Treatment of lupus nephritis by mycophenolate mofetil

BACKGROUND/AIMS

Mycophenolate mofetil (MMF) has been increasingly used for the treatment of lupus nephritis (LN). The aim of this study was to examine the efficacy and safety of MMF used with low doses of corticosteroids as maintenance therapy in patients with LN.

METHODS

The study covered 35 patients, most of them with proliferative types of LN (5 WHO class III, 26 class IV), while 1 had class V and 3 class VI nephritis. MMF was administered in the dose of 1.5-2 g/24 h and prednisone at 10-20 mg/day. The treatment effects were followed over a 12-month period.

RESULTS

After 3 months of therapy significant reduction in proteinuria was achieved (2.1 +/- 2.4 g/24 h vs. 1.0 +/- 1.0 g/24 h, p < 0.01) and maintained to the end of the study. In parallel, a significant rise in serum albumin, a fall of cholesterol and a significant increase in mean glomerular filtration rate were noted. Complete remission was achieved in 16 patients (45.7%), including all patients in class III and V plus 10 patients in class IV. Not a single adverse effect was observed.

CONCLUSION

MMF combined with low doses of steroids is an effective and safe treatment for the maintenance of stable remission of LN.

Asymptomatic microscopic haematuria in young males

AIM

The study involved 120 young males (aged 20.5 +/- 2.5 years) having undergone successful kidney biopsy because of asymptomatic haematuria with the aims to assess the prevalence of histological diagnosis and the natural history of the disease.

METHODS

The patients were selected from the population of conscripts who were referred to our clinic as a result of asymptomatic microhaematuria. All patients had a negative history of kidney disease, normal creatinine clearance (Ccr), while extrarenal causes of microhaematuria were excluded. The patients were divided into a group of 62 patients with isolated microhaematuria (IMH; proteinuria < 0.3 g/day) and a group of 58 patients with asymptomatic microhaematuria and proteinuria (AMHP; proteinuria > 0.3 g/day). After kidney biopsy patients were monitored for 3-9 years.

RESULTS

Normal biopsies and minor abnormalities were more frequent in IMH than in AMHP patients, who had IgA nephritis more frequently and significantly higher total pathohistological score. Based on the clinical and histological features, recommendations on patients' ability for military service were made. During the follow-up period, normal Ccr maintained in all patients. Macrohaematuria appeared in 42 patients and proteinuria worsened in eight patients (seven with AMHP). Urinary abnormalities disappeared in 20 patients with IMH and in eight with AMHP (p = 0.04).

CONCLUSION

Minimal histological changes and disappearance of urinary abnormalities were more frequent in IMH than in AMHP patients. Kidney biopsy is useful only in patients with AMHP but it is not necessary in IMH patients.

Mycophenolate mofetil combined with steroids: New experiences in the treatment of idiopathic retroperitoneal fibrosis

Background/Aim. Idiopathic retroperitoneal fibrosis (IRF) is an uncommon disease characterized by a retroperitoneal fibrotic tissue that often involve the ureters, leading to the obstructive nephropathy and variable impairment of renal function. Findings strongly suggest an autoimmune etiology. Surgery, medical treatment with immunosuppressive drugs, or a combination of both are proposed. The optimal treatment has not been established yet. The aim of this study was to present our experience with combined immunosuppressive therapy of IRF, steroids (S) and mycophenolate mofetil (MMF). Methods. We prospectively followed four patients with IRF from January 2004 to December 2006. Three patients had an active disease with bilateral hydronephrosis. In the two of them acute renal failure was presented, and ureteral catheters were inserted in one in order to manage ureteral obstruction. One patient has came to our unit with a relapse of IRF and incipient chronic renal failure after the prior therapy with ureterolysis and immunosuppressive drugs (azathioprine and tamoxifen). All patients received steroids and MMF. Two patients were treated with intravenous methylprednisolone pulses (250 mg each), for three consecutive days, followed by oral prednisone 0.5 mg/kg/day. The other two patients received oral prednisone at the same dose. Prednisone was gradually tappered to a maintenance dose of 10 mg/kg/day. Simultaneously, all patients received MMF, initially 1 g/day with the increase to 2 g/day. Results. After four weeks of the therapy all symptoms disappeared, as well as a hydronephrosis with a decrease of erythrocyte sedimentation rate and Creactive protein (CRP) to normal level in all patients. Three patients remain in remission untill the end of the follow up. One patient had a relapse because of stopping taking the therapy after six months. He was treated by oral prednisone 0.5 mg/kg/day, which was gradually decreased. After twelve weeks hydronephrosis disappeared and CRP returns to the normal level. Conclusion. The combination of steroids and mycophenolate mofetil led to the remission of IRF with a strong and quick immunosuppressive effect. It also provided avoiding the long-term use of high steroid dose and surgical procedures. .

[Ten year experience in kidney transplantation in patients undergoing peritoneal dialysis (1996-2006)]

INTRODUCTION

Kidney transplantation is nowadays considered the most sophisticated method of treatment of chronic terminal renal insufficiency. The advancement in surgical technique and the use of new immunosuppressive medications provide a longer survival period of both the patient and the graft.

MATERIAL AND METHODS

The objective of this paper is a retrospective presentation of the ten-year monitoring of kidney transplantation in patients undergoing peritoneal dialysis performed at the Military Medical Academy.

RESULTS AND DISCUSSION

During that period, 32 patients underwent the transplantation (18 men and 14 women of the average age of 32.48+/-2.1). The total of 34 transplantations were performed, out of which 2 were retransplantations. Patient monitoring period was 7-92 months. The immunosuppressive therapy was quadrupled in 17 (50%) patients and tripled in 17 (50%) of them. The loss of the graft in the early period following the transplantation occurred in 5 (15.6%) patients due to trombosis a. renalis, out of whom two were retransplantation cases. Registered surgical vascular complications included 5 (15.6%) bleeding, 4 (12.5%) hematomes and 6 (18.7%) lymfocells. Delayed graft function occurred in 5 (14.7%) and acute rejection in 7 (20.5%) patients while the disease reccured in 2 patients. As for the complications, rejection without the loss of graft was registered in 4 (12.5%) pts, ureter stenosis in 3 (8.82%) pts, bacterial infections in 4 (12.5%) pts and reactivation of CMV infections in 9 (26.4%) pts. Our patients are observed for the maintenance of stable medium volume of serum creatinine (which is 123.6 +/-10.2 umol/l in the early stage and 133.24+/-11.1 umol/l in the end of the monitoring period as well as the medium volume of clearence creatinine (which is 64.80+/-3.5 ml/min at the early phase of monitoring period and 69.47+/-3.3 ml/min. in the end).

CONCLUSION

Our group of renal transplantation patients, undergoing peritoneal dialysis was with stable renal function registered through the monitoring period.

[Comparative study of the efficacy of different regimens of intermittent subcutaneous dosing of erythropoietin beta in treatment of renal anemia in chronic dialysis patients]

INTRODUCTION

The use of erythropoietin (EPO) in the treatment of renal anemia is justified by more than 15 years of experience. Clinical trials have shown that subcutaneous erythropoietin beta (Recormon - F. Hoffmann-La Roche) therapy once weekly, or even once every two weeks has proven successful. The aim of this study was to evaluate the efficacy of different regimes of Recormon therapy in maintaining stable levels of hemoglobin (Hb) and hematocrit (HCT) in hemodialysis patients.

MATERIAL AND METHODS

An open, comparative, multicenter study was divided into three arms of patients and lasted for 24 weeks. 98 patients with stable Hb level (>100 g/l), were treated with a stable dose of Recormon, and had a ferritin level > 200 microg/l and transferrin saturation >20%. During the first 8 weeks all were on the usual 2-3 times weekly epo dosage. 8 weeks later, 70 patients received epo once weekly, while 28 patients (group 1) maintained the same regimen for the entire study period. After another 8 weeks, 21 of those 70 patients receiving epo once weekly, received it once every two weeks (group 3), while 49 patients continued once weekly regimen to the end of the trial (group 2). The primary efficacy parameter was the percentage of patients maintaining their target Hb and HCT levels (>100 g/l and >30% for HB and HCT respectively).

RESULTS

86 patients (87.75%) completed the study (25 from group 1, 42 from group 2 and 19 from group 3). One patient was excluded because he was transplated during the study, one due to uncontrolled hypertension, while 10 patients, all from the same center, were excluded due to protocol violation (4-week gap in epo therapy due to problems with epo supply). Efficacy analysis included per-protocol population (86 patients). Hb levels remained stable (>100 g/l) in all three groups. Although there were statistically significant differences in Hb levels between visits (p=0,026), there were no statistically significant differences between groups throughout the study (p=0,439). HCT levels remained stable (>30%) in all three groups throughout the study, without statistically significant differences between visits (p=0,053) and between groups (p=0,155). The average epo doses were not statistically significantly different between visits (p=0,676) or between groups (p=0,512). The main tolerability parameters: sitting systolic (SSBP) and diastolic (SDBP) blood pressures were monitored at all visits. Statistical analysis showed that there were no differences in SSBP or SDBP between visits or groups of patients throughout the study.

CONCLUSION

All three dosing regimens of subcutaneous epo beta were statistically equivalent in maintaining target Hb and HCT levels. Once weekly or once every two weeks administration of epo beta does not lead to dose increase, and provides greater opportunities to individualize treatment for every single patient and may lead to better compliance.

Extramedular plasmacytoma in the urinary bladder: Unusual localization

Background. Multiple myeloma is a plasmaproliferative disease characterized by the uncontrolled proliferation of a pathogenic plasma cell clone engaged in the production of monoclonal immunoglobulin. This condition affects the bone marrow, but it can be manifested in any other organ or tissue. The urinary bladder involvement is extremely rare. Case report. We reported a 70-year-old male with the history of multiple myeloma, receiving chemotherapy containing melphalan and prednisone (MP). Two years after the treatment, there was a renal failure associated with oligoanuria, hematuria and bilateral hydronephrosis. The urine cytology tests revealed the atypical cells, so was suspected obstructive uropathy to be caused by urothelium cancer. However, only upon the cystoscopy and biopsy performed on the urinary bladder mass, plasmacytoid infiltration diagnosis was confirmed. This extremely rare variant was presented throughout the illness period and proved to be resistant to the administered chemotherapy. Conclusion. When renal failure associated with hematuria and bilateral hydronephrosis is presented in a patient with multiple myeloma, this unusual and rare extramedular localization should be also considered.

[Comparative analysis of the efficacy and biocompatibility of various methods of dialysis]

BACKGROUND/AIM

The efficacy and biocompatibility of hemodialysis have a singnificant impact on dialysis patient morbidity and mortality rate. The aim of our study was to compare the efficacy and biocompatibility of different hemodialysis modalities in our patients.

METHODS

A total of 55 patients were included in the study, and on the basis of dialysis modality, they were divided in four groups: group I--post-dilution on-line hemodiafiltration (n=15), group II--bicarbonate high-flux polysulphone hemodialysis (n=15), group III--bicarbonate low-flux polysulphone hemodialysis (n=15), and groupe IV--bicarbonate cuprophane hemodialysis (n=10). The efficacy was evaluated on the basis of urea reduction rate (URR), urea Kt/V index and serum beta2-microglobuline reduction rate, and the biocompatibility was evaluated on the basis of the leukocyte count fall during the first fiftheen minutes of dialysis session, and of the serum C-reactive protein (CRP) level.

RESULTS

The highest mean URR was achieved in the group I (70.53 +/- 6.49%), and it was significantly higher in comparison with the average URR in the group IV (54.8 +/- 6.35%) (p = 0.001). The average value of urea Kt/V index in the group I (1.48 +/- 0.22) was significantly higher in comparison with the average value in the group II 1.30 +/- 0.22 (p < 0.05), group III (1.05 +/- 0.22), and group IV (0.98 + 0.22) (p = 0.001). Serum beta2-microglobuline reduction rate was 68.93 +/- 8.25% in the group I, and 58.86 +/- 7.98% in the groupe II (p = 0.01). During the first 15 minutes of hemodialysis the leukocyte number was decreased by 12.57 +/- 9.35% in the group 1, 13.61 +/- 9.64% in the group 11, 18.3 +/- 13.24 in the group III and 62.3 +/- 15.4 in the group IV, on average. The mean serum level of CRP was 9.4 +/- 6.47 mg/l in the group IV, and less than 3.5 mg/l in the group I of the patients (p = 0.001).

CONCLUSION

Postdilution on-line hemodiafiltration in comparison with standard hemodialysis provided the more effective elimination of small and middle uremic toxins molecules and a significantly higher degree of biocompatibility. The patients treated with standard hemodialysis frequently do not achieve the minimal value of urea Kt/V index prescribed by National Kidney Foundation-Dialysis Outcomes Quality Inatiatives standards. These patients also have significantly higher serum CRP values which suggest the state of chronic microinflammation.

Lupus nephritis: histopathologic features, classification and histologic scoring in renal biopsy

Lupus nephritis (LN) is one of the most significant manifestations in systemic lupus erythematosus (SLE), although in some cases there is no direct correlation among clinical, serologic and histologic findings. Therefore, renal biopsy and histopathologic classification by the activity and chronicity assessment of LN are considered necessary before the initiation of the treatment. In this paper 311 renal biopsies in patients with LN were analyzed and classified according to the WHO Classification published in 1974. Renal biopsy specimens were routinely processed for standard analysis by light microscopy (LM), immunofluorescent (IF), and electron microscopy (EM). Biopsy findings were compared with the common clinical symptoms. It is important to recognize that histopathologic lesions in the analyzed tissue might precede the symptoms and clinical manifestations, and therefore are an important factor in the appropriate therapeutic approach. Histopathological assessment of the class of LN represents an important predictor in most patients because the lesions of LN class I and class II most often have no progression and consequently do not require an aggressive treatment. Diffuse proliferative glomerulonephritis (class IV) as a severe form of renal lesion requires the application of high doses of corticosteroids and cytotoxic medicaments. The established quantitive indexes have significant predictive value. Activity index (AI) evaluates the presence of fresh inflammatory and potentially reversible lesions and chronicity index (CI) evaluate the presence of irreversible glomerular lesions such as sclerosis, tubular atrophy, interstitial fibrosis, etc. High AI and low CI, particularly in the class IV of LN, suggest the necessity of an aggressive treatment of the inflammatory process aiming to preserve the renal function. High CI and low AI characterize irreversible sclerosing lesions, where an aggressive treatment is considered unnecessary. Our experience suggests the necessity of introducing the new morphologic elements into the activity and chronicity scoring system which would correlate better the clinical symptoms. This should provide higher reliability of scoring, since it evaluates important elements in clinical-morphologic diagnosis of LN.

[Application of tiazofurin in the study of regulation of AMP deaminase in intact malignant cells]

AMP deaminase has a key position in regulation of the pool of adenine nucleotides and energetics in malignant cells. The aim of this investigation was to elucidate mechanism of regulation of activity of AMP deaminase in intact tumor cells. Using tiazofurin, which profoundly decreases the level of GTP, and guanosine which markedly increases its concentration in the Ehrlich ascites tumor cells under aerobic conditions, we have shown that this nucleotide is probably the major regulator of AMP deaminase activity in situ. This regulation, however, should be considered in relation to the time and the changes which occur during transition of the cells from aerobic to anaerobic phase, and reverse, when other factors, like concentrations of the substrate and ATP are involved.

[Acute post-streptococcal glomerulonephritis in adults--corticosteroid therapy, yes or no?]

The aim of this study was to investigate the influence of the corticosteroid therapy on the development and prognosis of proststreptococcal glomerulonephritis (PSGN) in the period of five years. The investigation included a group of 54 patients who were in the acute phase of poststreptococcal glomerulonephritis (PSGN) when they were 18-22 years old. Corticosteroids were administered per os with the starting dose of 0.5 mg/kg bm, and the dose was subsequently decreased by 5 mg every 10 days to 20 mg/per day within 8 weeks of therapy. We have treated ten patients and all were with severe clinical manifestations of the disease (acute renal failure, oliguria, edemas, hypertension) and severe histopathologic (HP) finding of kidney tissue on the initial biopsy. On the basis of clinical parameters, HP changes on the repeated biopsy of the kidney and five years follow-up, we have concluded that the remission of the disease was achieved in patients who had received corticosteroid therapy. Clinical findings were confirmed by PH findings of repeated biopsies with less expressed residues of the disease. Corticosteroid therapy should be administered in adult patients who are in the acute phase of the disease, with clinical and HP severe form of PSGN, since the risk for the further progress of more serious sequelae of the disease is significantly decreased.

[Analysis of a 4-year follow-up of the results of kidney transplantation from living related donors]

The aim was to present a four-year experience in living related kidney transplantation. A total of 43 patients (9 females and 34 males) were enrolled in this study. The standard triple immunosuppressive therapy (steroids, azathioprine and cyclosporine) was administered in 19 (44.1%) patients, and in 20 (46.5%) mycophenolate mophetil in daily dose of 2 g instead of azathioprine. In 5 (14.2%) patients with high immunological risk and delayed graft function was administered antithymocite globulin in duration of 7-14 days, prophylactically. In 3 (6.97%) patients graft loss was caused by vascular complications and in 1 (2.32%) by infection as the complication. During the first post-transplantation year acute rejection was noticed in 8 (34.7%) patients and in 3 (37.5%) it was steroid resistant. The graft loss was never caused by acute rejection. Six-months graft survival was noticed in 91.1% patients and one-year graft survival in 88.4% patients. One-year patient survival was 100%. Short term results in living related kidney transplantation are excellent and nowadays, due to improvement in immunosuppressive therapy, the success in this type of kidney transplantation is mainly limited by surgical and infective complications.

[Cytomegalovirus infection in patients with kidney diseases]

Cytomegalovirus (CMV) has a prominent position as the cause of severe cytomegalovirus infection (CMVI) in immunocompromised persons, such as: patients with primary or secondary immunodeficiency (risk group), blood/hemoproducts recipients, especially recipients of tissue and organ transplants, which have implications for difficult providing of CMV-seronegative (safe) blood. However, CMV-disease is manifested in the minority of immunocompetent persons. Sera of patients from the Center for Hemodialysis of the Clinic of Nephrology of the Military Medical Academy (MMA) were tested on the presence of CMVI markers. All patients belonged to the risk group considering the chronicity of the main disease, receiving of the large quantities of blood and as the possible potential recipients of kidney transplants. Testing was performed by commercial serologic-enzyme-immune tests (Abott--USA, Behring--Germany) for CMV antibodies of IgG and IgM classes by which was determined serologic state of patients. Test results: out of 106 tested sera samples, 100 (99.33%) were CMV-seropositive (CMV-IgG), 27 (25.47%) were positive on recent CMVI (CMV-IgM), 99 (93.39%) received the blood previously, the majority of patients were with the diagnosis of primary glomerulopathy--68 (64.15%) and tubulointerstitial nephropathy--32 (30.18). Such results indicate the potentional possibility of reactivation of latent CMV and development of CMVI, and in transplant recipients--its rejection. It can occur if appropriate measures of prevention from CMVI are not timely undertaken, which includes the providing of CMV-seronegative-safe blood/hemoproducts, as well as the appropriate application of combined medicamentous therapy by chemical agents and immunomodulators-specific hyperimmune anti-CMV immunoglobulins.

[Cyclosporin A in the therapy of nephrotic syndrome caused by focal-segmental glomerulosclerosis]

The use of Cyclosporin A (CsA) in treatment nephrotic syndrome in the primary focal and segmental glomerulosclerosis (FSGS) is controversial. A prospective study was comprised of 10 adult patients with nephrotic syndrome caused by FSGS, treated with CsA and corticosteroids. Six patients were females, 4 males, aged 35 +/- 8 years. The daily urinary protein excretion ranged from 7 to 15 g/24 h (range 11.16 +/- 2.61 g/24 h). The follow-up interval lasted from 6-18 months. The serum CsA levels ranged from 80-120 ng/ml. Prednisone was administered orally 10-15 mg/day. Two months after the therapy onset, all patients experienced clinical improvement and reduction in the urinary daily protein excretion (range 9.74 +/- 2.14 g/24 h) with tendency to decrease, while a stable overall renal function was maintained. During 6 months, 6 patients were in remission (0.5 +/- 0.2 g/24 h), in two patients the proteinuria was retained 1.6-1.8 g/24 h and two patients had proteinuria 3.2-3.6 g/24 h. During the follow up period of this patients' group in the period of 18 months, the values of proteinuria were never above 3 g/24 h (1.15 +/- 0.9 g/24 h). These are encouraging results from initial treatment of FSGS with CsA and small doses prednisone.

[Treatment of chronic viral hepatitis B in secondary membranoproliferative glomerulonephritis using recombinant alfa-2 interferon]

A patient suffering from viral hepatitis B and secondary membranoproliferative glomerulonephritis was presented. He was treated with recombinant alfa-2 interferon. The therapy led to clinical and biochemical remission of the liver and kidney lesions. The example of our patient justifies the use of recombinant alfa-2 interferon in the patients with chronic viral hepatitis B and secondary glomerulonephritis.

[Urticarial vasculitis--a syndrome with low complement levels and secondary glomerulopathy]

In female patient, aged 41, 3 years ago appeared skin changes of urticarial type, and occasional pain in the joints of shoulders and hands, followed by complete weakness and exhaustion, as well as the occurrence of face and eyelid edema. Laboratory findings confirmed the presence of hypocomplentemia with proteinuria, microhematuria and cylindruria. Histopathologic (HP) finding of skin biopsy was leukocytoclastic vasculitis, and HP finding of the kidneys was mesangioproliferative glomerulonephritis. The regression of skin changes was observed during hospitalization after Dapsone was administered. The therapy started with corticosteroids (Prednisone 40 mg/day with weekly dose from 5 mg to 30 mg). In spite of the therapy, hypocomplementemia and proteinuria up to 335 mg/24 h have maintained for a year in the later controls in an outpatient department. The patient is without discomfort, and renal function is stable.

[Complications of percutaneous transluminal renal angioplasty--case report]

Complications of percutaneous transluminal renal angioplasty (PTRA) most frequently occur on dilated artery, and rarely on peripheral punctured artery. In the study was presented 24-year old female patient in whom the painful tumor developed five days after PTRA at the spot of axillary artery punction. Tumor caused the lesion of brachial plexus by the compression, which was the reason for urgent surgery.

[Amyloid tumor in a patient on a regular hemodialysis program]

Amyloidosis is frequent complication in the patients subjected to hemodialysis, and is most frequently manifested in carpal tunnel syndrome, scapulohumeral periarthritis, osseous cysts and exceptionally as solitary tumor. A patient in presented, aged 72 years, who had undergone chronic dialysis for 10 years, in the last 4 years with symptoms and signs of amyloidosis, such as scapulohumeral periarthritis and erosive arthritis of the knee with recurrent effusions. A year ago he had noticed a tumor in the left popliteal cavity that had been progressively increasing and had limited the movements of the knee. After the extirpation, the diagnosis of amyloid tumor was confirmed by histopathologic analysis.

[Pulsed doses of cyclophosphamide in the treatment of Wegener's granulomatosis]

The aim of the study was to analyze the efficacy and toxicity of the therapy with pulse dose of cyclophosphamide in patients with Wegener's granulomatosis. The diagnosis was established in three patients (2 male, 1 female, average age 58.3 years) upon the clinical picture, laboratory-immunologic and histopathologic findings. The initial therapy was conducted by pulse doses of cyclophosphamide (0.6 and 0.8 g/kg), glucocorticoids (0.5 g), repeated plasmapheresis and pulse doses of immunoglobulin (0.4 g/kg). All patients achieved remission with complete recovery of renal function in one patient. The therapy with pulse doses of cyclophosphamide (time-period between pulses from 1 to 3 months), together with glucocorticoids taken orally for 24 months, was continued for the following 18 months. Stable remission (4-15 months) was maintained in all the patients after the immunosuppressive therapy was over. The treatment of Wegener's granulomatosis by cyclophosphamide and glucocorticoid pulse doses with the application of plasmaphereses and immunoglobulin pulse doses in the initial therapy lead to the remission of progressive types of long duration.

[Acquired renal cystic disease and renal carcinoma in patients on chronic hemodialysis]

The patient, aged 49 years, on chronic dialysis for 5 years, was admitted to Clinic of Nephrology of Military Medical Academy to establish the cause of the anemic syndrome. During the investigation, ultrasonographically, and by computed tomography of kidneys and Color-Doppler sonography it was discovered, and by renovasography confirmed, the carcinoma of the left kidney, together with the acquired polycystic renal disease. Left nefrectomy was performed. The tumor of 2 cm without regional invasion and with no evident distant metastases was histopathologically described as a well differentiated clear cell renal carcinoma. The increased frequency of renal carcinoma in uremic patients with acquired cystic renal disease compared to the common population, the absence of classic clinical picture, small tumor dimensions and asymptomatic course in the majority of patients necessitates the detailed search for suspected changes and routine screening once a year in all the patients on chronic dialysis program.

[Significance of inflammatory cytokines in the pathogenesis of IgA nephropathy]

Prospective study was performed on the concentrations of inflammatory cytokines IL-1, TNF and IL-6 in serum and urine (ELISA tests) were determined in the scope of total clinical-laboratory and histologic treatment in 59 patients with primary IgA nephropathy. Control group consisted of 20 healthy subjects. IL-6 was not detected either in serum of patients with IgAN, or in control examinees. TNF alpha and IL-1 beta were detected in control patients' sera and in patients with IgAN, but detected concentrations were not significantly different. IL-1 beta in urine was detected in 82.8%, TNF alpha in 90.0%, and IL-6 in 40% of our patients with IgAN. The concentrations of IL-1 beta were significantly higher compared to IL-1 beta concentrations in urine of healthy subjects and significantly correlated with the severity of glomerular and tubulointerstitial changes, as well as with the degree of proteinuria. Direct and indirect toxicity of TNF alpha on renal structures was confirmed in significantly higher concentrations of that cytokine in urine of patients with mesangial sclerosis of different percentage compared to the patients with isolated mesangial hypercellularity. Also in the patients with index of chronic lesion over 7 significantly higher TNF alpha concentrations in urine were found compared to the patients with lesion index 0-3 and 4-7. Creatinine clearance was in negative correlation with TNF alpha concentrations in urine of our patients with IgAN. Concentrations of IL-6 in urine were in correlation neither with laboratory parameters of renal function, nor with the degree of histologic changes.

Treatment of IgA nephropathy with nephrotic syndrome using pulse doses of IgG

This paper presents the preliminary results of the treatment of nephrotic syndrome in IgA nephropathy (IgAN) using pulse doses of IgG. Diagnosis was established only by percutaneous ultrasonically-guided renal biopsy, as well as on the basis of typical immunofluorescence and light microscopy findings. Histopathologic changes were classified according to the World Health Organization classification for IgAN, by determination of average glomerular, vascular and interstitial fibrosis indices and the degree of tubular atrophy. IgG therapy was administered in three patients with nephrotic syndrome associated with IgAN characterized by minimal histological changes, i.e., by diffuse mesangioproliferative glomerulonephritis. Initial IgG pulse dose was 0.4 g/kg, given as slow intravenous infusion during three consecutive days in the course of the three-month period. Maintenance therapy consisted of intramuscular IgG in the doses of 2.5 g twice a month, for the next three months. After a six-month treatment, clinical and biochemical remission was achieved in patients with minimal histologic changes, but in other two patients with diffuse mesangioproliferative glomerulonephritis, the effect of the therapy consisted of reduced proteinuria by more than 50%, with the renal function restored to the level before therapy. Transient increase in the serum creatinine level was found in two patients. These preliminary results with IgG pulse therapy, although obtained on a small number of patients, suggest the drug's potent immunomodulatory properties, but its complexity and levels of actions should be further investigated.

[The molecular logic of life--a half century of development in biochemistry and molecular biology]

Tremendous progress has been made in biochemistry and molecular biology during the past fifty years which substantially changed our understanding of fundamental processes of life. The progress has been especially made in the field of molecular genetics, biomembranes, cell signaling and bioenergetics. Based on the analysis of the genetic information and human genome organization and function, our understanding of health and disease is rapidly changing: the era of Molecular Medicine has emerged. The discoveries in biochemistry and molecular biology are beginning to migrate from the research laboratories into clinical practice introducing fundamentally new methods in diagnostics and therapy.

[Treatment of nephrotic syndrome in IgA nephropathy with IgG pulsed doses]

The preliminary results of nephrotic syndrome treatment in IgA nephropathy (IgAN) with pulse IgG doses have been presented. The diagnosis of IgAN has been made exclusively by percutaneous ultrasonically guided biopsy of kidneys, on the basis of characteristic finding of immunofluorescent and light microscopy. Histopathological changes were classified upon the Classification of World Health Organization for IgAN with the calculation of average glomerular, vascular and indices of interstitial fibrosis and tubular athrophy. The therapy with IgG was applied in 3 patients with nephrotic syndrome in complex of IgAN with minimal histologic changes, i.e. diffuse mesangioproliferative glomerulonephritis. Initial pulse dose of IgG was 0.4 g/kg and it was administered in slow intravenous infusion for three days running during three months. The therapy of maintenance consisted of intramuscular administration of IgG in the dose of 2.5 g, twice a month, for the next three months. After the six-month treatment, clinical and biochemical remission was achieved in the patient with minimal histologic changes, and in the other two patients with diffuse mesangioproliferative glomerulonephritis the effect of therapy was revealed in proteinuria decrease for over 50% and the preserved renal function on the level before the therapy has started. Temporary increase of creatinine serum concentration was registered in two our patients. Preliminary results of pulse therapy with immunoglobulin G, although obtained on the small patient number, imply its powerful immunomodulatory features, which complexity and action levels should be more investigated.

[Acute renal insufficiency in hemorrhagic fever with renal syndrome]

In the Clinic for Nephrology of Military Medical Academy, 116 patients with hemorrhagic fever with renal syndrome (HFRS) have been treated in the period from January 1989 to December 1995. The patients were hospitalized with advanced acute renal failure (ARF). The largest number of our patients got ill from HFRS from the middle of March till the end of May and during August when the other frequency elevation was noticed. Most frequently the disease has the course that is followed up by phases. Positive finding of antibodies to HFRS virus was noticed in all 116 patients (Hantaan 45%, Belgrade 35%, Puumala 20%). According to clinical symptoms, signs and syndromes that follow up HFRS, the most of our patients were with more severe disease type. The ARF treatment with dialysis was necessary in 45% our patients. The most severe clinical forms were caused by Belgrade strain. Very favorable effect of "an early dialysis" to the disease course and outcome was observed. By this approach in HFRS therapy, the patient's mortality was decreased to 0.86%. The development of chronic renal failure as HFRS sequela is possible, but not so frequent.

[Characteristics of membranous glomerulonephritis]

The diagnosis of primary glomerulonephritis was made in 20 patients from January 1990 to December 1995. They were followed-up up to 5 years. Various therapeutic modalities were applied: 12 patients were treated with pronison per os, in 5 patients (42%) the disease remission was achieved, the other 5 (42%) patients had frequent recurrences of nephrotic syndrome, while 2 patients (16%) were with renal failure. In 7 patients at the beginning of treatment "pulse" methil prednisolone of 500 mg/48 h and 200 mg/48 h of cyclophosphamide was administered per os. Remission was achieved in 5 (71%) patients, and renal failure developed in 1 patient. Four patients, refractery to previous therapy, were treated with cyclosporin A and remission was achieved in 1 patient with proteinuria less than 2 g/d. The other patient had relapses of nephrotic syndrome, and renal failure has developed in the other two patients. Corticosteroids are drugs of choice in the treatment of lighter forms of MGN. In case of resistence to corticosteroid therapy or the progression of renal failure, cyclophosphamide should be included in the therapy, but in the patient refracte to this treatment, therapy with cyclosporin A should be attempted.

[The national program for the early detection and treatment of premalignant and malignant diseases of the lower genital system in women]

Lower genital tract malignancies are often seen in our female population; their detection is often delayed and treatment fails frequently. Latest scientific data on their etiology and newer methods of their detection and treatment in the early stages opens roads in the field of primary and secondary prevention and for the effective therapy, as well. In order to improve current status of the women's health in this field, on October 10, 1995 year, the Section for cervical pathology and colposcopy in addition to Yugoslav Association of Gynecologists and Obstetricians (UGOJ), has been established. One of the most important aims of the Section is introduction of premalignant and malignant diseases of female lower genital tract. So far, the Section has: 1. Submitted the Program proposal to the Ministry of Health of Serbia; on the basis of that proposal, on April 10, 1996 year, the Ministry issued: "Expert instruction for the conduction of assignments aimed at early detection of the cancer of the uterine cervix". In that act obligatory for all health institutions, that have gynecology depts, all activities and goals for National Program introduction are prescribed. 2. The Yugoslav School for pathology of the cervix, vagina, vulva and colposcopy, opened in 1996, year, under the patronage of the Ministry of Health of the Republic Serbia provides the theoretical and practical training for the Program carriers and medical doctors receiving their training in gynecology and obstetrics. The first generation, the School attendees consisted of 149 doctors from the entire country. 3. Creation and submission of a draft common Health Form intended for the computerized and professional use, to provide for more efficient introduction of the National Program. The Form, should be introduced by the Health Ministry as an Official Health Document, to be used by all OBG institutions. 4. Submitted proposal of the activities and tasks in the field of Program realisation according to Health institutions' profiles. 5. Creation of the draft Protocol for actual activities and procedures in order to provide for an early detection and treatment of premalignant and malignant diseases of the female lower genital tract. Having the future mandatory character of this Protocol, the Section will divulge it to the professional audience. 6. Created a project of the National program and submitted it at the beginning of 1996 year, to the Republic Bureau of Health protection, with a request for its financial support in that program. In addition to the activities mentioned, the section management undertook and is taking measures for faster achievement of the aim-of the National Program introduction. Official Health institutions are assigned responsibilities of the Program introduction, the funding and a resolve all the legal, organisational and financial issues. Results that we are expected from this Program include introduction of the primary and secondary measures aimed at disease prevention; early detection of the diseases and its treatment; reduction of the numbers of cases in the advanced stages; significant improvement of gynecological status, and reduction of costs of the treatment of advanced stages of disease. The results should stimulate all, and become must for all subjects involved in the National Program realisation. The Program introduction into the daily OBG practice is a prerequisite of already well established practice in a number of countries, saving life and limb of most women affected by the lower genital tract malignancies.

[IgA nephropathy--IgA1 disease]

The aim of this study was to prove the increased IgA1 production in patients with IgA nephropathy compared to the control group of healthy subjects, by determination of serum subclasses IgA, IgA1 and IgA2 levels. That with the exclusive presence of IgA1 in kidney tissue, justified the assertion that IgAN was IgA1 disease. Eighteen patients with IgA nephropathy, 15 male and 3 female, average age 17-54 (mean +/- SD = 34.1 +/- 5.18) were included in the prospective study. The diagnosis was proved by immunofluorescent assay of bioptic kidney material obtained by ultrasonically guided biopsy. The total serum IgA and IgA1 and IgA2 subclasses levels were determined in the patients and healthy conscripts from the control group. The methods of immunonephelometry and radial immunodiffusion were used. Increased IgA values were found in 22.75% and of IgA1 subclass in 38.85% patients. Patients with IgA nephropathy had significantly higher IgA1 values (p < 0.01), compared to the control group. There was no significant difference in IgA2 subclass levels. Renal function did not significantly affect IgA1 and IgA2 subclasses values.

[Endemic nephropathy in the region of Bela Crkva in Banat]

The village of Kusić is situated 8 km southwestern of Bela Crkva, at the very border, separated from Romania by the river Nera. Due to frequent disease occurrence in the village Kusić, the pelustration of population was done in 1978 and 1989, and during the later follow-up, many patients were examined either in hospital or in outpatient clinics. The aim was to confirm a suspicion on the existence of the focus of endemic nephropathy in the village of Kusić. In 1978 and 1989 abnormal proteinuria was found in 17.7% and 16.7% examines from the village of Kusić, respectively-significantly higher than in surrounding villages: Grebenac, Vracev Gaj, Banatska Palanka and Kruscica (p < 0.01). Slow progression to the lasser degree of anemia was found in the patients with proteinuria, compared to the control group. Eight of 10 regularly dialyzed patients died, and in 4 patients urothelial carcinoma was diagnosed. In all of them nephroureterectomy was performed, and one patient with advanced disease died 6 months after surgery. On the basis of cited data, by their comparison and further prospective observation of the patients from the village of Kusić, it was concluded that the new focus of endemic nephropathy existed in southeastern Banat.

[Ultrasound guided percutaneous biopsy of the kidney]

In the course of 5 years, 582 ultrasound guided percutaneous renal biopsies were performed in 558 patients. Kidney tissue was obtained in 507 patients (90.9%), and in 485 (86.9%) the obtained sample was sufficient to establish the diagnosis. Complications following renal biopsies were observed in 221 patients, or 38% of total biopsies. There were 212 (36.4%) clinically moderate complications. The most frequent ones were asymptomatic hematomae (32.6%), and infrequently lumbar pain (2.4%) and hematuriae lasting less than 12 hours (1.4%). In 9 patients 10 (1.7%) serious clinical complications in the form of hematuria lasting more than 12 h (1%), large perirenal hematomae (0.5%) and urinary infections (0.2%). In the older age group and in patients with pronounced renal failure no significant difference in the incidence of complications was observed. Ultrasound guided percutaneous renal biopsy is a safe diagnostic method, and the associated complications do not seriously curb its use. The therapy of complications is primarily conservative, and only rarely surgical.

[Correlation of inflammatory cytokines in the urine and serum with clinico-laboratory and pathohistologic features in patients with IgA nephropathy]

Complete examination of 21 patients with IgA nephropathy included determination urine and serum IL-6, TNF alpha and INF gamma levels by ELISA (Luzernachen, Luzern Switzerland). Control group included 15 healthy volunteers. Urine IL-6 levels ranging 37-274.1 pg/ml were detected in 15 (71.2%) patients with IgA nephropathy. IL-6 serum levels were undetectable. In the control group serum and urine levels were also undetectable. Correlation between the IL-6 level and proteinuria degree and endogenous creatinine clearance rate has not revealed statistically significant relationship. In relation to histologic groups (minimal changes, focal glomerulonephritis, mesangial proliferative, diffuse sclerosing) patients with minimal changes had (statistically) significantly higher IL-6 urine levels than the third and fourth group. Average the urine levels were 145.8 +/- 166.6 pg/ml and the serum ones were 148 +/- 101 pg/ml. In relation to the control group (statistically) significant difference was not found. Correlation between TNF alpha level and proteinuria degree and creatinine clearance rate has revealed (statistically) significant relationship (p < 0.05). Average interferon gamma serum levels in lgA nephropathy patients were 312.0 +/- 111.8 and in comparison with the control group (statistically) significant difference was found (p < 0.01). The obtained results suggest the important role of cytokine production disregulation associated with the pathogenesis of IgA nephropathy.

[Nephrotic proteinuria in poststreptococcal glomerulonephritis]

Nephrotic proteinuria in acute poststreptococcal glomerulonephritis is rare. In 62 patients aging from 18 to 22 years, proteinuria of > 3 g/24 hrs was found ins 5 (8%) patients, 0.3 to 3 g/24 hrs in 36 (58%) and 0.15 to 0.3 g/24 hrs in 21 (34%) patients. Proteinuria in many patients disappeared after 3 months and in later follow up it was found in about 30% of patients. Out of 5 patients with proteinuria of > 3 g/24 hrs 3 had persistent pathological urinary analysis, 2 patients were rebiopsied after 5 and 3 years from the disease onset, the morphological changes were moderate. In 2 patients after acute phase had been over came to the clinical healthy (with normal urinary analysis) lasting for 2 years and in the rebiopsy less marked pathological changes were described. Immunofluorescent analysis in the all patients were negative. Patients with initial nephrotic proteinuria in poststreptococcal glomerulonephritis have bad prognosis and often develop chronic disease.

[Epidemiology of poststreptococcal glomerulonephritis in the military population]

Acute poststreptococcal glomerulonephritis appears often in children and our interest is the incidence of the disease in young adults (aged 18 to 22 years) especially in military people. In Nephrology Clinic of the Military Medical Academy (In the period from 1978 to the end of 1993) 153 patients were treated and sporadic cases developed after respiratory infection. Only 5 patients developed the disease after skin infection with Streptococcus B hemolyticus group A. A large number of patients acquired the disease in the period from February to April and from October to December and most of them in the time interval from 5 to 7 years. A substantial, number of patients were treated in 1982 (13), followed by 22 in 1989, and the trend continued in 1990 (24 patients) while only 6 patients presented in 1993. So, the incidence of the disease in the military population is not high (10 +/- 6 patients year and it was sporadic cases and more after respiratory infection.

[Clinical and morphologic characteristics of adult IgA nephropathy]

Within the period 1987-1992 IgA nephropathy was diagnosed at the Nephrology Clinic of the Military Medical Academy in 61 patients aged from 17 to 41 years (mean +/- SD = 24.31 +/- 6.39). The aim of the study was to evaluate their importance as markers of progressive forms of IgA nephropathy by analysis of mutual relationship of clinical-laboratory and histopathological characteristics. Clinical form of the disease with recurrent macroscopic hematurias existed in 30 (49.2%) patients, and oligosymptomatic form in 31 (50.8%) patients. Acute renal failure of reversible oliguric character had 5 (8.2%) patients. Patients with recurrent macroscopic hematurias had more progressive course of IgA nephropathy which could be indirectly seen from the parameters of the global renal function. The most frequent histological form of IgA nephropathy was diffuse mesangioproliferative glomerulonephritis registered in 30 (49.2%) patients.

The role of glutamine oxidation and the purine nucleotide cycle for adaptation of tumour energetics to the transition from the anaerobic to the aerobic state

It is proposed that the purine nucleotide cycle and glutamine oxidation play a key role in the adaptation of tumour energetics to the transition from the anaerobic to the aerobic state. In support of this proposal, it was found that glutamine and inosine markedly increase total adenylates in the presence of oxygen, whereas the addition of hadacidin abolishes this effect. Transition of the cells from the anaerobic to the aerobic state, and vice versa, in the presence of glutamine plus inosine revealed that there are two components of the adenine nucleotide pool, one which is stable and the other which is variable and responds to the aerobic-anaerobic transition. This part of the pool undergoes degradation or resynthesis owing to activation of the enzymes of the purine nucleotide cycle. Resynthesis of the pool is accompanied by substantial net utilization of aspartate, which is produced by glutamine oxidation. This is supported by the experiments in which the cells were alternately incubated with nitrogen or oxygen, demonstrating that hadacidin significantly decreased utilization of aspartate and regeneration of ATP owing to inhibition of adenylosuccinate synthase.

Interaction of metabolism of aspartate and inosine and energy state of malignant cells

1. Oxidation of glutamine in Ehrlich ascites-carcinoma cells results in a large accumulation of aspartate. 2. The addition of inosine causes a marked decrease in aspartate production from glutamine. This may be related to the resynthesis of AMP from aspartate and IMP, the latter being produced from inosine via the salvage pathway for purine nucleotides. In accordance with this assumption, a significant production of lactate was observed, which comes probably from the ribose moiety of inosine. Since lactate is known to inhibit production of aspartate from glutamine, this may explain the effect of inosine. 3. Addition of glutamine together with inosine increased cellular ATP content. This was not the case if glutamine or inosine was present separately or if inosine was added together with lactate, pyruvate or glucose. The effect did not occur if amino-oxyacetate, an inhibitor of transaminases, was added. These findings suggested again that production of aspartate is important for resynthesis of ATP from IMP via the purine nucleotide cycle. 4. If the cells were exposed to prolonged anaerobic incubation, addition of glutamine and inosine markedly increased O2 uptake and [ATP], suggesting the crucial importance of aspartate production by glutamine oxidation for the recovery of energy metabolism in the cells.

Kinetics of glutamine-efflux from liver mitochondria loaded with the 14C-Labeled substrate

Glutamine transport across the inner membrane of rat liver mitochondria was studied by the method of loading the organelles with [14C]glutamine and by measuring efflux of the metabolite at 0 degree C. The release of [14C]glutamine from loaded mitochondria was prevented by mersalyl, whereas the efflux was started by the addition of glutathione. The rate of glutamine efflux from the mitochondria was measured by the inhibitor stop technique with mersalyl plus N-ethylmaleimide. It was found that up to 10 mM glutamine there is no significant activity of glutaminase, whereas at about 20 mM of the substrate the enzyme is activated. The rate of the efflux measured after the addition of the optimal amount of glutathione was 10 nmol glutamine/min per mg protein. This is 5-times faster than the rate of glutaminase activity at 0 degree C. The pH optimum of glutamine carrier is between 6.5 and 7.0. Low concentration of succinate inhibits the efflux due to formation of pH gradient in coupled mitochondria, whereas a higher concentration of succinate inhibits the carrier directly. 2-Oxoglutarate and glutamate strongly inhibit the rate of glutamine efflux, the inhibition by glutamate being very pronounced at its physiological concentration. D-Glutamine does not inhibit the rate of the efflux, indicating that the transport of L-glutamine is stereospecific.

Importance of the flux of phosphate across the inner membrane of kidney mitochondria for the activation of glutaminase and the transport of glutamine

The effect of mersalyl, an inhibitor of phosphate transport across the inner mitochondrial membrane, was investigated on the uncoupled respiration of pig kidney mitochondria in the presence of glutamine as substrate and on the activity of the phosphate-dependent glutaminase in the intact organelles. In addition, the submitochondrial location of the enzyme was reinvestigated. (1) It was found that mersalyl completely inhibits uncoupled respiration of the mitochondria in the presence of glutamine as substrate, whereas respiration with glutamate was not affected. The same amount of mersalyl which inhibits coupled oxidation of glutamine also inhibits coupled oxidation of glutamate and some other substrates. (2) Mersalyl strongly inhibited the activation of glutaminase in intact mitochondria only in the presence of inhibitiors of electron transport or of an uncoupler. The addition of a detergent prevented or fully released the inhibition. The effect of mersalyl was observed even when the mitochondria were pre-incubated with phosphate or incubated in the phosphate-free medium. If mersalyl and carbonyl cyanide m-chlorophenylhydrazone (CCCP) were added 3 min after pre-incubation with phosphate the same intramitochondrial concentration of the anion as in control experiments was found, whereas the activity of glutaminase was severely inhibited. These findings suggest that the activation of the enzyme by phosphate in intact nonenergized mitochondria occurs only if the activator moves across the inner mitochondrial membrane. (3) Mersalyl (plus CCCP) markedly decreased [14C]glutamine- and [32P]-phosphate-permeable mitochondrial spaces. A close correlation between the decrease of phosphate and glutamine permeable spaces and the inhibition of glutaminase activity was found. (4) If the activation energy of the enzyme was determined with frozen mitochondrial preparations, a discontinuity or break in the Arrhenius plot was observed, whereas the presence of a detergent completely abolished the break. Digitonin or ultrasonic treatment of the mitochondria followed by separation of the membrane and the soluble fraction revealed that glutaminase is a membrane-bound enzyme. On the basis of these findings it is concluded that there is an association between the transport on one side and the transport of glutamine and glutaminase activity on the other. It is possible that the movement of phosphate across the membrane activates the enzyme which facilitates diffusion of glutamine down a concentration gradient. However, the existance of a specific glutamine-phosphate carrier is not ruled out.

[Prolonged and postmature pregnancy terminated in non-hospital institutions]

Out of 4023 deliveries, the authors came across 291 prolonged ones, of which 39 were postmature deliveries. They followed the issue of these pregnancies in the conditions of non-hospital health care. The mortality rate of postmature deliveries was 10.2%. It is recommended that all prolonged and postmature pregnancies are referred to larger hospital-type maternity wards where more help can be offered to the pregnant woman and where the actual state of the fetoplacental unit can be properly followed. However, in cases when prolonged and postmature pregnancies are to be terminated in a non-hospital institution because of the women's refusal to go a larger maternity ward, it is proposed in present conditions to use as a diagnositc means also amnioscopy in addition to cytohormonal analysis.

Possible mechanisms of the efflux of glutamate from kidney mitochondria generated by the activity of mitochondrial glutaminase

The transport of glutamate across the inner membrane of kidney mitochondria and the influx of glutamine into the mitochondria was studied using an oxygen electrode, the swelling technique and by continous recording of the activity of the mitochondrial glutaminase by an NH4+-sensitive electrode. It is well known that the enzyme is activated by inorganic phosphate and strongly inhibited by glutamate. 1. Avenaciolide, Bromocresal purple and Bromothymol blue inhibited the respiration of the mitochondria almost completely in the presence of glutamate as substrate but not in the presence of glutamine. Production of aspartate during the oxidation of glutamine was not significantly inhibited by avenaciolide but it was markedly suppressed by Bomocresol purple and Bromothymol blue. 2. Swelling of kidney mitochondria in an isosmotic solution of glutamine and ammonium phosphate was not inhibted by avenaciolide or Bromocresol purple indicating that these substances do not inhibit the penetration of the mitochondrial membrane by glutamine or phosphate. 3. The activity of the mitochondrial glutaminase was strongly inhibited by avenaciolide or Bromocresol purple in the presence of inhibitos of respiration or an uncoupler but not in ther absence. Experimental data suggest that this was caused by the inhibition of glutamate efflux. The addition of a detergent removed this inhibition. On the basis of these observations it was concluded that two mechanisms exist which enable glutamate to leave the inner space of kidney mitochondria: (a) an electrogenic efflux coupled to the respiration-driven proton translocation and the presence of a membrane potential (positive outside) and (b) an electroneutral glutamate-hydroxyl antiporter which is inhibted by avenaciolide and which operates in both directions. Our observations do not support the existence of the electrogenic glutamine-glutamate antiporter or glutamate-aspartate exchange in the mitochondria studied.