Shinsuke Nomura

Irradiation Prolongs Survival of Alport Mice

Alport syndrome is a hereditary nephropathy that results in irreversible, progressive renal failure. Recent reports suggested that bone marrow transplantation (BMT) has a beneficial, short-term effect on renal injury in Alport (Col4a3(-/-)) mice, but its long-term effects, especially with regard to survival, are unknown. In this study, Alport mice received a transplant of either wild-type or Col4a3(-/-) bone marrow cells. Surprising, laboratory evaluations and renal histology demonstrated similar findings in both transplanted groups. Transplanted cells accounted for >10% of glomerular cells at 8 wk, but type IV collagen alpha3 chains were not detected in glomerular basement membranes of either group by immunofluorescence or Western blot analysis, although Col4a3 mRNA in the kidney could be amplified by reverse transcription-PCR in knockout mice that received a transplant of wild-type bone marrow. Both transplanted groups, however, survived approximately 1.5 times longer than untreated knockout mice (log rank P < 0.05). These data suggested that irradiation, which preceded BMT, may have conferred a survival benefit; therefore, the survival time of knockout mice was assessed after sublethal irradiation (3, 6, and 7 Gy) without subsequent BMT. A strong positive correlation between irradiation dosage and survival time was identified (P < 0.0001). In conclusion, the improved survival observed in Alport mice that received a transplant of wild-type bone marrow might be primarily attributed to as-yet-unidentified effects of irradiation.

Population analysis of mesothelium in situ and in vivo exposed to bicarbonate-buffered peritoneal dialysis fluid.

Population analysis of mesothelium (PAM) done using the in vivo and almost in situ technique of mesothelial cell imprints revealed that lactate-buffered solutions had detrimental effects upon cell viability, that high glucose concentration affected cytokinesis, whereas the association of both components led to a decreased density population of cells showing a larger surface area. In the present study, PAM was done on mesothelium of mice exposed to bicarbonate-buffered peritoneal dialysis fluid (BBF) with glucose concentrations of 1.5 and 4.25%, for periods of time of 2 h, 15 and 30 days, as well as after recovery intervals of 7 and 30 days, BBF did not affect mesothelial cell viability. However, the increased incidence of multinucleated cells observed with both glucose concentrations, more marked with the 4.25% solution, suggests a detrimental effect upon the mechanism of cytokinesis. Furthermore, the higher the glucose concentration, the higher the mean-cell cytoplasmic surface area and the proportion of large cells, both resulting most probably from the regulatory volume increase developed by cells continuously exposed to hyperosmolar fluids. So far, evidence presented in this study suggests once more that BBF is remarkably more compatible with a higher quality of adaptation and survival of the exposed mesothelium than the lactated fluid. The question of whether the alterations induced by the high concentration of glucose result from a specific effect of glucose, by the coincidental hyperosmolarity, or by both still remains unanswered.

Myelofibrosis Secondary to Renal Osteodystrophy

A hemodialyzed women with secondary hyperparathyroidism who recovered well from myelofibrosis after a total parathyroidectomy with autotransplantation of parathyroid tissue to the forearm (PTx) is described. Before the operation, she had received regular transfusions to maintain an adequate hematocrit even under recombinant human erythropoietin (rhEpo) therapy. She showed splenomegaly and leukoerythroblastosis was present in her peripheral blood. A bone marrow biopsy and bone marrow scintigraphy confirmed the diagnosis of myelofibrosis. After PTx, her hematocrit gradually increased without any transfusion. It has been maintained around 35% now 16 months since the operation. Her spleen has also gradually decreased in size. In addition, no leukoerythroblastosis has been found in the peripheral blood. Serial follow-up scintigraphy of bone marrow revealed a decline in extramedullary hematopoiesis. These findings indicated that her myelofibrosis was the result of secondary hyperparathyroidism, and that this complication is potentially reversible if accurate treatment is given. Physicians dealing with the end-stage renal disease should be aware of this complication to avoid additional transfusions.

Relevance of resistive index ultrasonographic measurement in renal transplantation

The usefulness of the ultrasonographic measurement of resistive index (RI) is not yet fully understood. To obtain a better definition of its relevance in renal disease we studied this parameter in a group of 212 renal transplant patients, aged between 15 and 55 years: 81 first grafts with an excellent renal function, 44 hypertensive patients, 30 type II diabetics, 29 cases of chronic graft dysfunction, 28 cases during an episode of acute rejection. RI was measured in three different renal vascular areas: prerenal, interlobar and cortical. A two-way analysis of variance showed a statistical significance for the site of RI sampling and the type of pathology. There was no interaction between the two variables studied (p = 0.30). Plasma creatinine levels, analyzed as covariate, showed a high statistical correlation with RI values (p = 0.0001). The mean RI of the 80 transplanted patients with normal creatinine plasma levels showed a remarkable homogeneity and a statistically significant progressive reduction of the values from the main renal artery to the interlobar and cortical vessels (p = 0.00001). In the other groups a greater dispersion of data was present. RI values significantly increased in hypertensive and diabetic patients (p = 0.05) but more in acute rejection (p = 0.0001) or chronic graft dysfunction (p = 0.01). In acute rejection and in chronic graft dysfunction the curve of RI values tended to become flat, while in hypertensive and diabetic patients the aspect of the curve became steeper. In conclusion, RI is a hemodynamic index that reflects the vascular status of the explored area and is not only the simple expression of reduction of the kidney functional units. The differences observed in the various kidney areas stress the importance of measuring this parameter at more than one vascular site. The increase in RI values on the kidney cortex vessels is likely to be an index of glomerular hyperfiltration. If this hypothesis is true the measure of RI might be a reliable method for diagnosing in the kidney vascular damage, glomerular hypertension and hypertrophy.

Treatment of a Patient with End-Stage Renal Disease, Severe Iron Overload and Ascites by Weekly Phlebotomy Combined with Recombinant Human Erythropoietin

A 41-year-old hemodialyzed woman developed ascites and was found to have secondary iron overload. The dose of administered iron was approximately 11-12 g, and her serum ferritin level was 15,000 ng/ml (15,000 micrograms/l). There were no signs of congestive heart failure, fluid overload, or liver cirrhosis. A program of weekly phlebotomy combined with recombinant human erythropoietin (rhEPO) therapy was tried to eliminate the iron congestion. After 9 months of this therapy, about 5 g of iron had been removed. The ascites completely disappeared, and her serum ferritin level fell to 5,800 ng/ml (5,800 micrograms/l). This suggests that such combined therapy would be useful when iron overload must be corrected rapidly. Before therapy, the sterile ascitic fluid showed exudative characteristics with 3.7 g/dl (37 g/l) of total protein. The serum-ascites albumin difference was 0.6 g/dl (6 g/l), and the fluid contained 1,400 inflammatory cells/mm3 (1.4 X 10(9)/l). Notably, the serum-ascites albumin difference increased in parallel with iron elimination. These findings suggested that iron deposition may have played a role in changing the permeability of the peritoneum, or in impairing lymphatic drainage, both of which are presumed to be pathogenetic factors of nephrogenic ascites.

Human trehalase : Characterization, localization, and its increase in urine by renal proximal tubular damage

By using polymerase chain reaction, cDNA encoding human renal trehalase has been isolated. The partial amino acid sequence deduced by the cDNA showed homologies in rabbit, Tenebrio molitor and silkworm trehalase. Northern blots showed renal trehalase mRNA to be about 2.0 kb. To examine the properties of renal and urinary human trehalase, the trehalase cDNA was inserted in the pMAL-cRI vector downstream from the malE gene, which encodes maltose-binding protein. Transfection of the recombinant pMAL-cRI in Escherichia coli provided high levels of expression of the maltose binding protein-trehalase fusion protein. A rabbit was immunized with purified fusion protein, and antihuman trehalase antibodies were obtained. Immunoblot analysis disclosed that renal and urinary trehalase exhibited a molecular mass of about 75 kDa. Analysis by indirect fluorescent microscopy demonstrated that the enzyme located in only proximal tubular cells. Urinary trehalase activity was low in the healthy infants and elevated in patients with asphyxia. Markedly high activity was observed in a patient with Lowe syndrome. The immunoreactive urinary trehalase with 75 kDa was increased dependent on the elevation of the activity. On the basis of these findings, we conclude that the increase of urinary trehalase reflects the extent of renal tubular damage, and we propose that urinary trehalase can be a specific marker of renal tubular damage.

Malignant Hypertension and Antiphospholipid Syndrome

Dr. A.E. Sirvent, Avda Orihuela 4, 6 D, E-03006 Alicante (Spain) Dear Sir, The kidney is now recognized as another target organ in the antiphospholipid syndrome (AS) [1]. Renal involvement is consistent with thrombosis of the major renal vessels and noninflammatory microvascular disease [2-4]. In the clinical findings renal failure has been emphasized over systemic hypertension. We report here on a patient with systemic malignant hypertension and throm-botic microangiopathy (TM) with no other occlusive complications. A 29-year-old man was hospitalized with acute renal failure during a malignant hypertensive episode, after developing hypertension in the 3 months prior to admission. Thrombocytopenia was also detected. Physical examination showed: blood pressure 230/ 130 mm Hg, grade IV retinal changes, no abdominal bruits were heard; the signs were compatible with congestive heart failure. The most significant laboratory findings were: hemoglobin lOg/dl, WBC 14,000/μl (normal differential count), platelets 47,000/μl, normal coagulation tests, fíbrinogen 490 mg/dl and schistocytes on a peripheral blood smear. Urea was 35 mmol/l, creatinine 884 μmol/l, LDH 971 U/l, haptoglobin 11 mg/dl, and urine contained proteinuria 2.1 g/day, 10-15 erythrocytes/hpf. Chest X-ray revealed pulmonary edema and cardiomegaly, and echo-cardiography indicated left ventricular hypertrophy, normal ejection fraction and mild mitral regurgitation. The abdominal ultrasound showed a right kidney of 11.9 cm and a left kidney of 8.7 cm. No evidence of kidney infarction was seen in the renal CT scan. The magnetic resonance angiogram disclosed normal aorta and renal arteries. The following laboratory data were negative or normal: urine cultures, urine catecholamines and VMA, HBsAg, serology for HCV, cryoglobulins, rheumatoid factor, ANCA, anti-GBM, ANA, anti-DNA, anti-SSA (Ro), anti-SSB (La), anti-Sm, anti-RNP antibodies, C3, C4, VDRL, brain CT, cystography, lupus anticoagulant; anticardiolipin antibodies (aCL) IgG 63.3 GPL/ml (n.v. < 23), IgM 3.1 MPL/ml (n.v. < 11), and repeated after 8 weeks, IgG 40 GPL/ml (ELISA). Antiplatelet antibodies were positive. The kidney biopsy showed TM; no deposits were noted in the immunofluores-cence study. Blood pressure was controlled. An increase in platelets and normalization of LDH was achieved following plasma exchange with FFP as the replacement fluid; upon withdrawal of the plasma exchange, thrombocytopenia recurred. After receiving the aCL determination

Sensitivity to Calcium Intake in Calcium Stone Forming Patients

The absorptive or renal origin of hypercalciuria can be discriminated using an acute oral calcium load test (ACLT). Of 86 patients with calcium oxalate kidney stones, 28 (23%) were found to be hyperca

Effects of ACE inhibitor on renal anemia in predialysis patients.

Shinsuke Nomura, MD, Nephrology Division, Department of Medicine, Kawasaki Medical School, Kurashiki, Okayama 70101 (Japan) Dear Sir, The role of angiotensin-converting enzyme inhibitors (ACEI) in inducing anemia has been reported in people with normal renal function [1], in patients with chronic renal failure on hemodialysis [2] and in kidney transplant patients [3, 4]. Several mechanisms of ACEI-induced anemia have been hypothesized. ACEI may decrease angioten-sin II, which stimulates erythropoietin production. They may decrease renal tissue hyp-oxia due to their property for increasing renal blood flow. Or, by decreasing renin levels, they may diminish one likely precursor of erythropoietin [2, 5]. The association between renal anemia and ACEI in patients at the predialysis stage has not been well discussed. Therefore, we carried out a retrospective analysis of 39 predialysis patients checking their medical records during the follow-up period at our outpatient clinic. Among patients in whom regular renal replacement therapy had been initiated from 1984 to 1993 at Kawasaki Medical School Hospital, 39 Japanese patients (23 males) were entered into the study with the following restrictive criteria: (1) age 30-65; (2) followed up by us from when serum creatinine level had been less than 2.0 mg/dl to the initiation of renal replacement therapy; (3) never showed microcytic hypochromic anemia during the period; (4) had no malignancies, liver cirrhosis, or collagen diseases, (5) no anabolic steroid, recombinant human erythropoietin (rhEpo) or transfusion was given during the period. Patients with diabetic ne-phropathy and polycystic kidney disease were excluded from the study. Twenty of them had chronic glomerulonephritis or nephrosclerosis diagnosed by renal biopsy. When their serum creatinine level increased to over 3.0 mg/dl (phase A) and over 7.0 mg/dl (phase B), the patients were divided into three groups according to the medication they were taking for hypertension: group 1 (no antihypertensive agents was prescribed): group 2 (ACEI was prescribed for at least over 2 months), and group 3 (other antihypertensive agent(s) was prescribed, such as calcium antagonists, α-and ß-blockers). Most of the prescribed ACEI were capto-pril or enalapril. Patients in whom ACEI was prescribed in combination with other agents were put into group 2. As shown in figure 1 ‚ the hematocrit level of group 2 at phase B was significantly lower than in group 1, while no difference was found at phase A (unpaired t test). There was no difference in

Prospective case control study to determine the effect of lovastatin on serum testosterone and cortisol concentrations in hyperlipidemic nephrotic patients with chronic renal failure.

In order to investigate the effects of lovastatin on adrenal and gonadal function, we prospectively determined the basal and gonadorelin-stimulated concentrations of testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and the cortisol response to adrenocorticotropic hormone (ACTH) in a sample of 25 male patients with advanced chronic renal failure, hypercholesterolemia and proteinuria. Hormone studies were done prior to and after lovastatin treatment. The values of these patients were compared with those of a matched healthy control group. Before starting treatment with lovastatin, the patients showed significantly lower testosterone concentration and higher LH concentration than the control group. After stimulation with gonadorelin, they also showed a lower increase in testosterone and LH. After 12 months of lovastatin treatment, a significant decrease in the concentration of cholesterol, LDL C, VLDL C and apo B was observed, but neither the basal testosterone concentration nor the response to gonadorelin stimulation was modified. Before treatment, basal and ACTH-stimulated serum cortisol levels did not differ from those of the control group. After lovastatin treatment, neither the basal serum cortisol levels nor the response to ACTH was modified. We conclude that in the patients studied, although the decrease in testosterone concentration may be partially attributable to a decrease in its synthesis, lovastatin treatment does not increase testosterone deficit. This is either because this drug does not inhibit gonadal hydroxymethylglutaryl CoA reductase at the does given or because the cholesterol which LDL C provides the cell with is enough to maintain testosterone synthesis.