Acute exacerbation of immunoglobulin A nephropathy complicated by alveolar hemorrhage after coronavirus disease 2019 vaccination: A case report

RATIONALE

Reports have suggested a relationship between coronavirus disease 2019 (COVID-19) vaccination and new-onset or recurring renal diseases, of which immunoglobulin A (IgA) nephropathy is a representative disease. Alveolar hemorrhage in patients with IgA nephropathy is rare but reportedly has a high mortality and morbidity. To our knowledge, there have been no reports regarding the development of IgA nephropathy with alveolar hemorrhage following COVID-19 vaccination.

PATIENTS CONCERN

A 23-year-old Japanese man presented with hemoptysis and peripheral edema a few days after receiving a second dose of a COVID-19 mRNA vaccine. Severe renal failure and alveolar hemorrhage were noted thereafter, and renal biopsy showed crescentic glomerulonephritis with mesangial proliferation accompanied by mesangial electron-dense deposits containing IgA. Renal biopsy tissue also showed chronic histological changes suggestive of acute exacerbation of preexisting IgA nephropathy.

DIAGNOSIS

The diagnosis of IgA nephropathy complicated by alveolar hemorrhage was made.

INTERVENTIONS AND OUTCOMES

Renal function did not recover despite treatment with high-dose steroids; the patient was maintained on hemodialysis and eventually underwent successful renal transplantation.

LESSONS

The present case suggested that although extremely rare, severe renal failure requiring renal replacement therapy could occur in patients with IgA nephropathy after COVID-19 vaccination. Future accumulation of similar cases is needed to predict the risk of renal injury following vaccination.

Glomerular lipidosis as a feature of renal-limited macrophage activation syndrome in a transplanted kidney: a case report

BACKGROUND

Glomerular lipidosis is a rare histological feature presenting the extensive glomerular accumulation of lipids with or without histiocytic infiltration, which develops under various conditions. Among its various etiologies, macrophage activation syndrome (MAS) is a condition reported to be associated with histiocytic glomerular lipidosis. Here we describe the first case of glomerular lipidosis observed in a renal allograft that histologically mimicked histiocytic glomerulopathy owing to MAS.

CASE PRESENTATION

A 42-year-old man underwent successful living-donor kidney transplantation. However, middle-grade proteinuria and increased serum triglyceride levels indicative of type V hyperlipidemia developed rapidly thereafter. An allograft biopsy performed 6 months after the transplantation showed extensive glomerular infiltration of CD68+ foam cells (histiocytes) intermingled with many CD3+ T-cells (predominantly CD8+ cells). Furthermore, frequent contact between glomerular T-cells and histiocytes, and the existence of activated CD8+ cells (CD8+, HLA-DR+ cells) were observed by double immunostaining. There was no clinicopathological data suggesting lipoprotein glomerulopathy or lecithin cholesterol acyltransferase deficiency, both of which are well-known causes of glomerular lipidosis. The histological findings were relatively similar to those of histiocytic glomerulopathy caused by MAS. As systemic manifestations of MAS, such as fever, pancytopenia, coagulation abnormalities, hyperferritinemia, increased liver enzyme levels, hepatosplenomegaly, and lymphadenopathy were minimal, this patient was clinicopathologically diagnosed as having renal-limited MAS. Although optimal treatment strategies for MAS in kidney transplant patients remains unclear, we strengthened lipid-lowering therapy using pemafibrate, without modifying the amount of immunosuppressants. Serum triglyceride levels were normalized with this treatment; however, the patient's extensive proteinuria and renal dysfunction did not improve. Biopsy analysis at 1 year after the transplantation demonstrated the disappearance of glomerular foamy changes, but the number of glomerular infiltrating cells remained similar.

CONCLUSION

To our knowledge, this is the first reported case of glomerular lipidosis in a transplanted kidney. Increased interaction-activation of histiocytes (macrophages) and CD8+ T-cells, the key pathogenic feature of MAS, was observed in the glomeruli of this patient, who did not demonstrate overt systemic manifestations, suggesting a pathological condition of renal-limited MAS. The clinical effects of triglyceride-lowering therapy were limited, suggesting that hypertriglyceridemia was not the cause of but rather may be a consequence of renal-limited MAS.

First Multicenter Clinical Trial on Machine Perfusion Preservation for Marginal Donor Kidney Transplantation in Japan

BACKGROUND

Machine perfusion has not been widely used because of its low demand in Japan; however, we believe its advantages may increase the number of organ transplants.

METHODS

Here, we report the first clinical trial of machine perfusion for kidney transplantation in Japan. We used the CMP-X08 perfusion device (Chuo-Seiko Co, Ltd, Asahikawa, Hokkaido, Japan) to preserve the donated organs. The flow rate, perfusion pressure, renal resistance, and temperature were monitored during continuous hypothermic perfusion.

RESULTS

From August 2020 to the present, 13 cases of perfusion-preserved kidney transplantation have been performed. Of these, ten and 3 cases were performed using organs donated after brain death (DBD) and cardiac death (DCD), respectively. The average age of the recipients was 55.9 ± 7.3 (45-66) years. The average dialysis period was 14.8 ± 8.4 (0-26) years. The donor's final creatinine level before organ retrieval was 1.58 ± 1.0 (0.46-3.07) mg/dL. The warm ischemic times of the 3 DCD donors were 3, 12, and 18 minutes. The average total ischemic time was 12.0 ± 3.7 (7.17-19.88) hours. The average MP time was 140 (60-240) minutes. A total of 7 cases had delayed graft function. The best creatinine level during hospitalization was 1.17 ± 0.43 (0.71-1.85) mg/dL. There were no primary non-functional cases, and perfusion preservation was safely performed in all cases.

CONCLUSIONS

Therefore, we present this report as the first clinical trial on machine perfusion for kidney transplantation from marginal donors with DBD and DCD in Japan.

Cytokine modulation in abdominal septic shock via the crucial role of IL-6 signaling in endothelial dysfunction

Background

Early recovery from shock improves prognosis in septic shock patients. We determined whether cytokine modulation by Continuous Renal Replacement Therapy (CRRT) following acute care surgery resulted in stable hemodynamics in them. To investigate our hypothesis, we measured proinflammatory cytokines IL-6, IL-1ra and the coagulation cascade activator plasminogen activator inhibitor-1 (PAI-1) following CRRT with polymyxin B immobilized fiber (PMX-DHP) which has been utilized as an adjuvant treatment option for patients with severe septic shock.

Methods

66 septic shock patients requiring 2 h direct hemoperfusion therapy PMX-DHP were included. 36 patients of them also received continuous hemodiafiltration (CHDF) after performing PMX-DHP. Circulatory dynamics and levels of inflammatory mediators, namely IL-6, IL-1ra, and PAI-1 were assessed before, immediately after, and 24 h initiation of PMX-DHP.

Results

Mean Arterial Pressure (MAP) rose intentionally by PMX-DHP just after enforcement 24 h later (p < 0.01). Levels of IL-6, IL-1ra, and PAI-1 significantly decreased after PMX-DHP (p < 0.05) and this trend was observed up to 24 h post initiation of PMX-DHP (p < 0.05). IL-6 modulation by PMX-DHP was enhanced with using CHDF and there was a significant correlation between IL-6 and MAP (p < 0.0001). In addition, levels of Il-6 and PAI-1 showed a significant correlation.

Conclusion

Our data showed employing CRRT as cytokine modulators could be an additional therapeutic strategy to improve septic shock outcomes via the crucial role of IL-6 signaling in endothelial dysfunction.

Atezolizumab plus bevacizumab versus lenvatinib or sorafenib in non-viral unresectable hepatocellular carcinoma: an international propensity score matching analysis

BACKGROUND

A growing body of evidence suggests that non-viral hepatocellular carcinoma (HCC) might benefit less from immunotherapy.

MATERIALS AND METHODS

We carried out a retrospective analysis of prospectively collected data from consecutive patients with non-viral advanced HCC, treated with atezolizumab plus bevacizumab, lenvatinib, or sorafenib, in 36 centers in 4 countries (Italy, Japan, Republic of Korea, and UK). The primary endpoint was overall survival (OS) with atezolizumab plus bevacizumab versus lenvatinib. Secondary endpoints were progression-free survival (PFS) with atezolizumab plus bevacizumab versus lenvatinib, and OS and PFS with atezolizumab plus bevacizumab versus sorafenib. For the primary and secondary endpoints, we carried out the analysis on the whole population first, and then we divided the cohort into two groups: non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) population and non-NAFLD/NASH population.

RESULTS

One hundred and ninety patients received atezolizumab plus bevacizumab, 569 patients received lenvatinib, and 210 patients received sorafenib. In the whole population, multivariate analysis showed that treatment with lenvatinib was associated with a longer OS [hazard ratio (HR) 0.65; 95% confidence interval (CI) 0.44-0.95; P = 0.0268] and PFS (HR 0.67; 95% CI 0.51-0.86; P = 0.002) compared to atezolizumab plus bevacizumab. In the NAFLD/NASH population, multivariate analysis confirmed that lenvatinib treatment was associated with a longer OS (HR 0.46; 95% CI 0.26-0.84; P = 0.0110) and PFS (HR 0.55; 95% CI 0.38-0.82; P = 0.031) compared to atezolizumab plus bevacizumab. In the subgroup of non-NAFLD/NASH patients, no difference in OS or PFS was observed between patients treated with lenvatinib and those treated with atezolizumab plus bevacizumab. All these results were confirmed following propensity score matching analysis. By comparing patients receiving atezolizumab plus bevacizumab versus sorafenib, no statistically significant difference in survival was observed.

CONCLUSIONS

The present analysis conducted on a large number of advanced non-viral HCC patients showed for the first time that treatment with lenvatinib is associated with a significant survival benefit compared to atezolizumab plus bevacizumab, in particular in patients with NAFLD/NASH-related HCC.

Nonalcoholic steatohepatitis in hepatocarcinoma: new insights about its prognostic role in patients treated with lenvatinib

BACKGROUND

Hepatocellular carcinoma (HCC) treatment remains a big challenge in the field of oncology. The liver disease (viral or not viral) underlying HCC turned out to be crucial in determining the biologic behavior of the tumor, including its response to treatment. The aim of this analysis was to investigate the role of the etiology of the underlying liver disease in survival outcomes.

PATIENTS AND METHODS

We conducted a multicenter retrospective study on a large cohort of patients treated with lenvatinib as first-line therapy for advanced HCC from both Eastern and Western institutions. Univariate and multivariate analyses were performed.

RESULTS

Among the 1232 lenvatinib-treated HCC patients, 453 (36.8%) were hepatitis C virus positive, 268 hepatitis B virus positive (21.8%), 236 nonalcoholic steatohepatitis (NASH) correlate (19.2%) and 275 had other etiologies (22.3%). The median progression-free survival (mPFS) was 6.2 months [95% confidence interval (CI) 5.9-6.7 months] and the median overall survival (mOS) was 15.8 months (95% CI 14.9-17.2 months). In the univariate analysis for OS NASH-HCC was associated with longer mOS [22.2 versus 15.1 months; hazard ratio (HR) 0.69; 95% CI 0.56-0.85; P = 0.0006]. In the univariate analysis for PFS NASH-HCC was associated with longer mPFS (7.5 versus 6.5 months; HR 0.84; 95% CI 0.71-0.99; P = 0.0436). The multivariate analysis confirmed NASH-HCC (HR 0.64; 95% CI 0.48-0.86; P = 0.0028) as an independent prognostic factor for OS, along with albumin-bilirubin (ALBI) grade, extrahepatic spread, neutrophil-to-lymphocyte ratio, portal vein thrombosis, Eastern Cooperative Oncology Group (ECOG) performance status and alpha-fetoprotein. An interaction test was performed between sorafenib and lenvatinib cohorts and the results highlighted the positive predictive role of NASH in favor of the lenvatinib arm (P = 0.0047).

CONCLUSION

NASH has been identified as an independent prognostic factor in a large cohort of patients with advanced HCC treated with lenvatinib, thereby suggesting the role of the etiology in the selection of patients for tyrosine kinase treatment. If validated, this result could provide new insights useful to improve the management of these patients.

TAFRO Syndrome in a Kidney Transplant Recipient That Was Diagnosed on Autopsy: A Case Report

A 57-year-old man who received a kidney transplant 4 years previously owing to unknown underlying disease presented with thrombocytopenia and fever. Hepatosplenomegaly and lymphadenopathy were observed, and development of prominent anasarca and worsening of renal function yielded the diagnosis of TAFRO syndrome. He was treated with high-dose steroids and plasmapheresis, and a thrombopoietin receptor agonist was administered for refractory thrombocytopenia. However, his general condition worsened, and he died on day 92. Histopathological analysis of a kidney autopsy specimen showed thrombotic microangiopathy characterized by glomerular endothelial swelling, mesangiolysis, and double contours of the glomerular capillary walls. His bone marrow showed megakaryocytic hyperplasia with mild reticulin fibrosis. Interestingly, these clinical and pathological features were remarkably similar to those the patient demonstrated before the kidney transplant, suggesting the recurrence of TAFRO syndrome. TAFRO syndrome is a rare systemic disorder whose concept has recently been established, but information on its long-term outcome is scarce. To our knowledge, this is the first case of TAFRO syndrome developing in a kidney transplant recipient, which suggests that disease recurrence occurs many years after the kidney transplant.

Individual Lymphocyte Sensitivity to Steroids as a Reliable Biomarker for Clinical Outcome after Steroid Withdrawal in Japanese Renal Transplantation

Recently, steroid reduction/withdrawal regimens have been attempted to minimize the side effects of steroids in renal transplantation. However, some recipients have experienced an increase/resumption of steroid administrations and acute graft rejection (AR). Therefore, we investigated the relationship between the individual lymphocyte sensitivity to steroids and the clinical outcome after steroid reduction/withdrawal. We cultured peripheral blood mononuclear cells (PBMCs) isolated from 24 recipients with concanavalin A (Con A) in the presence of methylprednisolone (MPSL) or cortisol (COR) for four days, and the 50% of PBMC proliferation (IC₅₀) values and the PBMC sensitivity to steroids were calculated. Regarding the experience of steroid increase/resumption and incidence of AR within one year of steroid reduction/withdrawal, the IC₅₀ values of these drugs before transplantation in the clinical event group were significantly higher than those in the event-free group. The cumulative incidence of steroid increase/resumption and AR in the PBMC high-sensitivity groups to these drugs before transplantation were significantly lower than those in the low-sensitivity groups. These observations suggested that an individual’s lymphocyte sensitivity to steroids could be a reliable biomarker to predict the clinical outcome after steroid reduction/withdrawal and to select the patients whose dose of steroids can be decreased and/or withdrawn after transplantation.

Pharmacodynamic Drug-Drug Interaction on Human Peripheral Blood Mononuclear Cells Between Everolimus and Tacrolimus at the Therapeutic Concentration Range in Renal Transplantation

Background

Everolimus (EVL) plus tacrolimus (TAC) therapy is effective and safe in renal transplantation. However, the pharmacokinetic and pharmacodynamic information for EVL combined with TAC is limited. We investigated the pharmacodynamic drug–drug interaction between EVL and TAC at their therapeutic concentration range.

Material/Methods

Isolated peripheral blood mononuclear cells (PBMCs) from 22 healthy participants aged 22 to 24 years were cultured with concanavalin A (Con A) in the presence of EVL and/or TAC for 4 days, and the proliferation rate of the PBMCs was calculated.

Results

TAC promoted the inhibitory efficacy of EVL against the mitogen-activated proliferation of PBMCs at the EVL therapeutic concentration range. When 0.175 ng/mL or more of TAC was combined with 30 ng/mL or more of EVL, the antagonistic effect of TAC on the inhibitory efficacy of EVL against the mitogen-activated proliferation of PBMCs was observed. Conversely, when 0.4 ng/mL TAC and 10 ng/mL or more of EVL were combined, the antagonistic effect of EVL on the inhibitory efficacy of TAC against the mitogen-activated proliferation of PBMCs was observed.

Conclusions

The pharmacodynamic synergistic efficacy of EVL and TAC in combination on mitogen-activated PBMCs was evident at the therapeutic concentration range, which is used in renal transplantation. However, these drugs antagonize each other to suppress the proliferation of activated PBMCs at concentrations higher than those clinically used.

Immunological inflammatory biomarkers as prognostic predictors for advanced hepatocellular carcinoma

Background

The immunological inflammatory biomarkers for advanced hepatocellular carcinoma are unclear. We aimed to investigate the association of immunity and inflammatory status with treatment outcomes in patients with advanced hepatocellular carcinoma who received molecular-targeted agents as primary treatment.

Patients and methods

We enrolled 728 consecutive patients with advanced hepatocellular carcinoma who received sorafenib (n = 554) or lenvatinib (n = 174) as primary treatment in Japan between May 2009 and June 2020. Changes in the neutrophil-to-lymphocyte ratio before and 1 month after treatment and their impact on survival were evaluated. The cut-off values of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio for predicting overall and progression-free survival were calculated using receiver operating characteristic curves.

Results

The neutrophil-to-lymphocyte ratio, but not the platelet-to-lymphocyte ratio, was an independent prognostic factor. Patients with decreased neutrophil-to-lymphocyte ratio survived significantly longer than patients with increased neutrophil-to-lymphocyte ratio (median overall survival: 14.7 versus 10.4 months, P = 0.0110). Among patients with a low pre-treatment neutrophil-to-lymphocyte ratio, the overall survival did not differ significantly between those with decreased and those with increased neutrophil-to-lymphocyte ratio after 1 month (median: 19.0 versus 14.8 months, P = 0.1498). However, among patients with high pre-treatment neutrophil-to-lymphocyte ratio, those whose neutrophil-to-lymphocyte ratio decreased after 1 month showed significantly longer survival than those whose neutrophil-to-lymphocyte ratio increased (median: 12.7 versus 5.5 months, P < 0.0001). The therapeutic effect was not correlated with pre-treatment neutrophil-to-lymphocyte ratio or platelet-to-lymphocyte ratio.

Conclusions

The neutrophil-to-lymphocyte ratio is a prognostic factor, along with liver function and tumor markers, in patients with advanced hepatocellular carcinoma who received molecular-targeted agents as primary treatment. Thus, the neutrophil-to-lymphocyte ratio could be a prognostic biomarker for advanced hepatocellular carcinoma primarily treated with immunotherapy.

•

NLR was an independent prognostic factor with advanced HCC, along with liver function and tumor markers.

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Patients with decreased NLR 1 month after treatment survived significantly longer than patients with increased NLR.

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The therapeutic effect was not correlated with pre-treatment NLR or PLR.

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NLR is a prognostic factor in patients with advanced HCC who received molecular-targeted agents as primary treatment.

•

Thus, NLR could be a prognostic biomarker for advanced HCC treated with immunotherapy.

Development of pure red cell aplasia by transmission and persistent infection of parvovirus B19 through a kidney allograft

We report a case of pure red cell aplasia (PRCA) caused by parvovirus B19 (PVB19) infection, which was transmitted through a kidney allograft. The patient underwent a living-donor kidney transplant from his wife at the age of 60. Despite successful engraftment with a normal creatinine level, he developed severe anemia that required frequent blood transfusions 2 months after transplantation. Renal anemia was unlikely as his serum erythropoietin level was extremely high. A bone marrow aspiration test demonstrated the existence of large proerythroblasts. Although anti-PVB19 IgM antibody levels were not increased, polymerase chain reaction (PCR) detected PVB19 DNA in his serum. Thus, he was diagnosed as having PRCA induced by PVB19 infection. PCR analysis of total DNA isolated from 0-hour biopsy sections showed the existence of PVB19 DNA. Furthermore, PVB19 proteins was detected on renal tubules of 0-hour allograft by immunoperoxidase staining. Thus, transmission of PVB19 through the allograft was confirmed. A single course of intravenous immunoglobulin (IVIG) therapy resulted in substantial improvement; however, the effect was limited, and severe anemia relapsed after 5-6 months. Several courses of IVIG with adjustment of immunosuppressive drugs resulted in long-term remission. Our case demonstrates that donor-transmitted PVB19 infection should be suspected in kidney transplant recipients who develop refractory anemia during the early post-operative phase.

Long-Term Survival After Multidisciplinary Treatment Including Surgery for Metachronous Metastases of Small Intestinal Gastrointestinal Stromal Tumors after Curative Resection: A Case Report

Patient: Male, 56-year-old

Final Diagnosis: Metachronous metastases of small intestinal gastrointestinal stromal tumors

Symptoms: Abdominal and/or epigastric pain

Medication: —

Clinical Procedure: Operation • chemotharapy

Specialty: Gastroenterology and Hepatology

Visualization and quantification of anastomotic perfusion in colorectal surgery using near-infrared fluorescence

BACKGROUND

Anastomotic leakage (AL) is one of the most troublesome complications in colorectal surgery. Recently, near-infrared fluorescence (NIRF) imaging has been used intraoperatively to detect sentinel lymph nodes and visualize the blood supply at the region of interest (ROI). The aim of this study was to evaluate the role of visualization and quantification of bowel perfusion around the anastomosis using NIRF system in predicting AL.

METHODS

A prospective study was conducted on patients who had laparoscopic surgery for colorectal cancer at our institution. Perfusion of the anastomosis was evaluated with NIRF imaging after intravenous injection of indocyanine green (ICG). The time course of fluorescence intensity was recorded by an imaging analyzer We measured the time from ICG injection to the beginning of fluorescence (T₀), maximum intensity (I_max), time to reach I_max (T_max), time to reach I_max 50% ([Formula: see text]) and slope (S) after the anastomosis.

RESULTS

Tumor locations were as follows; cecum: 2, ascending colon: 2, transverse colon: 7, descending colon: 1, sigmoid colon: 2, rectosigmoid colon: 3 and rectum: 6 (one case with synchronous cancer). All operations were performed laparoscopically. Four patients were diagnosed with or suspected to have AL (2 patients with grade B anastomotic leakage after low anterior resection, 1 patient with minor leakage in transverse colon resection and 1 patient needing re-anastomosis intraoperatively in transverse colon resection). T₀ was significantly longer in the AL group than in patients without AL (64.3 ± 27.6 and 18.2 ± 6.6 s, p = 2.2 × 10^-3).

CONCLUSIONS

Perfusion of the anastomosis could be successfully visualized and quantified using NIRF imaging with ICG. T₀ might be a useful parameter for prediction of AL.

Early Outcomes of Living-Donor Kidney Transplantation With Immunosuppression Therapy Induction With Tacrolimus Extended-Release: A Comparison With Cyclosporine

BACKGROUND

Extended-release tacrolimus (TacER), administered once daily, offers improved adherence with reduced side effects while still maintaining an immunosuppressive potency equivalent to that of conventional tacrolimus preparations.

METHODS

The study included 83 patients who received consecutive living-donor kidney transplants at our facility from June 2013 to December 2016. Comparisons were made between 48 cases of induction with TacER and 35 cases of induction with cyclosporine (CyA). The observation period was 3 months after transplantation. Transplanted kidney function, rejection, infectious disease, lipid abnormalities, and glucose tolerance were compared.

RESULTS

The 2 groups showed no significant difference in donor background or transplanted kidney function. Within the 3-month observation period, an acute rejection response was observed in 2 cases in the TacER group and in 8 cases in the CyA group. After transplantation, hyperlipidemia requiring medication was observed more frequently in the CyA group. The 2 groups did not show a marked difference in systemic infection or renal calcineurin inhibitor toxicity in histopathologic examination of the transplanted kidneys 3 months after surgery.

DISCUSSION

Proactive use of TacER leads to improved adherence while yielding immunosuppressive potency equivalent to that of conventional tacrolimus preparations; however, tacrolimus has a potent blood sugar-elevating effect; thus, direct comparison with the CyA group is important for assessing the side effects.

CONCLUSION

TacER has the potential to also reduce side effects in the early stages after surgery, suggesting its potential as a drug of first choice.

An Examination of Pregnancy Cases After Kidney Transplantation: Single-Center Experience

INTRODUCTION

The number of young women who wish to become pregnant opting for kidney transplants is increasing, as becoming pregnant under hemodialysis or peritoneal dialysis is associated with many risks. However, there have been reports indicating that these patients are subject to a higher risk of miscarriage compared to women with normal renal function. We examine and report cases of patients that experienced pregnancy after undergoing kidney transplantation at our hospital.

SUBJECTS AND METHOD

Of the kidney transplantation cases that were performed at our hospital between 1985 and 2016, there were 7 cases of pregnancy. The serum creatinine levels, urine protein findings, etc, of these 7 cases were examined during the pre-pregnancy, pregnancy, childbirth, and postpartum periods.

RESULTS

All 7 cases were able to give birth. There were two cases of transient postpartum hypertension. There were no cases of obvious pregnancy toxemia or fetal growth retardation. Two of the cases resulted in the failure of the transplanted kidneys.

DISCUSSION

According to previous studies on pregnancy and childbirth after kidney transplantation, the presence of high blood pressure and proteinuria as well as the renal function at the time of pregnancy is closely associated with postpartum renal function. Urine protein was detected prior to pregnancy in both cases and resulted in the failure of the transplanted kidneys. The influence of immunosuppressants on the mother and fetus is also an important consideration.

CONCLUSION

We believe it is extremely important to ensure a thorough informed consent process prior to pregnancy and systematic use of immunosuppressants for young female transplant recipients.

Prophylactic use of intravenous prostaglandin E1 for radial arterial spasm in uremic patients undergoing construction of arteriovenous hemodialysis fistulas

Radial arterial spasm in uremic patients undergoing construction of internal arteriovenous (AV) dialysis fistulas was investigated transcutaneously using ultrasonic Doppler flowmetry. In 6 of 16 control patients, the radial arterial blood flow was significantly decreased for 20 min after anastomosing, indicating vasospasm. Vasospasm did not occur in 15 patients who were continuously administered prostaglandin E1 (PGE1) intravenously (10 ng/kg/min) during surgery. The arterial blood flow was significantly increased in patients receiving PGE1 in comparison with control patients not receiving PGE1 and in whom vasospasm did not occur. Regarding patency of hemodialysis access, the fistula was obstructed in one control patient with radial arterial spasm, but not in patients with PGE1 infusion. Our study suggests that PGE1 may be effective in preventing vasospasm in patients undergoing placement of internal AV dialysis fistulas.

Clinical Outcomes and Results of Pathological Findings of 1-year Protocol Biopsy in Recipients of ABO-Incompatible Living Donor Kidney Transplantants

OBJECTIVES

ABO-incompatible kidney transplantation has increased the possibility of finding suitable living donors for patients with renal failure. However, there are inevitable immunological risks, including a high risk of early post-transplantation complications. The purpose of this study was to evaluate recipient outcomes following ABO-incompatible kidney transplantation.

METHODS

Seventy-one patients who had undergone living-donor kidney transplantation (LDKT) at our center between January 2008 and December 2013 were divided into ABO-incompatible (ABOi; n = 21) and ABO-compatible (ABOc; n = 50) groups. Baseline data, graft function, immunosuppressant use, and the results of biopsy 1 year after LDKT were compared between the groups.

RESULTS

Recipient preemptive LDKT rates were significantly different between groups (P = .017). Graft function, incidence of infection, and rates of T-cell-mediated rejection and borderline changes requiring medication were not significantly different. There was no acute antibody-mediated rejection. Selectivity of the immunosuppressant, tacrolimus, was significantly different between groups (P < .01); however, steroid withdrawal rates, mycophenolate mofetil doses, and calcineurin inhibitor trough levels were not different. Regarding biopsy data, interstitial fibrosis scores were significantly different between groups (P = .011), as were interstitial fibrosis and tubular atrophy scores (P = .045) and arteriolar hyalinosis score (P = .022).

CONCLUSION

ABOi LDKT was relatively safe, with no significant difference in the incidence of rejection compared to ABOc LDKT. Managing chronic pathological changes and arteriolar hyalinosis prophylaxis after ABOi LDKT may result in more successful outcomes.

A Novel Assessment of Vascular Regions Using an Intraoperative Near-Infrared Fluorescence

INTRODUCTION

The risk of complications and transplant renal function increases in multiple arterial renal transplantations compared with single arterial renal transplantations. Even when multiple arteries are involved, with the introduction of laparoscopic nephrectomy, I mainly choose the left side kidney. Therefore, the number of renal artery reconstructions is increasing, and simultaneous imaging of arterial rebuilding during the donor nephrectomy is important.

MATERIAL

Between 2006 and 2015, we performed 132 living donor kidney transplantations at our center and analyzed 32 cases that were diagnosed pre- and intraoperatively.

METHOD

We compared the single renal artery (SRA) and multiple renal arteries (MRA) groups and analyzed the number of renal arteries, reconstruction methods, donor and recipient ages, sex, total ischemic times, and 1-month serum creatinine values.

RESULT

In the MRA and SRA groups, the average recipient age was 52.3 and 47.0 years, respectively, while the average donor age was 52.9 and 53.1 years, respectively. In SRA and MRA groups, total ischemic time (TIT) was 96.1 and 143.6 min (P < .01). Serum creatinine level 1 month post-transplantation was 1.54 and 1.25, respectively (P < .001). Here we experienced 12 cases of living renal donor nephrectomy with multiple vessels in which the vascular supply territory was first assessed in April 2013 using an intraoperative near-infrared fluorescence camera system. In addition, regarding TIT, it is possible to shorten surgery by using individual anastomosis and ligation.

CONCLUSION

By managing multiple donors; arteries by nephrectomy, it is possible to improve kidney transplantation results.

Formal nucleophilic borylation and borylative cyclization of organic halides

Recent advances in borylations of organic halides, including both transition-metal-catalyzed and metal-free methods are summarized. Borylative cyclization is also discussed.

Postoperative Compensatory Changes and Blood Flow Parameter of the Preserved Kidney in Elderly Living Related Donors Evaluated by Doppler Ultrasonography

INTRODUCTION

Elderly kidney donors have recently become more common in living related kidney transplantation in Japan. Therefore, it is important to evaluate whether kidney function in elderly donors after nephrectomy is preserved over long periods of time. Doppler ultrasonography measurement is practical for donors after nephrectomy because it involves simple and noninvasive examinations. Doppler ultrasonography can detect compensatory hypertrophy and blood flow parameters, namely resistive index (RI) and pulsatility index (PI), of the preserved kidney in living donors.

PATIENTS AND METHODS

Our study included 58 donors, divided into 2 groups according to age; the elderly donor group was comprised of those 65 years old or older. We measured length, width, and short diameter of the preserved kidney using Doppler ultrasonography, and calculated kidney volume.

RESULTS

The elderly group was comprised of 13 patients. In this group, the median preserved kidney volume was 145.0 cm(3) (101.8-193.5) before nephrectomy, and 127.6 cm(3) (99.0-183.4) and 145.5 cm(3) (141.3-148.6) at 1 and 12 months after nephrectomy, respectively. We did not observe significant compensatory hypertrophy in the preserved kidneys of elderly donors postoperatively. Both the mean PI and RI values of elderly donors increased progressively after nephrectomy. No compensatory hypertrophy occurred in the preserved kidneys of elderly donors, although the PI and RI did increase in these donors.

CONCLUSION

Our results indicate that nephrectomy caused nephrosclerosis in the preserved kidneys of elderly donors and that prevention of hypertension may be important after nephrectomy in elderly donors.

A requirement of serotonergic p38α mitogen-activated protein kinase for peripheral immune system activation of CNS serotonin uptake and serotonin-linked behaviors

Alterations in central serotonin (5-hydroxytryptamine, 5-HT) neurotransmission and peripheral immune activation have been linked to multiple neuropsychiatric disorders, including depression, schizophrenia and autism. The antidepressant-sensitive 5-HT transporter (SERT, SLC6A4), a critical determinant of synaptic 5-HT inactivation, can be regulated by pro-inflammatory cytokine signaling. Systemic innate immune system activation via intraperitoneal lipopolysaccharide (LPS) injection rapidly elevates brain SERT activity and 5-HT clearance. Moreover, the pro-inflammatory cytokine interleukin (IL)-1β rapidly stimulates SERT activity in raphe nerve terminal preparations ex vivo, effects that are attenuated by pharmacological p38 MAPK inhibition. To establish a role of serotonergic p38α MAPK signaling in LPS/IL-1β-induced SERT regulation and attendant behavioral responses, we pursued studies in mice that afford conditional elimination of p38α MAPK in 5-HT neurons (p38α(5HT-)). We found p38α(5HT-) and control (p38α(5HT+)) littermates to be indistinguishable in viability and growth and to express equivalent levels of SERT protein and synaptosomal 5-HT transport activity. Consistent with pharmacological studies, however, IL-1β fails to increase SERT activity in midbrain synaptosomes prepared from p38α(5HT-) animals. Moreover, although LPS elevated plasma corticosterone and central/peripheral pro-inflammatory cytokines in p38α(5HT-) animals, elevations in midbrain SERT activity were absent nor were changes in depressive and anxiety-like behaviors observed. Our studies support an obligate role of p38α MAPK signaling in 5-HT neurons for the translation of immune activation to SERT regulation and 5-HT-modulated behaviors.

Synergistic Effects of Calcineurin Inhibitors and Steroids on Steroid Sensitivity of Peripheral Blood Mononuclear Cells

The steroid receptor (SR) complex contains FKBP51 and FKBP52, which bind to tacrolimus (TAC) and cyclophilin 40, which, in turn, bind to cyclosporine (CYA); these influence the intranuclear mobility of steroid-SR complexes. Pharmacodynamic interactions are thought to exist between steroids and calcineurin inhibitors (CNIs) on the SR complex. We examined the effect of CNIs on steroid sensitivity. Methylprednisolone (MPSL) sensitivity was estimated as the concentration inhibiting mitosis in 50% (IC50) of peripheral blood mononuclear cells and as the area under the MPSL concentration-proliferation suppressive rate curves (CPS-AUC) in 30 healthy subjects. MPSL sensitivity was compared between the additive group (AG) as the MPSL sensitivity that was a result of addition of the proliferation suppressive rate of CNIs to that of MPSL and the mixed culture group (MCG) as MPSL sensitivity of mixed culture with both MPSL and CNIs in identical patients. IC50 values of MPSL and cortisol sensitivity were examined before and 2 months after CNI administration in 23 renal transplant recipients. IC50 and CPS-AUC values of MPSL were lower in the MCG than in the AG with administration of TAC and CYA. The CPS-AUC ratio of MCG and AG was lower in the TAC group. IC50 values of MPSL and cortisol tended to be lower after administration of TAC and CYA, and a significant difference was observed in the IC50 of cortisol after TAC administration. Steroid sensitivity increased with both TAC and CYA. Furthermore, TAC had a greater effect on increasing sensitivity. Thus, concomitant administration of CNIs and steroids can increase steroid sensitivity.

Clinical significance of peripheral blood lymphocyte sensitivity to glucocorticoids for the differentiation of high-risk patients with decreased allograft function after glucocorticoid withdrawal in renal transplantation

PURPOSE

A reliable biomarker to differentiate high-risk recipients who will experience a decrease in allograft function after glucocorticoid withdrawal has not been established in renal transplantation. We examined the clinical significance of peripheral blood lymphocyte sensitivity to glucocorticoids in vitro for the differentiation of the high-risk patients after glucocorticoid reduction/withdrawal in renal transplant recipients.

METHODS

The study included 44 renal transplant recipients with stable allograft function. Peripheral lymphocyte responses to suppressive effects of cortisol, methylprednisolone, cyclosporine, and tacrolimus in mitogen assay procedures in vitro were examined. Clinical outcome after glucocorticoid reduction/withdrawal was retrospectively compared between recipients with lymphocytes normally sensitive to the drugs and those with hyposensitivity. The receiver-operating characteristic (ROC) curve analysis was undertaken for setting the cutoff IC50 values of the drugs against the T cell mitogen-induced lymphocyte proliferation to differentiate the high-risk recipients with decreased allograft function after glucocorticoid withdrawal.

FINDINGS

The median (range) IC50 value for cortisol in the recipients who showed decreased renal function due to glucocorticoid withdrawal was 10,000 (570.9-72,279.3) ng/mL (n = 9), which was significantly higher than the value of 351.6 (2.0-10,000) ng/mL in the recipients who had not experienced glucocorticoid withdrawal symptoms (n = 35) (P < 0.001). Similarly, the median (range) IC50 value for methylprednisolone in the recipients who showed decreased renal function after glucocorticoid withdrawal was 69.1 (21.5-1442.7) ng/mL (n = 9), which was significantly higher than the value of 13.8 (0.7-1000) ng/mL in the recipients who had not experienced glucocorticoid withdrawal symptoms (n = 30) (P < 0.003). In contrast, there was no significant difference in the median IC50 values of cyclosporine and tacrolimus between the 2 recipient subgroups. The ROC curve analyses for the IC50 values of the immunosuppressive drugs estimated the cutoff value of cortisol and methylprednisolone to be 3580.0 and 21.5 ng/mL, respectively. The ROC AUCs for cortisol and methylprednisolone were 0.83 and 0.84, respectively. According to the cutoff IC50 value, the incidence of decreased allograft function in the low cortisol sensitivity (IC50 >3580.0 ng/mL) subgroup was 7 of 13 patients, which was significantly higher than that of the higher sensitivity subgroup of 2 of 31 (P = 0.0012). A similar case was observed using the cutoff IC50 value of methylprednisolone (P = 0.0012), whereas recipient grouping according to the cutoff IC50 values of cyclosporine and tacrolimus failed to differentiate the high-risk recipients with decreased allograft function after glucocorticoid withdrawal.

IMPLICATIONS

Glucocorticoid pharmacodynamics in lymphocytes of individual patient origin is a reliable biomarker for differentiation of renal transplant recipients who will experience a safe reduction/withdrawal of glucocorticoid.

Time course analysis of mechanical ventilation-induced diaphragm contractile muscle dysfunction in the rat

Controlled mechanical ventilation (CMV) plays a key role in triggering the impaired diaphragm muscle function and the concomitant delayed weaning from the respirator in critically ill intensive care unit (ICU) patients. To date, experimental and clinical studies have primarily focused on early effects on the diaphragm by CMV, or at specific time points. To improve our understanding of the mechanisms underlying the impaired diaphragm muscle function in response to mechanical ventilation, we have performed time-resolved analyses between 6 h and 14 days using an experimental rat ICU model allowing detailed studies of the diaphragm in response to long-term CMV. A rapid and early decline in maximum muscle fibre force and preceding muscle fibre atrophy was observed in the diaphragm in response to CMV, resulting in an 85% reduction in residual diaphragm fibre function after 9-14 days of CMV. A modest loss of contractile proteins was observed and linked to an early activation of the ubiquitin proteasome pathway, myosin:actin ratios were not affected and the transcriptional regulation of myosin isoforms did not show any dramatic changes during the observation period. Furthermore, small angle X-ray diffraction analyses demonstrate that myosin can bind to actin in an ATP-dependent manner even after 9-14 days of exposure to CMV. Thus, quantitative changes in muscle fibre size and contractile proteins are not the dominating factors underlying the dramatic decline in diaphragm muscle function in response to CMV, in contrast to earlier observations in limb muscles. The observed early loss of subsarcolemmal neuronal nitric oxide synthase activity, onset of oxidative stress, intracellular lipid accumulation and post-translational protein modifications strongly argue for significant qualitative changes in contractile proteins causing the severely impaired residual function in diaphragm fibres after long-term mechanical ventilation. For the first time, the present study demonstrates novel changes in the diaphragm structure/function and underlying mechanisms at the gene, protein and cellular levels in response to CMV at a high temporal resolution ranging from 6 h to 14 days.

Correlation between post kidney transplant anemia and kidney graft function

BACKGROUND

Posttransplant anemia (PTA) influences kidney graft function and prognosis; however, there is no consensus regarding target hemoglobin (Hb) levels.

METHODS

We examined several cases of PTA to identify any correlation between Hb levels and graft function. We evaluated 84 kidney transplant recipients (50 men and 34 women; mean age, 46.7 years) who were treated at our department between February 2004 and March 2012 and were available for a 2-year post-transplant follow-up.

RESULTS

Hb levels and serum creatinine levels before transplantation and at 1, 3, 6, 12, and 24 months after transplantation were compared. We examined the correlation between the degree of anemia and renal function among the patients. Data were analyzed using Spearman's rank correlation coefficient and Friedman tests. The mean pretransplantation Hb level was 10.4 g/dL, whereas Hb levels at 6, 12, and 24 months after transplantation were significantly increased to 11.6, 12.2, and 12.4 g/dL, respectively, suggesting an improvement in anemia after the transplantation. Correlation analysis between anemia and kidney graft dysfunction revealed significant correlations at 1, 3, 12, and 24 months after transplantation. Subjects were stratified for correlation analysis according to Hb level at 24 months after transplantation: <10, 10-10.9, 11.0-11.9, 12.0-12.9, and ≥ 13.0 g/dL. A significant improvement in kidney graft function was noted in patients with an Hb level ≥ 11 g/dL at 2 years after transplantation. Anemia improved significantly by 3 months after transplantation.

CONCLUSIONS

A significant correlation between PTA and kidney graft function was apparent, and the prognosis for kidney graft function was poor in patients with Hb levels ≤ 11 g/dL.

Relationship among collagen amount, distribution and architecture in the M. longissimus thoracis and M. pectoralis profundus from pigs

The relative distribution of types I and III collagens and collagen fibre architecture in the perimysium and endomysium were compared to the longissimus thoracis (LT) and pectoralis profundus (PP) muscles in pigs. The LT muscle was composed of type I myofibres 16.8%, IIA 12.9% and IIB 70.2%, and the PP muscle was 25.4, 23.1 and 51.5%, respectively. The total collagen amount differed significantly between the LT (2.66 mg/g) and PP (4.13 mg/g) muscle (P<0.001). On image analysis of the immunohistochemical preparations for types I and III collagens, the percentage area of the perimysium to the total collagen area showed significant differences between the muscles, where perimysial type I collagen occupied 25.4% of the total area in the LT muscle and 45.7% in the PP and perimysial type III 37.6 and 54.5%, respectively (P<0.001). In scanning electron microscopic photographs of the macerated preparation, very thick collagen layers composed of several fibre bands were observed in the perimysia of the PP muscle and appeared differently from the thinner perimysia with a few bands in the LT. Similar architecture of endomysial collagen fibres were observed around every myofibre type in the PP muscle and also in the LT. The fine surface cover of reticular collagen fibres around an adipocyte was shown as a global cast. These results suggested that the total collagen amount of the PP muscle was related mainly to the well developed perimysia composed of several collagen bands, indicating tougher meat compared with the LT muscle.

Long-term recurrence-free survival after liver transplantation from an ABO-incompatible living donor for treatment of hepatocellular carcinoma exceeding Milano criteria in a patient with hepatitis B virus cirrhosis: a case report

The early results of liver transplantations (OLT) in patients with advanced hepatocellular carcinoma (HCC) were poor because of frequent tumor recurrence. However, OLT has significant, theoretical advantage that it removes both the tumor and the organ that is at a risk of malignancy. The Japanese law on organ transplantation limited the availability of cadaveric liver donors until its revision on July 17, 2011. ABO-incompatible OLT was formerly contraindicated because performed anti-A/B antibodies on recipient endothelial cells raised the risk of antibody-mediated humoral graft rejection. We have herein described four successful cases of steroid withdrawal among adult patients who underwent living donor OLT from ABO-incompatible donors. In addition, we transplanted a liver from a living donor into an ABO-incompatible recipient on August 9, 2004. The 55-year-old man with HCC due to hepatitis B virus (HBV) a cirrhosis had a Child-Pugh score of C, and Model for End-stage Liver Disease score of 22. Two tumors greater than 5 cm, exceeded the Milan criteria. His des-gamma-carboxy prothrombin level was 6 mAu/mL, and alpha-fetoprotein, 18.78 ng/mL. Antirejection therapy included multiple perioperative plasmaphereses and splenectomy; with an immunosuppressive regimen consisting of tacrolimus, methylprednisolone, and mycophenolate mofetil. The maintenance dose of immunosuppression did not differ from that of ABO-identical cases. After transplantation, we used intrahepatic arterial infusion therapy with prostaglandin E1 (PG E1). The patient had complications of portal vein thrombosis, hepatic artery thrombosis, and acute myocardial infarction, which were treated by interventional radiology in the posttransplantation period. We controlled the HBsAb titer by administering hepatitis B immunoglobulin and lamivudine (200 IU/L doses) for 1 year after OLT and 100 IU/L doses thereafter. As a result, the patient achieved long-term, disease-free graft survival without steroids. He currently has good liver function and leads a normal lifestyle. Our results suggested the feasibility of controlling antibody-mediated humoral rejection and other complications in living donor liver transplantations into ABO-incompatible adults via intrahepatic arterial PG E1 infusion splenectomy, and plasmapheresis with regular immunosuppression. Withdrawal of steroids, HBV vaccination, and lamivudine, an nucleoside analog reverse transcriptase inhibitor, have achieved long-term (7 years) survival without recurrent HBV infection or tumor.

Steroid withdrawal based on lymphocyte sensitivity to endogenous steroid in renal transplant recipients

Though steroid withdrawal is done in many renal transplant recipients, some patients must restart steroids. Little report has investigated steroid withdrawal under pharmacodynamic monitoring. We assessed lymphocyte sensitivity to endogenous cortisol as a biomarker for determining the safety of steroid withdrawal in renal transplant patients, as we hypothesized that patients hyposensitive to cortisol could not be sufficiently immunosuppressed by their intrinsic cortisol as a substitute for the reduced or withdrawn steroid. Lymphocyte sensitivity to cortisol was examined in 30 long stable renal transplant recipients. Lymphocyte sensitivity to cortisol and its relationship with the clinical outcome after steroid reduction and withdrawal was investigated. The lymphocyte sensitivities to cortisol were estimated as IC(50) of lymphocyte blastogenesis. The lymphocyte proliferation rate for concentration of serum cortisol compared between incident and non-incident groups. Serum creatinine levels (S-Cr) increased in a significantly higher number of patients hyposensitive to cortisol (IC(50)≧10000 ng/ml) than in normally sensitive patients (IC(50)<10000 ng/ml). The incidences of steroid withdrawal syndrome and necessity for increasing steroid dose or restarting steroid administration were also higher in the patients hyposensitive to cortisol. The patients in whom the lymphocyte proliferation rate was less than 60% did not show increase in S-Cr, experience steroid withdrawal symptoms, or require an increase in the steroid dose or restart of steroid administration. The patients who have the normal IC(50) values of cortisol, can withdraw steroid more safely. The lymphocyte sensitivity to cortisol may be a useful biomarker for selecting patients who can sustain steroid withdrawal.

Higher Sensitivity of Peripheral Blood Lymphocytes to Endogenous Glucocorticoid in Renal Transplant Recipients Treated With Tacrolimus, as Compared to Those Treated With Cyclosporine

Lymphocyte sensitivity to endogenous glucocorticoid cortisol could be a biological marker for safe reduction and withdrawal of steroids in renal transplant recipients. We compared peripheral lymphocyte sensitivity with cortisol between transplant recipients treated with tacrolimus (Tac) and those treated with cyclosporine. The suppressive efficacies of cortisol against T-cell mitogen-stimulated proliferation of peripheral lymphocytes were investigated in 44 renal transplant patients, who either had reduced or been withdrawn from steroid treatment. Twenty of the 44 patients were treated with Tac, and the other 24 patients were treated with cyclosporine A (CyA). The lymphocyte sensitivity to cortisol was compared between these two patient groups. The cortisol IC50 values in the Tac and CyA groups were 0.09 ± 0.12 and 14.2 ± 12.7 ng/ml, respectively. Lymphocyte sensitivity to cortisol in the Tac-treated group was significantly higher than that in the CyA-treated group (p = 0.0283). On the other hand, incidences of steroid withdrawal syndrome and increases in serum creatinine concentration were not significantly different between the Tac and CyA groups. Lymphocyte sensitivity to cortisol was higher in the Tac-treated patients than that in the CyA-treated ones. Since the cortisol sensitivity of peripheral lymphocytes is suggested to be a predictive marker for safe steroid withdrawal, Tac administration shows promise in aiding successful withdrawal of steroid treatment in long-term renal transplant recipients.

Characterization of intestinal absorption of quinidine, a P-glycoprotein substrate, given as a powder in rats

The characteristics of intestinal absorption of quinidine, a P-glycoprotein (P-gp) substrate in biopharmaceutics classification system (BCS) Class I, after oral administration as a powder in No. 9 HPMC capsule (diameter 2.6 mm; length 8.4 mm, volume 25 microl) was examined in rats from the following viewpoints: (i) main absorption site of quinidine, (ii) effect of dosage amounts (or luminal concentrations) of quinidine (10 mg vs 0.1 mg/kg), (iii) contribution of P-gp in quinidine absorption (0.1 mg/kg), and (iv) effect of gastric pH on quinidine absorption. Quinidine administered orally at a dose of 10 mg/kg was discharged from the stomach steadily with time and disappeared rapidly from the proximal intestine, where P-gp expression was low. In contrast, quinidine administered at a dose of 0.1 mg/kg remained longer in the gastrointestinal lumen than that administered at a dose of 10 mg/kg. The pretreatment with cyclosporine A, a P-gp inhibitor, greatly increased the intestinal absorption of quinidine given at a dose of 0.1 mg/kg. The gastric pH in untreated control rats was pH 3.6, and the treatment with ranitidine (10mg/kg, ip), a H2 blocker, increased to pH 6.4. The recovered amounts of quinidine 30 min after administration were 21.1% of dose in control rats and 94.7% in ranitidine-treated rats. The value of plasma AUC(0-6h) of quinidine in ranitidine-treated rats was about 40% that in untreated control rats. In conclusion, quinidine was rapidly and efficiently absorbed at the proximal intestine under ordinary circumstances. However, the oral bioavailability was modulated by various factors including the dose (or luminal concentration at the absorption site), presence of P-gp inhibitors, and gastrointestinal pH.