Akira Shinoda

Current status of renal replacement therapy in Japan

The study of the current status of renal replacement therapy in Japan is based on the analysis of data from the registry reports for regular dialysis therapy and kidney transplantation. The total number of patients receiving regular dialysis therapy was 123,926 at the end of 1992: 117,809 (95.1%) on hemodialysis and 6,117 (4.9%) on peritoneal dialysis. The primary diseases of newly accepted patients were chronic glomerulonephritis (42.2%), diabetic nephropathy (28.4%), nephrosclerosis (5.9%), polycystic kidney disease (2.7%), chronic pyelonephritis (1.6%), and others. The number of kidney transplant patients in Japan was 8,384 at the end of 1991: 6,154 (73.4%) received a living donor transplantation and 2,230 (26.9%) received a cadaver donor transplantation. Overall 5-year survival rates of dialysis patients were 60.4%: 69.7% for chronic glomerulonephritis, 41.7% for diabetic nephropathy, 39.6% for nephrosclerosis, 73.6% for diffuse polycystic kidney disease, and 66.6% for chronic pyelonephritis. The causes of death of dialysis patients were heart failure (31.1%), cerebrovascular accident (13.6%), infectious diseases (11.3%), malignancies (7.1%), cachexia/uremia (6.7%), myocardial infarction (5.8%), and others. The gross mortality rate of dialysis patients was increased in cases of less than 4 hours of the average length of each dialysis session, less than 4% and more than 9% of the average weight loss during each dialysis session, less than 1.0 of Kt/V, and less than 0.9 and more than 1.7 g/kg/d of protein catabolic rate. Overall 5-year patient and graft survival rates of kidney transplant patients since 1964 were 82.7% and 60.3%: 84.4% and 65.0% in living donor cases, and 77.4% and 46.2% in cadaver donor case, respectively. Those since 1983 were 90.1% and 68.2%: 91.3% and 72.6% in living donor cases, and 87.8% and 59.3%, respectively. Graft survival rates were superior in cases treated with combined steroid, cyclosporine and azathioprine or mizoribine, to those treated with other immuno-suppressive regimens, and they decreased as the number of HLA-A, -B and -DR increased.

Regression of acquired cystic disease of the kidney after successful renal transplantation

The effect of renal transplantation on acquired cystic disease of the kidney in patients who have been on hemodialysis for more than 5 years was examined in 7 cases by computer-assisted tomography (CT scan). Almost all acquired cysts disappeared, and the size of the original kidneys decreased remarkably in 2 cases 8--10 months after transplantation. 3 other patients, in whom CT scans were performed only after transplantation, showed contracted scarred kidneys with few or no cysts. The involution of acquired cysts was incomplete in 1 case, in whom the cysts persisted for 3 years and 2 months, despite normal renal function. The last case, who was off hemodialysis only for 4 months, exhibited enlargement of the original kidneys and an increase in the number of cysts. These results suggest that a significant number of acquired renal cysts in dialyzed patients with end-stage kidney disease regress rapidly after successful renal transplantation, but this is not always so.

Ten-Year Prospective Study on the Development of Renal Cell Carcinoma in Dialysis Patients

A prospective study was undertaken to investigate the development of renal cell carcinoma in dialysis patients. Three renal cell carcinomas were detected among 96 hemodialysis patients in 1979, and screening by computed tomographic (CT) scan was continued yearly until 1989. During this 10-year period, one renal cell carcinoma was found in the second year and another in the ninth year. Autopsy performed on seven of 19 patients who died showed one case of small clear cell carcinoma accompanying acquired cystic disease. In 33 males, kidneys were found to have enlarged 2.7 +/- 1.7 times over the 10-year follow-up due to acquired cysts, while no change in kidney volume was noted in 24 females. Native kidneys in nine of 12 patients who maintained functioning grafts were reduced in size. The patient with the largest kidney enlargement (11.5 times) died from retroperitoneal bleeding in 1989. These prospective study results suggest that both the incidence and prevalence of renal cell carcinoma in dialysis patients is high. Furthermore, major complications of acquired renal cystic disease seem to occur predominantly in males.

Sex differences in acquired cystic disease of the kidney on long-term dialysis.

Acquired cystic disease of the kidney in chronic glomerulonephritic patients who had been on hemodialysis more than 3 years (4.5 +/- 1.2 years at the base line examination), were followed for 3.6 +/- 0.5 years (at the follow-up examination) by computed tomography (CT scan). The renal volume in the 25 male patients was significantly greater at the follow-up examination than at the base line examination. On the other hand, the renal volume in the 12 female patients was similar on both examinations. The enlargement of kidney volume more than twofold during the follow-up was seen in 9 of 25 male and none of 12 female patients. The grade of cystic transformation was increased in male patients during the follow-up period. These results indicate that sex-related endogenous substances might play a role in the pathogenesis of acquired cystic disease.

Renal cortex visualization and analysis of dynamic CT curves of the kidney.

Renal cortex visualization and dynamic renal computed tomography (CT) were carried out by bolus injection of contrast medium. In vivo renal cortex visualization showed that renal cortex volume and cortex thickness are both inversely correlated with age. The percentage volumes of cortex and columns of Bertin are correlated inversely in non renal-failure subjects. Percentage volumes of cortex tend toward low values in renal failure and status after renal transplantation. In analyzing dynamic renal CT curves, the corticomedullary junction time is a good index of mild impairment of renal function.

Evidence for Patchy Renal Vasoconstriction in Man: Observation by CT Scan

We report the first demonstration of patchy vasoconstriction of the kidney in man, together with temporary impairment of renal function. Observations were made by computerized tomography (CT scan). Such vasoconstriction might occur during the mild form or the recovery phase of acute renal failure.

Renal Cell Carcinoma of the Native Kidney after Renal Transplantation

We report a patient with small renal cell carcinoma of the native kidney long after renal transplantation, which was considered to have developed before transplantation, and review the characteristics

Magnetic Resonance Imaging in Renal Infarction and Ischemia

Two cases of renal segmental infarction and 1 case of renal patchy ischemia demonstrated by magnetic resonance imaging (MRI) are reported. MRI of renal infarction in two renal grafts following surgical ligation revealed an area of noncorticomedullary differentiation and an area with a low signal intensity. Renal ischemia in 1 patient with acute renal dysfunction with severe loin pain and patchy renal vasoconstriction was visualized as an ill-defined focus of low signal intensity in the renal cortex, indicating a long T1 relaxation time. Delayed wedge-shaped contrast enhancement was demonstrated on CT scan in the same area. The common finding in renal infarction and ischemia in our cases was the area of low signal intensity on MRI.

Severity of Acquired Renal Cysts in Native Kidneys and Renal Allograft With Long-Standing Poor Function

To identify factors related to the development of uremic acquired cystic disease of the kidney, native and grafted kidneys were examined in four men and three women after kidney transplantation. The incidence and severity of cystic transformation of native kidneys and grafts were compared by plain computed tomographic scans. In a uremic environment (serum creatinine level of greater than or equal to 265 mumol/L [3 mg/dL] for an average of 5.0 years; range, 2.8 to 8.2 years), acquired renal cysts were formed in both the native kidneys and the graft in three of the male and one of the female patients. Cysts were extensive in the native kidneys but relatively infrequent in the grafts in three of the men. One male subject was found to have acquired cysts only in the native kidney. Acquired renal cysts developed even in grafts undergoing chronic rejection, and increased numbers were found in native kidneys that were in uremic conditions for long periods, both before and after renal transplantation. These results suggest that the duration of uremia is the most important factor in the development of acquired renal cysts.

Cystic transformation in native kidneys in renal allograft recipients with long-standing good function

Acquired renal cystic disease develops in the native kidneys of patients with renal allografts with long-standing poor function. However, there has been no long-term prospective study of the regression or development of cysts in native kidneys of renal allograft recipients with good long-term function (serum creatinine: 114 +/- 24 mumol/l). We followed 61 renal allograft recipients for 63.5 +/- 29.0 months (mean +/- SD) using computed tomography (CT scan) every 1 or 2 years after transplantation. The cyst grade at pretransplantation was significantly reduced at the first study after transplantation (0.98 +/- 1.39 vs. 0.57 +/- 0.96; p less than 0.01). Baseline study after transplantation revealed that the incidence of cysts in native kidneys was 22/61 (36.1%) and 26/61 (42.6%) in the follow-up study. In 32 patients (52.5%), there were no visible cysts in the native kidneys. In 9 patients (14.8%), there was no change in the number of cysts during follow-up, while in another 9 patients the number of cysts decreased. On the other hand, the number of cysts increased in 11 patients (18.0%) during follow-up. The mean follow-up duration was longer in the group with an increased number of cysts than in the groups with no visible cysts or a decrease in number. Biochemical analysis of cyst fluid from newly developed cysts in 2 patients showed differences from the pattern in acquired renal cystic disease of hemodialysis patients. These results indicate that after regression of acquired cysts in most allograft recipients, no or only a few cysts persist in patients with good graft function. The remaining cysts continue to regress further in some patients.(ABSTRACT TRUNCATED AT 250 WORDS)