Single and Multiple-Dose Kinetics of Ofloxacin in Patients on Continuous Ambulatory Peritoneal Dialysis (CAPD)

To evaluate the pharmacokinetics of ofloxacin, a novel quinolon antibiotic, in patients with end-stage renal disease (ESRO) on continuous ambulatory peritoneal dialysis (CAPO), we investigated 6 patients in a single-dose study and 9 patients in a multiple-dose study, all without peritonitis. In the single-dose study, patients received 200 mg ofloxacin orally. Serum concentrations (Cmax) peaked at 3.1 ± 0.3 mg/L (x ± SEM), 1.6 ± 0.5 h after p. 0. administration of the drug. Elimination half-life ( t112) was 26.8 ± 2.5 h. Peritoneal clearance accounted for 10% of the total body clearance. After 5- h dwell time, ofloxacin concentrations in the dialysate were 1.5 ± 0.2 mg/L, which is above the MIC90 for most bacteria responsible for peritonitis in patients on CAPO. In the multiple dose study, 200 mg ofloxacin were administered twice, with a time interval of 12 h, followed by 200 mg for 9 days every morning. Mean trough serum levels were 2.6 ± 1.0 mg/L, mean peak concentrations were 4.1 ± 1.7 mg/L. Mean ofloxacin concentrations in the peritoneal effluent were 1.9 ± 0.9 mg/L. It is concluded that an oral loading dose of 400 mg on the first day and a maintenance dose of 200 mg ofloxacin/day does not lead to significant accumulation, even though the elimination by the peritoneal route is only small. The proposed dosing regimen could be an adequate therapy of peritonitis and exit-site infections in patients on CAPO since levels reached in the dialysate effluent are bactericidal. The clinical usefulness in the treatment of peritonitis has to be proven in further studies.

Effectiveness and Safety of Recombinant Human Erythropoietin (r-HuEPO) in the Treatment of Anemia of Chronic Renal Failure in Non Dialysis Patients

Seventy-five non-dialized patients with chronic renal failure (CRF) and severe renal anemia were enrolled in a study, receiving r-HuEPO subcutaneously thrice weekly for 6 months. In 64 patients (85%) 7 weeks of treatment with a weekly dose of 158 U/kg were required to achieve Hb concentrations within the target range of 10 to 12 g/dl. Of the 11 patients (15%) who failed to achieve the target Hb range, none were considered to be non-responders as they were excluded for unrelated reasons prior to week 16 (8 cases), or were iron deficient (2 cases), or had bleeding complications (1 patient). Maintaining the Hb concentration at a level of 10.5 g/dl required a mean r-HuEPO dose of 92 U/kg per week. Adverse events were generally mild or moderate. The most commonly reported were hypertension (8%), viral infection/including flu-like syndrome (7%), nausea (7%), and dizziness (5%). Statistically significant increases in mean creatinine concentrations observed after 12 and 24 weeks were most likely due to the progression of renal disease. These results confirm that 50 U/kg of r-HuEPO given 3 times per week subcutaneously provide a safe and effective therapy for anemic predialysis patients.

Strategies for the Treatment of Acute Renal Failure in Intensive Care Units: The Aspect of Dosing

Despite all the medical progress, the mortality rate in intensive care units for patients with acute renal failure (ARF) remains high, among specific patient populations, up to 88% [Letourneau I, Dorval M, Belanger R, Legare M, Fortier L, Leblanc M. Acute renal failure in bone marrow transplant patients admitted to the intensive care unit. Nephron Apr 2002; 90 (4), 408-412.]. Recent trial results indicate that patient survival may be improved by adequate renal replacement therapy. In particular, the dose of intermittent and continuous renal replacement therapies has proved to be a significant factor affecting patient survival. Daily intermittent hemodialysis, e.g., is superior to alternate-day intermittent hemodialysis, and with continuous therapies, survival is related to the filtration rate. Further relevant factors include early initiation of renal replacement therapy, choice of biocompatible membranes and the application of bicarbonate-buffered replacement solutions for defined patient groups. The advantages offered by continuous techniques could be demonstrated for individual patient groups; in meta-analyses, advantages were shown for the total population of patients with ARF. Other than for patients with chronic renal failure (NKF-DOQI. Clinical practice guidelines for hemodialysis adequacy. Am J Kid Dis 1997; Vol. 30, 515-566.), there are no current clinical guidelines for a standard treatment of intensive care patients with ARF. Therefore, such a treatment standard still needs to be determined.

Continuous venovenous haemofiltration using a citrate buffered substitution fluid

Different methods of regional anticoagulation using citrate in continuous renal replacement therapy have been described in the past. However, these procedures were usually very complex or did not reach modem requirements for effective continuous renal replacement therapy. Furthermore, little is known about long-term acid-base stability and citrate levels during the treatment. We describe a system in which citrate is used both as anticoagulant and as the sole buffer substance in continuous venovenous haemofiltration. Our citrate-containing, calcium-free substitution fluid was used in predilution mode with a constant ratio between blood flow (120 to 150 ml/min) and substitution flow (2400 to 3000 ml/hour). Anticoagulation was limited to the extracorporeal circuit. Twenty patients with acute renal failure on mechanical ventilation were treated, four for eight hours, four for 24 hours and 12 as long they needed continuous renal replacement therapy (9.6 +/- 5.0 days, range 4.0 to 39.3 days). We achieved stable acid-base and electrolyte balance in all patients. We observed no bleeding complications (patient activated clotting time 112.4 +/- 17.1 s, post-filter circuit activated clotting time 270.5 +/- 80.3 s) and achieved appropriate filter life times (48.6 +/- 13.2 h). Predilution, citrate-based substitution fluid provides both anticoagulation within the extracorporeal circuit and control of acid-base balance in critically ill patients at risk of bleeding in acute renal failure. It is easy to apply and safe. Clearance can be varied as long as a constant ratio between blood and substitution flow is maintained.

Intravenous iloprost: a new therapeutic option for patients with post-transplant distal limb syndrome (PTDLS)

The purpose of this study was to investigate the application of intravenous iloprost as a novel therapy for the treatment of post-transplant distal limb syndrome (PTDLS). PTDLS is a benign but disabling complication in the first year after renal transplantation. It is characterized by bilateral, often incapacitating pain in the feet and or knees on motion and a significant rise in alkaline phosphatase levels on laboratory evaluation. On MRI, bone marrow edema of the affected bone regions can be demonstrated. PTDLS differs from steroid induced osteonecrosis of the hip in terms of localization, an average cumulative steroid dosage within expected limits, and a benign outcome, as PTDLS does not progress to overt cell necrosis. From August 2003 to April 2005 we treated 10 patients with MRI-proven diagnosis of PTDLS following a standardized regimen of intravenous iloprost over 5 days. Iloprost led to prompt pain relief measured on a visual analogous scale (VAS) ranging from 1 to 10 (5.6 +/- 1.5 before vs. 2.1 +/- 1.3 after treatment, p = 0.0004). PTDLS represents a benign but disabling complication following renal transplantation. Intravenous iloprost might be a promising therapeutic concept leading to a quick relief of symptoms without relevant side effects.

Renovascular disease: a review of diagnostic and therapeutic procedures

The clinical importance of renovascular disease, atherosclerotic or of other origin, arises from the fact, that renal artery stenosis (RAS), if hemodynamically significant (> 70% diameter reduction), induces arterial hypertension, renal insufficiency or both. The prevalence of RAS rises with increasing age and with the presence of atherosclerosis of the aorta, carotid, coronary and peripheral arteries. Typical clinical symptoms, as uncontrolled hypertension or renal dysfunction in the absence of pathological urinary findings, are helpful to select patients for further screening methods: We see a prominent role of color duplex sonography as a screening procedure. Intra-arterial angiography remains gold standard for the diagnosis of RAS. The major problem in daily clinical practice is the differentiation between patients in which hypertension and kidney function can be improved or normalized by removal of RAS and those with ''fixed'' hypertension and irreversible kidney dysfunction and therefore to decide if it is worth while to perform invasive treatment as angioplasty or surgery. In this setting, the proof of hemodynamic significance is essential and is indicated especially when the stenosis has a diameter reduction of < 50-70% only. Methods proving a critical stenosis are intra-arterial measurement of the pressure gradient, measurement of differential renal vein renin and duplex sonography. In addition, predictors of treatment outcome should be considered. Studies analyzing if patients improve with blood pressure and kidney function after removal of RAS have shown that high grade stenosis and/or very high blood pressure indicate a good outcome. Further prognostic factors are the absence of parenchymal disease and/or positive functional test. In the presence of a critical stenosis in a patient with a clear clinical problem with hypertension and/or renal dysfunction a positive effect of invasive treatment seems warranted despite the risks that must be considered as well in angioplasty as in surgery. The selection for the type of invasive treatment requires a clarification of the treatment goals in the individual patient, the evaluation of the morphology and localization of the stenosis as the presence of other vascular disease (aortic aneurysm, peripheral artery disease etc.) and the assessment of the risk according to the type of intervention.

Biocompatibility parameters in in-vitro simulated automated versus continuous ambulatory peritoneal dialysis

BACKGROUND

In peritoneal dialysis, the usage of automated peritoneal dialysis (APD) has been steadily increased. As APD means larger volumes of solution and more frequent contact times with fresh dialysate, an additive negative impact on biocompatibility data, exceeding the known effect of conventional PD fluids, seems possible. For an in-vitro comparison of APD and CAPD, a new cell culture system has recently been established.

METHODS

A double chamber cell culture system with human mesothelial cells on top of a permeable membrane and growth medium beyond was used for mimicking CAPD and APD. Reflecting the in vivo equilibration pattern, we compared an eight-hour CAPD with a CCPD setting, using a conventional PD solution. Cell viability was assessed with a MTT assay and cell function via constitutive and stimulated IL-6 release. CA125 was measured as a parameter of mesothelial cell integrity, and TGF-1beta was measured as an index of induction of fibrosis.

RESULTS

Both the CAPD and the CCPD mode resulted in a significantly lower MTT assay and stimulated IL-6 release compared to growth medium. TGF-1beta and CA125 release did not differ between the PD modes and control. The CAPD and the CCPD mode itself did not differ with regard to MTT assay, IL-6 release, TGF-1beta and CA125 generation.

CONCLUSION

From the in-vitro model imitating the acute exposure of mesothelial cells with conventional PD fluid in a CCPD and CAPD mode, there is no evidence that APD, due to the larger volumes of solution and more frequent contact times with fresh dialysate, has an acute, additive negative impact on biocompatibility parameters indicative for peritoneal host defense, mesothelial cell integrity and peritoneal fibrosis.

Influence of genetic polymorphisms of the renin-angiotensin system on IgA nephropathy

BACKGROUND

We evaluated the impact of the three major genetic polymorphisms of the renin-angiotensin system [angiotensinogen (AGT) gene M235T, angiotensin-converting enzyme (ACE) gene-I/D and angiotensin II-type 1 receptor (AT1R) gene A1166C polymorphisms] as risk factors in IgA nephropathy.

METHODS

The clinical course of 107 patients with biopsy proven IgA nephropathy followed up for 6.6 +/- 5.8 years was examined. The genetic polymorphisms were determined by PCR amplification.

RESULTS

The allele frequencies of the polymorphisms studied were similar in patients and control subjects. AGT-M235T genotype was associated with the presence of nephrotic syndrome (p < 0.05), correlated to the number of antihypertensive drugs agents taken (p < 0.01) and influenced the rate of deterioration of renal function (p < 0.05). Combined analysis of AGT-M235T and ACE-I/D polymorphisms detected an interaction on affecting progression (p < 0.05). ACE-inhibition had a more pronounced effect in certain AGT-M235T and ACE-I/D genotypes (p < 0.05) and their combined analysis showed a synergistic effect (p < 0.01). No association between AT(1)R-A1166C polymorphism and any of the parameters studied was observed.

CONCLUSIONS

Our results suggest that angiotensinogen-M235T polymorphism is an important marker of progression in IgA nephropathy in Caucasian patients, especially when analyzed in combination with ACE-I/D polymorphism.

Cytokine removal in septic patients with continuous venovenous hemofiltration

Despite the progress that has been made in intensive care medicine, multiple organ failure is still associated with high mortality. Apart from the prevention of infectious complications, numerous efforts are being made to improve the treatment of sepsis through adequate antibiotic therapy, the development of new respirator therapies, better control of the hemodynamic situation, and adequate renal replacement therapy. Some authors advocate continuous renal replacement therapy not only for acute renal failure but also for the elimination of inflammatory molecules such as cytokines. Continuous renal replacement therapy improves the cardiovascular hemodynamics in patients with multiple organ failure. Therapeutic options such as volume control, clearance of uremic toxins, correction of acid base disturbances and temperature control are improved. Suitable renal replacement therapy improves not only cardiovascular hemodynamics but also patient survival. In current practice, continuous renal replacement therapy is not used to eliminate mediators such as cytokines. In patients with multiple organ failure and compromised cardiovascular hemodynamics, renal replacement therapy should be carried out as early as possible. In the following review, experimental and clinical findings concerning mediator elimination by continuous and intermittent renal replacement therapy are summarized.

Successful treatment of renovascular hypertension has no effect on insulin sensitivity

BACKGROUND

The association of insulin resistance (IR) and essential hypertension is well known, but a causal relationship has not been proven. Patients with secondary hypertension as a result of renal artery stenosis (RAS) usually do not reveal IR, but no study has addressed the effect of blood pressure reduction after successful treatment of RAS on insulin sensitivity and glucose effectiveness.

PATIENTS AND METHODS

The insulin sensitivity index (SI) and glucose effectiveness (SG) were measured before and after successful intervention of an angiographically proven significant RAS in 18 out of 23 patients (eight males/10 females; mean age 51.5 +/- 13.1 years) in which improvement/cure of arterial hypertension was achieved. After a mean of 10.7 months, patients were reevaluated for 24-h blood-pressure measurement, kidney function, adrenaline, noradrenaline, plasma-renin-activity (PRA), aldosterone, atrial natriuretic peptide (ANP) and cyclic guanosine monophosphate (cGMP), and glucose metabolism parameters such as basal insulin, glucose disappearance constant (K-value), SI and SG. For calculation of SI and SG, insulin and glucose data from the modified frequent sampling intravenous glucose tolerance test (FSIGT) were submitted to the MINMOD program.

RESULTS

After intervention, systolic 24-h blood pressure had decreased from 156.1 +/- 16.4 mmHg to 139.9 +/- 15.1 mmHg, and diastolic 24-h blood pressure from 97.1 +/- 14.7 mmHg to 87.3 +/- 13.4 mmHg. No significant change in SI (before 4.3 +/- 2.0, after 4.8 +/- 2.0 min(-1) per microU mL(-1)) or SG (before 1.55 +/- 0.42x10(-2) min(-1), after 1.8 +/- 0.48x10(-2) min(-1)) was observed. Aldosterone decreased from 246.7 +/- 180.7 to 115 +/- 61.4 (P=0.009) as PRA decreased from 12.4 +/- 11.4 to 4.2 +/- 7.6 ng mL h(-1) (P=0.01). Creatinine clearance, and adrenaline and noradrenaline levels as well as ANP and cGMP did not change after treatment for RAS. Subsequent to the definition of IR (SI < or =3.2x10(-4) min(-1) per microU mL(-1)) some differences among these two subgroups (SI < or =3.2, or SI>3.2) could be found. Patients with IR (n=8) were characterized by a higher body mass index (BMI), higher basal insulin values and significantly lower cGMP values. Only the group without IR (n=10) developed significant improvement of systolic blood pressure.

CONCLUSION

We conclude that blood pressure reduction by treatment of RAS does not alter insulin action and that there is no link between the circulating concentrations of renin/aldosterone and glucose metabolism in renovascular hypertension (RVH). The results do not support the hypothesis of a direct link between blood pressure in RVH and the individual state of insulin sensitivity. However, patients with a normal SI are more likely to experience an almost normalization of arterial blood pressure after treatment for RAS.

Infection with polyomavirus type BK after renal transplantation

Tubulointerstitial nephritis caused by polyomavirus of the subtype BK (BK virus nephropathy, BKN) is an important cause of deterioration of renal allograft function after kidney transplantation. In 3 cases of BKN diagnosed at our center, the suspected diagnosis made on the basis of urine cytology and serum PCR was confirmed by electron microscopy and immunohistology of the renal graft biopsy. In 1 patient, stable renal function without further virus detection was seen after reduction of the immunosuppression. In 2 further patients there was loss of graft function. BKN is an important differential diagnosis of unclear deterioration of renal graft function. The risk is particularly high with use of tacrolimus and mycophenolate mofetil (MMF). Urine cytology and serum PCR are suitable screening tests, histology provides conclusive evidence. The only therapeutic option available at present is reduction of immunosuppressive therapy.

[Gitelman's syndrome: an important differential diagnosis of hypokalemia]

HISTORY AND CLINICAL FINDINGS

A 26-year-old woman presented with fatigue, muscle cramps and weakness. Since the age of 8 years she had moderate hypokalemia of unknown origin that was confirmed on multiple occasions. There was no family history of disease.

INVESTIGATIONS

Laboratory tests showed moderate to severe hypokalemia with a serum potassium concentration of 2.7 to 3.0 mmol/l, hypomagnesemia, metabolic alkalosis and pronounced stimulation of the renin-angiotensin-aldosterone system. Despite normal serum calcium levels, urinary calcium excretion was below the detection threshold. Increased natriuresis was observed after administration of furosemide, but not after administration of hydrochlorothiazide. This finding pointed to the presence of a non-functional thiazide-sensitive sodium/chloride cotransporter in the distal convoluted tubule, characteristic for Gitelman's syndrome. Genetic analysis confirmed the diagnosis of Gitelman's syndrome and documented two heterozygous mutations in the gene encoding the sodium/chloride cotransporter.

TREATMENT AND COURSE

The patient was treated with 160 mmol potassium and 30 mmol magnesium supplementation per day. Serum potassium was normalized and magnesium serum levels increased. Weakness and fatigue improved markedly.

CONCLUSION

Gitelman's syndrome is an important differential diagnosis in the evaluation of the normotensive patient with hypokalemia.

Influence of uremia on cell viability and cytokine release of human peritoneal mesothelial cells

INTRODUCTION

There is still no evidence whether human peritoneal mesothelial cells (HPMC) from patients with end-stage renal failure are altered in cell viability or show a different pattern of the release of proinflammatory cytokines. Also the serum of patients with uremia may contain substances stimulating the cytokine release of HPMC.

STUDY DESIGN

The IL-1beta-induced IL-6/IL-8 release of HPMC from healthy donors and from patients with end-stage renal disease (ESRD) were measured before the start of chronic peritoneal dialysis (PD) and during PD therapy. Additionally the influence of uremic and non-uremic serum on IL-6 and IL-8 release of normal HPMC was studied. Cell viability was assessed by MTT assay and by the measurement of intracellular ATP (chemoluminescence assay). HPMC were obtained from the following patient groups: (1) non-uremic control patients (n = 7); (2) patients with ESRD undergoing PD catheter implantation for the first time (n = 7), and (3) patients on PD undergoing catheter exchange for noninfectious reasons (n = 6). Pooled human serum from PD patients and normal controls were used for stimulation experiments. HPMC from different donors were grown to confluence (second passage) and then stimulated with IL-1beta (1,000 pg/ml in M199) for 24 h. IL-6 and IL-8 concentrations were measured in the supernatant by ELISA. Additionally uremic and non-uremic sera were incubated with HPMC from normal donors for 24 h with a subsequent 24-hour IL-1beta stimulation. Mesothelial cell protein mass was determined by the Bradford reagent.

RESULTS

Non-uremic patients and ESRD patients did not differ with regard to the global cell viability of HPMC according to MTT assay activity or the intracellular ATP concentration. However, HPMC from uremic patients produced more IL-8 on IL-1beta stimulation than the non-uremic controls (group 2, 53.5 +/- 15.7 pg/microg; group 3, 70.5 +/- 27.3 pg/microg vs. group 1, 24.0 +/- 11.8 pg/microg). HPMC from patients on chronic PD additionally released significantly more IL-6 (30.5 +/- 13.8 pg/microg) on IL-1beta stimulation than uremic patients before the onset of PD (6.2 +/- 2.6 pg/microg; p < 0.01). Incubation of normal HPMC with the serum from uremic donors produced an enhanced stimulated IL-8 release compared to the exposition with normal control serum (50.6 +/- 6.1 vs. 20.8 +/- 2.9 pg/microg; p < 0.01).

CONCLUSION

HPMC from uremic patients more readily release IL-8 on stimulation with IL-1beta. On chronic PD treatment IL-6 release was further enhanced. Not further classified serum components in uremia also enhance IL-6 and IL-8 release of HPMC.

Effect of filtration volume of continuous venovenous hemofiltration in the treatment of patients with acute renal failure in intensive care units

OBJECTIVE

We evaluated the variable Kt/V, which has become established in the therapy of end-stage renal disease in acute renal failure, to assess the influence of the filtration volume of continuous venovenous hemofiltration on Kt/V. We measured the variables of acid-base balance and uremia control.

DESIGN

Prospective interventional pilot study.

SETTING

Medical intensive care unit of a university hospital.

PATIENTS

Fifty-six patients with acute renal failure and continuous venovenous hemofiltration treatment.

INTERVENTIONS

The patients were consecutively treated with a filtration volume of either 1 L/hr (group 1) or 1.5 L/hr (group 2).

MEASUREMENTS AND MAIN RESULTS

Patients with a filtration volume of 1.5 L/hr achieved a Kt/V of 0.8 per day, which was significantly higher than in the patient group treated with 1 L/hr (0.53, p <.05). The filtration volume of 1.5 L/hr led to a markedly better control of blood urea nitrogen concentrations, 69.3 +/- 6.6 mg/dL vs. 52.1 +/- 5.2 (p <.05), and to a much quicker and longer lasting compensation of acidosis. Both groups had acidotic pH at the beginning of therapy (group 1, 7.29 +/- 0.02; group 2, 7.29 +/- 0.02, nonsignificant). In group 2, a significantly higher pH value than in group 1 was measured after 24 hrs of continuous venovenous hemofiltration (p < .001; 7.39 +/- 0.02 vs. 7.31 +/- 0.02). The pH values in group 1 did not normalize until after 4 days. The filtration volume of 1.5 L/hr led to a quicker increase in bicarbonate concentrations after 24 hrs of therapy (group 1, 2.8 +/- 3.2 mmol/L; group 2, 6.5 +/- 3.1 mmol/L, p <.001).

CONCLUSIONS

The standardized urea clearance Kt/V is a valuable tool in the treatment of acute renal failure. Higher Kt/V levels were associated with a better control of uremia and acid-base balance. However, there were no differences in the clinical course, patient survival, percentage of patients with or without renal failure who were transferred from the intensive care unit, or Acute Physiology and Chronic Health Evaluation III scores.

Hemodynamically relevant hematuria several months after biopsy of a kidney graft: an unusual cause

We report the case of a 52-year-old female patient, who after a complicated living donor kidney transplantation, underwent kidney biopsy for suspected rejection. Duplex scanning revealed a small, asymptomatic arteriovenous (AV) fistula which was assessed as being hemodynamically unimportant. During follow-up, several urinary tract infections occurred and recurrent short episodes of hematuria were attributed to cystitis, urethritis and urosepsis. Eight months later, the patient developed suddenly massive hematuria, tamponade of the urinary bladder and hemorrhagic shock as well as urosepsis. Duplex sonography showed a massive pseudoaneurysm in addition to the AV fistula. Arteriography confirmed the Duplex sonographic findings and embolization was performed after treatment of concomitant urosepsis. The fistula was closed completely and bleeding ceased. Although AV fistulas are rare complications of kidney biopsies and in most cases they remain asymptomatic, life-threatening hematuria can present several months after a biopsy due to the development of a pseudoaneurysm. Concomitant infectious complications of the urinary tract, bleeding disorders and other factors can be misleading during the assessment of the cause of gross hematuria. Regular Duplex sonographic follow-up examinations in patients with AV fistulas are advisable.

Operative treatment of renal autonomous hyperparathyroidism: cause of persistent or recurrent disease in 304 patients

BACKGROUND

Subtotal parathyroidectomy (SPTX) and total parathyroidectomy with autotransplantation (TPTX and AT) are standard procedures in the treatment of renal autonomous hyperparathyroidism. In contrast to primary hyperparathyroidism, the persistence/recurrence rate is reported of up to 12.0%.

PATIENTS AND METHODS

Between 1986 and 2000 we operated on 304 patients with renal autonomous hyperparathyroidism including 14 patients who were admitted after a primary operation in an outside hospital. Mean observation period was 51.4+/-38.9 months.

RESULTS

The overall persistence/recurrence rate in our patients was 9.0% (26/290). After SPTX, excluding patients with an incomplete operation, it was 3.7%, and after TPTX and AT it was 6.0%. Reasons for developing recurrent or persistent disease in these patients were removal of less than 3.5 glands ( n=12), hyperplastic autograft ( n=5), and supernumerary gland ( n=4). After the first reoperation 7 patients (26.9%) had persistent or recurrent disease.

CONCLUSIONS

An incomplete primary operation caused by missed cervical glands was the major reason for persistent ( n=8) or recurrent ( n=4) disease after different operative strategies in renal autonomous hyperparathyroidism.

Perioperative levels of atrial natriuretic peptide and troponin-T in patients with uncomplicated coronary artery surgery

BACKGROUND

HYPOTHESIS

increased ANP levels after uncomplicated coronary artery surgery (CAS) indicate functional reduction.

METHODS

EXPERIMENTAL DESIGN

prospective, randomized. Preoperative upto the 12 week postoperative.

SETTING

Thoracic and Cardiovascular Surgery, University of Düsseldorf.

PATIENTS

15 patients (mean age: 58+/-6.1 years; 13 months, 2 weeks; no myocardial infarction, no congestive heart failure) with 3 vessel disease.

INTERVENTIONS

levels of atrial natriuretic peptide (ANP) (pg/ml; radioimmunoassay), Troponin T (TnT) (ng/ml; ELISA test), haemodynamic parameters, ECG monitoring, m-mode echocardiography (Echo).

MEASURES

increase of ANP, TnT levels during extracorporeal circulation (ECC), decrease after operation.

RESULTS

Maximal increase of ANP from preoperative 90+/-10 (M+/-SEM) pg/ml (p<0.05) up to intraoperative 380+/-38 pg/ml. Ten days postoperative ANP (26+/-33 pg/ml) still threefold increased compared to preoperative level. Increasement of TnT from preoperative 0.02+/-0.01 ng/ml upto intraoperative 3.44+/-0.47 ng/ml. Ten days postoperative TnT concentration normal (0.13+/-0.11 ng/ml). Correlation of ANP and TnT five min after bypass up to 6 hrs postoperative (p<0.05, r =3.4). Increase of left atrial diameter preoperative 42.2+/-1.1 mm up to 46.8+/-1.2 mm (p<0.05) 10 days postoperative. LVEDD, EF changed from preoperative 51.1+/-0.9 mm, 73+/-2% to 54.5+/-1.2 mm, 65+/-4% 10 days postoperative.

CONCLUSIONS

Threefold increase of ANP 10 days postoperative and return of TnT levels to normal under consideration of datas of echo show, that ANP is suitable to indicate the meanterm, functional, myocardial reduction. Increased ANP levels, atrial dilatation and dysfunction are important signs of cardial functional reduction after CAS.

Contrast-enhanced MR urography in the evaluation of renal transplants with urological complications

AIM

The diagnostic work-up of renal transplants with impaired function due to urological problems can be difficult. This study was performed to assess sensitivity and specificity of non-invasive contrast-enhanced MR urography (MRU).

METHODS AND MATERIALS

Thirty-five patients with renal transplants (25 - 71 years, mean: 53.4 years) with sonographically diagnosed hydronephrosis or perirenal fluid collections were assessed by MR urography. MR examinations were carried out at a 1.5 T clinical scanner (Vision, Siemens, Erlangen, Germany) with a 512 matrix contrast-enhanced fat-suppressed T1-weighted FLASH 3D sequence in breath-hold technique. MIP reconstructions were used to produce MR urography. MRU diagnoses were compared to operative results.

RESULTS

In all patients, images with sufficient contrast in the renal collecting system were obtained. Hydronephrosis was confirmed in 20 patients, 8 patients showed a different pathology while 7 had normal findings. Compared to operative results, sensitivity of MRU was 100% with a specificity of 78%, respectively. One ureteral stone was misdiagnosed as a stricture, and 2 suspected ureteral stenoses could not be found upon operation.

CONCLUSIONS

Contrast-enhanced MR urography is a highly sensitive and specific non-invasive method to evaluate patients suspected of having typical post-transplant urological complications. It may replace invasive procedures such as antegrade pyelography in the pre-operative work-up.

Myocardial revascularization in patients with end-stage renal disease: comparison of percutaneous transluminal coronary angioplasty and coronary artery bypass grafting

BACKGROUND

Ischemic heart disease is the major cause of death in patients with end-stage renal disease. The high prevalence of coronary artery disease results in a rising number of dialysis patients requiring myocardial revascularisation.

OBJECTIVE

The objective of this study was to compare the outcomes of recurrent angina, myocardial infarction, rate of reinterventions and cardiovascular death following percutaneous coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG) in patients with end-stage renal disease.

PATIENTS AND METHODS

In a retrospective investigation 40 patients with chronic renal failure undergoing primarily PTCA and 65 patients undergoing CABG were included. Both groups were comparable for gender, duration on dialysis and the number of cardiovascular risk factors per patient. Patients undergoing PTCA were younger (53 +/- 12 years vs. 57 + 8 years; p < 0.05) and more often diabetics (30% vs. 14%; p < 0.05).

RESULTS

Most patients in both groups had a multi-vessel disease (95% in the CABG group vs. 74% in the PTCA group), in the CABG group there were significantly more patients with a triple-vessel disease (62% with vs. 40% in the PTCA group; p < 0.01), PTCA was primarily successful in 95% of the patients while complete revascularization was achieved in 88% of patients undergoing CABG. The perioperative mortality after CABG was 4.8% as compared to none after interventional revascularisation. The cumulative freedom of angina after 6, 12 and 24 months after intervention was significantly lower after PTCA (54%, 40%, 29%) than after bypass grafting (97%, 94%, 90%, p < 0.001). The frequency of reinterventions following PTCA was significantly higher compared to patients following CABG (p < 0.001). After PTCA 15 patients needed further revascularisations, 8 of them underwent CABG, whereas after CABG only two patients required additional myocardial revascularisation. There was no significant difference in the overall mortality between both groups; the survival rate after 12 and 24 months was 95% and 82% after PTCA and 93% and 86% after CABG, respectively.

CONDITION

Although patients receiving CABG had a more severe coronary artery disease the overall mortality was comparable and clinical and functional outcome was improved compared to patients after coronary angioplasty.

Effects of candesartan and perindopril on renal function, TGF-beta1 plasma levels and excretion of prostaglandins in stable renal allograft recipients

AIMS

Although on account of their nephroprotective effects, ACE inhibitors and angiotensin receptor antagonists appear to be advantageous for patients after renal transplantation, their use in these patients has been limited up to now. This is in part due to the risk of inducing a decrease in the glomerular filtration pressure gradient with subsequent impairment of allograft function. The aim of the present study was to investigate the effects of ACE inhibitors and angiotensin receptor antagonists on renal function, excretion of prostaglandins as a parameter of glomerular hemodynamics and TGF-beta1 plasma levels during an 8-week withdrawal phase in pretreated patients.

PATIENTS AND METHODS

Sixteen patients with stable long-term allograft function undergoing therapy with candesartan (group 1) and 16 patients with stable long-term allograft function undergoing therapy with perindopril (group 2) were included in the study. Any signs of chronic allograft dysfunction were defined as exclusion criteria. Renal function, albuminuria, TGF-beta1 plasma levels as well as the excretion of thromboxane B2 and 6-keto-prostaglandin-F-1alpha were monitored during an 8-week withdrawal phase of the angiotensin receptor antagonist or ACE inhibitor, respectively. Normotension was maintained throughout the study period through adjustment of other anti-hypertensive drugs.

RESULTS

Creatinine clearance as well as TGF-beta1 plasma levels and the excretion of prostaglandins remained unchanged after discontinuation of candesartan or perindopril. However, after withdrawal of the substances a significant increase in albuminuria was noted in both patient groups throughout the observation period. After 8 weeks, median albuminuria had increased by 63% in group 1 and by 163% in group 2.

CONCLUSIONS

We were able to demonstrate that the use of ACE inhibitors and angiotensin receptor antagonists in patients after renal transplantation is safe. Favorable effects of both substances on albuminuria were detectable in patients who showed no signs of chronic allograft dysfunction according to the usual criteria. Therefore, a nephroprotective effect of candesartan as well as of perindopril, is highly probable in patients after renal transplantation. Further investigations regarding routine use in these patients are therefore mandatory.

One-compartment model for amino acids and other biological molecules in peritoneal dialysis

OBJECTIVES

Investigation of the main factors determining the concentration-time course of amino acids and biological molecules in serum and dialysates.

METHODS

In a randomized, 3-period crossover study, 11 patients were treated once with each of 3 peritoneal dialysis solutions, 1 containing amino acids and bicarbonate, 1 containing glucose and bicarbonate and 1 containing glucose and lactate. Nineteen amino acids, 3 proteins, 2 metabolites and 2 ions were measured in serum and dialysate. A standard compartment model was fitted to the data.

RESULTS

The amino acids differed significantly in their kinetic characteristics (p < 0.001), mainly volume of distribution and elimination rate. Differences in absorption were small compared to the interpatient variation. The average transport rate from serum to dialysate was 0.50-1.14 h(-1), from dialysate to serum 0.33-0.41 h(-1), for elimination from the central compartment 0.35 to 2.27 h(-1), for volume of distribution 0.29 to 0.83 l/kg, for serum protein binding 19-47%, for amount in tissue 82 - 95%, for endogenous metabolic rate 16-151 micromol x kg(-1) x h(-1). The volume of distribution correlated with the R group (polar positive < aliphatic < polar uncharged). For the various proteins, the 2 bicarbonate solutions had higher serum-to-dialysate transport rates than the lactate solution (p = 0.018-0.601).

CONCLUSION

The compartment model demonstrated its usefulness. Accordance with literature data for healthy volunteers indicated the validity of the estimates.

Renal involvement in sarcoidosis--a report of 6 cases

This report concerns 6 patients with renal involvement in sarcoidosis. Two of the patients had no clinical symptoms at all. In 3 patients, no extrarenal organ manifestation was found. All 6 patients had elevated levels of serum creatinine, 2 were hypercalcemic. Five patients manifested with mild proteinuria, but in none of the cases was a nephritic sediment with erythrocytes found. Kidney biopsies in 5 patients showed epitheloid cell granulomatous interstitial nephritis, and 1 patient presented with nephrocalcinosis. All patients were treated with corticosteroids. The serum creatinine levels decreased significantly in 4 patients (> 50% decrease), and slightly in 2 patients, elevated serum calcium levels were normalized. Thus, even in the absence of other organ manifestations, sarcoidosis can be the cause of renal insufficiency, and it responds well to corticosteroid treatment. These patients demonstrate the importance of kidney biopsy in the unexplained deterioration of renal function.

Different effects of cyclosporine a and FK506 on potassium transport systems in MDCK cells

BACKGROUND

Hyperkalemia and metabolic acidosis are common manifestations in patients receiving the immunosuppressive agent cyclosporine A (CsA) and the recently introduced FK506. We compared the acute toxic and antiproliferative effects as well as the effects on the transport activity of Na(+)/K(+)-ATPase and Na(+)/K(+)/2Cl(-) cotransporter of CsA and FK506 in an established cell line of distal/collecting tubule origin (MDCK cells).

METHODS

MDCK cells were exposed to various concentrations of CsA or FK506 and the effects on cell viability (MTT test and neutral red uptake), plasma membrane integrity (lactate dehydrogenase (LDH) release) and cell proliferation (bromodeoxyuridine (BrdU) incorporation) were compared. For transport studies, after confluence, MDCK cells were exposed to CsA or FK506 for 48 h in the presence and absence of aldosterone. Ouabain- and bumetanide-sensitive (86)Rubidium uptake measurements were used to study the activity of the Na(+)/K(+)-ATPase and Na(+)/K(+)/2Cl(-) cotransporter at the surface of intact cells.

RESULTS

After 24 h of exposure CsA reduced the number of viable cells to 50% at 30 microM, whereas for FK506 2-3 times higher concentrations had to be employed. Similarly, LDH release was stimulated tenfold by 30 microM CsA but only fourfold by 70 microM FK506. In contrast, DNA synthesis was affected at lower concentrations of FK506 than of CsA. In cells treated for 24 h BrdU incorporation was significantly inhibited by 3 microM FK506, whereas a similar inhibition required 10 microM CsA. The transport activity of Na(+)/K(+)-ATPase and of Na(+)/K(+)/2Cl(-) cotransporter were significantly decreased (37 and 63%, respectively) on CsA administration (8 microM). In CsA-treated cells the K(+) channel blockers barium (1 mM), TEA (10 mM) and quinine (1 mM) did not further inhibit the transport activities suggesting that CsA might also act via inhibition of K(+) channels. FK506 at 8 microM had no effect on Na(+)/K(+)-ATPase transport activity but stimulated Na(+)/K(+)/2Cl(-) cotransporter activity by 59%. The stimulatory effect was abolished by K(+) channel blockers indicating that recycling of K(+) might increase by FK506. The simultaneous presence of aldosterone (5 microM) protected the cells from the inhibitory effect of CsA on Na(+)/K(+)-ATPase and Na(+)/K(+)/2Cl(-) cotransporter activity. The stimulatory effect of FK506 on the Na(+)/K(+)/2Cl(-)cotransporter activity was completely abolished in the presence of aldosterone.

CONCLUSIONS

Both CsA and FK506 showed acute toxicity in MDCK cells in vitro with the effects of FK506 being less pronounced. CsA and FK506 had different effects on the in vivo transport rates of the Na(+)/K(+)-ATPase and the Na(+)/K(+)/2Cl(-) cotransporter; CsA inhibited the activity of the Na(+)/K(+)-ATPase and the Na(+)/K(+)/2Cl(-) cotransporter whereas FK506 stimulated the activity of Na(+)/K(+)/2Cl(-) cotransporter. These effects were abolished by the application of aldosterone.

[Aortoiliac reconstruction after kidney transplantation. Strategies to avoid ischemic damage of the transplant]

INTRODUCTION

The rising life expectancy of patients undergoing kidney transplantation and the improvement in the function rate of the allografts have led to an increasing number of patients suffering from arteriosclerosis-related diseases of the aortoiliac arteries. In these particular cases, an interruption of the blood supply of the allograft is always necessary for operative repair of the aortic and iliac arteries. This means a high risk of ischemic damage to the transplanted kidney.

PATIENTS AND METHODS

Between 1987 and 2000, 1,076 kidney transplantations were performed in our department. During this time, 14 reconstructive operations of the aortoiliac arteries were performed in 12 patients (6 women, 6 men, average age 55.2 (45-71) years). Operations were indicated in patients suffering from occlusive disease with imminent extremity or allograft loss, and symptomatic or asymptomatic aneurysms with a maximum diameter of more than 4 cm. In patients presenting with thoracoabdominal (1) and abdominal aortic aneurysms (3), protection of the transplanted kidney was performed by axilloiliac or axillofemoral bypass. Hypothermic flush-perfusion of the allograft containing PGE1 and heparin was performed in seven of nine operations for occlusive disease.

RESULTS

None of the patients presented with a permanent decrease in kidney function, six patients showed temporary creatinine elevation, and in nine patients creatinine levels at discharge were lower than they were preoperatively. None of the patients died.

CONCLUSION

Reviewing all reported methods of allograft protection, we recommend a three-step strategy including sequential clamp technique (ischemia < 30 min.), hypothermic flush-perfusion (ischemia < or = 60 min.), and temporary axilloiliac/femoral shunt (ischemia > 60 min), depending on the expected renal ischemia time.

Comparison of body fluid distribution between chronic haemodialysis and peritoneal dialysis patients as assessed by biophysical and biochemical methods

BACKGROUND

The control of extracellular volume is a key parameter for reducing hypertension and the incidence of cardiovascular mortality in dialysis patients. In recent years bioimpedance measurement (BIA) has been proven as a non-invasive and accurate method for measuring intracellular and extracellular fluid spaces in man. In addition, plasma atrial natriuretic peptide (ANP) and cyclic guanosine monophosphatase (cGMP) concentrations have been shown to reflect central venous filling. Using these methods, we compared body fluid status between stable patients on haemodialysis and peritoneal dialysis.

METHODS

Thirty-nine chronic haemodialysis patients, 43 chronic peritoneal dialysis patients and 22 healthy controls were included in the study. Multifrequency BIA was performed using the Xitron BIS4000B device (frequencies from 5 to 500 kHz were scanned and fitted) in patients before and after haemodialysis. Peritoneal dialysis patients were measured after drainage of the dialysate. Plasma ANP and cGMP levels were measured in plasma using a (125)I solid phase RIA. Serum albumin concentrations and serum osmolality were measured in all patients. The body fluid data were analysed in relation with the clinical findings.

RESULTS

Total body water (TBW) was 0.471+/-0.066 l/kg before haemodialysis and 0.466+/-0.054 l/kg after haemodialysis. Peritoneal dialysis patients had a TBW (0.498+/-0.063 l/kg) that was greater than the before and after dialysis values of haemodialysis patients. The extracellular body fluid (V(ecf)) was increased pre-haemodialysis. It was even greater in peritoneal dialysis patients compared with patients both pre- and post-haemodialysis (pre 0.276+/-0.037 l/kg; post 0.254+/-0.034 l/kg; peritoneal dialysis 0.293+/-0.042 l/kg, P<0.05). However, plasma ANP concentrations (representing intravascular filling) in peritoneal dialysis patients were comparable with post-haemodialysis values (284+/-191 pg/ml vs 286+/-144 pg/ml). The correlation coefficient between sysRR and V(ecf) was r=0.257 in haemodialysis (P=0.057) and r=0.258 in peritoneal dialysis (P<0.05). A significant negative correlation was found between serum albumin and V(ecf)/TBW in peritoneal dialysis patients (r= -0.624).

CONCLUSION

Body fluid analysis by BIA demonstrated that TBW and V(ecf) were increased in peritoneal dialysis patients, and were comparable or even greater than values found before haemodialysis. However, plasma ANP levels indicated that intravascular filling was not increased in peritoneal dialysis. The ratio of V(ecf) to TBW was correlated to systolic pressure and negatively to serum albumin in peritoneal dialysis patients.

[Glomerulonephritis secondary to chronic infection of a ventriculoatrial shunt]

HISTORY AND ADMISSION FINDINGS

A 39-year-old man was referred for assessment of a nephrotic syndrome. He reported deteriorating health with bouts of fever and microhaematuria and proteinuria in the past year. At the age of 24 years a ventriculoatrial shunt had been inserted for an internal hydrocephalus. At another hospital he was given steroids for a nephrotic syndrome suspected of being associated with membranoproliferative glomerulitis, but the disease progressed. On admission he had severe generalised oedema with a temperature of 38,5;C. His general condition was poor. He had no neck stiffness.

INVESTIGATIONS

Parameters of inflammation were raised. Serum creatinine and creatinine clearance were normal. Levels of complements C3 and C4 were reduced. The proteinuria was 9g/24h. Renal biopsy revealed type 1 membranoproliferative glomerulonephritis. Micrococcus roseus/varians was demonstrated several times by aerobic blood cultures.

TREATMENT AND COURSE

The findings suggested chronically infected ventriculoatrial shunt as cause of the glomerulonephritis. The shunt was, therefore, removed. The same pathogens were grown from it on aerobic culture medium. Six months after removal and replacement of the shunt and treatment of the infection the proteinuria had fallen to 0.45 mg/h; serum creatinine was 1.0 mg/dl.

CONCLUSION

When membranoproliferative glomerulonephritis has been demonstrated, secondary forms should be considered in the differential diagnosis. In most cases specific treatment can prevent progression of the renal disease.

[Effect of cyclosporin A on renal function in patients with glomerulonephritis]

BACKGROUND AND OBJECTIVE

Cyclosporin A ( CsA) plays a confounding part in the treatment of nephrotic syndrome. Renal hemodynamics and glomerular permselectivity were investigated in patients with glomerulonephritis to analyse the antiproteinuric action of CsA and to differentiate between nephrotoxic and immunosuppressive effects.

METHODS

We studied 19 patients with nephrotic syndrome after 6 months of treatment with CsA (membranous glomerulonephritis-MGN, n = 10; focal segmental sclerosing glomerulonephritis - FSGN, n = 5; minimal changes glomerulonephritis - MCGN, n = 4). Patients were studied three times within 3 weeks with (A) and without (B) CsA treatment (A-B-A'). Blood pressure, creatinine, proteinuria, C(In), C(PAH), C(Dex) were measured (analysis according to the model of Deen et al., Am J Physiol. 1985; 249 : 374).

RESULTS

GFR (C (In)) increased significantly after withdrawal of CsA from 54 +/- 7.3 to 64 +/- 8.5 ml/min (p < 0.01). Proteinuria increased after withdrawal of cyclosporin (B) between 21 % (MGN) and 45 % (FSGN). After withdrawal of CsA (B) there was no change of FC(dex) in patients with MGN and FSGN. Withdrawal of CsA in patients with MCGN induced a significant decrease in glomerular selectivity in the high molecular range.

CONCLUSION

These data demonstrate that CsA is able to induce even in the short term a significant increase in glomerular permselectivity in MCGN. The acute effects on GFR predominantly determined the acute antiproteinuric effects in patients with MGN and FSGN.

Peritoneal dialysis fluids with a physiologic pH based on either lactate or bicarbonate buffer-effects on human mesothelial cells

Conventional lactate (Lac)-buffered peritoneal dialysis (PD) solutions have turned out to be detrimental to human peritoneal cells, especially because of a low pH. In the present study, we focus on potential differences between Lac and bicarbonate (Bic) as a buffer when adjusted to a physiological pH. All test fluids were buffered with either 40 mmol/L of Lac or 34 mmol/L of Bic, sterile filtered, and adjusted to a pH of 7.4. Osmotic agents used were 1.36% glucose (Glu), 3.86% Glu, 1% amino acids (AA), and 7.5% Glu polymer (Glupoly). Human peritoneal mesothelial cells (HPMCs) were isolated from the omentum majus, grown to confluence, and incubated after the second passage for 15 minutes (37 degrees C and 5% carbon dioxide) with the test fluids. Cytotoxicity was controlled by measuring apoptotic and necrotic cells with cytofluorometry. Aerobic cell metabolism (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assay) and intracellular adenosine triphosphate (ATP) concentrations were measured to assess cell viability. Release of interleukin-6 (IL-6) from HPMCs was determined as a parameter of cellular host defense. No significant difference in apoptosis or necrosis rates was found between the solutions adjusted to normal pH. However, in the MTT assay, Bic solutions were superior to corresponding Lac pendants at an identical pH of 7.4 (P < 0.01). Intracellular ATP concentrations reflected a very similar pattern (P < 0.05). Glupoly in combination with Lac showed an impaired pattern with both the MTT and ATP assays. Regarding IL-1beta-stimulated IL-6 release, there was a small, but not significantly better, response for Bic. Differences in manifest cell cytotoxicity reflected by apoptosis and necrosis rates could not be detected comparing PD solutions buffered with Lac or Bic at a physiological pH. However, distinct parameters of cell metabolism were superior with Bic compared with Lac. Especially Glupoly was inferior in combination with Lac as a buffer.