ST. We conclude that ST are decreased in HD patients and that the cutoff value of ST for detecting HCV should be set at lower levels to enhance their diagnostic yield.

The present study was designed to determine whether brain natriuretic peptide (BNP) is synthesized in the human adrenal gland and, if so, to investigate the BNP content of adrenal tissue and the changes in BNP messenger ribonucleic acid (mRNA) in patients with primary aldosteronism. A considerable amount of BNP-like immunoreactive substances was extracted from the adrenal glands of kidney donors for transplantation (0.21 +/- 0.02 pmol/g wet tissue; n = 3) and the remnant nontumorous adrenal glands of patients with primary aldosteronism (0.20 +/- 0.05 pmol/g wet tissue; n = 3; mean +/- SEM). Immunohistochemical study with a specific antihuman BNP antibody revealed that BNP-like immunoreactivity was localized in the adrenal medullary area, and an in situ hybridization study indicated that the BNP mRNA was mainly expressed in the cells of adrenal medulla. Using a reverse transcription and polymerase chain reaction technique, BNP complementary DNA was cloned from the human adrenal gland, and the sequence was identical to that of BNP identified in the atria. The level of BNP mRNA in the adrenal glands of patients with primary aldosteronism (n = 4) was obviously elevated compared to that in the kidney donors (n = 4), as determined by Northern blot analysis. Quantitative polymerase chain reaction measurements of BNP and atrial natriuretic peptide (ANP) mRNAs showed that both of the adrenomedullary natriuretic peptide gene transcriptions were enhanced in patients with primary aldosteronism, but the amount of ANP mRNA was far higher than that of BNP mRNA in the human adrenal gland. Our results are the first to indicate that BNP is synthesized in the human adrenal medulla, and that such medullary BNP synthesis increases in patients with primary aldosteronism. These facts support the proposal that adrenomedullary BNP along with ANP may play some role in water and electrolyte homeostasis or act in a paracrine manner to regulate adrenocortical functions.

Deferoxamine (DFO) was administered during the first 2 hours of hemodialysis and aluminum (Al) kinetics was studied during the next dialysis in 24 hemodialysis patients. After DFO administration, plasma Al and ultrafiltrable fraction of plasma Al increased significantly, and a reduction of 37.4 % in plasma Al after dialysis was obtained. The results demonstrated that DFO administered at the beginning of dialysis was effective in enhancement of Al removal during the subsequent dialysis. In the treatment of Al intoxication in hemodialysis patients, an administration of DFO at the beginning of every other dialysis is recommended.

Epidermal growth factor (EGF) concentrations in the plasma, kidneys and urine of 31 streptozotocin-diabetic rats and 21 insulin-treated diabetic rats were measured to study the role of EGF in initiating renal hypertrophy in the diabetic rats. Renal hypertrophy occurred from day 7 in the diabetic rats, but not in the insulin-treated rats. Renal EGF was not different between the diabetic and control rats, while that in the insulin-treated rats was significantly less than in the diabetic rats. There were no significant changes in plasma EGF in any of the rats. Urine EGF was 119 +/- 7.9 ng/day at day 7 in the control rats but it was significantly increased from day 2 in the diabetic rats (320 +/- 52.9 ng/day at day 2 and 298 +/- 18.4 ng/day at day 7), while in the insulin-treated rats it was significantly less than that in the diabetic rats (134 +/- 8.34 ng/day at day 2 and 220 +/- 15.2 ng/day at day 7). Since the kidney is the main source of urine EGF and EGF has been shown to induce renal growth both in vitro and in vivo, we conclude that EGF may have initiated renal hypertrophy in diabetic rats.

Eight nonnatriuretic (daily Na excretion less than 50 mEq), 4 natriuretic (daily Na excretion greater than 50 mEq), and 4 steroid-responsive nephrotic patients, and 12 normal controls were studied with a 4-hour water immersion with measurements of electrolytes, plasma atrial natriuretic peptide (ANP), plasma renin activity (PRA), and plasma aldosterone (PA) [corrected]. Four nonnatriuretic patients further received 25 g albumin infusion, with a subsequent 2-hour water immersion study. The results are as follows: (1) In the nonnatriuretic patients, the extremely low basal Na excretion rate, high PRA, and PA levels indicated a state of active Na retention. In spite of the water-immersion induced suppression of PRA and PA and a comparable magnitude of plasma ANP increment, the natriuretic response to water immersion was blunted in the nonnatriuretic patients. (2) In the natriuretic patients, water immersion resulted in a similar magnitude of natriuresis but a higher degree of plasma ANP increment in comparison to the normal controls. (3) Natriuretic and plasma ANP responses to water immersion were not different between the steroid-responsive patients and normal controls. (4) The increase in plasma ANP and the suppression of PRA and PA after 25 g albumin infusion did not result in natriuresis until the further suppression of PRA and PA and the further stimulation of plasma ANP by subsequent water immersion. The above results indicate that the natriuretic and plasma ANP responses to water immersion are related to the basal Na status in nephrotic patients.(ABSTRACT TRUNCATED AT 250 WORDS)