Search PubMed⌕ Search

Biomedical subjects

S Koshikawa

Publications and source records attributed to S Koshikawa.

At least 73 records · Page 4Linked to original sources
PubMed1989

Elimination of beta 2-microglobulin by a new polyacrylonitrile membrane dialyser: mechanism and physiokinetics.

The performance and mechanism of beta 2-microglobulin (beta 2 M) removal by a new polyacrylonitrile membrane dialyser (CX2), and the physiokinetics of beta 2 M during treatment were studied. In vitro experiments showed that mean pore size of the CX2 membrane was 120 A, and the molecular cut-off point was less than 66,000 daltons. The diffusive capacity of the PAN 12CX2 dialyser (1.2 m2) for beta 2 M was calculated to be 27.3 ml/min at a blood flow of 200 ml/min, and it was considered that, compared to the elimination by local filtration induced by back-filtration and adsorption, diffusion was the major eliminating mechanism for beta 2 M. Although the elimination of beta 2 M increased linearly by augumentation of the ultrafiltration volume, diffusion was a major contributing factor for beta 2 M removal even in haemodiafiltration. Serum beta 2 M decreased to 51% and 44% of initial values after correction of haemoconcentration by a clinical haemodialysis or haemodiafiltration even under relatively low blood and filtrate flow conditions, and sieving coefficient and clearance of CX2 for beta 2 M compared well with in vitro results. The one-pool model simulation demonstrated that from 50 to 60 mg of beta 2 M was transferred from the intra- to the extracellular space during treatment. These results indicate that CX2 effectively eliminates beta 2 M mainly by diffusion, and that beta 2 M transfer to the plasma space during haemodialysis and haemodiafiltration may be accelerated.

Amyloidosis↗
PubMed1989

Autoregulation of renal blood flow in streptozocin-induced diabetic rats.

Autoregulation of renal blood flow (RBF) was studied in male Wistar rats. We studied 11 control rats, 11 rats with severe streptozocin (STZ)-induced hyperglycemia (diabetic group), and 10 moderately hyperglycemic rats made diabetic by injection of STZ but given 2-8 U s.c. insulin daily (insulin-treated group). RBF was measured by an electromagnetic flowmeter during stepwise reduction of renal perfusion pressure 4-8 wk after injection of STZ (older group). RBF autoregulation of the diabetic group was impaired compared with the control group. In the insulin-treated group, autoregulatory capability was less attenuated than in the diabetic group. The average autoregulatory index (ARI) of the diabetic group (0.61 +/- 0.05) was greater than that of the control (0.24 +/- 0.02, P less than .01) and the insulin-treated (0.33 +/- 0.07, P less than .05) groups. To study the relationship between autoregulation and the duration of diabetes, an autoregulatory study was also made in a group of 22 rats (11 diabetic and 11 control) that were tested 2-3 wk after injection of STZ (younger group). The ARI in the younger diabetic group was smaller than that in the older diabetic group (P less than .05). The results suggest that in uncontrolled diabetes RBF fluctuates with blood pressure change, and protection against hypertensive injury of glomerular capillaries may be diminished. Autoregulatory disability develops with time, and insulin treatment diminishes impairment of autoregulation. These findings may also explain the adverse consequences of hypertension on the progression of diabetic nephropathy in poorly controlled diabetes.

Animals↗
PubMed1988

Effect of recombinant human erythropoietin on the anemia of chronic renal failure.

Phase I and Phase II studies of recombinant human erythropoietin (rhEpo) were conducted in normal volunteers and in anemic patients with chronic renal failure on maintenance hemodialysis. Three hundred U/person of rhEpo was administered intravenously to healthy normal volunteers in the Phase I study, resulting in no subjective or objective changes. In the Phase II study, 66 patients with chronic renal failure on maintenance hemodialysis with less than 20% hematocrit values were treated with rhEpo in doses of 50 U/kg to 200 U/kg two or three times a week. Hematocrit values increased significantly during the 12 weeks, and the patients' conditions improved. Patients previously requiring blood transfusions became transfusion-independent during our study. There were no obvious side effects, thus indicating the safety and efficacy of rhEpo in the anemia of chronic renal failure.

Adult↗
PubMed1988

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.

Adult↗
PubMed1988

Evaluation of beta 2-microglobulin removal with high-performance hemodiafiltration.

Several lines of evidence suggest that beta 2-microglobulin (beta 2M) accumulation in long-term hemodialysis (HD) patients results in so-called dialysis-associated amyloidosis (DAA), which is clinically manifested by carpal tunnel syndrome, osteoarthropathy, and the other organ involvements. For the purpose of preventing the beta 2M accumulation, the efficiency of beta 2M removal during (HPM), hemofiltration (HF), HD, and charcoal hemodiafiltration (HDF) with high-performance membranes (HPM), hemofiltration (HF), HD, and charcoal hemoperfusion was evaluated. Among 27 patients treated with these methods, significant beta 2M removal was noted in HDF with HPM and HD with polyacrylonitril (PAN) membrane. However, treatment of HDF with HPM for more than 6 months caused no remarkable improvement in clinical symptoms of patients, and serum beta 2M levels decreased in only two out of 15 patients. These results imply that beta 2M might be most effectively removed by HDF with HPM and HD with PAN membrane, but further long-term studies will be necessary to conclude whether these procedures could become successful therapeutic regimen for DAA.

Adult↗
PubMed1988

Glomerular deposition of food antigens in IgA nephropathy.

Recently, we reported on the importance of food antigens on the pathogenesis of an experimentally-induced model of, and some patients with, IgA nephropathy. In this paper, the glomerular deposition of food antigens (casein, lactalbumin, peanut protein, soy bean protein, rice protein, ovalbumin) was investigated by an immunofluorescence technique in 28 patients with IgA nephropathy and 32 controls (ten with lupus nephritis, three with Henoch-Schoenlein purpura nephritis and 19 with other glomerulonephritis). Glomerular IgA deposition was demonstrated in all IgA nephropathy and Henoch-Schoenlein purpura nephritis, and in four lupus nephritis. Positive findings of food antigens, observed as mesangial pattern, were obtained in eleven cases (39.3%) with casein, 21 (75.0%) with soy bean protein and one (3.6%) with rice protein in IgA nephropathy, even though no such findings were seen in the control group. Eleven of 28 patients with IgA nephropathy were positive with soy bean protein alone, nine were positive with soy bean protein + casein, one was positive with soy bean protein + casein + rice protein, and one was positive with casein alone. The deposition of food antigens was not observed in six cases only. Furthermore, no correlation was noted between the deposition of food antigens and the deposition of IgA1, IgA2 or J chain, in vitro binding of the secretory component, or histopathological grades. These results suggest that the exact meanings of glomerular deposition are unclear. Food antigens are postulated, however, as possibly participating strongly in the pathogenesis and as being localized in the glomerular mesangium as an antigen in some patients with IgA nephropathy.

Adolescent↗
PubMed1988

Clinical effect of recombinant human erythropoietin on anemia associated with chronic renal failure. A multi-institutional study in Japan.

Clinical effect and safety of recombinant human erythropoietin (r-HuEPO) were evaluated in 66 hemodialysis patients with intractable anemia. Initially, 50U/kg dry weight (DW) of r-HuEPO was administered intravenously at the end of every hemodialysis procedure for 4 weeks, then the dosage was increased to 100 and 200U/kg DW for poor responders. The patients' hematocrits rose from 19.8 +/- 2.3% (pretreatment) to 30.2 +/- 4.9% after 12 weeks. From 206 U of blood transfusion requirement in the 3-month period before the study, only 34 U were needed after treatment. Serum iron and ferritin levels fell significantly during the study, and iron storage was considered to be one of the decisive factors in the response to r-HuEPO. Blood pressure rose in the course of r-HuEPO administration, but uncontrollable hypertension was rarely observed. There was no significant adverse effect of r-HuEPO except for this mild hypertension. These results indicate that r-HuEPO is an excellent therapeutic aid for the anemia associated with chronic renal failure.

Adult↗
PubMed1987

Estimation of circulating immune complexes following oral challenge with cow's milk in patients with IgA nephropathy.

We recently reported on an experimentally induced model of IgA nephropathy in mice by long-term oral immunization under the reticuloendothelial dysfunction, which was found to be effectively inhibited by the administration of the antiallergic agent sodium cromoglycate (SCG). On the basis of these findings, we investigated the participation of food antigens in patients with IgA nephropathy. We studied 24 patients with IgA nephropathy, 11 patients with primary glomerulonephritis (PGN) except IgA nephropathy and 11 healthy controls. Serum levels of immunoglobulins (IgG, IgA, IgE) and circulating immune complexes containing IgG (IgG-CIC) or IgA (IgA-CIC) were measured in the fasting state and 30, 60, 120 or 180 min after oral challenging with cow's milk (400 ml). After the oral challenge IgA-CIC levels remained within the normal range in healthy controls and in patients with PGN, while 3 out of the 24 patients with IgA nephropathy showed a transient elevation and 2 cases showed a significant rise of IgA-CIC levels. The levels of IgG, IgA, IgE and IgG-CIC remained uninfluenced by the challenge test in all subjects. In addition, we carried out the same challenge test under SCG administration. These cases indicating an oral-challenge-induced IgA-CIC elevation demonstrated an inhibition of this elevation, and in 3 out 7 patients who showed hyper-IgA-CIC-emia before and after oral challenge IgA-CIC levels returned to the normal range through SCG administration. These results suggest that food antigens participate strongly in the pathogenesis of some patients with IgA nephropathy, and that SCG is an effective agent for such patients.

Animals↗