Biomedical subjects

T Kiuchi

Publications and source records attributed to T Kiuchi.

At least 55 records · Page 3Linked to original sources

PubMed1999

Postoperative flow cytometry crossmatch in living donor liver transplantation: clinical significance of humoral immunity in acute rejection.

BACKGROUND: The role of humoral immunity in acute rejection in solid organ transplantation remains controversial, although it is known that the presence of antidonor antibodies may precipitate graft rejection. We investigated the clinical relevance of antidonor humoral immunity for living donor liver transplantation (LDLT) by means of flow cytometry crossmatch (FCXM). METHODS: T cell FCXM using fresh donor peripheral lymphocytes was performed before and up to 1 month after LDLT in 58 patients. Ten patients received ABO-incompatible grafts. IgM and IgG antidonor antibodies were analyzed in relation to clinical acute rejection as defined by liver function tests with or without histological evidence. RESULTS: Pretransplantation FCXM was positive for five patients (8.6%), resulting in two cases of positive posttransplantation FCXM and two rejection episodes. Twelve patients (20.7%) showed positive posttransplantation FCXM. The incidence of acute rejection within 1 month was 100% in FCXM-positive patients and 17.4% in FCXM-negative patients (P<0.001). Thirteen (76.5%) of 17 rejection episodes in ABO-compatible cases were associated with concomitant antidonor IgM antibody. IgG antibody was also identified in six of these episodes. Antidonor antibodies disappeared after rejection treatments in all cases, but with some delay in clinical improvement. On the other hand, no antidonor antibodies were detected in any of the four rejection episodes in ABO-incompatible cases. CONCLUSIONS: Early acute rejection in LDLT is significantly associated with antidonor T cell antibody formation in ABO-compatible cases. This suggests a definite role for donor-specific humoral immunity in acute rejection. Rejection episodes without antidonor antibodies may suggest graft injury by pure cellular immunity, or possibly the presence of humoral immunity triggered by antigens not present on donor T cells.

ABO Blood-Group System↗

PubMed1999

Soluble forms of CD95 and CD95 ligand after living related liver transplantation.

BACKGROUND: Soluble forms of CD95 and CD95 ligand (sCD95 and sCD95L, respectively) can increase in the serum of patients with some inflammatory disease. In this study, we investigated the serum levels of sCD95 and sCD95L in liver transplantation recipients. METHODS: Serum levels of sCD95 and sCD95L in living related liver transplant recipients were analyzed by ELISA and their relation to the clinical findings estimated. RESULTS: Serum samples from the recipients did not show detectable levels of sCD95L but showed significantly increased levels of sCD95. The increase of sCD95 was positively associated with that of total-bilirubin and incidence of rejection, infection, and graft ischemia. CONCLUSIONS: The present results indicate an existence of sCD95 in the recipients of living related liver transplants. The increased serum levels of sCD95 may modify the immunological situation of the recipients after transplantation or represent the ongoing graft damage.

Adolescent↗

PubMed1999

Impact of graft size mismatching on graft prognosis in liver transplantation from living donors.

BACKGROUND: Although living donor liver transplantation for small pediatric patients is increasingly accepted, its expansion to older/larger patients is still in question because of the lack of sufficient information on the impact of graft size mismatching. METHODS: A total of 276 cases of living donor liver transplantation, excluding ABO-incompatible, auxiliary, or secondary transplants, were reviewed from graft size matching. Forty-three cases were highly urgent cases receiving intensive care preoperatively. Cases were categorized into five groups by graft-to-recipient weight ratio (GRWR): extra-small-for-size (XS; GRWR<0.8%, 17 elective and 4 urgent cases), small (S; 0.8< or =GRWR< 1.0%, 21 and 7), medium (M; 1.0< or =GRWR<3.0%, 119 and 19), large (L; 3.0< or =GRWR<5.0%, 67 and 10), and extra-large (XL; GRWR> or =5.0%, 9 and 3). RESULTS: Smaller-for-size grafts were associated not only with larger and older recipients, but also with rather older donors. Posttransplant bilirubin clearance was delayed and aspartate aminotransferase corrected by relative graft size was higher in XS and S. Posttransplant hemorrhage and intestinal perforation were more frequent in XS and S, and vascular complications and acute rejection were more frequent in larger-for-size grafts. Consequently, graft survival in XS (cumulative 58% and actuarial 42% at 1 year) and S (76% and 74%) was significantly lower compared with that in M (93% and 92%) in elective cases. Graft survival in L (83% and 82%) and XL (75% and 71%) did not reach statistical significance. CONCLUSIONS: The use of small-for-size grafts (less than 1% of recipient body weight) leads to lower graft survival, probably through enhanced parenchymal cell injury and reduced metabolic and synthetic capacity. Although large-for-size grafts are associated with some anatomical and immunological disadvantages, the negative impact is less pronounced.

Actuarial Analysis↗

PubMed1999

Native hepatectomy after auxiliary partial orthotopic liver transplantation.

In countries where a living donor is the only source of the graft, the limited size of the graft is of serious concern when considering extending the procedure to adult recipients. In order to overcome this problem, auxiliary partial orthotopic liver transplantation (APOLT) was applied to the concept that the residual native liver would support the graft function until the graft expanded enough to work by itself. We herein report on a 20-year-old woman with primary sclerosing cholangitis (PSC), who received a small-size liver graft by APOLT. Computed tomography and scintigraphy showed that the graft had regenerated sufficiently 1 month after the operation. The diseased residual native liver is potentially carcinogenetic. Therefore, second-stage native hepatectomy was done 35 days after the first operation. Histopathologic examination of the resected native liver revealed biliary cirrhosis with PSC but no evidence of cholangiocarcinoma. Second-stage native hepatectomy after APOLT seems to be a curative treatment for chronic end-stage liver disease with graft size mismatch that may be as good as orthotopic liver transplantation.

Adolescent↗

PubMed1999

Living related liver transplantation from heterozygote genetic carriers to children with Wilson's disease.

We reviewed the outcome of children undergoing living related liver transplantation (LRLT) for Wilson's disease (WD), and specifically addressed the potential risk associated with the use of donors who were heterozygous for the Wilson genetic defect. LRLTs were carried out in 11 children with WD, nine of whom presented with fulminant hepatic failure and two with end-stage hepatic insufficiency. The age of the patients ranged from 6 to 16 yr. Eight patients had hepatic encephalopathy and were plasmapheresed preoperatively. The donors (all parents: six fathers and five mothers) were all one-haplotype matched with their respective recipients, and were all therefore heterozygote carriers of the WD genetic defect. The serum ceruloplasmin levels were within normal limits in all donors (mean: 20.0 +/- 2.85 mg/dL). All recipients but one had low serum ceruloplasmin levels with a mean value of 11.6 +/- 7.36 mg/dL before transplantation. The serum ceruloplasmin levels had increased to an average of 21.0 +/- 3.76 mg/dL after LRLT at the latest evaluation, which ranged between 7 and 75 months after transplantation. A marked reduction in urinary copper excretion was observed in all recipients after transplantation. Of eight recipients presenting preoperatively with Kayser-Fleischer (K-F) rings, this abnormality resolved completely after LRLT in five patients and partially in three. All recipients are alive and remain well, and none have developed signs of recurrent WD after a mean follow-up period of 31 months (range 7-75 months). In conclusion, LRLT is an excellent choice for effective treatment of WD, and grafts chosen from heterozygote carriers of the condition do not appear to confer any risk of recurrence in the recipients.

Adolescent↗

PubMed1999

Portal blood flow and liver regeneration in auxiliary partial orthotopic liver transplantation in a canine model.

Functional competition has been shown to lead to a detrimental outcome in auxiliary liver transplantation. We evaluated the interaction in auxiliary partial orthotopic liver transplantation between the native liver and the graft in terms of portal flow and regeneration. The need for diversion of the portal flow to the graft was also assessed. Reduced-size liver grafts were transplanted orthotopically after partial hepatectomy in beagles. There were two groups: the preserved group, where portal inflow to the native liver was preserved, and the ligated group, where it was interrupted. Portal flow was measured serially and liver regeneration was evaluated on postoperative day 5. Functional competition was not observed in the preserved group. On the other hand, ligation of the native liver portal vein had no obviously detrimental effects on the remnant native liver. This leads to the conclusion that the portal vein to the native liver can be safely ligated to prevent functional competition.

Animals↗

PubMed1999

Bioavailability and diuretic effect after administration of retarded capsules of bumetanide in human subjects.

Retarded capsules containing 1 mg bumetanide (BN) were prepared and their in vivo absorption and diuretic effect after oral administration in human subjects were studied. For comparison, commercially available tablets of BN (rapid effect) were administered orally. The mean value of the area under the plasma concentration time curve (AUC) after administration of retarded capsules was about one half that of the tablets. The mean maximum plasma concentration (Cmax) and the mean maximum urinary excretion rate of BN after administration of retarded capsules were also about one half compared to those of the tablets. Cumulative urinary volumes for 24 h, however, were not significantly different between retarded capsules and tablets. Peak times for the urinary excretion rate of BN, urine flow rate and the Cmax after administration of retarded capsules were significantly delayed compared to those of tablets. Clockwise hysteresis relationships between the urine flow rate and plasma concentration or urinary excretion rate of BN were observed after administration of retarded capsules. From these studies, retarded capsules of BN possessed a mild diuresis and its diuretic effect was maintained for a few hours after administration.

Administration, Oral↗

PubMed1999

Innovative techniques for and results of portal vein reconstruction in living-related liver transplantation.

BACKGROUND: Portal vein reconstruction is a crucial factor affecting the outcome of a successful living-related liver transplantation. We describe here our experience with portal vein reconstruction in 314 cases of living-related liver transplantation with use of novel surgical modalities to enable the transplant surgeons to deal with any size mismatch between the donor's and recipient's portal veins. METHODS: Portal vein reconstruction was classified into 2 major groups, anastomosis without and with a vein graft. When there was no stenosis of the recipient portal vein and the diameter was the same, the portal trunk was used for anastomosis. When the diameter mismatch was minimal, branch patch anastomosis was feasible. When the recipient portal vein was significantly stenotic and the portal vein of the graft was long enough, we removed the stenotic trunk and constructed an anastomosis between the graft portal vein and the confluence of the recipient portal vein. When the graft portal vein was short, a vein graft was interposed. The vein patch technique was preferable when the diameter of the graft vein was not large enough for the interposition technique. RESULTS: Anastomosis without vein graft included trunk anastomosis (n = 156), branch patch anastomosis (n = 39), and confluence anastomosis (n = 22). Anastomosis with vein graft used the interposition technique (n = 77) and vein patch technique (n = 27). The origin of the grafts was mostly from the maternal left ovarian vein (70%) or the paternal inferior mesenteric vein (27%). Complications related to portal vein reconstruction occurred in 16 (5%) patients: portal vein thrombosis in 8, stenosis in 7, and fatal rupture in 1 patient. The incidence of complications was similar for all techniques except for confluence anastomosis. CONCLUSION: Our innovative techniques should be helpful for overcoming diameter or length mismatches in portal vein reconstruction in pediatric liver transplantation.

Adolescent↗

PubMed1999

[The clinical usefulness of high-dose intravenous immunoglobulin therapy for chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy].

To explore the optimum dose of intravenous immunoglobulin (i.v.Ig) for treating patients with chronic inflammatory demyelinating polyrneuropathy and multifocal motor neuropathy, we compared the usefulness of i.v.Ig among 3 treatment doses. Fifty-nine patients were randomly divided into three treatment dosage groups: 20 patients for Group I using 50 mg/kg/day x 5 days, 19 patients Group II using 200 mg/kg/day x 5 days, and 20 patients Group III using 400 mg/kg/day x 5 days. We assessed clinically and electrophysiologically the effectiveness of the treatment at 5 weeks after the initial infusion. For patients in Group I and II who had not improved (or worsened) with the first treatment, we gave a one-step larger dose in the second treatment (i.e. 200 mg/kg/day x 5 days for those who had been given 50 mg/kg/day x 5 days, 400 mg/kg/day x 5 days for those who had been given 200 mg/kg/day x 5 days) after more than 9 weeks. We found that 15% of the patients in Group I, 21% in Group II and 60% in Group III improved dose-dependently with the first intravenous immunoglobulin treatment. Seven (47%) of 16 patients in Group I and 4 (40%) of 11 patients in Group II improved after the second treatment with larger doses. Adverse reactions including chill sensation, fever, skin eruption and increase in blood GOT and GPT levels were transient and mild. One patient in Group III developed left hemiparesis showing the small infarction in the right thalamus during the course of the treatment, but the symptom was mild. In conclusion, the high-dose intravenous immunoglobulin therapy (400 mg/kg/day x 5 days) is useful for treating patients with CIDP and MMN, although care must be taken of the risk of causing cerebral infarctions.

Adolescent↗

PubMed1999

Asialoglycoprotein receptor scintigraphy in evaluation of auxiliary partial orthotopic liver transplantation.

UNLABELLED: The purpose of this study was to evaluate asialoglycoprotein receptor scintigraphy in the post-transplant monitoring of liver graft and native liver functions in recipients of auxiliary partial orthotopic liver transplantation (APOLT) from living donors. METHODS: We performed 36 asialoglycoprotein receptor scintigraphies on 13 patients who had undergone APOLT for noncirrhotic metabolic liver diseases or for small-for-size grafts. The portal vein of the native liver was separated in 12 patients. Anterior dynamic images including the heart and both livers were obtained for 16 min after intravenous injection of 99mTc-diethylenetriamine pentaacetic acid-galactosyl human serum albumin (GSA), and thereafter static SPECT images of both livers were obtained. Uptake rates from the blood to the graft and to the native liver were determined separately by Patlak plot graphical analysis. Relative uptake of GSA by the graft was calculated from transverse SPECT images. The relative volume of the graft liver was determined by CT. RESULTS: The relative uptake of GSA by the graft was higher or increased more rapidly than the relative volume of the graft in 8 of 11 patients with no severe complications concerning the graft. The relative uptake by severely damaged graft liver in 2 patients was much lower than the relative volume. The uptake rate of GSA by the graft was low in these 2 patients. The uptake rate by the native liver decreased when the portal vein was separated. CONCLUSION: The relative uptake of GSA was a better indicator of graft liver function than was anatomic volume. The uptake rate provided additional independent information of each liver. Asialoglycoprotein receptor scintigraphy is useful for distinguishing and monitoring the graft and native liver functions in patients who had undergone APOLT.

Adolescent↗

PubMed1998

Selective portal blood flow diversion in auxiliary partial orthotopic liver transplantation to induce regeneration of the graft.

Experience with auxiliary partial orthotopic liver transplantation (APOLT) is still very limited and many questions remain to be solved. In this article, we present the case of a 5-year-old girl with ornithine transcarbamylase deficiency who initially did well after APOLT. During a severe rejection episode 16 months after transplantation, she developed encephalopathy and hyperammonemia. Despite a good clinical and histopathological response to antirejection therapy, the graft had become smaller and the native liver had undergone compensatory hypertrophy. After we surgically ligated the right portal branch, the graft recovered and the patient was able to stop her medication 1 month after surgery. We have estimated that the minimum volume of normal liver required to correct the metabolic defect in ornithine transcarbamylase deficiency is 8 cm3/kg. The ligation of the right portal branch was a safe and effective method of inducing a gradual and progressive involution of the hypertrophic native liver and regeneration of the atrophic graft.

Atrophy↗

PubMed1998

Background and prognostic implications of perireperfusion tissue injuries in human liver transplants: a panel histochemical study.

BACKGROUND: Hepatic graft reperfusion is associated with inflammatory processes of unknown relevance to the fate of graft. This study aimed to clarify this relevance by histochemical analyses of human hepatic grafts. METHODS: Paired tissue samples were taken at the end of cold preservation and 2 hr after reperfusion (n=39). From six additional grafts, biopsies were performed at the end of cold preservation only. Injury or inflammatory markers of sinusoidal endothelium (von Willebrand factor-related antigen [vWF]), Kupffer cells (25F9), platelets (CD62), neutrophil leukocytes (CD11b), interleukin (IL)-1beta, intercellular adhesion molecule (ICAM)-1, and HLA-DR were evaluated semiquantitatively by indirect immunoperoxidase staining. Steatosis was also evaluated by hematoxylin and eosin staining. RESULTS: vWF, CD62+ platelet aggregation, CD11b+ leukocytes, and IL-1beta levels increased after reperfusion, and these levels correlated with prereperfusion levels. Not only vWF, CD62+ platelets, CD11b+ leukocytes, IL-1beta, ICAM-1, and steatosis after reperfusion, but also IL-1beta, ICAM-1, and steatosis before reperfusion correlated with postoperative peak transaminase. Furthermore, vWF, CD11b+ leukocytes, 25F9+ macrophages, and ICAM-1 after reperfusion were associated with primary graft nonfunction and strong expressions of ICAM-1 or HLA-DR with early acute rejection. Although some markers (IL-1beta, CD62+ platelets, and CD11b+ leukocytes) correlated with preharvesting parameters (donor age or length of intensive care unit stay), none showed any significant correlation with cold preservation. CONCLUSION: Synergistic inflammatory events in the hepatic graft at reperfusion, which have a significant impact on the later clinical course, are largely defined and precipitated by injury or activation of nonparenchymal cells preceding reperfusion or even graft harvesting.

Adolescent↗

PubMed1998

Auxiliary partial orthotopic liver transplantation from living donors: significance of portal blood flow.

BACKGROUND: Auxiliary liver transplantation has several advantages over standard orthotopic liver transplantation. However, functional competition has been reported even in auxiliary partial orthotopic liver transplantation (APOLT). We evaluated herein the interaction in APOLT between the native liver and the graft in terms of portal blood flow and regeneration. The need for diversion of the portal blood flow to the graft was also assessed. METHODS: A total of 15 patients received APOLT from living donors. Portal blood flow to the native liver was preserved in 6 patients, and the portal vein to the native liver was preemptively transected at the time of transplantation in 9 patients. RESULTS: Of the patients with preservation of the portal blood flow to the native liver, two showed inadequate graft portal blood flow just after operation, and in the other three patients the graft portal blood flow decreased or the graft atrophied after deterioration of the graft function. In the patients with preemptive transection of the portal vein to the native liver, optimal graft portal blood flow was obtained, and the native liver, supplied only by arterial inflow, supported a small-for-size graft until the graft regenerated. The damage to the native liver was minimal. CONCLUSIONS: Functional competition may occur in APOLT with preservation of the portal blood flow to the native liver, whereas preemptive transection of the native liver portal vein is a safe procedure and effectively prevents the portal steal phenomenon.

Adolescent↗

PubMed1998

Living-related liver transplantation and neurological outcome in children with fulminant hepatic failure.

BACKGROUND: Fulminant hepatic failure (FHF) in children is associated with high mortality under medical management. Living-related liver transplantation (LRLT) is an accepted measure to treat the children with end-stage liver disease. Reversibility of hepatic encephalopathy is crucial for the quality of life among the survivors after transplantation. METHODS: A retrospective review was made of the records of children undergoing LRLT at this hospital between May 1992 and November 1996. RESULTS: Eleven children with FHF underwent emergency LRLT. The mean age was 5 years (range, 2 months to 15 years). The indication for transplantation was persistent or worsening hepatic encephalopathy and severe coagulopathy, despite repeated plasma exchanges or exchange transfusions. The cause of FHF was non-A, non-B hepatitis in seven children, hepatitis B in two children, herpes simplex virus hepatitis in one child, and fulminant Wilson's disease with intravascular hemolysis in one child. The grade of hepatic encephalopathy was II in four children, III in two, and IV in five. The actuarial survival rate was 73% after a mean follow-up of 28 months (range, 13-67 months). Short-term neurological morbidity was present in two children with grade IV encephalopathy who also showed brain edema on cranial computed tomography. Eight survivors exhibited no long-term neurological deficit; the mean intelligence or developmental quotient was 97 (range, 86-110) at the end of the follow-up period. CONCLUSIONS: LRLT is an effective option for the treatment of FHF in children. The long-term neurological status is satisfactory among survivors.

Brain Edema↗

PubMed1998

Transmission of hepatitis B virus from hepatitis B core antibody-positive donors in living related liver transplants.

BACKGROUND: In order to clarify the risk of hepatitis B virus (HBV) transmission from hepatitis B core antibody-positive (HBcAb(+)) donors and to evolve a new strategy to counter such a risk, we undertook a retrospective (1990-1995) and prospective (1995-1996) analysis of our experience with living related liver transplantation involving HBcAb(+) donors. METHODS: Between June 15, 1990, and June 30, 1995, HBcAb(+) individuals were not excluded as donor candidates at our institutions. For 171 liver transplants, 16 donors were HBcAb(+). Between July 1, 1995, and June 30, 1996, HBcAb(+) individuals were generally excluded as donor candidates; however, three recipients were given liver grafts from HBcAb(+) donors because other donor candidates presented even higher risks. In the latter period, recipients with transplants from HBcAb(+) donors underwent prophylactic passive immunization with hyperimmune hepatitis B immunoglobulin (HBIG). The serum of 10 HBcAb(+) donors was examined by nested polymerase chain reaction for the presence of HBV-DNA, but it was not detected in any of them. However, the same examination of the liver tissue of five such donors yielded positive results in all cases. RESULTS: In the first 5-year period, out of 16 recipients with HBcAb(+) donors, 15 became hepatitis B surface antigen-positive after transplant. The three recipients with HBcAb(+) donors during the second 1-year period, who were treated by prophylactic passive immunization with HBIG, remained hepatitis B surface antigen-negative and negative for serum HBV-DNA after transplant. CONCLUSIONS: HBV exists in the liver of healthy HBcAb(+) individuals, but not in the blood. Therefore, HBV is thought to be transmitted to recipients by liver grafts from the HBcAb(+) donors at a significantly high rate. The prevention of viral activation and clinical disease development by means of passive immunization with HBIG seems promising, although the follow-up period in our study may be too short for any definitive conclusions.

DNA, Viral↗

PubMed1998

One-way donor-recipient HLA-matching as a risk factor for graft-versus-host disease in living-related liver transplantation.

Although one-way matching between an HLA-homozygous donor and a haploidentical recipient is a recognized risk factor in transfusion-associated graft-versus-host disease (GVHD), its impact in living-related liver transplantation (LRLT) has so far not been investigated. We present a case of fatal acute GVHD in our LRLT program that was attributed to one-way HLA matching between donor and recipient. Although the disappearance of donor cells in peripheral blood was suggested by genetic analysis, severe septicemia led to a fatal outcome. We further reviewed 280 LRLT cases and correlated one-way HLA matching with outcome. A total of 8 out of 280 donors (2.9%) and 11 out of 278 recipients (4.0%) were completely HLA homozygous in our LRLT program. Complete one-way HLA matching linked to GVHD was observed in four cases, including the present case. Although other contributing factors also need to be clarified, one-way HLA matching is a definite risk factor for GVHD in LRLT. We advocate caution before proceeding with one-way HLA donor-recipient combinations.

Fatal Outcome↗

PubMed1998

Treatment of ornithine transcarbamylase deficiency in girls by auxiliary liver transplantation: conceptual changes in a living-donor program.

BACKGROUND/PURPOSE: Ornithine transcarbamylase (OTC) deficiency is an X-chromosome-linked genetic disorder resulting in hyperammonemia hepatic dysfunction, coma, and serious neurological sequelae. This report describes an experience in treating this condition with living-related liver transplantation. METHODS: Three children with OTC were treated with a living-related liver transplantation. Potential donors were evaluated with the allopurinol loading test to exclude heterozygotes. FK506 and low-dose steroids were used for immunosuppression. Auxiliary partial orthotopic transplantation (APOLT) was used in two of the cases. RESULTS: All three children survived and are doing well without protein restriction. CONCLUSIONS: These observations suggest that in OTC removal of the native liver is not necessary because (1) a partial liver segment with normal enzyme activity corrects the hyperammonemia, (2) in case of graft failure the native liver is an available backup, and (3) the native liver has the ability to recover function. As long as living-related donors serve as the main source of donor organs, APOLT is a safer approach to liver transplantation in OTC.

Amino Acid Metabolism, Inborn Errors↗

PubMed1998

Discrepant intracellular pH changes following intracellular Ca2+ increases induced by glutamate and Ca2+ ionophores in rat hippocampal neurons.

We investigated changes in intracellular pH (pHi) in relation to intracellular Ca2+ concentration ([Ca2+]i) in primary cultured hippocampal neurons treated with glutamate. [Ca2+]i and pHi were imaged with fluorescent dyes and confocal microscopy. Exposure to 1 mM glutamate for 10 min increased [Ca2+]i and evoked acidosis. These changes persisted for at least 60 min, even after removal of glutamate. The increase in [Ca2+]i and the acidosis were not observed in Ca2+-free solution and were attenuated in the presence of MK-801, an NMDA receptor antagonist. We also found that the increase in [Ca2+]i and acidosis could be induced by addition of Ca2+ to the extracellular solution in the cells pretreated with glutamate in Ca2+-free solution, even if glutamate did not exist in the extracellular solution. On the other hand, ionomycin and Br-A23187, calcium ionophores, increased [Ca2+]i to almost the same level as glutamate and increased pHi. Extracellular Ca2+ was also indispensable for the increase in [Ca2+]i and the alkalosis. These results suggest the followings: 1) intracellular acidosis by glutamate is dependent on the presence of extracellular Ca2+; 2) the acidosis does not result from only the increase in [Ca2+]i; and 3) glutamate induces the irreversible disorder of regulatory mechanisms of [Ca2+]i not only by Ca2+-dependent process, but also by Ca2+-independent process.

Animals↗