Transformations: the material representation of historical experiments in science teaching

Some experiments from the history of physics became so famous that they not only made it into the textbook canon but were transformed into lecture demonstration performances and student laboratory activities in the nineteenth and twentieth centuries. While, at first glance, some of these demonstrations as well as the related instruments do resemble their historical ancestors, a closer examination reveals significant differences both in the instruments themselves and in the practices and meanings associated with them. In this paper, I analyse the relation between the research instruments and the respective teaching demonstrations. In doing so, I particularly distinguish between demonstrations that address the process of the actual experimental procedures, and those that focus on the outcome or results (the product) of the experiment. This distinction will be illustrated in some exemplary case studies from the late nineteenth century and the early twentieth in which both the historical experiment and the related educational devices are analysed. The tension between the historical experiment on the one hand, and the different variants of the teaching version on the other, result in the educational as well as epistemological problems that are discussed in this paper.

Kidney transplantation during mass disasters - from COVID-19 to other catastrophes A Consensus Statement by the DESCARTES Working Group and Ethics Committee of the ERA

Mass disasters are characterized by a disparity between health care demand and supply, which hampers complex therapies like kidney transplantation. Considering scarcity of publications on previous disasters, we reviewed transplantation practice during the recent COVID-19 pandemic, and dwelled upon this experience for guiding transplantation strategies in the future pandemic and non-pandemic catastrophes. We strongly suggest continuing transplantation programs during mass disasters, if medical and logistic operational circumstances are appropriate. Postponing transplantations from living donors and referral of urgent cases to safe regions or hospitals are justified. Specific preventative measures in anticipated disasters (such as vaccination programs during pandemics or evacuation in case of hurricanes or wars) may be useful to minimize risks. Immunosuppressive therapies should consider stratifying risk status and avoiding heavy immune suppression in patients with a low probability of therapeutic success. Discharging patients at the earliest convenience is justified during pandemics, whereas delaying discharge is reasonable in other disasters, if infrastructural damage results in unhygienic living environments for the patients. In the outpatient setting, telemedicine is a useful approach to reduce the patient load to hospitals, to minimize the risk of nosocomial transmission in pandemics and the need for transport in destructive disasters. If it comes down to save as many lives as possible, some ethical principles may vary in function of disaster circumstances, but elementary ethical rules are non-negotiable. Patient education is essential to minimize disaster-related complications and to allow for an efficient use of health care resources.

[Present practise patterns of renal replacement therapy in German intensive care medicine]

About 50% of all critically ill patients develop acute kidney injury (AKI) and approximately 15% receive renal replacement therapy (RRT). Although RRT is frequently used in intensive care units in Germany, it is currently unknown which RRT procedures are available, which qualification the involved staff has, which anticoagulation strategies are used and how RRT doses are prescribed. To investigate quality and structural characteristics of the performance of RRT in intensive care units throughout Germany, the German Interdisciplinary Society of Intensivists (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin [DIVI]) performed an inquiry among their members. A total of 897 members participated in the survey in which practical aspects were queried. In 69.1% of the cases, RRT was performed in hospitals with more than 400 beds and in 74.5% in university hospitals or other primary care hospitals. Furthermore, 93.3% of clinics are equipped with continuous and 75.8% with intermittent renal replacement devices. In 91.9%, indication for initiation of RRT was performed by trained physicians specialized in intensive care medicine or nephrologists. Intermittent as well as continuous modalities are both present in three-quarters of cases, which allows for individualized therapy. However, the documentation of dialysis dose needs to be improved.

Laboratory Notes, Laboratory Experiences, and Conceptual Analysis: Understanding the Making of Ohm's First Law in Electricity

Georg Simon Ohm's work in the field of electricity led to what is now considered to be the most fundamental law of electrical circuits, Ohm's Law. Much less known is that only months earlier, Ohm had published another law-one that differed significantly from the now accepted one. The latter entailed a logarithmic relation between the length of the conductor and a parameter that Ohm called "loss of force." This paper discusses how Ohm came up with an initial law that he felt compelled to correct a few months later. We analyze Ohm's publication as well as his laboratory notes, relating them to our own laboratory experiences while using the replication method to study his work. We also discuss the conceptual background of Ohm's work. We conclude that he was significantly influenced by French studies in the field of electricity, most notably the ones by Charles Augustin Coulomb.

Re-examining the early history of the Leiden jar: Stabilization and variation in transforming a phenomenon into a fact

In this paper, we examine the period that immediately followed the invention of the Leiden jar. Historians of science have developed narrations that emphasize the role of grounding during the process of charging the jar. In this respect, this episode shows significant aspects that can be used to characterize science, scientific knowledge production, and the nature of science. From our own experimentation, we learned that grounding was not necessary in order to produce the effect. These experiences inspired us to go back to primary sources. In doing so, we came to a new understanding of the early period after Kleist's and Musschenbroek's initial creation of the effect. From our analysis, we conclude that it is not the grounding which was perceived as a major innovation (as well as a challenge) during this early period of the discussion but the concept of an electrical circuit. This understanding was fundamental in characterizing the Leiden jar as a new device challenging the then current knowledge of experimental practices in the field of electricity.

[Treatment of acute renal failure in Germany: a structural analysis]

INTRODUCTION

There are no reliable data on the structure and practice of the care of critically ill patients with acute renal failure in Germany.

METHODS

We carried out a detailed survey by sending a questionnaire to 2265 German Intensive Care Units. The questionnaire contained 19 questions regarding renal replacement therapy.

RESULTS

423 German intensive care units participated in the survey. Most of the ICUs are headed interdisciplinary (47%) or by anesthesiologists (30%), with significant differences depending on the size of the clinic, with primarily interdisciplinary management in smaller clinics. The offered type of renal replacement therapy varies significantly, the smaller the house the fewer methods are available. Thus, intermittent dialysis procedures are offered only in 35% of hospitals with up to 400 beds. The indication for the initiation of acute renal replacement therapy in intensive care is provided predominantly (53%) by an anesthesiologist. A nephrologist is only involved in 22% of all intensive care units. The indication is based primarily on a "clinical criteria", but these are poorly defined.

CONCLUSION

Our results demonstrate the need for cross-disciplinary standards for the treatment of acute renal failure in German intensive care units.

A phase 1, single-dose study of fresolimumab, an anti-TGF-β antibody, in treatment-resistant primary focal segmental glomerulosclerosis

Primary focal segmental glomerulosclerosis (FSGS) is a disease with poor prognosis and high unmet therapeutic need. Here, we evaluated the safety and pharmacokinetics of single-dose infusions of fresolimumab, a human monoclonal antibody that inactivates all forms of transforming growth factor-β (TGF-β), in a phase I open-label, dose-ranging study. Patients with biopsy-confirmed, treatment-resistant, primary FSGS with a minimum estimated glomerular filtration rate (eGFR) of 25  ml/min per 1.73  m(2), and a urine protein to creatinine ratio over 1.8  mg/mg were eligible. All 16 patients completed the study in which each received one of four single-dose levels of fresolimumab (up to 4  mg/kg) and was followed for 112 days. Fresolimumab was well tolerated with pustular rash the only adverse event in two patients. One patient was diagnosed with a histologically confirmed primitive neuroectodermal tumor 2 years after fresolimumab treatment. Consistent with treatment-resistant FSGS, there was a slight decline in eGFR (median decline baseline to final of 5.85 ml/min per 1.73  m(2)). Proteinuria fluctuated during the study with the median decline from baseline to final in urine protein to creatinine ratio of 1.2  mg/mg with all three Black patients having a mean decline of 3.6  mg/mg. The half-life of fresolimumab was ∼14 days, and the mean dose-normalized Cmax and area under the curve were independent of dose. Thus, single-dose fresolimumab was well tolerated in patients with primary resistant FSGS. Additional evaluation in a larger dose-ranging study is necessary.

An experimenter's gotta do what an experimenter's gotta do--but how?

The aim of this essay is to discuss the relation between experimenter and instruments in terms of how they interact: how the instrument requires a particular performance from the experimenter, how the experimenter requires a particular performance from the instrument, how a particular purpose of the experimental procedures requires a particular performance from the experimenter and the instrument, and, finally, how both-experimenter and instrument in their interplay-are subject to standards that can be related to social, political, or epistemological criteria. The author draws on his own experiences in analyzing experiments using the replication method.

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.

Influence of interleukin-6 G-174C gene polymorphism on coronary artery disease, cardiovascular complications and mortality in dialysis patients

BACKGROUND

Inflammation is a well recognized central component of atherosclerotic processes in chronic kidney disease. Interleukin-6 (IL-6) levels are a strong determinant of cardiovascular mortality in dialysis patients. We evaluated the impact of IL-6 gene G-174C polymorphism associated with modified IL-6 production on the development of coronary artery disease (CAD), cardiovascular events and mortality in chronic dialysis patients.

METHODS

We studied n = 463 patients on chronic dialysis with angiographically confirmed (n = 218) or excluded (n = 245) CAD followed up for 65 months after initiation of dialysis. Monitored were arterial hypertension, diabetes mellitus, hyperlipidemia, smoking, CRP and fibrinogen. IL-6 gene G-174C polymorphism was determined by PCR amplification.

RESULTS

The CC genotype was associated with an impaired patient survival (p < 0.05) remaining an independent risk factor for death in multivariate analysis (HR for CC genotype: 3.58, CI: 1.41-9.07, p < 0.01). CC genotype carrying CAD patients suffered significant frequently cardiovascular events (revascularization, myocardial infarction, death) compared to GG/GC genotype carriers (85.2% vs. 66.5, p < 0.05). However, the IL-6 gene G-174C polymorphism was not related to the onset and development of CAD itself (ns) and the inflammation parameters CRP and fibrinogen did not differ between the genotypes under investigation (ns).

CONCLUSIONS

Our results suggest that IL-6 gene G-174C polymorphism is associated with the incidence of cardiovascular events and mortality in chronic dialysis patients.

The enlightened microscope: re-enactment and analysis of projections with eighteenth-century solar microscopes

Solar microscopes and their techniques attracted particular attention in the second half of the eighteenth century. This paper investigates the grounds for this interest. After a general introduction to the solar microscope, it discusses the use of original instruments to gain access to the visual culture of solar microscopes and the issues raised by these reenactments. Experiences involved in this process serve as a basis for reassessing the original source materials. Thence emerges a different account of the meaning of the solar microscope in the eighteenth century and possible reasons for its popularity.

Cyclosporin in idiopathic glomerular disease associated with the nephrotic syndrome : workshop recommendations

Management of idiopathic glomerular disease associated with nephrotic syndrome (INS) remains controversial and one of the most complex areas relates to utilization of the drug cyclosporin. This is despite its demonstrated effectiveness in several histologic types of the INS in randomized controlled trials. Cyclosporin is effective in inducing remission of proteinuria in approximately 80% of steroid-sensitive cases of minimal change disease (MCD). Cyclosporin is also effective in both the induction of remission and long-term preservation of renal function in steroid-dependent/-resistant MCD and steroid-resistant focal segmental glomerulosclerosis (FSGS). The overall response rate in FSGS is lower than in MCD, and long-term therapy (>12 months) may be required to both achieve remission and sustain it. Cyclosporin therapy is also of benefit in reducing proteinuria in 70-80% of patients with steroid-resistant membranous nephropathy (MGN). In MGN, the maximum benefit is often delayed compared to MCD (>12 weeks). Cyclosporin is generally well tolerated and safe. The major concern remains the nephrotoxicity, but with careful monitoring of the patient's renal function; minimizing the maintenance dose and utilizing repeat renal biopsy in those receiving long-term therapy, this risk can be minimized. The algorithms have been developed derived from the best evidence in the literature in each of the histologic types to help provide a guide to the integration of cyclosporin into the management of INS for the practicing nephrologist.

Hodgkin disease-like posttransplantation lymphoproliferative disorder of donor origin in a renal allograft recipient

Posttransplantation lymphoproliferative disorder (PTLD) develops in 1.6% of renal allograft recipients. More than 90% are of recipient origin. There are only a few reports of Hodgkin disease-like PTLD in allograft patients. We report the case of a Hodgkin disease-like PTLD of donor origin in a 16-year-old renal allograft recipient. Fourteen months after transplantation, an increasing inhomogeneous structure in the hilar region of the transplanted kidney became apparent and was excised. Histological examination showed Hodgkin- and Sternberg-Reed-like cells. Immunostaining showed CD20-positive and CD15-negative cells and Epstein-Barr virus (EBV) involvement (EBV-encoded small nonpolyadenylated RNA and EBV-determined nuclear antigen 2). DNA fingerprinting analysis proved the lymphoma to be of donor origin. Treatment consisted of nephrectomy, discontinuation of immunosuppression therapy, and local radiation. Three years after lymphoma removal, the patient was still without relapse and underwent retransplantation with stable function of the second allograft for more than 2 years now.

Different effect of cyclosporine A and mycophenolate mofetil on passive Heymann nephritis in the rat

BACKGROUND

While cyclosporine A (CsA) is an effective therapy for nephrotic syndrome, it has nephrotoxic side effects. We compared the anti-proteinuric effects and nephrotoxicity in rats with passive Heymann nephritis (PHN) of CsA and mycophenolate mofetil (MMF).

METHODS

PHN was induced in female Wistar rats. Two treatment groups consisting of 8 rats each received either 25 mg of CsA or 25 mg of MMF/kg body weight/day and were compared with untreated controls. Kidney function and proteinuria were monitored over 4 weeks. Western blots were used for densitometric analysis of renal cyclooxygenase-2 (COX-2) protein expression. Thromboxane B2 (TxB2) and 6-keto-PGF(1alpha) were determined by radioimmunoassays (RIAs) in renal tissue and urine.

RESULTS

Rats with PHN exhibited a marked proteinuria of 12.76 +/- 4.42 vs. 0.73 +/- 0.28 mg/24 h (p < 0.01) and showed increased glomerular concentrations of TxB2 and 6-keto-PGF(1alpha) (992.6 +/- 216.9 and 1,187.0 +/- 54.2 pg/mg protein, respectively) compared with healthy controls (595 +/- 196.17 and 729 +/- 297.84, respectively) and a strongly induced COX-2 protein expression. CsA and MMF treatment reduced PHN-related proteinuria to 2.10 +/- 1.47 and 1.47 +/- 7.2 mg/24 h, respectively. In rats with PHN, CsA induced a significant deterioration of renal function and enhanced urine excretion of thromboxane A2, paralleled by a significant, twofold increase in COX-2 protein expression and renal prostaglandins. By contrast, MMF treatment in rats with PHN was not nephrotoxic and had no effect on prostaglandin production. COX-2 protein expression under MMF was suppressed.

CONCLUSION

While the antiproteinuric efficacy of MMF and CsA in PHN was comparable, the absence of nephrotoxicity might favor MMF in the treatment of nephrotic syndrome. The CsA-induced increase in COX-2 expression and COX-2-dependent prostacyclin may indicate a mechanism that compensates nephrotoxicity in the diseased and CsA-exposed kidney.

COX-2 dependent PGE(2) downregulates alpha(v) integrin expression via the EP(3) receptor in cultured mesangial cells

BACKGROUND

In experimental glomerulonephritis, inhibition of cyclooxygenase 2 (COX-2) enhances the renocortical expression of pathogenic alpha(v) integrins.

AIMS

To study whether this effect is mediated by prostaglandin E(2) (PGE(2)) acting through its EP(3) receptor in cultured rat mesangial cells (MCs).

METHODS

MCs were incubated with lipopolysaccharide (LPS), celecoxib, PGE(2), or the selective EP(3) agonist, MB28767. The expression of COX-2, EP(3), and alpha(v) integrin mRNA was measured by reverse transcriptase polymerase chain reaction.

RESULTS

LPS upregulated COX-2 expression 2.8-fold and alpha(v) integrin expression twofold. The COX-2 inhibitor celecoxib increased alpha(v) integrin mRNA expression twofold. Both exogenous PGE(2) and the specific EP(3) receptor agonist, MB28767, reduced constitutive alpha(v) integrin mRNA expression to half normal values. COX-2 dependent PGE(2) suppressed the expression of alpha(v) integrin mRNA mediated by the EP(3) receptor in MCs.

CONCLUSIONS

These results suggest that COX-2 suppresses the expression of alpha(v) integrins by an increased production of PGE(2) activating its EP(3) receptor in glomerulonephritis.

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.

Cyclosporine A and chlorambucil in the treatment of idiopathic focal segmental glomerulosclerosis

BACKGROUND

The therapy of nephrotic syndrome in focal segmental glomerulosclerosis (FSGS) is still a matter of controversy.

METHODS

We performed a prospective randomized study of the treatment of nephrotic syndrome due to FSGS. We compared 2 specific treatment protocols to assess the effect of treatment on proteinuria and renal function. Fifty-seven patients were randomly assigned to 2 groups: group 1 (n = 34) received steroids and cyclosporine, and group 2 (n = 23) received steroids and chlorambucil for 6 months. When treatment was refractory to chlorambucil, the patients in this group were treated with cyclosporine. Creatinine, blood urea nitrogen, proteinuria, lipids, and arterial hypertension were monitored at regular intervals.

RESULTS

Patients showed a mean serum creatinine of 1.5 +/- 0.2 mg/dL (132.6 +/- 17.7 micromol/L) and proteinuria of 4.8 +/- 2.8 g/24 h with no differences between the groups. At the end of the chlorambucil therapy, patients in group 2 had creatinine levels of 1.8 +/- 0.6 mg/dL (159.1 +/- 53 micromol/L) and proteinuria levels of 3.4 +/- 1 g/24 h. All patients in this group were given cyclosporine. After 4 years the mean creatinine level in group 1 was 1.7 +/- 0.4 mg/dL (150.3 +/- 35.4 micromol/L) and the proteinuria level was 2.5 +/- 1 g/24 h. In group 2, the mean creatinine level was 1.9 +/- 0.6 mg/dL (168 +/- 53 micromol/L) (not significant [NS]) and the mean proteinuria level was 2.3 +/- 1.1 g/24 h (NS). Full remission occurred in 23% of the patients in group 1 (n = 8) and 17% of the patients in group 2 (n = 4; NS). Partial remission was observed in 38% of the patients in group 1 (n = 13) and 48% in group 2 (n = 11; NS). The number of patients who developed end-stage renal disease was comparable in both groups: 4 of 34 patients in group 1 after 2.5 +/- 0.8 years, and 5 of 23 patients in group 2 (NS).

CONCLUSION

Additional treatment with chlorambucil was found to be ineffective in FSGS. Patients responded to treatment with steroids or cyclosporine, but additional treatment with chlorambucil did not improve the patient's outcome. Future studies must focus on the long-term prognosis of these patients.

Effects of the Genetic Polymorphisms of the Renin-Angiotensin System on Focal Segmental Glomerulosclerosis

BACKGROUND/AIMS

We analyzed the influence of angiotensin-converting enzyme (ACE) I/D, angiotensinogen (AGT) M235T and angiotensin-II-type-1 receptor (AT1R) A1166C genetic polymorphisms on the clinical course of focal segmental glomerulosclerosis (FSGS).

METHODS

This study consisted of 71 patients with nephrotic syndrome due to biopsy proven FSGS and 100 healthy controls. According to the slope of the reciprocal serum creatinine (1/Cr, >or= or <-0.1 dl x mg(-1) x year(-1)) patients were classified into group A (slow progressors, n = 50) and group B (fast progressors, n = 21). Genotyping was performed using polymerase chain reaction (PCR).

RESULTS

There were no relevant differences in the allele frequencies of the investigated polymorphisms between patients with FSGS and controls. Patients carrying the T- allele of the AGT polymorphism required a larger number of antihypertensive agents (MM: 1.35 +/- 1.0 vs. MT/TT: 2.0 +/- 1.2, p < 0.05). The ACE-ID/DD genotypes were more frequently found in patients with fast progression (group A: II: 38.0%, ID/DD: 62.0% vs. group B: II: 14.3%, ID/DD: 85.7%, p < 0.05). The AT1R-A1166C polymorphism was not associated with any of the parameters studied.

CONCLUSION

The course of FSGS is in part genetically determined by polymorphisms of the renin-angiotensin-system. The ACE-I/D polymorphism was shown to be a risk factor of progression of renal disease and the AGT-M235T polymorphism was associated with the severity of arterial hypertension.

COX-2 inhibition and prostaglandin receptors in experimental nephritis

BACKGROUND

Renal cyclooxygenases (COX) produce the prostaglandins (PG) E2, I2 and thromboxane (TxA2), which interact with distinct G protein-coupled receptors. We investigated the expression of the three EP receptors EP2, EP3 and EP4 and the receptors for PGI2 (IP) and TxA2 (TP) in rats with passive Heymann nephritis (PHN). We studied their regulation by COX-2 inhibition with celecoxib.

MATERIALS AND METHODS

Four groups of Wistar rats were studied: healthy rats (group A), healthy rats treated with celecoxib (group B), rats with PHN (group C), and rats with PHN receiving celecoxib (group D). Expression of the mRNA for all receptors in the renal cortex and for the EP3 receptor in cultured mesangial cells (MCs) was determined by semiquantitative reverse transcriptase polymerase chain reaction. Stable prostaglandin metabolites were measured in the urine by radioimmunoassay.

RESULTS

Rats with PHN (group C) showed an 1.8-fold increase of cortical EP3 receptor mRNA expression as compared with controls (group A). In celecoxib-treated PHN rats (group D) the mRNA expression of the EP3 and EP4 receptors was significantly reduced to 1.0-fold and 0.7-fold induction, respectively. Furthermore, the excretion of bicyclo-prostaglandin E2 (PGE2) was inhibited by celecoxib. No changes were observed in the expression of the other PG-receptors. In cultured MC, PGE2 enhanced the EP3 mRNA expression.

CONCLUSIONS

These data suggest a predominant role of the EP3 receptor in the transduction of PGE2-actions in PHN. It was concluded that COX-2-dependent PGE2 is able to potentiate its effects in the kidney by up-regulating its own receptors.

[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.

Selective cyclooxygenase-2 inhibition upregulates renal cortical alpha V integrin expression

BACKGROUND

Cyclooxygenase-2 (COX-2), the inducible isoform of the cyclooxygenases, is upregulated in various inflammatory renal diseases and responsible for prostaglandin formation. As prostaglandins are known to influence cell adhesion processes, we investigated the effect of COX-2 inhibition on the expression of alpha(v) integrins, which are also enhanced in renal diseases and control the adherence between the endothelium and the extracellular matrix (ECM) in the glomerulus.

METHODS

Healthy female Wistar rats and animals with previously induced passive Heymann nephritis (PHN) received either 5 mg/kg body weight/day celecoxib or a placebo. After 28 days, renal cortical mRNA expression of COX-2 and alpha(v) integrin subunits was determined.

RESULTS

Rats with PHN showed a significant 1.7-fold increase in renal cortical mRNA expression of alpha(v) integrin subunits. Treatment with celecoxib increased cortical alpha(v) integrin mRNA expression 2.2-fold (p < 0.05) in healthy animals and 4.0-fold (p < 0.05) in rats with PHN, but lowered COX-2 mRNA expression in rats with PHN to 0.8-fold (p < 0.05). An inverse correlation between the expression of COX-2 and alpha(v) integrins in rats with PHN was demonstrated.

CONCLUSIONS

It is suggested that COX-2-derived prostaglandins suppress the expression of alpha(v) integrins. This implies a previously unknown role for COX-2 in chronic inflammation in the kidney.

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.

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.

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.

[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.

HRCT findings of amiodarone pulmonary toxicity: clinical and radiologic regression

Amiodarone is an antiarrhythmic drug that can cause interstitial pneumonitis leading to pulmonary fibrosis. A 62-year-old man suffering from atrial fibrillation and recurrent dyspnea was treated with amiodarone. After 15 months of treatment, HRCT revealed bilateral interstitial and alveolar opacifications with high-attenuating pleural-parenchymal consolidations, suggesting amiodarone induced pneumonitis. Three months after cessation of amiodarone treatment, HRCT shows complete regression of pneumonitis. Amiodarone pneumonitis can be misinterpreted and mistreated in patients with further underlying diseases. The present case report demonstrates the diagnostic value of HRCT in the diagnosis of interstitial pneumonitis.

Systemic mycophenolate mofetil in comparison with systemic cyclosporin A in high-risk keratoplasty patients: 3 years' results of a randomized prospective clinical trial

BACKGROUND

With the use of systemic cyclosporin A (CsA), graft prognosis after high-risk penetrating keratoplasty has improved considerably. However, the application of CsA is limited owing to a variety of severe side effects. In this prospectively randomized study mycophenolate mofetil (MMF), a safe and efficient immunosuppressive medication after renal transplantation, was compared with CsA after high-risk penetrating keratoplasty.

METHODS

Twenty-nine high-risk keratoplasty patients were treated with MMF 2x 1 g daily; another 27 patients received CsA, aiming at blood trough levels of 120-150 ng/ml. Systemic immunosuppression was scheduled for 6 months. In both groups oral corticosteroids (fluocortolone 1 mg/kg) were administered for 3 weeks postoperatively.

RESULTS

During the first year after operation, no graft failure was recorded. Two years postoperatively 92%/82% and 3 years postoperatively 74%/69% of grafts were clear in the MMF and CsA group, respectively (Kaplan Meier P=0.33, logrank test). In total, two graft failures were recorded in the MMF group and four in the CsA group. Three years postoperatively 53% of the grafts were rejection-free in the MMF group and 73% in the CsA group (Kaplan Meier P=0.46, log-rank test). Eight endothelial immune reactions were observed in the MMF group (three under systemic immunosuppression/five thereafter; six mild/two severe) and five in the CsA group (three under systemic immunosuppression/two thereafter; three mild/two severe). Side effects occurred in six patients under MMF and 11 under CsA.

CONCLUSIONS

Concerning efficacy, no statistically significant difference between systemic MMF and systemic CsA administered for 6 months after high-risk penetrating keratoplasty could be shown. Systemic MMF was proven to be at least as safe as CsA. The main mechanism in improving graft survival is a shift from severe to milder endothelial immune reactions, as already demonstrated for CsA. Thus, MMF may become an alternative to CsA for immunosuppression after penetrating high-risk keratoplasty. About 2 years postoperatively, pharmacologically induced relative immunological tolerance slowly decreases. Therefore, long-term administration of systemic MMF should be evaluated in further studies.

Angiographic progression of coronary artery disease in patients with end-stage renal disease

BACKGROUND

Patients with end-stage renal disease have an increased risk of developing coronary artery disease (CAD). The cardiovascular mortality of dialysis patients is 10-15 times higher compared with the general population. The aim of our study was to evaluate the morphological progression of coronary arteriosclerosis in this cardiovascular high-risk group by visual assessment and quantitative coronary angiography. Methods and results. In 26 patients with chronic renal failure (age, 47+/-11 years; 15 male; duration of dialysis, 23+/-25 months) the severity of CAD and degree of coronary stenoses were assessed in two coronary angiograms after a mean follow-up interval of 30+/-15 months (12-60). Baseline angiography revealed CAD in 13/22 patients (59%). The second angiography was performed as screening procedure prior to renal transplantation (n=20) and/or as follow-up angiography after coronary angioplasty (n=10). Visual assessment showed a progression defined by the development of haemodynamically relevant stenosis of >50% luminal diameter in 13 patients. Quantitative angiographic evaluation was performed in a total of 45 segments showing >25% narrowing at the second angiogram. A progression (>15% luminal reduction) was found in 17 of 45 segments, a new lesion (initial luminal diameter <20%) was detected in nine segments, resulting in progression or new lesion in 16 patients (62%). Patients with or without progression did not differ in age, duration of dialysis treatment, number of cardiovascular risk factors, or serum total cholesterol and fibrinogen levels. After percutaneous transluminal coronary angioplasty (PTCA) a restenosis was seen in seven of 16 primarily successfully dilated segments. After the second angiography, myocardial revascularization was performed in eight patients (1 PTCA, 7 coronary artery bypass graft).

CONCLUSIONS

Patients with end-stage renal disease have a high prevalence of CAD. In line with the clinical course, CAD patients on maintenance dialysis undergo rapid angiographic progression of CAD, which results in a high rate of subsequent myocardial revascularizations.

Post-transplant distal-limb bone-marrow oedema: MR imaging and therapeutic considerations

BACKGROUND

In recent years a previously unrecognized pain syndrome of the distal lower limbs after organ transplantation has been noted. A relationship to cyclosporin A was suspected, but no clear aetiology and pathogenesis have been established.

METHODS

During the last 30 months we diagnosed the pain syndrome in 10 patients after renal transplantation. We prospectively followed and evaluated the patients during their clinical courses and through pathological laboratory findings and magnetic resonance imaging (MRI).

RESULTS

In all patients symptoms developed within 6 months of transplantation after otherwise uncomplicated clinical courses without graft rejection episodes. Impressive bone-marrow oedema on MRI as well as elevated serum alkaline phosphatase was seen in all patients, and often exceeded the duration of clinical symptoms. All patients were instructed to avoid stress to the extremities through immobility, and steroid doses were tapered down. Within 14 weeks, eight patients were free of symptoms. Two patients have not experienced remission after 3 and 4 months respectively. None of the patients developed signs of osteonecrosis.

CONCLUSION

Post-transplant distal limb bone-marrow oedema presents with distinct clinical findings and signs of bone-marrow oedema on MRI. Proven standard treatment does not exist. In our experience the elevation of the extremities, the strict avoidance of physical strain, and a stepwise withdrawal of steroids facilitates progressive disappearance of symptoms. Long-term damage to the affected ostial structures has not been seen, in contrast to avascular femoral-head necrosis.

[Therapy options in systemic AL-amyloidosis with renal involvement]

BACKGROUND AND OBJECTIVE

Despite significant efficacy of melphalan and prednisone in the therapy of systemic AL(light chain amyloid)amyloidosis the prognosis of the disease is poor. In patients with severe renal manifestation the reported results of low-dose melphalan therapy are inconclusive with respect to relief of clinical symptoms and overall prognosis.

PATIENTS AND METHODS

We report our results of therapy in a group of 22 patients (8 women, 14 men, mean age 60 years) with renal involvement as the main manifestation of systemic AL-amyloidosis without overt myeloma.

RESULTS

Ten patients were treated with low doses of melphalan and prednisone. No significant clinical improvement was observed in any case: the patients died an average of 12 months after diagnosis of the disease. Three patients were treated with high doses of melphalan followed by autologous stem cell transplantation. One patient died due to septicaemia after high-dose chemotherapy. Two of the patients experienced significant remission and live virtually free of clinical symptoms 12 and 18 months after therapy. Nine patients were treated only symptomatically: four of them were alive an average of 30 months after diagnosis of systemic AL-amyloidosis.

CONCLUSIONS

Only high-dose melphalan therapy offered a realistic chance of amelioration of clinical symptoms in our group of patients, although therapy-associated risks seem to be high. In patients with severe renal amyloidosis, who are not considered for high-dose therapy, particularly careful consideration of potential benefits and possible risks of conventional melphalan therapy is necessary, because the results of this approach are in doubt.

Etiology and pathogenetic mechanisms of optic disc swelling with visual loss. An interdisciplinary prospective pilot study of 102 cases

A nonrandomized, prospective, interdisciplinary pilot study of 102 patients with noncompressive optic disc swelling with visual loss (ODSWVL) was performed in order to investigate etiologic and pathogenetic mechanisms. Forty-six patients suffered from underlying inflammatory disease. Seventeen patients suffered from highly probable cardiogenic embolization, 16 patients from multiple vascular risk factors. The remaining patients of the noninflammatory disease group suffered from leukemia, previously unknown or severely decompensated diabetes mellitus, acute arterial hypertension, different kinds of coagulopathies and others. Ninety-six of the 102 patients required medical treatment according to general medical standards. Inhomogeneity of the underlying disease processes explains the ineffectiveness of different monotherapies in previous studies. Interdisciplinary search for the underlying causes allows causative treatment. ODSWVL and anterior ischemic optic neuropathy in particular seem to be a common final pathway of various pathogenetic mechanisms due to different etiologies rather than a disease entity by itself.

[Acute renal failure in hantavirus infections]

BACKGROUND

The acute renal failure remains a diagnostic challenge for the clinician.

CASE REPORTS

Between 1991 and 1996, acute renal failure caused by hantavirus infection was diagnosed in 4 previously healthy male patients. Main symptoms consisted of fever, headache, arthralgia, lumbar and abdominal pain as well as a decline in diuresis. The ultrasonography showed a slight splenomegaly in 2 patients. The clinical chemistry showed elevated serum creatinine from 2.2 mg/dl to 6.7 mg/dl and thrombocytopenia from 4000 to 150,000/microliter. The examination of the urine showed slight proteinuria and microhematuria. The kidney biopsy of 1 patient showed a reversible damage of the tubuli. The pathologic findings normalized within 3 weeks in 3 patients without need for dialysis. One patient developed a severe clinical course with acute renal failure and pulmonary edema requiring dialysis. In all patients, the renal function improved.