Minimal proteinuria one year after transplant is a risk factor for graft survival in kidney transplantation

It is generally accepted that one-year post-transplant proteinuria over 0.5 gm per day has a negative impact on renal graft survival. In this study, the effects of minimal proteinuria less than 0.5 g/day were analyzed in 272 renal recipients who had survived for one year with a functioning graft. Recipients were classified by one-year post-transplant proteinuria: no proteinuria group (<0.2 g/day), minimal proteinuria group (0.2-0.5 g/day), and overt proteinuria group (>or=0.5 g/day). Recipients were followed up for 87.1+/-21 months after transplantation and 38 (13.9%) lost their graft during follow-up. Fifteen percent of patients had minimal proteinuria and 7.8% had overt proteinuria. Five-year graft survival in the minimal proteinuria group was 83.0%, and that in the overt proteinuria group was 70%, in contrast to 97.1% in the no proteinuria group (p=0.01 for trend). In a multivariate analysis, the minimal proteinuria group (relative risk [RR], 4.90; 95% confidence interval [CI], 2.09-11.46) and the overt proteinuria group (RR, 8.75; 95% CI, 3.29-23.29) had higher risks of graft failure than the no proteinuria group. Even minimal proteinuria at one year after transplantation was strongly associated with poor graft outcome. Therefore, it appears logical to consider a low level of proteinuria as a risk factor for graft survival in renal recipients.

Hypoxia induces connective tissue growth factor mRNA expression

Connective tissue growth factor (CTGF) is known to be a profibrotic growth factor, which mediate the fibrotic effect of transforming growth factor-beta (TGF-beta) and to stimulate cell proliferation and matrix production. CTGF has been shown to be hypoxia-inducible in several cell types. Here we investigated the effect of hypoxia on CTGF gene expression in cultured mouse renal tubular cells (MTC). Quiescent cultures of MTC were exposed to hypoxia (1% O(2)) or normoxia in serum-free medium. The effects on hypoxia-induced CTGF expression were evaluated by Northern blot and real-time PCR. The roles of mitogen-activated protein kinase (MAPK) and TGF-beta were also determined using specific biochemical inhibitors. Exposure of quiescent tubular cells to hypoxia for 24 hr in a conditioned medium resulted in a significant increase TGF-beta. Hypoxia caused a significant increase in CTGF mRNA expression in MTC. Either JNK or ERK inhibitor did not block the hypoxia-induced stimulation of CTGF, whereas an inhibitor of p38 MAPK reduced the hypoxia-induced changes of CTGF. Although hypoxia stimulated TGF-beta production, neutralizing anti-TGF-beta1 antibody did not abolish the hypoxia-induced CTGF mRNA expression. The data suggest that hypoxia up-regulates CTGF gene expression, and that p38 MAPK plays a role in hypoxic-stimulation of CTGF. We also demonstrated that hypoxia induces CTGF mRNA expression via a TGF-beta1-independent mechanism.

N-terminal pro-brain natriuretic peptide levels predict left ventricular systolic function in patients with chronic kidney disease

N-terminal pro-brain natriuretic peptide (NT-proBNP) can be a useful marker for left ventricular (LV) dysfunction in patients without kidney disease. This study was conducted to clarify the relationship between NT-proBNP and LV systolic function in patients with decreased renal function. We studied 256 chronic kidney disease (CKD) patients, patients on dialysis were excluded. The median glomerular filtration rate was 24 (13-36) mL/min/1.73 m(2) and the median NT-proBNP was 4,849 (1,310-19,009) pg/mL. The prevalence of LV systolic dysfunction increased from the lower to the upper NT-proBNP quartiles (I, 17%; II, 34%; III, 61%; and IV, 72%; p<0.001 for trend). The NT-proBNP quartile was an independent predictor of LV systolic dysfunction after adjustment for renal function, compared with quartile I: II, odds ratio (OR) 3.99 (95% confidence interval [CI],1.34-11.93); III, OR 11.28 (95% CI, 3.74-33.95); and IV, OR 36.97 (95% CI, 11.47-119.1). Area under the curve and optimum cut points for NT-proBNP to detect LV systolic dysfunction were 0.781 and 2,165 pg/mL in CKD stage 3, 0.812 and 4,740 pg/mL in CKD stage 4, and 0.745 and 15,892 pg/mL in CKD stage 5. The NT-proBNP level was a predictor of LV systolic dysfunction in CKD patients. Optimum cut points should be stratified according to renal function.

Serum cholesterol in idiopathic and lupus-related protein-losing enteropathy

Abstract The characteristics of protein-losing enteropathy were evaluated in patients with systemic lupus erythematosus. Among the patients with systemic lupus erythematosus (n=380) in a tertiary hospital, we reviewed the records of seven patients with generalized edema, hypoalbuminemia without proteinuria and positive results on 99mTc-labelled human serum albumin scintigrams. Patient characteristics and laboratory findings were compared between these seven patients and patients with lupus enteritis (n=15) or idiopathic protein-losing enteropathy (n=11). Compared with the lupus enteritis patients, the erythrocyte sedimentation rate and serum total cholesterol levels were significantly increased in patients with systemic lupus erythematosus-related protein-losing enteropathy. Compared with idiopathic protein-losing enteropathy patients, the level of serum total cholesterol was significantly increased, but the level of serum albumin was decreased in patients with systemic lupus erythematosus-related protein-losing enteropathy. Among patients with systemic lupus erythematosus-related protein-losing enteropathy, four patients had high serum total cholesterol levels (>or=248 mg/dL) and achieved complete remission after receiving high doses of steroid treatment. However, three patients who had low serum total cholesterol levels (<or=219 mg/dL) responded poorly to the steroid-only treatment, and could achieve complete remission only after 3 months of cyclophosphamide pulse treatment with concurrent corticosteroid therapy. The levels of serum total cholesterol are intriguing feature in systemic lupus erythematosus-associated protein-losing enteropathy patients.

Association between changes in N-terminal pro-brain natriuretic peptide levels and changes in left ventricular mass index in stable hemodialysis patients

BACKGROUND/AIMS

Left ventricular (LV) hypertrophy is a powerful predictor of mortality in dialysis patients. Serial measurements of LV mass provide prognostic information. We evaluated the association between changes in biomarkers and changes in LV mass index (LVMI) in hemodialysis (HD) patients.

METHODS

This was a prospective study of 21 stable HD patients with preserved LV ejection fraction (> or =50%). Echocardiography and measurements of N-terminal pro-brain natriuretic peptide (NT-proBNP), brain natriuretic peptide (BNP) and cardiac troponin T were performed on the same day and repeated 6 and 12 months later.

RESULTS

At baseline, the NT-proBNP and BNP levels correlated with LVMI. Percent changes in LVMI were positively associated with those in log-transformed NT-proBNP levels during both the first (baseline vs. month 6, r = 0.78, p < 0.001) and the second 6 months (months 6 vs. 12, r = 0.73, p < 0.001). Among the 3 biomarkers, NT-proBNP was the only one that was related to changes in LVMI by multivariate correlation analysis, including age, sex, blood pressure, predialysis weight and use of angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker.

CONCLUSION

Our results show that changes in LVMI are closely correlated with variation in NT-proBNP levels in HD patients. These data have significant implications for the application of NT-proBNP as a biomarker for assessing changes in LVMI in HD patients.

Systemic lupus erythematosus complicated by acquired von Willebrand’s syndrome

Haematological abnormalities are common in systemic lupus erythematosus (SLE). In some cases of acquired von Willebrand syndrome (AvWS), von Willebrand disease (vWD) is associated with autoimmune or lymphoproliferative disorders. In this study, we describe a 36-year-old woman with SLE and AvWS. The patient was referred to our hospital because of easy bruisability and recurrent vaginal bleeding. She had no history of bleeding tendency and no family history of bleeding diathesis, but she had a history of recurrent arthralgia, photosensitivity and sicca symptoms. Tests for antinuclear, anti–double stranded DNA, anticardiolipin and anti–β2-glycoprotein I antibodies were all positive. Analysis of haemostatic parameters showed complete absence of von Willebrand factor ristocetin cofactor (vWF:Rco), von Willebrand antigen (vWF:Ag) and ristocetin-induced platelet aggregation (RIPA). Electrophoretic analysis of plasma showed a complete absence of high–molecular weight vWF multimer. The presence of antibody to vWF was detected by enzyme linked immunosorbent assay (ELISA). Treatment with corticosteroids improved SLE symptoms and corrected bleeding diasthesis. Also, the multimeric patterns of vWF became normalised and anti–vWF antibody disappeared. These findings indicated that this patient had SLE associated with AvWS, which was ameliorated by corticosteroid treatment.

Behcet's disease associated with bone marrow failure in Korean patients: clinical characteristics and the association of intestinal ulceration and trisomy 8

OBJECTIVES

The aim of this study was to determine the clinical characteristics of Behcet's disease (BD) associated with bone marrow failure (BMF), classified as conditions such as myelodysplastic syndrome (MDS) or aplastic anaemia (AA), in Korea.

METHODS

A retrospective analysis was made of 13 patients with BD associated with BMF (MDS 8 cases, AA 5 cases) and 66 patients with BD not associated with BMF. These patients all fulfilled the diagnostic criteria of the international BD study group.

RESULTS

BD patients with BMF showed significantly lower leucocyte count, haemoglobin level and platelet count when compared with patients without BMF (P < 0.001). BD patients with BMF had significantly higher serum CRP level at the time of BD diagnosis compared with patients without BMF (P = 0.03). Intestinal lesions were more frequent in BD patients with BMF than those without BMF (61.5% vs 13.6%, P = 0.001). Cytogenetic abnormality was observed in 90.9% of BD patients with BMF. Of the cytogenetic abnormalities, trisomy 8 was most common, occurring in 70% of the patients. In four patients with refractory BD associated with BMF, successful treatment of BMF by haematopoietic stem cell transplantation resulted in clinical remission of BD.

CONCLUSIONS

Our study indicates that intestinal ulceration is a characteristic finding in BD associated with BMF. It also suggests that cytogenetic aberration, especially trisomy 8, may play an important role in the pathogenesis of BD associated with BMF.

Metabolic syndrome, C-reactive protein, and chronic kidney disease in nondiabetic, nonhypertensive adults

BACKGROUND

Metabolic syndrome has been suggested as a risk factor for chronic kidney disease (CKD). Inflammation is associated with both metabolic syndrome and CKD. We investigated inter-relationships between C-reactive protein (CRP), metabolic syndrome, and CKD among 9586 subjects without diabetes or hypertension.

METHODS

Metabolic syndrome was defined according to the criteria of the revised Adult Treatment Panel III. CKD was defined as a glomerular filtration rate <60 mL/min/1.73 m(2) or as albuminuria. A CRP cutpoint of 3 mg/L was used to differentiate high and low CRP groups.

RESULTS

Chronic kidney disease was present in 6.2% of subjects without metabolic syndrome and in 13.1% of subjects with the syndrome (P < .001). In a multivariate model, high blood pressure (BP) (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.24-1.95), high fasting glucose (OR, 1.47; 95% CI, 1.19-1.81), abdominal obesity (OR, 1.52; 95% CI, 1.22-1.81), and high CRP (OR, 1.53; 95% CI, 1.18-1.98) were independently associated with prevalent CKD. Compared with low CRP/without metabolic syndrome, the multivariate-adjusted odds for CKD of high CRP/without metabolic syndrome and low CRP/with metabolic syndrome were 1.48 (95% CI, 1.10-2.0) and 1.90 (95% CI, 1.47-2.45), respectively. Subjects with high CRP and metabolic syndrome had a 3.26-fold greater odds of having CKD (95% CI, 2.00-5.31).

CONCLUSIONS

Metabolic syndrome and high CRP were independently associated with increased prevalence of CKD. The odds of CKD increased in the setting of high CRP and metabolic syndrome.

Association of metabolic syndrome with microalbuminuria in non-hypertensive type 2 diabetic patients

BACKGROUND

Several studies have shown that metabolic syndrome contributed to the development of incident chronic kidney disease in the general population. We evaluated the cross-sectional association between metabolic syndrome and microalbuminuria in patients with type 2 diabetes. We excluded patients with hypertension to distinguish the effects of metabolic syndrome from those of hypertension.

METHODS

A total of 642 non-hypertensive patients with type 2 diabetes were recruited. Metabolic syndrome was assessed according to the NCEP Guidelines and Asian-Pacific criteria for abdominal obesity.

RESULTS

Among all patients, 37.2% were diagnosed as having metabolic syndrome, and these patients had a higher prevalence of microalbuminuria than those without metabolic syndrome (19.7 vs. 13.6%, p = 0.044). There was a graded association between metabolic score and the prevalence of microalbuminuria (p = 0.006 for trend). After adjustment for sex, age, smoking status, C-reactive protein, and HbA(1c), patients with metabolic syndrome had increased odds of 1.58 (95% CI 1.01-2.47) for microalbuminuria. An increment in metabolic score was found to increase the risk of microalbuminuria by 1.34-fold (95% CI 1.07-1.66, p = 0.008).

CONCLUSION

This study demonstrated that metabolic syndrome was associated with an increased risk of microalbuminuria in non-hypertensive patients with type 2 diabetes.

The JAK2 V617F mutation in de novo acute myelogenous leukemias

A missense somatic mutation in JAK2 gene (JAK2 V617F) has recently been reported in chronic myeloproliferative disorders, including polycythemia vera, essential thrombocythemia and myelofibrosis with myeloid metaplasia, strongly suggesting its role in the pathogenesis of myeloid disorders. As activation of JAK2 signaling is occurred in other malignancies as well, we have analysed 558 tissues from common human cancers, including colon, breast and lung carcinomas, and 143 acute adulthood leukemias by polymerase chain reaction -- single strand conformation polymorphism analysis. We found three JAK2 mutations in the 113 acute myelogenous leukemias (AMLs) (2.7%), but none in other cancers. The mutations consisted of two V617F mutations and one K607N mutation. None of the AML patients with the JAK2 V617F mutation had a history of previous hematologic disorders. This is the first report on the JAK2 gene mutation in AML, and the data indicated that the JAK2 gene mutation may not only contribute to the development of chronic myeloid disorders, but also to some AMLs.

Serum uric acid is associated with microalbuminuria in prehypertension

Serum uric acid is associated with cardiovascular disease. However, the independent role of uric acid in the development of cardiovascular disease is uncertain. This study examined the cross-sectional association of serum uric acid level with microalbuminuria among 6771 subjects without diabetes or hypertension. Blood pressure was categorized as prehypertension (systolic blood pressure, 120 to 140 mm Hg or diastolic blood pressure, 80 to 90 mm Hg) and normotension (systolic blood pressure, <120 mm Hg and diastolic blood pressure, <80 mm Hg). Microalbuminuria was found in 4.0% of normotensive subjects (n=4819) and in 7.9% of prehypertensive subjects (n=1952). Prehypertensive subjects with microalbuminuria had higher uric acid level than those with normoalbuminuria (men, 387 [68] mmol/L versus 371 [69] mmol/L; P=0.017; women 286 [56] mmol/L versus 262 [54] mmol/L; P=0.006). However, the difference in serum uric acid level according to the presence or absence of microalbuminuria was not found in the normotensive group. Multiple logistic regression models showed that, in the prehypertensive group, after adjustment for other cardiovascular risk factors, the highest uric acid quartile entailed >2 times greater risk for microalbuminuria than the lowest quartile in both men (odds ratio, 2.12; 95% CI, 1.16 to 3.87) and women (odds ratio, 3.36; 95% CI, 1.17 to 9.69). In the normotensive group, serum uric acid quartile did not show the independent association with microalbuminuria. In conclusion, serum uric acid level was strongly associated with microalbuminuria in prehypertensive subjects.

Hemodialysis Using Heparin-Bound Hemophan in Patients at Risk of Bleeding

BACKGROUND/AIMS

Since heparin can bind to Hemophan, hemodialysis using heparin-bound Hemophan (HBH-HD) could be a useful modality in patients at risk of bleeding. We designed a simplified heparin binding technique and assessed the safety and efficiency of HBH-HD.

METHODS

To bind heparin to Hemophan, heparin solution (1 liter, 20 IU/ml saline) was recirculated through Hemophan (GFS plus 11, Gambro) for 1 h while the saline solution (700 ml/h) was removed. In 28 maintenance dialysis patients at risk of bleeding, we evaluated the heparin concentration (HC) and activated partial thromboplastin time (aPTT) during HBH-HD to assess the increased risk of bleeding. We compared the safety and efficiency of HBH-HD with that of routine hemodialysis with low-dose heparinization (R-HD) in a prospective cross-over study, and then analyzed the outcomes of 1,057 HBH-HD in 159 patients.

RESULTS

During HBH-HD, there was a slight increase in both HC (0.15 +/- 0.03 IU/ml, p < 0.01) and aPTT (43.7 +/- 5.7 s, p < 0.01) at 15 min after the initiation of dialysis compared to predialysis levels (0.11 +/- 0.03 IU/ml and 37.5 +/- 6.3 s). However, there was no increase in HC and aPTT at 60 min, 120 min and at the end of dialysis. In a cross-over study, aPTT during dialysis was markedly lower in HBH-HD than in R-HD (p < 0.01). The Kt/V (1.22 +/- 0.31, p > 0.05) and urea clearance (136 +/- 17 ml/min, p > 0.05) of HBH-HD did not significantly differ from those of R-HD (1.29 +/- 0.57 and 136 +/- 13 ml/min). However, the loss of total blood compartment volume of the dialyzer was greater in HBH-HD (17.5 +/- 9.2%, p < 0.01) than in R-HD (2.9 +/- 1.2%). Out of 1,057 HBH-HD, 982 HBH-HD (93%) were successfully completed while 75 HBH-HD (7%) resulted in severe clotting.

CONCLUSION

We conclude that the HBH-HD could minimize the bleeding risk and be an efficient HD technique in patients at high risk of bleeding. Careful observation for extracorporeal clotting is, however, required during HBH-HD.

Ultrastructural study on nephrin expression in experimental puromycin aminonucleoside nephrosis

BACKGROUND

Nephrin is a recently identified protein that is a key component of the slit diaphragm. This protein may play a crucial role in maintaining the glomerular filtration barrier, and mutations in the gene for nephrin reportedly lead to congenital nephrosis. However, the expression of nephrin in acquired glomerular disease has not yet been fully clarified. To address this issue, we analysed the expression and localization of nephrin by morphological analysis based on immunoelectron microscopy in normal glomeruli and in glomeruli from proteinuric experimental models.

METHODS

Twenty rats were divided into three experimental groups (n = 16 total) and a control group (n = 4). Rats in the experimental groups received a single intravenous injection of puromycin aminonucleoside (PAN), and were sacrificed at 1 (n = 4), 2 (n = 6) and 3 weeks (n = 6) post-injection. Nephrin expression was assessed by immunoelectron microscopy using a polyclonal antibody against nephrin and gold particles. It was quantified by counting the gold particles and the slit diaphragms and by measuring the average foot process width in microphotographs.

RESULTS

The average foot process width in the 1 week group (5924.5 +/- 1523.9 nm) was far greater than that of controls (1112.9 +/- 79.8 nm), but decreased thereafter. The average number of total gold particles per unit length (10 000 nm) of the glomerular basement membrane (GBM) underlying the foot processes was reduced at 1 week (26.0 +/- 9.5), compared with controls (335.3 +/- 125.5), but increased thereafter. Also, the average number of junctional gold particles per unit length of the GBM was lower than controls (208.4 +/- 1.7) at 1 week (10.1 +/- 3.5), but increased thereafter. There were no significant differences between the numbers of junctional gold particles per slit diaphragm among the groups, but significant differences were observed in the distributions of gold particles among the groups. Gold particles were more frequently seen in cytoplasm at 1 week.

CONCLUSIONS

The present ultrastructural studies showed that nephrin expression and its distribution were altered in PAN-treated rats, and this occurred in parallel with foot process effacement. Nephrin expression returned to normal with improved resolution of the effacement. Nephrin expression was found to be rather preserved in areas without foot process effacement, even in PAN-treated rats. The significance of the above findings in terms of proteinuria and foot process effacement needs further clarification.

Effect of panel-reactive antibody positivity on graft rejection before or after kidney transplantation

INTRODUCTION

Because it is well known that kidney transplant recipients with preformed lymphocytotoxic antibodies against HLA antigens have increased graft rejection rates, a serological crossmatch is routinely performed before kidney transplantation. But, the presence of these antibodies is not routinely monitored after transplantation. We investigated the panel-reactive antibody (PRA) response to know whether variations before or after kidney transplantation were associated with graft rejection.

METHODS

We prospectively analyzed sera from 350 renal allograft recipients from September 1998 to March 2003. Pretransplantation and posttransplantation sera at 3 or 5 weeks postoperatively were tested in PRA. Recipients were stratified into 3 groups according to their PRA levels group I, PRA = 0; group II, PRA = less than 50%, and group III, PRA = more than 50%.

RESULTS

The total graft rejection rate among 350 recipients was 9.4% (n = 33). Twenty-four pretransplantation PRA-positive recipients had a graft rejection rate of 20.8% (n = 5), compared with an 8.6% (n = 28) rate among 326 pretransplantation PRA-negative recipients. Six of 24 posttransplantation PRA-positive recipients (25%) experienced a graft rejection versus 27 (8.3%) of 326 posttransplantation PRA-negative subjects. Among the pretransplantation PRA stratae, the rejection rate in group III was 25% (1 of 4) versus 20% (4 of 20) in group II and 8.6% (28 of 326) in group I (P < .05). According to the postransplantation PRA level, 37.5% (3 of 8) in group III versus 18.8% (3 of 16) in group II and 8.3% (27 of 326) in group I (P < .05) had a graft rejection.

CONCLUSION

Our study suggests that the PRA response pretransplantation and in the early posttransplantation period correlates with the kidney allograft rejection rate.

Prognostic factors affecting graft and patient survival in cadaveric and living kidney transplantation

Numerous studies have reported various prognostic factors that affect graft and patient survival in living and cadaveric donor kidney transplantation (KT). The purpose of this study was to evaluate the clinical outcomes and prognostic factors affecting graft and patient survivals in living and cadaveric donor KT. Between February 1995 and December 2001, 421 patients who had undergone cadaveric donor KT (group I: 216 cases, 51.3%) or living donor KT (group II: 205 cases, 48.7%), were retrospectively analyzed. Five-year overall graft survival rates in living was significantly better than that in cadaveric donor KT, respectively (P = .0234). There was no difference in patient survival rates between the two groups. Such factors as absence of rejection, female donor, female recipient, adult KT according to recipient age (>14 years), and donor serum creatinine level just before transplantation (< 2.5 mg/dL) were significantly associated with good graft survival among cadaveric donor KT, whereas two factors-absence of rejection and adult KT according to recipient age (>14 years)-influenced graft survival in living donor KT. In multivariate analysis, the only significant prognostic factor related to graft survival was the presence of rejection. In conclusion, we suggest that the presence of rejection is the only factor that impairs graft survival in both cadaveric and living donor KT, while other factors affected graft survival differently in the two groups.

Bioequivalence of a prednisolone tablet administered as a single oral dose in healthy male volunteers

OBJECTIVE

A bioequivalence study ofprednisolone as Nisolone (test) tablets versus Delta-Cortef (reference) tablets was conducted.

PATIENTS AND METHODS

Eighteen healthy male Korean volunteers received both 20 mg formulations of prednisolone in this 2 x 2 crossover study with a 1-week washout period between the doses. Plasma concentrations of prednisolone were monitored over a period of 12 hours after the administration using high-performance liquid chromatography. The AUC (area under the plasma concentration-time curve from time zero to infinity) and AUCt (area under the plasma concentration-time curve from time zero to the last sampling time) were calculated using the trapezoidal rule-extrapolation method. The Cmax (maximum plasma drug concentration) and t(max) (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUC, AUCt and Cmax and untransformed t(max).

RESULTS

The geometric mean of AUCt was 1,786 ng/ml x h (test medication) and 1,787 ng/ml xh (reference medication). A Cmax of 409 ng/ml and 404 ng/ml was achieved for the test and the reference medication, respectively. Point estimates and 90% confidence intervals for AUCt (parametric) and Cmax (parametric) were 0.989 (0.942 approximately 1.039) and 1.013 (0.934 approximately 1.100), respectively. These results satisfy the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. The corresponding value of t(max) was -0.221 (-0.415 approximately 0.000).

CONCLUSION

The 2 medications of prednisolone examined are bioequivalent and, thus, may be prescribed interchangeably.

Polymerase chain reaction for the diagnosis of human polyomavirus-associated nephropathy in renal transplant recipients

Human polyomavirus type BK may be related to interstitial nephropathy or renal-allograft dysfunction. Patients with nephropathy due to infection with human polyomavirus may be identified early using the polymerase chain reaction(PCR). We attempted to evaluate whether the positive response in the PCR test of BK virus DNA in the plasma of renal transplant recipients affects the function of the renal allograft. Seventy-seven patients were prospectively analyzed according to the operative sex, age, sources of allograft, serum creatinine levels during PCR test for BK virus, postoperative type of immunosuppressant, and presence of graft rejection. Two groups were distinguished according to the PCR result for BK virus: group 1 (n = 12) positive PCR reaction and group 2 (n = 65) negative reaction. The mean follow-up was 32.6 weeks. The incidence of positive PCR tests for BK virus replication after renal transplantation was 15.6%. Decoy cells in the urine were detected in 20.7%. The incidence of BK virus nephropathy was 1.3%. The mean serum creatinine levels of group 1 and 2 at the time of the PCR tests were 1.34 and 1.22, respectively. The rejection rates in group 1 and 2 were 8% and 4.5%, respectively (P > .05). We consider that a PCR assay to detect BK virus in renal recipients blood may be useful to identify patients at risk for nephropathy. It may serve as a noninvasive indicator of BK virus replication, although this study is limited by the short follow-up and small numbers.

Bioequivalence of pravastatin tablet formulations assessed in Korean males

AIM

Determination of the bioequivalence of 2 pravastatin tablet formulations manufactured in Korea.

PATIENTS AND METHODS

Twenty-three healthy male Korean volunteers received each of the 2 pravastatin formulations at a dose of 20 mg in a 2 x 2 crossover study. There was a 1-week washout period between doses. Plasma concentrations of pravastatin were monitored using high-performance liquid chromatography over a period of 8 hours after administration. AUC(0-8h) (the area under the plasma concentration-time curve from time zero to the last measured time in plasma, 8 h) was calculated using the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUC(0-8h) and Cmax and untransformed tmax.

RESULTS

The point estimates and 90% confidence intervals for AUC(0-8h) (parametric) and Cmax (parametric) were 1.067 (0.968 to approximately 1.176) and 1.074 (0.999 to approximately 1.155), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. The corresponding value of tmax was 0.000 (-0.250 to approximately 0.250).

CONCLUSION

These results indicate that the 2 medications of pravastatin are bioequivalent and, thus, may be prescribed interchangeably.

Comparative bioavailability of silibinin in healthy male volunteers

AIM

To study a comparative bioavailability of Liverman capsule to Legaion capsule and Silymarin tablet (which contain silibinin) in 24 healthy volunteers.

VOLUNTEERS AND METHODS

Twenty-four healthy male Korean volunteers received each medicine at the silibinin dose of 120 mg in a 3 x 3 crossover study. There was a 1-week washout period among the doses. Plasma concentrations of silibinin were monitored by a high-performance liquid chromatography for over a period of 12 hours after the administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated by the trapezoidal rule extrapolation method. Cmax (maximum plasma drug concentration) and tmax (time to reach a Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf, AUC(0-12h), and Cmax and untransformed tmax.

RESULTS

After an oral administration of Liverman capsule, the pharmacokinetic parameters of silibinin, such as AUC(0-12h) (5.59, 4.24 and 13.9 microg/ml x h for Legalon capsule, Silymarin tablet and Liverman capsule, respectively) and AUCinf (6.00, 4.63 and 15.1 microg/ml x h) were significantly greater, Cmax (1.33, 1.13 and 6.04 microg/ml) was significantly higher and tmax (1.83, 2.10 and 0.875 h) was significantly faster than those after Legalon capsule and Silymarin tablet.

CONCLUSION

These results indicate that the absorption and the extent of relative oral bioavailability of silibinin after Liverman capsule were significantly faster and greater, respectively, than those after Legalon capsule and Silymarin tablet.

Anticoagulation during haemodialysis in patients at high-risk of bleeding

Routine haemodialysis is performed with systemic anticoagulation, usually with heparin, to prevent thrombosis in the extracorporeal blood circuit. However, systemic anticoagulation can produce haemorrhagic complications in patients at high risk of bleeding. To minimize the risk of bleeding, a number of alternative regimens have been proposed: regional heparinization with protamine reversal; minimal heparinization; no heparin with saline flushes; regional anticoagulation with citrate; or prostacyclin anticoagulation. Although the incidence of bleeding complications has been reduced, each of these methods has its own limitations and complications. Among the types of membrane used in dialysers, cellulose membranes have been made more biocompatible by attaching N,N-diethyl-aminoehtyl (DEAE) groups to cellulose backbone. Positively charged DEAE groups on Hemophan enable negative charged heparin to be bound with the membrane. Haemodialysis using heparin-bound Hemophan has been reported to be a possible modality for patients at risk of bleeding. We designed more simplified heparin binding technique and have performed haemodialysis using heparin-bound Hemophan in patients at risk of bleeding during the past 7 years. In this review, current strategies to minimize bleeding complications and our experience of haemodialysis using heparin-bound Hemophan will be discussed.

No effect of cysteine on the pharmacokinetics of intravenous azosemide in rats with protein-calorie malnutrition by pretreatment with 3-methylcholanthrene

The effects of cysteine on the pharmacokinetics of azosemide were investigated after intravenous administration of drug, 10 mg/kg, to male Sprague-Dawley rats pretreated with 3-methylcholanthrene fed on 23% protein diet (control rats) and 5% protein diet without (rats with protein-calorie malnutrition, PCM) or with (rats with PCMC) oral cysteine (250 mg/kg, twice daily starting from the fourth week) for 4 weeks. After intravenous administration to rats with PCM, the metabolites of azosemide excreted in urine and recovered from gastrointestinal tract decreased significantly than those in control rats, however, the plasma concentrations, total area under plasma concentration-time curve from time zero to time infinity (AUC) and time-averaged total body clearance (CL) were not significantly different between two groups of rats. It was reported that after intravenous administration of azosemide, 10 mg/kg, to rats with PCMC without pretreatment 3-methylcholanthrene, some pharmacokinetic parameters restored fully or more than the level of control rats; the time-averaged nonrenal clearance and apparent volume of distribution at steady state were comparable to those in control rats, but the terminal half-life and mean residence time were significantly shorter, AUC was significantly smaller, and time-averaged renal clearance and CL were significantly faster than those in control rats. However, the above mentioned effects of cysteine on the pharmacokinetic parameters of azosemide in rats with PCM were not observed with pretreatment with 3-methylcholanthrene.

Clinical usefulness of human cytomegalovirus antigenemia assay after kidney transplantation

BACKGROUND

Human (H) cytomegalovirus (CMV) infections are a major cause of morbidity and mortality among kidney transplants. We performed a prospective study to evaluate the clinical usefulness of HCMV antigenemia assay for preemptive treatment after kidney transplantation.

METHODS

A total of 100 patients were followed up by HCMV antigenemia assay at posttransplantation weeks 1, 3, 5, 7, 9, 13, 17, and 21. Asymptomatic patients with positive antigenemia were observed without specific antiviral therapy.

RESULTS

Most patients had been given cyclosporine A- and prednisolone-based immunosuppressive therapy (99.0%) and were HCMV seropositive before transplantation (99.0%). A positive antigenemia assay was detected in 41 patients among 97 eligible patients. Symptomatic CMV diseases were observed in 10 of 41 patients. HCMV infections were related to history of acute rejection and use of antithymocyte globulin. HCMV-related symptoms and signs were clearly correlated with the level of antigenemia. All patients who had an HCMV antigenemia titer of higher than 50 per 400,000 leukocytes developed HCMV-related symptoms and signs during the follow-up period. This criterion showed the highest positive predictive value and specificity in the development of symptomatic HCMV infection.

CONCLUSIONS

Data suggest that HCMV antigenemia titer can be used as a useful guide to preemptive treatment of HCMV infection after kidney transplantation in HCMV-positive donor and recipient.

Role of rho-kinase activity in angiotensin II-induced contraction of rabbit clitoral cavernosum smooth muscle

Isometric tension measurement using a selective Rho-kinase inhibitor (+)- (R)-trans4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide (Y-27632) and a selective myosin light chain kinase (MLCK) inhibitor 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML7) were used in rabbit clitoral cavernosum smooth muscle (CSM). N(G)-nitro-L-arginine methyl ester (L-NAME) was used to evaluate the relationship between NO release and Rho-kinase. Y-27632 significantly attenuated contractions induced by ANG II, dose-dependently. However, ML7 did not affect the contractile response to ANG II except in the high concentrations of ML7. Y-27632 inhibited contraction with phenylephrine (PhE), but ML7 did not inhibit contraction with PhE. Nitric oxide synthase inhibitor (NAME) did not affect the Y-27632-induced relaxation in the pre-contracted strip with PhE. The present study demonstrates that G-protein-coupled increase in myofilament Ca(2+) sensitivity mediated through the RhoA/Rho-kinase signal pathway is involved in the control by ANG II of the clitoral CSM tone. RhoA/Rho-kinase pathway acts in the ANG II-induced contraction independently of the NO pathway.

Laser mediated production of reactive oxygen and nitrogen species; implications for therapy

Laser therapy has gained wide acceptance applications to many medical disciplines. The side effect-effects from laser therapy involve the potential for interaction with cellular and extracellular matrix molecules to generate reactive oxygen species and reactive nitrogen species which in turn can initiate lipid peroxidation, protein damage or DNA modification. These issues are addressed in this short overview in the context of experimental models of laser-induced thrombosis.

Analysis of depression in continuous ambulatory peritoneal dialysis patients

It is well known that depression and sense of hopelessness worsen the quality of life in end-stage renal disease (ESRD) patients receiving dialysis. However, the characteristics of depression in continuous ambulatory peritoneal dialysis (CAPD) patients have not been analyzed in detail. We performed this study to investigate the severity of depression and the factors affecting depression in CAPD patients. With 96 CAPD patients, we evaluated each patient's depressive mood and hopelessness with CES-D (Center for Epidemiologic Studies Depression) scale and Beck Hopelessness Scale. We also evaluated the degree of stress of each patient with internal individual stress scale. Most CAPD patients experienced severe depression compared with the general population. Their depression was better explained by psychological factors, such as stress and sense of hopelessness, than by demographic or physical factors. On the basis of these findings, we suggest that the treatment of depression in CAPD patients might be possible by modulation of psychological factors.

Flow measurements via two-particle azimuthal correlations in Au + Au collisions at sqrt [s(NN)]=130 GeV

Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p(T). A breakdown of this epsilon scaling is observed for charged hadrons with pT >1.0 GeV/c.

Effects of neostigmine on the pharmacokinetics of intravenous parathion in rats

It was reported that the area under the plasma concentration-time curve from time zero to time infinity (AUC) of parathion was significantly smaller and the time-averaged total body clearance (CL) of parathion was significantly faster after intravenous administration of parathion to rats pretreated with dexamethasone than those in control rats. This was supported by significantly faster intrinsic clearance of parathion to form paraoxon in hepatic microsomal fraction of rats pretreated with dexamethasone. The above data suggested that parathion was metabolized to paraoxon by dexamethasone-inducible hepatic cytochrome P450 (CYP) 3A in rats. The purpose of this study is to explain the protective effects of neostigmine against paraoxon toxicity by suppressing CYP3A and hence decreasing formation of toxic metabolite, paraoxon by neostigmine. The pharmacokinetic changes of parathion and its active metabolite, paraoxon, were investigated after intravenous administration of parathion, 3 mg/kg, to control Sprague-Dawley rats and the rats pretreated with neostigmine (200 microg/kg, intraperitoneal injection 30 min before parathion administration). After 1-min intravenous infusion of parathion to rats pretreated with neostigmine, the AUC of parathion (65.1 versus 74.3 microg min/ml) was significantly greater and the CL of parathion (45.1 versus 40.4 ml/min/kg) was significantly slower than those in control rats. Based on in vitro hepatic microsomal studies, neostigmine inhibited significantly the erythromycin N-demethylase activity (1.03 versus 0.871 nmol/mg protein/min), mainly mediated by hepatic cytochrome P450 3A in rats. The above data suggested that the formation of paraoxon was inhibited in rats pretreated with neostigmine by inhibiting CYP3A.

Measurement of Lambda and Lambda(macro) particles in Au+Au collisions at the square root of S(NN) = 130 GeV

We present results on the measurement of Lambda and Lambda(macro) production in Au+Au collisions at square root of (S (NN) = 130 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The Lambda;/Lambda ratios are constant as a function of p(T) and the number of participants. The measured net Lambda density is significantly larger than predicted by models based on hadronic strings (e.g., HIJING) but in approximate agreement with models which include the gluon-junction mechanism.

Net charge fluctuations in Au + Au interactions at sqrt[s(NN)]=130 GeV

Data from Au + Au interactions at sqrt[s(NN)]=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays.

Centrality dependence of pi(+/-), K(+/-), p, and (-)p production from sqrt[s(NN)] = 130 GeV Au + Au collisions at RHIC

Identified pi(+/-), K(+/-), p, and (-)p transverse momentum spectra at midrapidity in sqrt[s(NN)] = 130 GeV Au+Au collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleons in a similar way for all particle species. Within errors, all midrapidity particle yields per participant are found to be increasing with the number of participating nucleons. There is an indication that K(+/-), p, and (-)p yields per participant increase faster than the pi(+/-) yields. In central collisions at high transverse momenta (p(T) > or =2 GeV/c), (-)p and p yields are comparable to the pi(+/-) yields.

Transverse-mass dependence of two-pion correlations in Au+Au collisions at square root[s(NN)] = 130 GeV

Two-pion correlations in square root[s(NN)] = 130 GeV Au+Au collisions at RHIC have been measured over a broad range of pair transverse momentum k(T) by the PHENIX experiment at RHIC. The k(T) dependent transverse radii are similar to results from heavy-ion collisions at square root[s(NN)] = 4.1, 4.9, and 17.3 GeV, whereas the longitudinal radius increases monotonically with beam energy. The ratio of the outwards to sidewards transverse radii (R(out)/R(side)) is consistent with unity and independent of k(T).

Measurement of single electrons and implications for charm production in Au+Au collisions at square root[s(NN)] = 130 GeV

Transverse momentum spectra of electrons from Au+Au collisions at square root[s(NN)] = 130 GeV have been measured at midrapidity by the PHENIX experiment at the Relativistic Heavy Ion Collider. The spectra show an excess above the background from photon conversions and light hadron decays. The electron signal is consistent with that expected from semileptonic decays of charm. The yield of the electron signal dN(e)/dy for p(T) > 0.8 GeV/c is 0.025+/-0.004(stat)+/-0.010(syst) in central collisions, and the corresponding charm cross section is 380+/-60(stat)+/-200(syst) microb per binary nucleon-nucleon collision.

Comparison of effects of angiotensin peptides in the regulation of clitoral cavernosum smooth muscle tone

The isometric tension measurement and in vitro autoradiography were used in clitoral cavernosum smooth muscle (CSM). Angiotensin ANG III, ANG IV, ANG II and ANG I induced contractions in clitoral CSM strips. ANG III and ANG I- induced contraction was five times less active than ANG II, whereas ANG IV-induced contraction was 1181-fold less potent than ANG II. Contractile responses to ANG III, ANG IV, ANG II and ANG I were significantly inhibited by type 1 ANG II (AT 1) receptor antagonist Dup 753 but not by type 2 ANG II (AT2) receptor antagonist PD 123,319. Pre-treatment with Nomega-nitro-L-arginine methyl ester, nitric oxide (NO) synthase inhibitor accentuated force of contraction induced by ANG III, ANG IV and ANG II. Amastatin, an aminopeptidase inhibitor enhanced ANG III- and ANG IV-induced contractions. Specific binding sites for 125I-ANG II were found in the clitoral CSM. Specific binding of 125I-ANG II was displaced by unlabeled ANG peptides. This study suggests that the contractile responses to all four peptides of the ANG family are mediated via AT1 receptors but not AT2 receptors. Further, the rank order of potency of contraction was as follows, ANG II> ANG I>ANG III>ANG IV. It is also suggested that peptides of the ANG family have a cross-talk with the NO system and aminopeptidase is involved in the modulation of the tone of clitoral CSM by ANG III and ANG IV.

Suppression of hadrons with large transverse momentum in central Au+Au collisions at root square[s(NN)] = 130 GeV

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 GeV/c<p(T)<5 GeV/c have been measured by the PHENIX experiment at RHIC in Au+Au collisions at root square[s(NN)] = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p+p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p+p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.

Photopatch testing in seven cases of photosensitive drug eruptions

OBJECTIVE

The most important goal in the management of photosensitive drug eruptions, as in other types of drug eruptions is identification of the causative drugs to prevent reexposure to them.

CASE SUMMARIES

Seven patients whose lesions were mainly distributed on sun-exposed areas underwent laboratory tests, phototests, and photopatch tests with suspected drugs. Phototests were done with ultraviolet A (UVA), UVB, and visible light. Drugs used in the photopatch tests were usually prepared as 10% concentrations in petroleum base, which did not produce reactions in 10 control subjects, followed by irradiation of suberythema doses of UVA. Systemic provocation by oral administration of small doses of causative drugs with irradiation of suberythema doses of UVA was performed to confirm the results of skin tests in four patients. Two patients were not rechallenged with the causative drugs. None of the patients had systemic lupus erythematosus, porphyria, or pellagra. All showed positive reactions to photopatch testing. Systemic provocation confirmed the results of photopatch tests in four patients. The two patients who were not rechallenged had no recurrence of lesions. One patient ingested only one drug at the time of eruptions, and provocation or avoidance was not attempted. A photoallergic mechanism was considered in five cases.

CONCLUSIONS

Although there is no information about the appropriate concentrations or vehicles for suspected drugs, photopatch testing could be reliable for identification of causes of photosensitive drug eruptions. Besides piroxicam (a well-known photosensitizer) and carbamazepine, isoniazid and triflusal were identified as the causes of the reactions.

Medullary nephrocalcinosis associated with long-term furosemide abuse in adults

BACKGROUND

The use of furosemide is well recognized as a predisposing factor of nephrocalcinosis in infants. Although furosemide is widely used for various medical conditions in adults, its association with nephrocalcinosis in adults is not well established.

METHODS

We studied 18 consecutive adult patients (male:female ratio 1:17, age range 21-59 years) who habitually took furosemide to control weight or oedema for long periods of time (range 3-25 years). The daily dose of continuous intake of furosemide ranged from 40 to 2800 mg. Nephrocalcinosis was evaluated using renal ultrasonography (US), computed tomography (CT), or kidney biopsies.

RESULTS

Renal US and CT revealed bilateral nephrocalcinosis of the medullary pyramids in 15 (83.3%) out of 18 patients. The duration of furosemide abuse was similar between nephrocalcinosis positive (NC(+)) and nephrocalcinosis negative (NC(-)) groups. The daily dose of furosemide was nearly 10 times higher in the NC(+) group (range 120-2800 mg, mean 538 mg) than the NC(-) group (range 40-80 mg, mean 67 mg). All patients showed variable degrees of renal insufficiency and there was no difference in creatinine clearance between the NC(+) and NC(-) groups (P>0.05). Kidney biopsies performed in three patients showed focal tubulo-interstitial fibrosis and atrophy and calcifications were observed in outer medullary tubulo-interstitium.

CONCLUSIONS

Long-term furosemide abuse can cause medullary nephrocalcinosis in adults, and the risk of developing of nephrocalcinosis seems to be correlated with the daily dose of furosemide. We suggest that long-term furosemide abuse should be suspected in adult patients when medullary nephrocalcinosis is incidentally detected by US or CT.

Elevated uric acid increases blood pressure in the rat by a novel crystal-independent mechanism

An elevation in circulating serum uric acid is strongly associated with the development of hypertension and renal disease, but whether uric acid has a causal role or whether it simply indicates patients at risk for these complications remains controversial. We tested the hypothesis that uric acid may have a causal role in the development of hypertension and renal disease by examining the effects of mild hyperuricemia in rats. Mild hyperuricemia was induced in rats by providing a uricase inhibitor (oxonic acid) in the diet. Hyperuricemic rats developed elevated blood pressure after 3 weeks, whereas control rats remained normotensive. The development of hypertension was prevented by concurrent treatment with either a xanthine oxidase inhibitor (allopurinol) or a uricosuric agent (benziodarone), both of which lowered uric acid levels. Blood pressure could also be lowered by reducing uric acid levels with either allopurinol or oxonic acid withdrawal. A direct relationship was found between blood pressure and uric acid (r=0.75, n=69), with a 10-mm Hg blood pressure increase for each 0.03-mmol/L (0.5-mg/dL) incremental rise in serum uric acid. The kidneys were devoid of urate crystals and were normal by light microscopy. However, immunohistochemical stains documented an ischemic type of injury with collagen deposition, macrophage infiltration, and an increase in tubular expression of osteopontin. Hyperuricemic rats also exhibited an increase in juxtaglomerular renin and a decrease in macula densa neuronal NO synthase. Both the renal injury and hypertension were reduced by treatment with enalapril or L-arginine. In conclusion, mild hyperuricemia causes hypertension and renal injury in the rat via a crystal-independent mechanism, with stimulation of the renin-angiotensin system and inhibition of neuronal NO synthase.

Effects of cysteine on the pharmacokinetics of intravenous phenytoin in rats with protein-calorie malnutrition

The effects of cysteine on the pharmacokinetics of phenytoin and one of its metabolites, 5-(p-hydroxyphenyl)-5-phenylhydantoin (pHPPH) were investigated after intravenous administration of phenytoin, 25 mg/kg, to control rats (4-week fed on 23% casein diet) and rats with PCM (protein-calorie malnutrition, 4-week fed on 5% casein diet) and PCMC (PCM with oral cysteine supplementation, 250 mg/kg, twice daily starting from the fourth week). In rats with PCM and PCMC, the phenytoin hydroxylation (to form pHPPH) activities were significantly smaller (164, 103 and 95.3 pmol/min per mg protein for the control rats, and rats with PCM and PCMC, respectively) than that in control rats. In rats with PCMC, the intrinsic clearance of phenytoin, CL(int) was significantly slower than those in control rats and rats with PCM (0.175, 0.131 and 0.044 ml/min). The above data suggested that the formation of pHPPH could be reduced in rats with PCM and PCMC. This was supported by significantly smaller 24-h urinary excretion of pHPPH (54.7, 35.6 and 32.5% of intravenous dose of phenytoin) in rats with PCM and PCMC than that in control rats. In rats with PCM, the maximum velocity (0.344, 0.203 and 0.196 microg/min), apparent volume of distribution in central compartment (44.4, 65.4 and 72.2 ml/kg) of phenytoin, and total area under the plasma concentration-time curve from time zero to time infinity (609, 714 and 1210 microg min/ml), renal clearance (20.5, 13.4 and 4.67 ml/min per kg) and 24-h urinary excretion (54.7, 35.6 and 32.5% of intravenous dose of phenytoin) of pHPPH were not returned to control levels by cysteine supplementation (rats with PCMC). This could be mainly due to the fact that the phenytoin hydroxylation activity in rats with PCMC was not returned to control level.

Hypokalemia induces renal injury and alterations in vasoactive mediators that favor salt sensitivity

We investigated the hypothesis that hypokalemia might induce renal injury via a mechanism that involves subtle renal injury and alterations in local vasoactive mediators that would favor sodium retention. To test this hypothesis, we conducted studies in rats with diet-induced K+ deficiency. We also determined whether rats with hypokalemic nephropathy show salt sensitivity. Twelve weeks of hypokalemia resulted in a decrease in creatinine clearance, tubulointerstitial injury with macrophage infiltration, interstitial collagen type III deposition, and an increase in osteopontin expression (a tubular marker of injury). The renal injury was greatest in the outer medulla with radiation into the cortex, suggestive of an ischemic etiology. Consistent with this hypothesis, we found an increased uptake of a hypoxia marker, pimonidazole, in the cortex. The intrarenal injury was associated with increased cortical angiontensin-converting enzyme (ACE) expression and continued cortical angiotensin II generation despite systemic suppression of the renin-angiotensin system, an increase in renal endothelin-1, a decrease in renal kallikrein, and a decrease in urinary nitrite/nitrates and prostaglandin E(2) excretion. At 12 wk, hypokalemic rats were placed on a normal-K+ diet with either high (4%)- or low (0.01%)-NaCl content. Despite correction of hypokalemia and normalization of renal function, previously hypokalemic rats showed an elevated blood pressure in response to a high-salt diet compared with normokalemic controls. Hypokalemia is associated with alterations in vasoactive mediators that favor intrarenal vasoconstriction and an ischemic pattern of renal injury. These alterations may predispose the animals to salt-sensitive hypertension that manifests despite normalization of the serum K+.

Vascular endothelial growth factor (VEGF121) protects rats from renal infarction in thrombotic microangiopathy

BACKGROUND

Renal thrombotic microangiopathy, typified by the hemolytic uremic syndrome, is associated with endothelial cell injury in which the presence of cortical necrosis, extensive glomerular involvement, and arterial occlusive lesions correlates with a poor clinical outcome. We hypothesized that the endothelial survival factor vascular endothelial growth factor (VEGF) may provide protection.

METHOD

Severe, necrotizing, thrombotic microangiopathy was induced in rats by the renal artery perfusion of antiglomerular endothelial antibody, followed by the administration of VEGF or vehicle, and renal injury was evaluated.

RESULTS

Control rats developed severe glomerular and tubulointerstitial injury with extensive renal necrosis. The administration of VEGF significantly reduced the necrosis, preserved the glomerular endothelium and arterioles, and reduced the number of apoptotic cells in glomeruli (at 4 hours) and in the tubulointerstitium (at 4 days). The prosurvival effect of VEGF for endothelium may relate in part to the ability of VEGF to protect endothelial cells from factor-induced apoptosis, as demonstrated for tumor necrosis factor-alpha (TNF-alpha), which was shown to be up-regulated through the course of this model of renal microangiopathy. Endothelial nitric oxide synthase expression was preserved in VEGF-treated rats compared with its marked decrease in the surviving glomeruli and interstitium of the antibody-treated rats that did not receive VEGF.

CONCLUSIONS

VEGF protects against renal necrosis in this model of thrombotic microangiopathy. This protection may be mediated by maintaining endothelial nitric oxide production and/or preventing endothelial cell death.

Dissociation between clearances of small and middle molecules in incremental peritoneal dialysis

OBJECTIVE

To evaluate the peritoneal clearance of middle molecules in comparison with the peritoneal clearance of small molecules in incremental peritoneal dialysis (PD).

STUDY DESIGN

Peritoneal clearances of creatinine and beta2-microgloblulin (B2M) were compared in 57 continuous ambulatory PD patients on full dose of 4 exchanges, and 54 incremental PD patients with 2 or 3 exchanges over 24 hours. Clearances were also compared when there were changes in the PD regimen, such as in the number of exchanges and the duration of the dwell time.

SETTING

Tertiary-care university hospital.

RESULTS

Peritoneal creatinine clearance increased almost linearly with the increase in the number of exchanges. In contrast, peritoneal clearance of B2M was 9.1 +/- 3.6 L/week, 8.8 +/- 4.4 L/week, and 7.9 +/- 2.5 L/week with 2,3, and 4 exchanges, respectively, per day, amounts that were not different from each other. Peritoneal clearance of B2M did not change when there was an increase in the number of dialysate exchanges from 2 to 3 and from 3 to 4 over a period of 24 hours; whereas the peritoneal clearance of creatinine increased. Peritoneal clearance of B2M almost doubled, from 5.4 +/- 2.7 L/week with 2 exchanges over 12 hours per day, to 9.5 +/- 4.4 L/week with the same 2 exchanges over 24 hours. The creatinine clearance did not change.

CONCLUSION

In contrast to peritoneal clearance of small molecules, such as creatinine, which was dependent on the number of dialysate exchanges, peritoneal clearance of middle molecules, such as B2M, depended mainly on the total dwell hours of PD and not on the number of exchanges of peritoneal dialysate in incremental PD. This might be another advantage of incremental PD, since peritoneal clearance of middle molecules in incremental PD over 24 hours can be comparable to that in full dose PD.

Intravenous immunoglobulin protects against experimental thrombotic microangiopathy

BACKGROUND

Intravenous immunoglobulin (IVIG) has been utilized in several forms of vasculitis and has many potential mechanisms of action, including the inhibition of C3 activation. We have previously demonstrated that IVIG can reduce glomerular injury in a model of membranous nephropathy mediated by C5b-9 [1]. C5b-9 has also been shown to mediate the thrombotic microangiopathy (TMA) induced by antibody to glomerular endothelial cells leading to a hemolytic uremic syndrome-type lesion [2].

METHODS

To test the hypothesis that IVIG might be effective in treating antibody-induced TMA, male uninephrectomized rats underwent right renal artery perfusion with goat anti-rat glomerular endothelial cell (GEN) antibody (20 mg/kg). Sheep IgG (200 mg/kg) was administered either 30 minutes before the renal artery perfusion (group I, N = 6) or 30 minutes postperfusion (group II, N = 9). A third control group received phosphate-buffered saline (PBS; group III, N = 12). A survival biopsy was performed at 15 minutes, and the animals were sacrificed on day 2.

RESULTS

There were no significant differences in proteinuria or hematocrit between the groups. Animals pretreated with IVIG had significantly improved survival and renal function, which was associated with a decrease in glomerular C3 deposition. The protective effect of IVIG was abolished if the administration was delayed 30 minutes after perfusion.

CONCLUSIONS

IVIG is effective in reducing injury in experimental TMA only if given prophylactically. The effect is mediated by inhibition of local intraglomerular complement activation.

Bioequivalence of clarithromycin tablet formulations assessed in Korean males

AIM

Determination of the bioequivalence of 2 clarithromycin tablet formulations manufactured in Korea.

PATIENTS AND METHODS

Twenty-four healthy male Korean volunteers received each of the 2 clarithromycin formulations at a dose of 250 mg in a 2 x 2 crossover study. There was a one-week washout period between doses. Plasma concentrations of clarithromycin were monitored by high-performance liquid chromatography over a period of 12 hours after administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated using the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and Tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf and Cmax and untransformed Tmax.

RESULTS

The point estimates and 90% confidence intervals for AUCinf (parametric) and Cmax (parametric) were 0.971 (0.886 approximately 1.063) and 0.982 (0.868 approximately 1.107), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. The corresponding value of Tmax was 0.000 (-0.250 approximately 0.250).

CONCLUSION

These results indicate that the 2 medications of clarithromycin are bioequivalent and, thus, may be prescribed interchangeably.

Measurement of the midrapidity transverse energy distribution from square root of [(s)NN] = 130 GeV Au + Au collisions at RHIC

The first measurement of energy produced transverse to the beam direction at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is presented. The midrapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that <E(T)>/<N(ch)> remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at square root[s(NN)] = 130 GeV is at least epsilon(Bj) = 4.6 GeV/fm(3), which is a factor of 1.6 larger than found at sqrt[s(NN)] = 17.2 GeV ( Pb+Pb at CERN).