Mitsuhiko Kuroda

Serum antioxidant activity in uremic patients.

Serum antioxidant activity (AOA) was examined in 35 healthy subjects and 111 patients with chronic renal failure (CRF), consisting of 13 patients in the predialysis stage, 11 requiring the start of regular dialysis therapy (RDT) and 87 undergoing RDT. Serum AOA was determined by assaying serum activity to inhibit malondialdehyde (MDA) generation. AOA levels were significantly lower in CRF patients, and the lowest levels were noticed in patients with uremic symptoms requiring the start of RDT. These levels were restored to a subnormal level during RDT. Defective serum AOA appears to be an endogenous metabolic consequence in uremia. Sera with low AOA tended to show high MDA levels, indicating that patients with low serum AOA were susceptible to cellular injury by lipid peroxidation. It is proposed that defective serum AOA may contribute to a certain uremic toxicity through peroxidative cell damage.

Hypouricemia Due to Renal Urate Wasting

We present 2 patients associated with hypouricemia. Serum uric acid levels were 1.6 and 1.3 mg/l00 ml, and the ratios of urate clearance to creatinine clearance were 34.1 and 39.4%, respectively, whil

Impaired Metabolism of Guanidinoacetic Acid in Uremia

In order to investigate the guanidinoacetic acid (GAA) metabolism in uremia, we have measured serum guanidino compounds in patients with chronic renal failure (CRF) in comparison with normal subjects, and the renal content of GAA and glycine amidinotransferase (GAT) activity in the kidney of experimental CRF rabbits. Serum concentrations of guanidinosuccinic acid (GSA) and methylguanidine (MG) in the patients with CRF were higher than those in the normal subjects, as well as serum urea nitrogen (BUN) and creatinine (Cr) levels. The serum GAA levels were however, significantly lower and showed a tendency to decrease inversely with the elevation of BUN in the patients with CRF under conservative therapy. On the contrary, in the patients under maintenance hemodialysis (MHD) therapy, the serum GAA level did not decrease in spite of the elevation of BUN. Four anephric patients under MHD therapy showed a level of serum GAA similar to the other MHD patients. In the CRF rabbits, the renal GAA content was significantly lower than in the sham-operated rabbits and showed an inverse correlation with BUN. Renal GAT activity was also significantly lower in the CRF rabbits, showing a positive correlation with serum GAA concentration and an inverse correlation with BUN. These results indicate that renal GAT activity decreases as the BUN level rises in the course of renal damage, resulting in lower concentration of serum GAA in the uremic state; in a more advanced stage of renal failure, the inability of the kidney to synthesize GAA may be compensated by other organ(s). Some dialyzable substances which might inhibit renal GAT activity may also be present.

Occurrence of Renovascular Hypertension in Two Sisters

Renovascular hypertension in two sisters, aged 22 and 20, respectively, has been described. Renal artery stenoses were observed unilaterally in the elder patient and bilaterally in the younger one. In both patients, the functional significance of unilateral stenosis of the renal artery was documented by the renal vein renin ratio between the affected side and the contralateral or less affected side. High blood pressure and elevated plasma renin activity have been normalized with a unilateral revascularization in the elder patient, and with the treatment of propranolol in the younger one. The histological examination of the stenotic renal artery in the elder patient showed a finding comparable to the perimedial fibroplasia in Harrison and McCormacks classification of idiopathic fibromuscular stenosis.

Prevalence of ATLV and HIV among Hemodialysis Patients in Japan

Human immunodeficiency virus (HIV) and adult T cell leukemia virus (ATLV) can both be transmitted through blood transfusions and blood products. HIV infections are up to the present time uncommon in Japan while the southwestern area of Japan is endemic for ATLV. This study examines the prevalence of HIV and ATLV among Japanese hemodialysis patients who may be at increased risk of viral exposure because they sometimes receive multiple blood transfusions. 1066 patients were examined including 66 from Okinawa--a highly endemic area for ATLV. 7 of the 1066 patients tested positive for HIV using an enzyme immunoassay but none were confirmed by Western Blot analysis. 30 patients tested positive for ATLV by both immunoassay and Western blot analysis. ATLV rates among hemodialysis patients were significantly higher than rates among local blood donor populations. HIV infections are currently not as serious in Japan among hemodialysis patients as ATLV infections. The prevalence of ATLV infections among these patients was related 1st to blood transfusions 2nd to prevalence in the local population and 3rd to migration from endemic areas. If blood bank screening begun in 1986 is successful the probability of these infections being transmitted by blood transfusions will be greatly reduced.

Prevalence of HTLV-1 Antibodies in Hemodialysis Patients in Japan

The southwestern region of Japan is known as a very high endemic area of human T-cell lymphotropic virus type 1 (HTLV-1), the etiologic agent for adult T-cell leukemia (ATL) and probable causative agent for tropical spastic paraparesis and its Japanese version, HTLV-1-associated myelopathy (HAM). Hemodialysis (HD) patients seem to be at high risk for HTLV-1 infection even in other regions of Japan because they sometimes receive multiple blood transfusions. We examined antibody against ATL-associated antigen (ATLA-Ab) in 1,132 HD patients, including 1,066 patients in nonendemic areas (Chubu and Tokyo) and 66 in a highly endemic area (Okinawa). The HD patients in Okinawa showed the highest prevalence, 21.2% (14/66), while those in the Chubu area showed the lowest, 1.1% (10/846), and those in the Tokyo area an intermediate value, 2.7% (6/220). The prevalence of HD patients in each area was significantly higher than that of local blood donors, reflecting an increased prevalence roughly corresponding to the respective endemic rate. The average prevalence of ATLA-Ab among the HD patients was 2.7% (30/1,132), which was similar to that of HBs antigen (3.2%). In the nonendemic areas, 15 of 16 patients with ATLA-Ab had a history of blood transfusions, showing a significant correlation to the presence of ATLA-Ab (P less than 0.01), although four had family histories related to the endemic area. The relative risk of the presence of ATLA-Ab for HD patients with a history of blood transfusions was calculated as 10.3. In the endemic area of Okinawa, the relationship to blood transfusion was not so close, probably masked by the high background prevalence.

Urinary prostaglandins and kallikrein in the course of acute renal failure

To examine the role of prostaglandins and the kallikrein system in the recovery from acute renal failure, we studied the sequential changes in urinary prostaglandins and kallikrein after the onset of oliguria. The six patients studied had acute tubular necrosis of the vasomotor type. Urinary PGE2, PGF2 alpha, the PGF2 alpha-main urinary metabolite, 6-keto-PGF1 alpha and TXB2 were all measured by radioimmunoassay. Urinary kallikrein was assayed by means of hydrolytic activity using a chromogenic tripeptide substrate. Following onset of diuresis, urinary PGE2 excretion was increased to normal, parallel to the increase in urine volume. In contrast, the ratio of urinary PGF2 alpha/PGE2 peaked at the onset of diuresis, indicating a relative increase in PGF2 alpha production at this time. Prior to this peak, urinary kallikrein concentrations reached the highest levels, suggesting a close connection with renal prostaglandin metabolism. On the other hand, changes in PGF2 alpha-MUM, 6-keto-PGF1 alpha and TXB2 were not found. These results indicate that there may be an interlocking acute alteration of the kallikrein-prostaglandin system occurring immediately before the resolution of oliguria, although the role of the acute shift to PGF2 alpha production observed needs further study.

Pseudocyst of the Pericardium Developing during Maintenance Hemodialysis

Two cases of pericardial pseudocyst which developed in the course of maintenance hemodialysis are reported. Both patients were usually free of complaints, although there was evidence of the previous pericarditis with recent accumulation of pericardial effusion. As a possible mechanism leading to pericardial pseudocyst formation, distension of a weak area of the thickened pericardium due to an increase in intrapericardial pressure was assumed. Therefore, pericardial pseudocyst is one of the likely complications of patients on maintenance hemodialysis.

The Role of the Liver as a Significant Modulator of the Serum Guanidinoacetic Acid Level in Man

The metabolism of guanidinoacetic acid (GAA) may be affected by the status of both the kidney and the liver, as GAA is synthesized in the kidney and metabolized to creatine in the liver’. Little attention has been focused on GAA metabolism in patients with liver damage, although there have been many studies on GAA metabolism in uremic patients2,3’4

A CASE OF TEMORAL ARTERITIS

定型的temporal arteritisの症例を経験し,ステロイド治療前後2回にわたり側頭動脈より生検を施行したので報告する. 1)症例は67才,男. 10年来の肩こりをみとめている.入院約1ヵ月前より頭痛が出現し,視力低下,体重減少を伴つた.側頭動脈は硬く怒張し,拍動は触れなかつた.第1回の右浅側頭動脈の生検では巨細胞を伴う肉芽腫性動脈炎を証明した.ステロイド薬1ヵ月投与後,臨床症状が改善し,側頭動脈の局所所見が全く正常化した時点で左浅側頭動脈より第2回生検を行なつた.その結果,高度の内膜肥厚,中外膜の線維化と新生血管の介在に加え,軽度の小円形細胞浸潤が残つており,ステロイド薬により臨床症状が改善しても組織像の反応は迅速でないと考えられた. 2)頭痛の激しい時期に視力低下をみとめたが,眼底はScheie H1S1-2と著変がなかつた. 3) polymyalgia rheumaticaかどうかは不明だが, 10年来の肩こりは下熱鎮痛剤に無反応でステロイド薬が著効を示し,頭痛と随伴して症状が出現するなどtemporal arteritisとの関連を強く示唆していた. 4)大動脈造影では大動脈弓およびその主幹動脈に著変はみとめず,腎生検像でも細小血管に異常はみとめられなかつた.