SAGES/AHPBA guidelines for the use of microwave and radiofrequency liver ablation for the surgical treatment of hepatocellular carcinoma or colorectal liver metastases less than 5 cm

BACKGROUND

Primary hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM) represent the liver's two most common malignant neoplasms. Liver-directed therapies such as ablation have become part of multidisciplinary therapies despite a paucity of data. Therefore, an expert panel was convened to develop evidence-based recommendations regarding the use of microwave ablation (MWA) and radiofrequency ablation (RFA) for HCC or CRLM less than 5 cm in diameter in patients ineligible for other therapies.

METHODS

A systematic review was conducted for six key questions (KQ) regarding MWA or RFA for solitary liver tumors in patients deemed poor candidates for first-line therapy. Subject experts used the GRADE methodology to formulate evidence-based recommendations and future research recommendations.

RESULTS

The panel addressed six KQs pertaining to MWA vs. RFA outcomes and laparoscopic vs. percutaneous MWA. The available evidence was poor quality and individual studies included both HCC and CRLM. Therefore, the six KQs were condensed into two, recognizing that these were two disparate tumor groups and this grouping was somewhat arbitrary. With this significant limitation, the panel suggested that in appropriately selected patients, either MWA or RFA can be safe and feasible. However, this recommendation must be implemented cautiously when simultaneously considering patients with two disparate tumor biologies. The limited data suggested that laparoscopic MWA of anatomically more difficult tumors has a compensatory higher morbidity profile compared to percutaneous MWA, while achieving similar overall 1-year survival. Thus, either approach can be appropriate depending on patient-specific factors (very low certainty of evidence).

CONCLUSION

Given the weak evidence, these guidelines provide modest guidance regarding liver ablative therapies for HCC and CRLM. Liver ablation is just one component of a multimodal approach and its use is currently limited to a highly selected population. The quality of the existing data is very low and therefore limits the strength of the guidelines.

P5666Impact of metabolic syndrome on the incidence of atrial fibrillation; a nationwide longitudinal cohort study in South Korea

Background/Introduction

There is a lack of studies for the association between the status of metabolic syndrome (MetS) and the risk of atrial fibrillation (AF)

Purpose

The present study aimed to evaluate the impact of MetS status for the incidence of AF in Korean population.

Methods

We used the data obtained from the Korean National Health Insurance Service from 2009 to 2016. This study enrolled a total of 7,830,602 men and women aged between 30 and 69 years without baseline AF who underwent national health examination between January 2009 and December 2009. They were evaluated to determine the risk of AF based on the status of MetS until December 2016. Based on the criteria of the National Cholesterol Education Program Adult Treatment Panel III, the status of MetS was defined into three groups according to number of MetS components: the normal (0), Pre-MetS (1–2), and MetS (3–5).

Results

During follow-up, 20,708 subjects (0.26%) were diagnosed with AF. After multivariable adjustment, the risk of AF was significantly higher according to the status of MetS (hazard ratios [HR] 1.391, 95% confidence interval [CI] 1.322–1.464 in Pre-MetS and HR 1.722, 95% CI 1.621–1.829 in MetS). Among the components of MetS, central obesity (HR 1.316, P<0.001), elevated blood pressure (HR 1.451, P<0.001), and elevated fasting glucose (HR 1.163, P<0.001) were associated with an increased risk of AF.

Conclusion

MetS and pre-MetS are significantly associated with an increased risk of AF in Korean adults. Of the components of MetS, central obesity, elevated blood pressure, and elevated fasting glucose are potent risk factors for the risk of AF in this population.

Influence of hepatitis B virus reactivation on the recurrence of HBV-related hepatocellular carcinoma after curative resection in patients with low viral load

It is unclear whether the reactivation of hepatitis B virus (HBV) influences the prognosis of hepatocellular carcinoma (HCC) after resection in patients with chronic hepatitis B. The aim of this study was to identify the influence of HBV reactivation on the recurrence of hepatitis B-related HCC after curative resection in patients with low viral load (HBV DNA <2000 IU/mL). We retrospectively analysed a total of 130 patients who underwent curative resection for HBV-related early stage HCC (single nodule; <5 cm/two or three nodules; <3 cm) with pre-operative HBV DNA levels <2000 IU/mL with serial HBV DNA tests. The predictive factors including HBV reactivation for the recurrence of HBV-related HCC after curative resection were investigated. Fifty-three patients (41%) had HBV reactivation after resection among 130 patients. HBV reactivation was observed in 22 of 53 patients with undetectable baseline HBV DNA and in 31 of 77 patients with detectable baseline HBV DNA. Cumulative recurrence rates after resection at 1, 2 and 3 years were 17.0%, 23.3% and 31.4%, respectively. The multivariable analysis demonstrated that the risk factors for the recurrence were the presence of microvascular invasion (hazard ratio (HR) 2.62, P = 0.003), multinodularity (HR 4.61, P = 0.005), HBV reactivation after resection (HR 2.03, P = 0.032) and HBeAg positivity (HR 2.06, P = 0.044). HBV reactivation after curative resection is associated with the recurrence of HBV-related HCC in patients with low viral load.

Serpin peptidase inhibitor clade A member 1 is a biomarker of poor prognosis in gastric cancer

Background:

In a previous study, we reported that serpin peptidase inhibitor clade A member 1 (serpinA1) is upregulated in Snail-overexpressing gastric cancer. Although serpinA1 has been studied in several types of cancer, little is known about its roles and mechanisms of action. In this study, we examined the role of serpinA1 in the migration and invasion of gastric cancers and determined its underlying mechanism.

Methods:

Expression levels were assessed by western blot analyses and real-time PCR. Snail binding to serpinA1 promoter was analysed by chromatin immunoprecipitation (ChIP) assays. The roles of serpinA1 were studied using cell invasion and migration assays. In addition, the clinicopathologic and prognostic significance of serpinA1 expression were validated in 400 gastric cancer patients using immunohistochemical analysis.

Results:

Overexpression of Snail resulted in upregulation of serpinA1 in gastric cancer cell lines, AGS and MKN45, whereas knockdown of Snail inhibited serpinA1 expression. Chromatin immunoprecipitation analysis showed that overexpression of Snail increased Snail recruitment to the serpinA1 promoter. Overexpression of serpinA1 increased the migration and invasion of gastric cancer cells, whereas knockdown of serpinA1 decreased invasion and migration. Moreover, serpinA1 increased mRNA levels and release of metalloproteinase-8 in gastric cancer cells. Serpin peptidase inhibitor clade A member 1 was observed in the cytoplasm of tumour cells and the stroma by immunohistochemistry. Enhanced serpinA1 expression was significantly associated with increased tumour size, advanced T stage, perineural invasion, lymphovascular invasion, lymph node metastases, and shorter overall survival.

Conclusions:

Serpin peptidase inhibitor clade A member 1 induces the invasion and migration of gastric cancer cells and its expression is associated with the progression of gastric cancer. These results may provide a potential target to prevent invasion and metastasis in gastric cancer.

PATHOME: an algorithm for accurately detecting differentially expressed subpathways

The translation of high-throughput gene expression data into biologically meaningful information remains a bottleneck. We developed a novel computational algorithm, PATHOME, for detecting differentially expressed biological pathways. This algorithm employs straightforward statistical tests to evaluate the significance of differential expression patterns along subpathways. Applying it to gene expression data sets of gastric cancer (GC), we compared its performance with those of other leading programs. Based on a literature-driven reference set, PATHOME showed greater consistency in identifying known cancer-related pathways. For the WNT pathway uniquely identified by PATHOME, we validated its involvement in gastric carcinogenesis through experimental perturbation of both cell lines and animal models. We identified HNF4α-WNT5A regulation in the cross-talk between the AMPK metabolic pathway and the WNT signaling pathway, and further identified WNT5A as a potential therapeutic target for GC. We have demonstrated PATHOME to be a powerful tool, with improved sensitivity for identifying disease-related dysregulated pathways.

Prospective, randomized study of ropivacaine wound infusion versus intrathecal morphine with intravenous fentanyl for analgesia in living donors for liver transplantation

Postoperative analgesia and care for living liver donors have become particular interests for clinicians as the use of living donor liver transplantation has increased. Local anesthetic-based analgesia has been known to provide effective pain control. In this prospective, randomized study, we compared the postoperative analgesic efficacy of local anesthetic-based analgesia (PainBuster) with the efficacy of opioid-based analgesia [intrathecal morphine (ITM) with intravenous (IV) fentanyl] in liver donors. Forty adult donors were randomly allocated to 1 of 2 groups: an ITM/IV fentanyl group (n = 21) and a PainBuster group (n = 19). Donors in the PainBuster group received 0.5% ropivacaine via a multi-orifice catheter (ON-Q PainBuster) placed at the wound. Donors in the ITM/IV fentanyl group received ITM sulfate (400 μg) preoperatively and a continuous IV fentanyl infusion postoperatively. A visual analogue scale (VAS) at rest and with coughing and rescue IV fentanyl and meperidine consumption were assessed for 72 hours after the operation. Side effects, including sedation, dizziness, nausea, vomiting, pruritus, respiratory depression, wound seroma or hematoma, and the first time to flatus, were recorded. The VAS score at rest during the first 12 postoperative hours was significantly lower for the ITM/IV fentanyl group. At other times, the VAS scores were comparable between the groups. In the PainBuster group, rescue IV fentanyl and meperidine use was significantly reduced 24 to 48 hours and 48 to 72 hours after surgery in comparison with the first 24 postoperative hours. The time to first flatus was significantly reduced in the PainBuster group. There were no differences in side effects. In conclusion, analgesia was more satisfactory with ITM/IV fentanyl versus PainBuster during the first 12 hours after surgery, but they became comparable thereafter, with a shortened bowel recovery time in the PainBuster group. The concurrent use of ITM with PainBuster may be considered in a future investigation.

Clinical significance of proteinuria at posttransplant year 1 in kidney transplantation

PURPOSE

Proteinuria in the nontransplant population is a progressive renal disease. We analyzed the prevalence and clinical significance of proteinuria as well as factors related to its degree at posttransplant year 1 among kidney transplant recipients.

METHODS

We measured protein in a 24-hour urine among 644 recipients from January 1996 to December 2010.

RESULTS

Among 372 male and 272 female recipients, the mean amount of urinary protein was 424.4 ± 1010 mg/d (range, 13.88-8691) including 388 (60.2%) subjects with microproteinuria and the other 256 (39.8%) with overt proteinuria. Nephrotic range proteinuria was observed in 17 (2.6%) and nonnephritic range proteinuria, in 239 (37.1%) recipients. The latter cohort was categorized into low-grade proteinuria (n = 224; 34.8%) and high-grade proteinuria (n = 15; 2.3%). Proteinuria at posttransplant 1 year highly correlated with serum creatinine values at posttransplant years 1 and 2 as well as estimated glomerular filtration rate but not creatinine clearance at postoperative year 2. A greater incidence of graft loss was observed among recipients with more severe proteinuria. Males, recipients with anti-hepatitis C virus antibody, unrelated donors, anti-thymocyte immunoglobulin at the time of reperfusion, maintenance immunosuppression with cyclosporine or without mycophenolate mofetil were strongly associated with the amount of proteinuria.

CONCLUSION

This study demonstrated the prevalence of proteinuria in kidney transplant recipient to be high. The presence as well as level of proteinuria were predictive markers for inferior allograft function.

Monitoring of cytomegalovirus-specific CD8+ T-cell response with major histocompatibility complex pentamers in kidney transplant recipients

INTRODUCTION

Cytomegalovirus (CMV) can reactivate causing serious clinical problems during immunosuppression. CMV-specific CD8(+) T cells play an important role in the control of CMV reactivation. Using pentameric major histocompatibility complex (MHC) peptide complexes, we investigated cellular immune responses to CMV among healthy individuals and kidney transplantation recipients in Korea, which is an endemic area of CMV infection.

MATERIALS AND METHODS

Analysis of CMV-specific T cells was performed on 28 healthy individuals and 40 recipients who bore human leukocyte antigen (HLA)-A2 or -A24. CMV pp65 pentamer-binding cells incubated with various monoclonal antibodies were measured by four-color flow cytometry.

RESULTS

Detectable levels of pentamer(+) CD8(+) T cells were present in 109/139 samples (78.4%) that stained with the A*02NLV-pentamer, while 15/67 samples (22.4%) stained with the A*24QYD-pentamer (P < .01). Among patients with HLA-A2, 22/24 (91.7%) samples showing positive CMV antigenemia revealed detectable pentamer(+) CD8(+) T cells, while 87/115 (75.7%) displaying negative CMV antigenemia had detectable pentamer(+) CD8(+) T cells (P = .04). There was no significant difference in percentages of pentamer(+) CD8(+) T cells between patients who did versus who did not experience episodes of CMV infection. The subpopulation of CMV-specific CD8(+) T cells in transplantation recipients was evaluated using phenotypic markers; memory cells comprised the majority of the CMV-specific CD8(+) T-cell population.

CONCLUSION

The A*02NLV-pentamer complex was useful to monitor CMV-specific T cells. However, MHC pentamer-based techniques did not provide a clear distinction between patients who are or are not at risk for CMV infection.

Alemtuzumab induction in deceased donor kidney transplantation

PURPOSE

Alemtuzumab (Campath-1H), a humanized monoclonal antibody directed against CD52, is a lymphocyte-depleting agent currently being evaluated as an induction agent in solid organ transplantation. This study analyzed the clinical outcomes and effects on peripheral blood lymphocyte subset counts in adult deceased donor renal transplant recipients who received an alemtuzumab-based induction protocol.

METHODS

Eleven kidney alone or simultaneous pancreas-kidney transplant recipients received 20 mg alemtuzumab on postoperative days 0 and 1, followed by calcineurin inhibitor-based maintenance immunosuppression after postoperative day 5. We collected 1-year data including recipient and donor demographic features, renal function and adverse events including endocrine impact, incidence of acute rejection episodes, infections or malignancies as well as hematologic and late immunologic parameters for correlation with patient or graft survival.

RESULTS

Mean HLA mismatch was 3.6 and 8/11 deceased donors were of the extended criteria type. Only 2 (18%) recipients displayed delayed graft function with a failure of the serum creatinine to decrease by 25% on the first day; however, their long-term outcomes were similar to other nonaffected patients. Serious adverse events were absent; there was no hyperlipidemia or new-onset diabetes. We failed to observe an acute rejection. The 3 (27%) recipients with infectious complications experienced pericardial tuberculosis, urinary tract infection, or invasive pulmonary aspergillosis. Two (18%) cases of posttransplantation lymphoproliferative disease were diagnosed in this study during the follow-up. Overall patient and graft survival rates were both 91%.

CONCLUSION

This study demonstrated that preconditioning with antibody-depletion using alemtuzumab was efficient with satisfactory patient and graft survivals at 1 year. Alemtuzumab induction was safe even for recipients of extended criteria donor renal transplantation.

Influence of human allogenic bone marrow and cord blood-derived mesenchymal stem cell secreting trophic factors on ATP (adenosine-5'-triphosphate)/ADP (adenosine-5'-diphosphate) ratio and insulin secretory function of isolated human islets from cadaveric donor

Successful islet transplantation (ITx) is not only dependent on the number of islets, but also their quality, including viability, metabolic activity, and function. Islet quality decreases during cultivation after the isolation procedure. To overcome this obstacle, we established the practice of islet and mesenchymal stem cells (MSCs) coculture. This coculture condition improved the ATP (adenosine-5'-triphosphate)/ADP (adenosine-5'-diphosphate) ratio and insulin secretory function in vitro. It is believed that the enhancement of islet quality in islet-MSCs cocultures may be caused by the secretion of active agents by MSCs. Herein we have shown that interleukin-6 (IL-6), vascular endothelial growth factor-A (VEGF-A), hepatocyte growth factor (HGF), and transforming growth factor-beta (TGF-beta) were significantly increased as measured by enzyme-linked immunosorbent assay (ELISA) in MSCs-cultured medium, factors that have been shown to improve the survival, function, and angiogenesis/revascularization of islets. These results indicated that the quality of human islets was enhanced by trophic molecules secreted by MSCs, which influence the intracellular islet ATP content and insulin secretory function.

Withdrawal of immunosuppression in pediatric liver transplant recipients in Korea

PURPOSE

We identified pediatric liver transplant recipients with successful withdrawal of immunosuppression who developed tolerance in Korea.

MATERIALS AND METHODS

Among 105 pediatric patients who received liver transplantation and were treated with tacrolimus-based immunosuppressive regimens, we selected five (4.8%) patients who had very low tacrolimus trough levels. Four of them were noncompliant with their medication and one was weaned off of immunosuppression due to life threatening posttransplant lymphoproliferative disorder. We reviewed the medical records with regard to the relationship of the donor-recipients, patient characteristics and prognosis, including liver histology, and compared our data with previous reports.

RESULTS

Four patients received the liver transplantation from a parent donor and one patient from a cadaver donor. A trial of withdrawal of the immunosuppressant was started a median of 45 months after transplantation (range, 14 months to 60 months), and the period of follow up after weaning from the immunosuppressant was a median of 32 months (range, 14 months to 82 months). None of the five patients had rejection episodes after withdrawal of the immunosuppression; they maintained normal graft function for longer than 3 years (median, 38 months; range, 4 to 53 months). The histological findings of two grafts 64 and 32 months after weaning-off of the medication showed no evidence of chronic rejection.

CONCLUSION

The favorable markers for successful withdrawal of immunosuppression were 1) long-term (> 3 years) stable graft function, 2) no rejection for longer than 1 year after withdrawal of immunosuppression, 3) non-immune mediated liver diseases, and 4) pediatric patients.

Development of functional human immune system with the transplantations of human fetal liver/thymus tissues and expanded hematopoietic stem cells in RAG2-/-gamma(c)-/- MICE

BACKGROUND

There is an increasing need for suitable animal models for the study of the human immune system and disease. The purpose of this study was to develop a practical in vivo model of human immune cell repopulation using ex vivo expanded human fetal liver-derived CD34(+) hematopoietic stem cells and subrenally coimplanted fetal liver/thymus tissues.

METHODS

Freshly isolated fetal liver-derived CD34(+) hematopoietic stem cells were frozen until injected and ex vivo expanded with various cytokines for 7 days. After fetal liver/thymus tissues were subrenally coimplanted into preirradiated Rag2(-/-)gamma(c)(-/-) mice, frozen and ex vivo expanded CD34(+) cells were injected intravenously. The peripheral blood of the mice was monitored for the detection of human cell engraftment using flow cytometry. Then we confirmed human T-cell function by in vitro function assays.

RESULTS

After fetal liver/thymus tissues were coimplanted into the irradiated Rag2(-/-)gamma(c)(-/-) mice, with frozen and ex vivo expanded CD34(+) hematopoietic stem cells, human cell engraftments were determined using hCD45 and multilineage markers. The cultured cells with the cytokine combination of stem cell factor, thrombopoietin, Flk2/Flk3 ligand (FL), and interleukin-3 showed stable and long-term engraftment compared to other combinations. The ex vivo expanded human fetal liver-derived CD34(+) hematopoietic stem cells, under our culture conditions, accomplished a large volume of expanded cells that were sustained, demonstrating self-renewal of the evaluated markers, which may have indicated long- term repopulation activity.

CONCLUSION

The results of this study demonstrated a practical mouse model of expanded human immune cells especially T cells in Rag2(-/-)gamma(c)(-/-) mice.

Isolation and characterization of mouse mesenchymal stem cells

OBJECTIVE

Mesenchymal stem cells (MSCs) have been studied in regenerative medicine because of their unique immunologic characteristics. However, before clinical application in humans, animal models are needed to confirm their safety and efficacy. To date, appropriate methods and sources to obtain mouse MSCs have not been identified. Therefore, we investigated MSCs isolated from 3 strains of mice and 3 sources for the development of MSCs in a mouse model.

MATERIALS AND METHODS

Male BALB/c, C3H and C57BL/6 mice were used to isolate MSCs from various tissues including bone marrow (BM), compact bone, and adipose tissue. The MSCs were maintained in StemXVivo medium. Immunophenotypes of the MSCs were analyzed by FACS and their growth potential estimated by the number of colony-forming unit fibroblasts.

RESULTS

All MSCs that were isolated from BM, compact bone, and adipose tissue showed plastic-adherent, fibroblastic-like morphologic characteristics regardless of the mouse strain or cell source. However, culture of BM MSCs was less successful than the other tissue types. The FACS phenotype analysis revealed that the MSCs were positive for CD29, CD44, CD105, and Sca-1, but negative for CD34, TER-119, CD45, and CD11b. According to the results of the characterization, the adipose tissue MSCs showed higher growth potential than did other MSCs.

CONCLUSION

The results of this study showed that culture of adipose tissue and compact bone-MSCs was easier than BM MSCs. Based on the results of immunophenotype and growth potential, C57BL/6 AT-MSCs might be a suitable source to establish a mouse model of MSCs.

Peroneal neuropathy after liver transplantation

INTRODUCTION

The incidence of peroneal neuropathy (PN), occurring predominantly in the left leg, increases after the incorporation of intermittent pneumatic compression (IPC) devices among adult liver transplantation (OLT) recipients in our hospital. The aim of this study was to investigate the possible risk factors for PN and the reason for the left-leg predominance.

METHODS

We retrospectively reviewed the medical records of 501 OLT recipients. The patients were first divided into 2 groups, PN (n = 33) and non-PN (n = 468), to assess possible risk factors. The patients were then categorized into IPC (n = 262) and non-IPC (n = 239) groups according to the use of IPC devices. In a subsequent prospective study, we measured the degree and duration of the tilt of the operating table during OLT to investigate their relationship to the predominant left-leg PN.

RESULTS

The rate of IPC device use was significantly greater among the PN than non-PN group (78.8% vs 50.4%, P < .01). The incidence of PN was significantly higher among the IPC than non-IPC group (9.9% vs 2.9%, P < .01). The degree and duration of left tilt of the operating table were greater and longer than the right tilt.

CONCLUSIONS

The use of IPC devices during OLT increased the occurrence of PN and the left tilt of the operating table was strongly related to the predominant left-leg PN. Careful protection of the vulnerable point and minimization of the tilting of the operating table is advised during OLT, especially when IPC devices are used.

Prolonged survival of islet allografts in mice treated with rosmarinic acid and anti-CD154 antibody

Pancreatic islet transplantation can correct the abnormal glucose metabolism of Type 1 diabetes. Although immunosuppressants greatly reduce the acute rejection rate in transplant patients, the long-term side effects can be debilitating. Therefore, researchers are seeking to develop new immunosuppressive regimens that induce maximal levels of immunosuppression with minor side effects. Rosmarinic acid (Ros A) is a secondary metabolite of certain herbs and has multiple biological activities, including anti-inflammatory effects. Here, we have investigated whether treatment of mice with a combination of Ros A and anti-CD154 monoclonal antibody (MR1) improves islet allograft survival in a murine model. After transplantation, the mice were treated with either Ros A, MR1, or both (the "double" treatment). Allograft survival was prolonged in the double-treated animals compared to animals that received only Ros A or MR1. As is the case with the single-treated animals at 15 days after transplantation, the double-treated recipients did not display a significant decrease in the expression of cytokines or the population of activated T cells. Infiltrating CD3(+) T cells were reduced in the MR1- or double therapy relative to control or RosA group. However, at the same time point, double-treated graft showed fewer apoptotic cells and increased expression of insulin and glucagons, compared to the single-treatment groups. Furthermore, long-term (>150 days) allografts that were received with double therapy exhibited larger islet clusters and contained more insulin- and glucagon-positive cells, relative to the MR1-treated grafts. In conclusion, treatment with both Ros A and MR1 has a synergistic effect in murine islet allotransplantation.

An optimization-based design procedure for asymmetric bidirectional associative memories

In this letter, we consider the problem of designing asymmetric bidirectional associative memories (ABAM). Based on a newly derived theorem for the ABAM model, we propose an optimization-based design procedure for obtaining an ABAM that can store given bipolar vector pairs with certain error correction properties. Our design procedure consists of generalized eigenvalue problems, which can be efficiently solved by recently developed interior point methods. The validity of the proposed method is illustrated by a design example.

Lysophosphatidylcholine as a death effector in the lipoapoptosis of hepatocytes

The pathogenesis of nonalcoholic steatohepatitis (NASH) is unclear, despite epidemiological data implicating FFAs. We studied the pathogenesis of NASH using lipoapoptosis models. Palmitic acid (PA) induced classical apoptosis of hepatocytes. PA-induced lipoapoptosis was inhibited by acyl-CoA synthetase inhibitor but not by ceramide synthesis inhibitors, suggesting that conversion products other than ceramide are involved. Phospholipase A(2) (PLA(2)) inhibitors blocked PA-induced hepatocyte death, suggesting an important role for PLA(2) and its product lysophosphatidylcholine (LPC). Small interfering RNA for Ca(2+)-independent phospholipase A(2) (iPLA(2)) inhibited the lipoapoptosis of hepatocytes. PA increased LPC content, which was reversed by iPLA(2) inhibitors. Pertussis toxin or dominant-negative Galpha(i) mutant inhibited hepatocyte death by PA or LPC acting through G-protein-coupled receptor (GPCR)/Galpha(i). PA decreased cardiolipin content and induced mitochondrial potential loss and cytochrome c translocation. Oleic acid inhibited PA-induced hepatocyte death by diverting PA to triglyceride and decreasing LPC content, suggesting that FFAs lead to steatosis or lipoapoptosis according to the abundance of saturated/unsaturated FFAs. LPC administration induced hepatitis in vivo. LPC content was increased in the liver specimens from NASH patients. These results demonstrate that LPC is a death effector in the lipoapoptosis of hepatocytes and suggest potential therapeutic values of PLA(2) inhibitors or GPCR/Galpha(i) inhibitors in NASH.

Preoperative lamivudine therapy in HBV DNA positive recipients: is it always necessary?

BACKGROUND/AIMS

Long-term preoperative lamivudine therapy has been recommended for patients with positive HBV DNA to suppress HBV replication before liver transplantation. However, it is unclear whether preoperative lamivudine therapy is mandatory in HBV DNA positive patients to reliably prevent HBV recurrence or whether transplantation should be delayed to allow time for sufficient preoperative lamivudine therapy.

METHODOLOGY

From January 2000 to January 2004, thirty-eight patients serum positive for HBV DNA who survived more than 3 months after transplantation and received postoperative combination prophylaxis with hepatitis B immune globulin and lamivudine were enrolled.

RESULTS

Total 2-year recurrence rate was 8.7%. When these 38 patients were divided into two groups according to preoperative lamivudine therapy duration: group 1 (n = 11) 4 weeks or more and group 2 (n = 27) less than 4 weeks, recurrences were detected in 3 (27.2%) and 4 (14.8%) patients in groups 1 and 2, respectively, i.e. a similar recurrence rate in both groups (p = 0.390). Moreover, in a subgroup of 20 patients who received preoperative lamivudine therapy for less than one week, only one (5%) experienced HBV recurrence.

CONCLUSIONS

Our findings indicate that postoperative combination prophylaxis is effective and that preoperative lamivudine therapy is unlikely to be obligatory despite a positive preoperative serum HBV DNA status.

Recurrence of hepatitis B is associated with cumulative corticosteroid dose and chemotherapy against hepatocellular carcinoma recurrence after liver transplantation

The incidence of hepatitis B (HB) recurrence after a liver transplantation has been reduced by prophylaxis with hepatitis B immunoglobulin (HBIG) and lamivudine. However, the long-term incidence of recurrence is <10%, and the factors associated with HB recurrence are unclear. This study analyzed the factors associated with HB recurrence in 203 recipients who underwent liver transplantation for HB in 3 major centers in Korea over 4 years. Eighty-five patients (41.9%) had a hepatocellular carcinoma (HCC). Preoperative active virus replicators with the HBeAg(+) (46.8%) and/or hepatitis B virus DNA(+) (39.4%) were observed in 136 patients (67.0%). The HB prophylaxis consisted of either HBIG monotherapy (n = 95, HBIG group) or combination therapy with lamivudine (n = 108, combination group). HB recurrence was defined as the appearance of the HBsAg. The follow-up period was 28.3 +/- 13.1 months (mean +/- SD). HB recurred in 21 patients (10.3%) after transplantation. The time from transplantation to recurrence was 16.3 +/- 9.4 months. Pre-LT DNA positivity was more prevalent in HBIG group (55.8%) than in the combination group (39.8%) (P = 0.015). However, the incidence of HB recurrence was similar in the HBIG (6.3%) and combination group (13.8%), as well as between the active replicators (12.5%) and nonreplicators (4.1%) (P < 0.05). There was a far higher incidence of HB recurrence in patients receiving corticosteroid pulse therapy (21.0% vs. 7.9%), patients who experienced HCC recurrence (31.3% vs. 8.6%), and patients receiving chemotherapy to prevent HCC recurrence (25.0% vs. 4.4%) (P < 0.05). The cumulative corticosteroid dose was higher in patients who experienced recurrence of HB (P = 0.002). Multivariable analysis confirmed the effect of the cumulative corticosteroid dose and chemotherapy to be risk factors. Liver transplantation for HB is safe, with low recurrence rates if adequate prophylaxis is used. However, the cumulative corticosteroid dose and the chemotherapy used for HCC were risk factors for HB recurrence, so careful monitoring for HB recurrence is needed in these patients.

Mild hepatic steatosis is not a major risk factor for hepatectomy and regenerative power is not impaired

BACKGROUND

An understanding of the regeneration power and operative risk of steatotic livers after hepatectomy is still unclear. We evaluated the volume regeneration and outcome of steatotic livers after donor hepatectomy.

METHODS

Fifty-four, consecutive living liver donors from September 2002 to December 2003 were evaluated prospectively by volumetric analysis, liver-spleen ratio, and liver attenuation index; the latter has been shown by serial computed tomographic scanning to be correlated strongly with histologic steatosis. Donors were followed up completely for at least 1 year (460-915 days) and were allocated according to histologic degree of macrovesicular steatosis: group 1, <5% (n = 36); group 2, 5%-30% (n = 18).

RESULTS

No mortality or hepatic failure was observed, and no donor required reoperation or intraoperative transfusion. The results of serial liver function tests, and major and minor morbidities were comparable between groups. Liver-spleen ratio and liver attenuation index remained at a constant level above normal values postoperatively in group 1, but increased rapidly above normal values in group 2. No difference in the rate of liver regeneration at 10 days after hepatectomy was found between the groups (P = .487), but the liver regeneration rate at 3 months after hepatectomy in group 1 was slightly higher than that in group 2 (P < .044). However, no difference was observed between the 2 groups at 1 year after hepatectomy (P = .4).

CONCLUSIONS

Mild hepatic steatosis is cleared immediately after hepatectomy, and early regeneration power is impaired, but the long-term regenerative power is comparable. Hepatectomy in donors with mild steatosis can be performed with low morbidity.

Change of hepatitis B virus DNA status in anti-HBc positive liver graft

BACKGROUND/AIMS

Many patients with positive anti-HBc, but negative HBsAg, are known to harbor occult HBV infection, which may transmit the virus through the graft in liver transplantation. We examined the change of HBV DNA within the liver allograft tissue of the donor with positive anti-HBc, but negative HBsAg, before and after the transplantation and assessed its significance.

METHODS

Twenty-eight patients with available posttransplant biopsies that received anti-HBc positive liver allografts between April 2000 and November 2003 were enrolled in the study. Intraoperative wedge biopsy of donor liver and needle biopsy of the recipient around the 12th postoperative day were used. HBV DNA within the liver tissue was identified by polymerase chain reaction technique using paraffin-embedded liver tissue.

RESULTS

Among 13 patients that showed positive amplification before transplantation, 10 turned negative and 3 remained positive after transplantation. One patient, who was negative, became positive after transplantation. Three patients had recurrent HBV infection, but none had positive PCR before or after transplantation and recurrence was not associated with PCR results. Donors with low anti-HBs titer were more likely to be PCR positive compared to donors with high anti-HBs serology (P<0.05).

CONCLUSIONS

Under adequate prophylactic measures, the presence of HBV DNA within the liver tissue does not affect recurrence and most allografts harboring HBV DNA before transplantation will eventually show viral clearance. However, many anti-HBc positive allografts are infected by HBV at subclinical level so vigilant surveillance is essential.

Steroid withdrawal in living donor renal transplant recipients using tacrolimus and cyclosporine: a randomized prospective study*

Steroids have been a mainstay of immunosuppressive regimens in renal transplantation despite their adverse effects. The introduction of new immunosuppressant has improved the survival rates and prompted trials of steroid withdrawal. We conducted a randomized prospective study to compare steroid withdrawal at 6 months post-transplant between tacrolimus + mycophenolate mofetil (MMF) (FK group) versus cyclosporine A + MMF (CsA group). Steroid was withdrawn at 6 months post-transplant under the condition of no rejection episode proven by biopsy and maintenance of serum creatinine level <2.0 mg/dl. Fourteen recipients were excluded because of acute rejection within 6 months or protocol violation. Steroid could be tapered off in 62 in FK group and 55 in CsA. Three cases in FK group and five in CsA had acute rejection within another 6 months after steroid withdrawal (P > 0.05). At 12 months, the incidence of post-transplant diabetes was 18.6% vs. 8.0% in FK and CsA group. And hypercholesterolemia was presented in 8.5% vs. 2.0%, hypertension in 47.5% vs. 56.0%, and serum creatinine level 1.18 +/- 0.24 mg/dl vs. 1.18 +/- 0.20 mg/dl, respectively (P > 0.05). Steroid withdrawal may be carried out successfully using both FK and CsA with MMF, but long-term follow-up is necessary.

Auxiliary partial orthotopic living donor liver transplantation in a patient with alcoholic liver cirrhosis to overcome donor steatosis

The efficacy of auxiliary partial orthotopic liver transplantation (APOLT) to overcome the problems associated with a markedly steatotic graft in a living donor has not been fully explored. We have recently performed APOLT in a patient with alcoholic liver disease, where the only potential candidate donor was affected by 50% macrovesicular steatosis and 30% microvesicular steatosis. The recipient's left liver was resected and the donor's left liver, corresponding to a 0.46% graft-to-recipient weight ratio, was orthotopically transplanted. The postoperative course of this patient was uneventful, except for a transient large amount of ascites. Native liver volume in the recipient serially decreased, and the volume of the graft serially increased after transplantation. Four months after transplantation, the donor and recipient are doing well with a normal liver function. In conclusion, APOLT may be a feasible solution for a markedly steatotic living donor graft in patients with alcoholic liver disease.

Technical refinement preserving segment 4 to donor in extended right hepatectomy

BACKGROUND/AIMS

Donor extended right hepatectomy, including the middle hepatic vein (MHV) and a part of segment 4 (Sg4), is performed to overcome inadequate graft for large adult recipient as resolving congestion of right anterior section. However, using this technique remnant donor liver is often too small. Here, we introduce a technical Modified extended right hepatectomy (MERH), in which the MHV was excavated preserving the entire Sg4 in the donor.

METHODOLOGY

We compared clinical outcomes between donors using our technique (n=12) that may result in Sg4 congestion, and right hepatectomy (RH, n=12) that may not. MERH was performed when the remnant donor liver had a volume exceeding 35% and showed no steatosis in preoperative imaging study.

RESULTS

No donor died, and there were no differences in operative time and postoperative recovery between the two groups (p>0.05). The regeneration of the remnant liver after MERH and RH were similar (160.2% vs. 187.7% at POD 10; 222.2% vs. 230.5% at 4 months) (p>0.05).

CONCLUSIONS

Our results show that MERH didn't impair recovery or liver regeneration in donors, and indicate that MERH will be useful in adult living donor liver transplantation.

Outcome of donors with a remnant liver volume of less than 35% after right hepatectomy

To overcome the barrier of size match, right lobe graft has been widely used in living donor liver transplantation (LDLT). We assessed donor outcome, with a focus on remnant liver volume (RLV) after right hepatectomy based on the experiences of 2 LDLT centers, as a means of guiding the establishment of safe RLV limits for donor right hepatectomy. Between January 2002 and December 2003, a consecutive 146 liver donors who underwent right hepatectomy with at least 12 months of follow-up were enrolled in this study. Donors were grouped into 2 groups according to RLV: group 1 (n = 74), <35% (range, 26.9-34.9) and group 2 (n = 72), > or = 35% (35.0-46.8). No donors died or suffered a life-threatening complication. Mean peak serum postoperative aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (IU/L) levels were 219.5 +/- 79.9 and 231.5 +/- 83.3 in group 1 and 210.3 +/- 81.6 and 225.8 +/- 93.0 in group 2 (P = 0.497 and 0.699), respectively. Mean peak serum total bilirubin (TB) (mg/dL) level in group 1 (3.4 +/- 1.6) was higher than in group 2 (2.8 +/- 1.4; P = 0.023). Overall 23 (15.8%) major morbidities, 10 in group 1 (13.5%) and 13 in group 2 (18.1%), occurred according to Clavien's system (P = 0.939). These included bleeding (n = 3 in group 1 and n = 6 in group 2; P = 0.282), ileus (n = 3 and 1; P = 0.324), biliary leakage (n = 4 and 4; P = 0.968), and pneumonia (n = 0 and 2; P = 0.149). Minor morbidities were also comparable in the 2 groups. In conclusion, the outcome of donors with an RLV of <35% was not different from that of donors with an RLV of > or = 35%, with the exception of transient cholestasis. Therefore, a remnant RLV of <35% does not appear to be a contraindication for right liver procurement in living donors.

In adult-to-adult living donor liver transplantation hepaticojejunostomy shows a better long-term outcome than duct-to-duct anastomosis

Roux-en-Y hepaticojejunostomy (RYHJ) has been the standard biliary reconstruction in adult-to-adult living donor liver transplantation (ALDLT). Recently, duct-to-duct anastomosis (DD) has been introduced. This study compared the outcomes of RYHJ and DD. For 4 years, 74 recipients underwent ALDLT and were followed up for at least 2 years. The patients were divided into three groups, RYHJ group (n = 18), DD with a stent (DD + S) group (n = 35), and DD without a stent (DD - S) group (n = 21). Overall, biliary complications were developed in 32.4% patients. The biliary complication rate was 11.1%, 48.5% and 33.3% in RYHJ, DD + S and DD - S groups, respectively (P = 0.047). Bile leaks occurred in 28.5% of DD + S group. The incidence of biliary stricture was 5.3%, 20.2% and 28.6% in RYHJ, DD + S and DD - S group, respectively. Most complications (83.3%) were resolved nonsurgically. RYHJ has a better long-term outcome than DD in ALDLT. Subgroup analysis of DD group showed that DD - S group had no bile leaks, but still had a higher incidence of bile duct strictures. However, because this study was a retrospective review there are limitations in analyzing the data and confirming the conclusion. A randomized-prospective study will be needed to confirm these findings.

The hepatic regeneration power of mild steatotic grafts is not impaired in living-donor liver transplantation

The aim of this study was to assess histologic changes in steatotic grafts, regenerative capacity, and the outcome of steatotic grafts in living-donor liver transplantation (LDLT). Between September 2002 and February 2004, 55 cases of LDLT with a liver biopsy performed on the 10th postoperative day were enrolled. Patients were grouped according to the intraoperative histologic degree of macrovesicular steatosis (MaS) as follows: Group 1, <5% (n = 24); Group 2, 5 to 15% (n = 24); and Group 3, 15 to 30% (n = 7). The intraoperative microscopic findings and the findings on the 10th postoperative day were compared. Immunohistochemistry was performed using antibody of proliferating cell nuclear antigen (PCNA) and Ki-67 to assess the regeneration power of grafts on the 10th postoperative day. The histologic degree of MaS on postoperative day 10 decreased from 5.22 +/- 1.04% (mean +/- standard deviation) to 2.17 +/- 1.90 in Group 2 (P < .001) and from 21.4 +/- 8.02 to 4.43 +/- 2.70 in Group 3 (P = .003). The number of positively stained hepatocytes in 10 high power fields was 48.0 +/- 17.1, 53.8 +/- 14.4, and 51.5 +/- 4.1 in each group by PCNA (P = .681), and 24.0 +/- 14.0, 25.5 +/- 11.8, and 21.6 +/- 6.8 by Ki-67 (P = .825), respectively. No primary graft nonfunction (PNF) or delayed graft function (DGF) occurred. Major complications were comparable among groups. In conclusion, in LDLT, steatosis disappeared immediately after transplantation and hepatic regeneration power was not impaired in grafts with less than 30% of MaS. Furthermore, a mildly steatotic graft did not increase the risk of graft dysfunction or morbidity in LDLT.

Experimental and numerical studies on convective heat transfer in a neonatal incubator

Thermo-neutrality is one of the major environmental factors affecting a premature or low-birth-weight neonate inside an incubator. Severe temperature differences inside an incubator lead to neonate heat loss, hypothermia and apnoea, which are closely related to air flow and air velocity. In the study, flow visualisations, hot-wire velocity measurements and computational fluid dynamics simulate the airflow inside a neonatal incubator. An anatomically correct neonate model is designed using a three-dimensional laser scanner system and a rapid prototyping machine. Flow visualisations demonstrate that large-scale rotating airflow is produced inside the chamber, and a number of small, stationary eddies are found in regions between the air inlet and the neonate. Hot-wire measurements show that air velocities along the long inlets are not uniform. Computational fluid dynamics show relatively uniform temperatures of about 34 degrees C on the neonate's anterior aspect and the highest temperature of 36.1 degrees C at the right armpit and the crotch. Flow fields from airflow visualisations, hot-wire measurements and computational fluid dynamics are very similar, both qualitatively and quantitatively. The small eddies produced between the neonate and the mattress could interfere with convective and evaporative heat transfers from the neonate. Therefore it is important to eliminate eddies around the neonate in future designs of neonatal incubators.

Pten regulates neuronal soma size: a mouse model of Lhermitte-Duclos disease

Somatic inactivation of PTEN occurs in different human tumors including glioblastoma, endometrial carcinoma and prostate carcinoma. Germline mutations in PTEN result in a range of phenotypic abnormalities that occur with variable penetrance, including neurological features such as macrocephaly, seizures, ataxia and Lhermitte-Duclos disease (also described as dysplastic gangliocytoma of the cerebellum). Homozygous deletion of Pten causes embryonic lethality in mice. To investigate function in the brain, we used Cre-loxP technology to selectively inactivate Pten in specific mouse neuronal populations. Loss of Pten resulted in progressive macrocephaly and seizures. Neurons lacking Pten expressed high levels of phosphorylated Akt and showed a progressive increase in soma size without evidence of abnormal proliferation. Cerebellar abnormalities closely resembled the histopathology of human Lhermitte-Duclos disease. These results indicate that Pten regulates neuronal size in vivo in a cell-autonomous manner and provide new insights into the etiology of Lhermitte-Duclos disease.

Charge exchange ionization in collision cells as a method to detect the presence of long-lived excited electronic states of polyatomic ions

Charge exchange ionization in collision cells installed in a double focusing mass spectrometer with reversed geometry has been used to detect the presence of a long-lived excited electronic state of benzene ion. In particular, the first collision cell located between the ion source and the magnetic sector was modified to serve as an ion source for the reagent ion generated by charge exchange with the primary ion. Strong reagent ion signals were observed when the ionization energies of the reagents (1,3-C4H6, CS2, CH3Cl) were lower than the recombination energy (approximately 11.5 eV) of the excited state benzene ion, while the signals were negligible for reagents (CH3F,CH4) with higher ionization energy. The fact that a strong signal is observable only for electronically exoergic charge exchange is useful for detecting the presence of a long-lived electronically excited state.

PTEN induces G(1) cell cycle arrest and decreases cyclin D3 levels in endometrial carcinoma cells

Inactivating mutations in the PTEN tumor suppressor gene occur in approximately 30-50% of endometrial carcinomas. PTEN is a phosphatase that negatively regulates the phosphoinositide 3-kinase signaling pathway, including the downstream effector AKT. To evaluate the role of PTEN in endometrial growth regulation, we expressed wild-type or mutant PTEN in endometrial carcinoma cell lines. As expected, expression of exogenous PTEN decreased levels of activated AKT in all cell lines examined. However, PTEN induced a G(1) cell cycle arrest specifically in endometrial carcinoma cells that lack endogenous wild-type PTEN. Growth of cells containing wild-type PTEN was unaffected by exogenous PTEN expression. Growth arrest required a functional phosphatase domain but not the PDZ interaction motif of PTEN. Overall levels of CIP/KIP and INK4 family members, the known inhibitory regulators of the G(1) phase of the cell cycle, were unchanged. However, PTEN induced a specific reduction of cyclin D3 levels and an associated increase in the amount of the inhibitor p27(KIP1) complexed with CDK2. Enforced expression of cyclin D3 abrogated the PTEN-induced cell cycle arrest. Although PTEN signaling directly regulates p27(KIP1) levels in some settings, in endometrial carcinoma cells, PTEN expression indirectly regulated p27(KIP1) activity by modulating levels of cyclin D3. These data support multiple mechanisms of PTEN-induced cell cycle arrest.

Sulfoxide-containing aromatic nitrogen mustards as hypoxia-directed bioreductive cytotoxins

A series of diaryl and alkylaryl sulfoxide-containing nitrogen mustards were synthesized and evaluated for their hypoxia-selective cytotoxicity against V-79 cells in vitro as well as for their metabolism profiles with the rat S-9 fractions. In general, the diaryl sulfoxides (4, 5, and 7-9) showed much greater hypoxia selectivity (11-27-fold) than the alkylaryl sulfoxides (approximately 3-fold) (1 and 3). The fused diphenyl sulfoxides (10 and 11), on the other hand, showed very low hypoxia selectivity (1.3-3-fold). Compound 10 was highly cytotoxic under both aerobic and anaerobic conditions, while 11 showed low cytotoxicity under both conditions. The bioreduction of 8 by the rat S-9 fraction under anaerobic conditions was inhibited by menadione and enhanced by benzaldehyde, acetaldehyde, or 2-hydroxypyrimidine suggesting the involvement of aldehyde oxidase in the reduction of the sulfoxides. Bioreductive metabolism studies of selected model sulfoxides suggested that diaryl sulfoxides are better substrates for aldehyde oxidase than alkylaryl sulfoxides.

Metabolism-based anticancer drug design

Many conventional anticancer drugs display relatively poor selectivity for neoplastic cells, in particular for solid tumors. Furthermore, expression or development of drug resistance, increased glutathione transferases as well as enhanced DNA repair decrease the efficacy of these drugs. Research efforts continue to overcome these problems by understanding these mechanisms and by developing more effective anticancer drugs. Cyclophosphamide is one of the most widely used alkylating anticancer agents. Because of its unique activation mechanism, numerous bioreversible prodrugs of phosphoramide mustard, the active species of cyclophosphamide, have been investigated in an attempt to improve the therapeutic index. Solid tumors are particularly resistant to radiation and chemotherapy. There has been considerable interest in designing drugs selective for hypoxic environments prevalent in solid tumors. Much of the work had been centered on nitroheterocyclics that utilize nitroreductase enzyme systems for their activation. In this article, recent developments of anticancer prodrug design are described with a particular emphasis on exploitation of selective metabolic processes for their activation.

N3-methyl-mafosfamide as a chemically stable, alternative prodrug of mafosfamide

The presence of an alkyl substituent at N3 in the oxazaphosphorine ring stabilizes N-substituted 4-(alkylthio)cyclophosphamides from spontaneous decomposition. Based on this finding, N3-methyl-mafosfamide was synthesized and examined as a chemically stable, biooxidative prodrug of mafosfamide. This prodrug was stable in aqueous buffer (pH 7.4, 37 degrees C) and underwent N-demethylation in a time dependent manner when incubated with rat hepatic microsomes. N3-Methyl-mafosfamide was 10-fold more cytotoxic in vitro than cyclophosphamide against mouse embryo Balb/c 3T3 cells (LC50 = 3.6 microM). Preliminary in vivo antitumor evaluation against L1210 leukemia in mice showed that this prodrug was active [Increase of life span (ILS) > 29%].

Chemically stable N-methyl-4-(alkylthio)cyclophosphamide derivatives as prodrugs of 4-hydroxycyclophosphamide

Two prototype N-methyl-4-thio-substituted cyclophosphamide (CP) derivatives (5 and 6), prodrugs of 4-hydroxycyclophosphamide (4-HO-CP), were designed to undergo oxidative N-demethylation to release the active alkylating agent. These prodrugs were chemically stable until oxidatively N-demethylated in the presence of hepatic microsomal P-450 enzymes. While the metabolism of 5 was enhanced in the presence of phenobarbital-induced microsomes, 6 was unaffected. Compound 6 was more active than 5 against L1210 leukemia cells grown in mice and exhibited statistically significant activity against the small cell lung cancer panel in the National Cancer Institute anticancer drug screen. Compound 5, like CP (1), was inactive in this screen. Thus, placement of a dithioester at the 4-position of N-methyl-HO-CP as in 6 markedly changes its spectrum of activity and has resulted in a new type of CP-based prodrug with antitumor activity against small cell lung cancer as well as leukemia cells in vitro as shown by their ability to inhibit tumor cell growth at concentrations as low as 10(-6) M.

Anticlastogenic effects of galangin against bleomycin-induced chromosomal aberrations in mouse spleen lymphocytes

Galangin, a flavonoid derivative, was tested for its anticlastogenic effect against the induction of chromosome aberrations by bleomycin. For an in vitro assay, galangin (0, 2 x 10(-8), 2 x 10(-7), and 2 x 10(-6) M) was added to mouse spleen lymphocyte cultures together with bleomycin (3 microgram/ml) at 24 h after Con A initiation of cultures. In an in vivo/in vitro experiment, galangin (0, 0.1, 1, 10, and 100 mg/kg) was administered to mice orally twice with a 24-h interval. Mice were killed 8 h later. Spleen lymphocytes were isolated and cultures were made. Bleomycin (3 microgram/ml) was added to the mouse spleen lymphocyte cultures at 24 h after Con A initiation. Both in vitro and in vivo/in vitro cultures were harvested at 42 h after initiation. The harvested cells were used for cytogenetic analyses. The results showed that in vitro or in vivo treatment of lymphocytes with galangin suppressed the induction of chromosome aberrations by bleomycin in a galangin dose-dependent manner. The galangin doses used were non-clastogenic to cells. The data from our in vitro and in vivo/in vitro studies confirmed each other and indicate that galangin is an anticlastogenic agent. The in vivo/in vitro protocol may be a useful means to assay the chemoprotective effects of chemicals in humans.

In vitro metabolism of aromatic nitriles

Studies on the metabolic fate of aromatic nitriles, in contrast to their aliphatic counterparts, have been minimal and the subject of controversy. The in vitro metabolic fate of several aromatic nitriles with varying substituents was investigated by using rat liver subcellular fractions, with a particular emphasis on the nitrile moiety. Benzonitriles and 4-cyanophenols underwent oxidative metabolism to produce ring-hydroxylated metabolites. On the other hand, 2-cyanophenol was resistant to metabolism. o-Tolunitrile was metabolized and produced o-cyanobenzyl alcohol and phthalide. Phthalide, however, was chemically derived from o-cyanobenzyl alcohol, the initial metabolite. 4-Nitrobenzonitrile was resistant to oxidation on the ring, but was readily reduced to the corresponding amine metabolite under both aerobic and anaerobic conditions. Nitroxynil (3-iodo-4-hydroxy-5-nitrobenzonitrile) was metabolized to produce 3-iodo-4-hydroxy-5-nitrobenzamide and 3-iodo-4-hydroxy-5-nitrobenzoic acid. The enzyme(s) responsible for this hydrolytic metabolism was primarily localized in the cytosol. Among the nitriles tested, o-tolunitrile and nitroxynil produced metabolites in which the nitrile moiety was modified. Nitroxynil, however, was the only compound that was directly metabolized on the nitrile moiety by the rat liver enzyme(s).

Structure-activity study of 5-substituted 1-carbobenzoxy-2-iminohydantoins as potential anticonvulsant agents

On the basis of our previous findings, a series of 5-substituted 2-iminohydantoins has been synthesized and tested for anticonvulsant activity to better understand the SAR of 2-iminohydantoins. Among the compounds tested, (S)-(+)-1-carbobenzoxy-2-iminohydantoin analogs with ethyl (6)-, n-propyl (7a)-, isopropyl (8)-, allyl (9)-, and sec-butyl (11)-substituted groups at the C5 of the iminohydantoin ring provided the best activities against the MES test with ED50 values in the range of 52-74 mg/kg. All of the above compounds except 8 also showed activity against the scMET test with ED50 values in the range of 141-223 mg/kg. All significantly active compounds (1, 6, 7a, 8, 9, and 11) possessed aliphatic hydrocarbon side chains of two- to three-carbon lengths at the C5 position. All of the compounds with no or minimal activity had either shorter or longer side chains. The compounds substituted at the C5 position by aryl groups, arylalkyl groups, or alkyl and arylalkyl groups containing heteroatoms also showed no activity against the MES and scMET tests. The results suggested that the C5 side chain with the correct stereochemistry in 2-iminohydantoins provides optimal anticonvulsant activity when the side chains are aliphatic hydrocarbons with the length, ignoring branching, of two to three carbons.

An N-hydroxylated derivative of cyanamide that inhibits yeast aldehyde dehydrogenase

A stable, N,O-dibenzoyl derivative (DBHC) of N-hydroxycyanamide, the latter the postulated bioactivation product of the alcohol deterrent agent, cyanamide, has been synthesized. DBHC was an effective inhibitor of yeast aldehyde dehydrogenase (AIDH) in vitro and inhibited this enzyme in a concentration-dependent manner with an IC50 of 25 microM. Hydrolysis of the benzoate moiety of DBHC with dilute NaOH gave rise to the formation of nitroxyl (HN = O), detected by gas chromatography as nitrous oxide (N2O), the end-product of nitroxyl dimerization and disproportionation. It is postulated that the nitroxyl liberated by esterase action on DBHC by yeast AIDH may be the reactive species that inhibits AIDH.

Synthesis and anticonvulsant activity of 2-iminohydantoins

Iminohydantoins selectively substituted at position C-5 and their 1-carbobenzoxy derivatives have been synthesized, and their anticonvulsant activity was evaluated in mice. In general, the more lipophilic 1-carbobenzoxy iminohydantoins were more potent than the unsubstituted counterparts. Evaluation of the individual enantiomers of the chiral iminohydantoins showed that the anticonvulsant activity resided primarily in the S isomers. In this study, (S)-(+)-1-carbobenzoxy-5-isobutyl-2-iminohydantoin (9a) was the most active member. This compound was not nearly as active as phenytoin against electrically induced convulsions, but was also active against pentylenetetrazole-induced seizures, suggesting a broader clinical potential. The closest analogue of phenytoin, viz., 5,5-diphenyl-2-iminohydantoin (1), failed to show any significant activity. Methylation on N-3 or the imino nitrogen of 1 also did not provide a compound with substantial activity. 2-Thiophenytoin was not active against electroshock seizures and showed only a weak activity against pentylenetetrazole. This study suggested that the structure-activity relationship of 2-iminohydantoins was quite different from that of 2-hydantoins.

Chemically stable, lipophilic prodrugs of phosphoramide mustard as potential anticancer agents

Benzyl phosphoramide mustard (3), 2,4-difluorobenzyl phosphoramide mustard (4), and methyl phosphoramide mustard (5) were examined as lipophilic, chemically stable prodrugs of phosphoramide mustard (2). These phosphorodiamidic esters are designed to undergo biotransformation by hepatic microsomal enzymes to produce 2. The rate of formation of alkylating species, viz., 2, from these prodrugs and their in vitro cytotoxicity toward mouse embryo Balb/c 3T3 cells were comparable to or better than that of cyclophosphamide (1). Preliminary antitumor screening against L1210 leukemia in mice, however, suggests that these prodrugs are devoid of any significant antitumor activity in vivo.

Effects of N-substitution on the activation mechanisms of 4-hydroxycyclophosphamide analogues

The activation mechanisms of the N-substituted 4-hydroxycyclophosphamide analogues 4-hydroxyifosfamide (2b), 4-hydroxytrofosfamide (2c), and 3-methyl-4-hydroxycyclophosphamide (2d) were compared with that of the unsubstituted parent compound 2a. The reaction kinetics of cis-2b, -2c, and -2d are qualitatively similar to those of 2a in that they undergo ring opening to the respective aldophosphamide intermediates 3, which can reclose to the cis- or trans-4-hydroxy isomers or undergo base-catalyzed beta-elimination to generate the corresponding phosphoramide mustard products 4. In contrast to the general acid catalysis observed for ring opening of 2a and 2d, the N-(chloroethyl)-substituted analogues 2b and 2c undergo specific base-catalyzed ring opening. This mechanistic difference was also illustrated by the rapid reaction of 2a and 2d with sodium 2-mercaptoethanesulfonate (Mesna) under acidic conditions to give the 4-(alkylthio)-substituted cyclophosphamide derivatives 5a and 5d. Compounds 2b and 2c did not react with Mesna to generate 5b and 5c under these conditions. Both the fraction of aldehyde/hydrate present at equilibrium and the cytotoxicity against L1210 cells in vitro decreased in the order 2c greater than 2b greater than 2a greater than 2d. The plasma-catalyzed acceleration of phosphoramide mustard generation previously reported for 2a was also observed for these analogues.

Spectroscopic detection of iminocyclophosphamide and its possible role in cyclophosphamide metabolism

Iminocyclophosphamide (4) has been identified by 1H NMR as a product from base treatment of 4-alkylthio-substituted cyclophosphamide derivatives, viz., cis-4-(propylthio)cyclophosphamide (cis-7). A maximum concentration of approximately 12% of total product was observed by treating cis-7 with ethyl propiolate and NaH or deuteriated dimsyl anion in anhydrous Me2SO-d6. Treatment of cis-7 with base alone established a rapid cis-/trans-7 equilibrium via the imine intermediate 4. Base-catalyzed expulsion of 1-propanethiol (8) from cis-7 and thiol trapping afforded formation of 4, which subsequently underwent elimination to the relatively more stable conjugated (vinylimino)-phosphamide (9). Iminocyclophosphamide (4) was also identified by fast atom bombardment mass spectrometry as a product generated upon analysis of cyclophosphamide derivatives substituted in the 4-position of the oxazaphosphorine ring with various leaving groups.