Radiation shielding analysis of a special linear accelerator for electron beam and X-ray.

The King AbdulAziz City for Science & Technology in the Kingdom of Saudi Arabia plans to build a 10 MeV, 15 kW linear accelerator (LINAC) for electron beam and X-ray. The accelerator will be supplied by EB Tech, Republic of Korea, and the design and construction of the accelerator building will be conducted in the cooperation with EB Tech. This report presents the shielding analysis of the accelerator building using the Monte Carlo N-Particle Transport Code (MCNP). In order to improve the accuracy in estimating deep radiation penetration and to reduce computation time, various variance reduction techniques, including the weight window (WW) method, the deterministic transport (DXTRAN) spheres were considered. Radiation levels were estimated at selected locations in the shielding facility running MCNP6 for particle histories up to 1.0×10+8. The final results indicated that the calculated doses at all selected detector locations met the dose requirement of 50 mSv/yr, which is the United State Nuclear Regulatory Commission (U.S. NRC) requirement.

Prevalence and clinical significance of cellular and acellular mucin in patients with locally advanced mucinous rectal cancer who underwent preoperative chemoradiotherapy followed by radical surgery.

AIM: The frequent presence of acellular mucin in specimens showing pathological complete response to preoperative chemoradiotherapy (CRT) and the poor response to preoperative CRT in mucinous rectal cancer have been reported. However, the prevalence and prognostic significance of cellular and acellular mucin have not been evaluated in resected specimens from patients with mucinous rectal cancer who undergo preoperative CRT. METHOD: We retrospectively evaluated the clinicopathological features and prognostic significance of mucin in resected specimens from 59 consecutive patients with mucinous rectal cancer who underwent long-course CRT followed by resection between January 2000 and December 2009. Patients were categorized according to the presence of mucin, as identified by pathological analysis. The clinicopathological findings and oncological results were compared. RESULTS: Mucin was identified in 25 of 59 patients with mucinous rectal cancer (42.4%). Mucin was more frequent in men (hazard ratio = 23.94, 95% confidence interval = 1.875-305.504, P = 0.015) and in specimens showing a good tumour response grade (hazard ratio = 64.26, 95% confidence interval = 6.940-595.045, P < 0.001). With a median follow-up of 67.7 (range 8.6-133.2) months, the 5-year overall survival (60.7% without mucin vs 51.4% with mucin, P = 0.898) and disease-free survival (59.9% without mucin vs 56.9% with mucin, P = 0.813) did not differ between the groups. CONCLUSION: The presence of mucin in rectal cancer with mucinous differentiation after preoperative CRT and resection is associated with male gender and a good tumour response grade, without significant impact on oncological outcome.

Optimal assessment of lymph node status in gallbladder cancer.

BACKGROUND: Lymph node (LN) metastasis is an important prognostic factor in gallbladder cancer (GBCA). LN status has been adopted as a critical element of staging systems. However, the influence of total lymph node count (TLNC) remains unclear. We determined the optimal minimum TLNC and compared the prognostic significance of LN status indices in GBCA. METHODS: We retrospectively reviewed medical records of 128 patients with T2 or greater GBCA who underwent LN dissection. We analyzed overall survival (OS) and relevance of the number of metastatic LNs, ratio of metastatic LNs to retrieved LNs (LNR), and TLNC in predicting OS. RESULTS: The median OS durations were 120, 35, and 18 months in T2, T3, and T4 GBCA. Five-year OS rates were 73%, 43%, and 0% in T2, T3, and T4 GBCA. LN status did not significantly impact OS in T2 or T4 GBCA. However, all LN indices were significantly correlated with OS in T3 GBCA. Furthermore, multivariate analysis revealed that a metastatic LN count of more than four and a TLNC of more than eight were independent prognostic factors of OS in T3 GBCA. CONCLUSIONS: TLNC and the number of positive LNs may be more important prognostic factors than LNR in T3 GBCA. Additionally, accurate staging may not be achieved in cases of T3 GBCA if the total number of retrieved LNs is less than eight. Thus, to ensure proper staging, we recommend that surgeons harvest more than eight LNs in patients with T3 GBCA.

Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas).

OBJECTIVES: Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality. DESIGN: Retrospective multinational study including SCN diagnosed between 1990 and 2014. RESULTS: 2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2-200)), 9% had resection beyond 1 year of follow-up (3 years (1-20), size at diagnosis: 25 mm (4-140)) and 39% had no surgery (3.6 years (1-23), 25.5 mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1). CONCLUSIONS: After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN. TRIAL REGISTRATION NUMBER: IRB 00006477.

Comparing self-efficacy and self-care behaviours between outpatients with comorbid schizophrenia and type 2 diabetes and outpatients with only type 2 diabetes.

People with schizophrenia show higher-than-normal rates of type 2 diabetes mellitus (T2DM); however, research on their understanding of diabetes self-efficacy and self-care behaviours is lacking. This study compared differences in scores of self-efficacy and self-care behaviours between outpatients with comorbid schizophrenia and T2DM and outpatients with T2DM alone. Data were collected using the Diabetes Management Self-Efficacy Scale and Summary of Diabetes Self-Care Activity questionnaire. In total, 105 outpatients with schizophrenia and T2DM and 106 outpatients with T2DM returned completed questionnaires. Results of this study revealed that outpatients with schizophrenia and T2DM had significantly lower total self-efficacy and self-care scores than outpatients with only T2DM. The stepwise regression analysis revealed that self-efficacy, the haemoglobin A1C level and current smoking were significant predictors of self-care behaviours in outpatients with comorbid schizophrenia and T2DM, which explained 33.20% of the variance. These findings help mental health professionals improve patient care through a better understanding of self-care behaviours among outpatients with comorbid schizophrenia and T2DM.

Splenic vein thrombosis and pancreatic fistula after minimally invasive distal pancreatectomy.

BACKGROUND: This study aimed to investigate the clinical relevance of splenic vein thrombosis (SVT) in the splenic vein remnant following minimally invasive distal pancreatosplenectomy (DPS). METHODS: Medical records of patients who underwent laparoscopic or robotic distal pancreatectomy (DP) with or without splenectomy between January 2006 and August 2012 were reviewed. Rates of SVT and clinically relevant postoperative pancreatic fistula (POPF) were compared in a group of patients undergoing DPS and a group having spleen-preserving DP. RESULTS: Seventy-nine patients had minimally invasive DP, of whom 38 (48 per cent) developed SVT in the splenic vein remnant. DPS was associated with POPF (P = 0.001) and SVT (P < 0.001). SVT length was closely related to the amount of peripancreatic fluid collection (P = 0.025) and POPF (P = 0.045). In a comparison of splenic vessel-sacrificing, spleen-preserving DP and DPS, postoperative platelet count was significantly higher in the DPS group (P < 0.001). In addition, grade of SVT (P = 0.092) and POPF (P = 0.065) tended to be associated with DPS, suggesting that SVT may be related to both splenectomy and POPF. CONCLUSION: Minimally invasive DPS is associated with SVT and POPF. Preservation of the spleen should be considered when treating patients with benign and borderline malignant tumours of the distal pancreas.

Mizoribine versus mycophenolate mofetil in combination therapy with tacrolimus for de novo kidney transplantation: evaluation of efficacy and safety.

The present study compared the efficacy and safety of mizoribine (MZR) with mycophenolate mofetil (MMF) in kidney transplantation. This multicenter, randomized clinical trial. Employed doses of study drug tailored to the immunosuppressive need. The primary efficacy outcome was the incidence of biopsy-proven acute rejection episodes (BPAR). The safety of the study drug was assessed using the incidences of adverse events, drug discontinuations, and abnormal laboratory results. The 7 (6.4%) BPARs above grade II were observed in the MZR group noninferior to the 2 (1.8%) in the MMF group (95% confidence interval, -0.007-0.097 > noninferiority limit [-0.2]). BPAR was significantly decreased in the MZR group after the dose change (17/41 [41.4%] vs 8/69 [11.6%]; P < .0001) and the incidence of BPAR was similar between the MZR and MMF groups after the dose change (P = .592). The uric acid level was significantly elevated in the MZR group (P = .002). In conclusion, the efficacy and safety of MZR were similar and statistically noninferior to MMF in combination therapy with tacrolimus.

Effect of fudosteine on mucin production.

Fudosteine is a novel mucoactive agent, although little is known about how fudosteine decreases mucin production. The present study examined the effects of fudosteine on MUC5AC mucin synthesis and cellular signalling. An animal model of lipopolysaccharide (LPS)-induced inflammation and a bronchial epithelial cell line model of tumour necrosis factor (TNF)-alpha-induced inflammation were used. Fudosteine was administered before stimulation with LPS or TNF-alpha. The MUC5AC mucin levels were assayed and the expression of the MUC5AC gene was measured. Western blotting was carried out for the detection of phosphorylated epidermal growth factor receptor (p-EGFR), phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) and phosphorylated extracellular signal-related kinase (p-ERK). MUC5AC mucin synthesis and the expression of the MUC5AC gene were increased by LPS in rats or TNF-alpha in NCI-H292 cells; these effects were inhibited by fudosteine treatment. After stimulation with LPS or TNF-alpha, the expression of p-EGFR, p-p38 MAPK and p-ERK were detected. Fudosteine treatment reduced the expression levels of p-p38 MAPK and p-ERK in vivo and of p-ERK in vitro. The present results suggest fudosteine inhibits MUC5AC mucin hypersecretion by reducing MUC5AC gene expression and the effects of fudosteine are associated with the inhibition of extracellular signal-related kinase and p38 mitogen-activated protein kinase in vivo and extracellular signal-related kinase in vitro.

Robotic tumor-specific mesorectal excision of rectal cancer: short-term outcome of a pilot randomized trial.

BACKGROUND: Laparoscopic colorectal resection has become popular. The recently developed da Vinci Surgical System promises to facilitate endoscopic surgery and overcome its disadvantages. This study therefore aimed to compare the short-term results between robotic tumor-specific mesorectal excision (R-TSME) using the da Vinci Surgical System and conventional laparoscopic tumor-specific mesorectal excision (L-TSME) in rectal cancer patients. METHODS: Between April 2006 and February 2007, 36 patients were randomly assigned to receive R-TSME or L-TSME. During the study, 18 patients underwent robotic low anterior resection using the da Vinci Surgical System, and 18 patients had conventional laparoscopic low anterior resection. Patient characteristics, perioperative clinical results, complications, and pathologic details were compared between the two groups. RESULTS: The patient characteristics were not significantly different between the two groups. The mean operating time, hemoglobin change, and conversion rate were not significantly different between the groups. Complications were treated conservatively and did not require surgical intervention in the R-TSME group. The average length of stay was 6.9 +/- 1.3 days in the R-TSME group and 8.7 +/- 1.3 days in the L-TSME group (p < 0.001). The specimen quality of the R-TSME group was acceptable. CONCLUSION: Tumor-specific mesorectal excision was performed safely and effectively using the da Vinci Surgical System and the perioperative outcomes were acceptable.

HBV X protein targets hBubR1, which induces dysregulation of the mitotic checkpoint.

Accurate chromosomal segregation is monitored by the mitotic checkpoint, and an increased rate of chromosomal missegregation leads to chromosomal instability (CIN). Here, we demonstrate that the HBV X protein (HBx) binds BubR1, a component of the mitotic checkpoint complex and co-localizes with BubR1 at the kinetochores. HBx binding to BubR1 attenuates the association between BubR1 and CDC20, an activator of the anaphase-promoting complex/cyclosome (APC/C) and induces slippage of mitotic arrest in the presence of microtubule poisons. In addition, HBx binding to BubR1 results in the accumulation of lagging chromosomes and chromosome bridges. In contrast, a C-terminally truncated HBx mutant (HBx(1-100)) fails to bind BubR1 and does not cause aberrant chromosomal segregation. This provides a novel mechanism for dysregulation of the mitotic checkpoint by a viral pathogen linking it to the accumulation of chromosomal instability in HBV-associated hepatocarcinogenesis.

A novel function for HSF1-induced mitotic exit failure and genomic instability through direct interaction between HSF1 and Cdc20.

Although heat-shock factor (HSF) 1 is a known transcriptional factor of heat-shock proteins, other pathways like production of aneuploidy and increased protein stability of cyclin B1 have been proposed. In the present study, the regulatory domain of HSF1 (amino-acid sequence 212-380) was found to interact directly with the amino-acid sequence 106-171 of Cdc20. The association between HSF1 and Cdc20 inhibited the interaction between Cdc27 and Cdc20, the phosphorylation of Cdc27 and the ubiquitination activity of anaphase-promoting complex (APC). The overexpression of HSF1 inhibited mitotic exit and the degradations of cyclin B1 and securin, which resulted in production of aneuploidy and multinucleated cells, but regulatory domain-deficient HSF1 did not. Moreover, HSF1-overexpressing cells showed elevated levels of micronuclei and genomic alteration. The depletion of HSF1 from cells highly expressing HSF1 reduced nocodazole-mediated aneuploidy in cells. These findings suggest a novel function of HSF1 frequently overexpressed in cancer cells, to inhibit APC/C activity by interacting with Cdc20, and to result in aneuploidy development and genomic instability.

Laparoscopic cholecystectomy only could be an appropriate treatment for selected clinical R0 gallbladder carcinoma.

BACKGROUND: Laparoscopic cholecystectomy (LC) for gallbladder carcinoma still is controversial except for the early stages of gallbladder carcinoma (Tis). This study was designed to evaluate and revisit the role of LC in treating gallbladder carcinoma. METHODS: Available medical records of patients with surgeries for gallbladder carcinoma were retrospectively investigated from August 1992 to February 2005. RESULTS: Among 219 patients treated for gallbladder carcinoma, 57 (26%) underwent LC. A total of 16 patients (28.1%) underwent subsequent radical cholecystectomy (LC-RC), and 41 (71.9%) were only followed up without radical surgery (LC). Tis was found in 11 patients (19.3%), T1a in 3 patients (5.3%), T1b in 8 patients (14%), T2 in 19 patients (33.3%), and T3 in 16 patients (28.1%). The findings showed R0 in 14 cases of the radical cholecystectomy group, and clinical R0 was noted in 30 cases of the LC-only group. No survival differences were noted between LC and LC-RC (p = 0.2575), especially in the case of T2 lesions (p = 0.6274), nor between the R0 and clinical R0 (p = 0.5839). However, significant survival differences were noted between the R2 and R0 groups, and between R2 and clinical R0, respectively (p < 0.001). CONCLUSIONS: The findings show that LC could be appropriate treatment for gallbladder carcinoma only in selected cases of clinical R0 lesions.

Analysis of allograft biopsy specimens in renal transplants with proteinuria: is proteinuria a culprit of graft loss?

It has been proposed that proteinuria occurring after renal transplantation may be not only a marker but also a culprit of allograft dysfunction. We retrospectively analyzed the data from 55 patients who underwent transplant renal biopsy for proteinuria and/or azotemia occurring beyond 1 year after transplantation. Proteinuria was considered as significant when > or = 30 mg/dL, and the results of transplant biopsy were categorized according to the Banff 97 classification. Logistic regression was used to estimate odds ratios (OR) for graft loss associated with proteinuria and transplant pathology. The patients were followed for 86.0 +/- 32.8 months after transplantation, and transplant biopsy was performed at 54.1 +/- 31.0 months. Proteinuria at 1 year after transplantation noted in 29.1% of patients was not significantly associated with graft loss (OR = 1.94, 95% CI from 0.59 to 6.41). In addition, proteinuria at the time of transplant biopsy was not significantly associated with graft loss. Chronic allograft nephropathy was the most frequent transplant pathology. Only glomerulonephritis was significantly associated with proteinuria at the time of the transplant biopsy. On the other hand, graft loss was significantly associated with the presence of proteinuria both at 1 year after transplant biopsy and at the final follow-up. These results suggest that posttransplantation proteinuria is an important marker of graft dysfunction, but is not predictive of graft loss in biopsy-proven cases. Appropriate management guided by the results of a transplant biopsy may improve the outcome.

Induction of cell cycle arrest and apoptosis in human breast cancer cells by quercetin.

Quercetin, a widely distributed bioflavonoid, has been shown to induce growth inhibition in certain cancer cell types. In the present study we have pursued the mechanism of growth inhibition in MCF-7 human breast cancer cells. Quercetin treatment resulted in the accumulation of cells specifically at G2/M phase of the cell cycle. Mitotic index measured by MPM2 staining clearly showed that cells were transiently accumulated in M phase, 24 h after treatment. The transient M phase accumulation was accompanied by a transient increase in the levels of cyclin B1 and Cdc2 kinase activity. However, 24 h or longer treatment caused a marked accumulation of cells in G2 instead of M phase. Levels of cyclin B1 and cyclin B1-associated Cdc2 kinase activity were also decreased. We also found that quercetin markedly increased Cdk-inhibitor p21CIP1/WAF1 protein level after treatment for 48 h or longer, and the induction of p21CIP1/WAF1 increased its association with Cdc2-cyclin B1 complex, however, up-regulation of p53 by quercetin was not observed. Quercetin also induced significant apoptosis in MCF-7 cells in addition to cell cycle arrest, and the induction of apoptosis was markedly blocked by antisense p21CIP1/WAF1 expression. The present data, therefore, demonstrate that a flavonoid quercetin induces growth inhibition in the human breast carcinoma cell line MCF-7 through at least two different mechanisms; by inhibiting cell cycle progression through transient M phase accumulation and subsequent G2 arrest, and by inducing apoptosis.

Thymidine-dependent attenuation of the mitochondrial apoptotic pathway in adenosine-induced apoptosis of HL-60 cells.

OBJECTIVE: We previously reported that adenosine-induced apoptosis in HL-60 cells was attenuated by cotreating the cells with pyrimidine nucleosides. The mechanism involved in this adenosine-induced apoptosis by the differential supply of nucleosides is studied here with a particular focus on the regulation of apoptosis-associated mitochondrial events. METHODS: Time-dependent changes in the mitochondrial membrane potential (MMP) after treatment with adenosine and/or thymidine were monitored. RESULTS: The cells did not show any decrease of MMP level up to 2.5 h after 1 mM adenosine exposure, whereas cytochrome c release, caspase-9 and caspase-3 activity, and DNA fragmentation were already activated, suggesting that mitochondrial depolarization is not a prerequisite of other apoptosis-related mitochondrial events. In contrast, the translocation of Bax to mitochondria and the release of cytochrome c began within the first hour of adenosine treatment. CONCLUSION: Thus, it is believed that adenosine-induced apoptosis is mediated by the activation of the caspase cascade by cytochrome c release with concomitant increase of Bax in the mitochondria, which implies that the translocation of Bax might be a leading event in the adenosine-induced apoptosis. Moreover, we found that most of the apoptotic parameters in adenosine-induced cellular changes, such as translocation of Bax, the release of cytochrome c, and the consequent activation of caspase-9 and caspase-3, were attenuated by thymidine supplement, thus indicating that the sensing of a nucleoside or nucleotide balance might be an upstream event of cytochrome c release. Therefore, it can be concluded that thymidine can attenuate adenosine-induced apoptosis by modulating the earliest stage of the mitochondrial apoptotic pathway.

Ionizing radiation can overcome resistance to TRAIL in TRAIL-resistant cancer cells.

Although the majority of cancer cells are killed by TRAIL (tumor necrosis factor-related apoptosis-inducing ligand treatment), certain types show resistance to it. Ionizing radiation also induces cell death in cancer cells and may share common intracellular pathways with TRAIL leading to apoptosis. In the present study, we examined whether ionizing radiation could overcome TRAIL resistance in the variant Jurkat clones. We first selected TRAIL-resistant or -sensitive Jurkat clones and examined cross-responsiveness of the clones between TRAIL and radiation. Treatment with gamma-radiation induced significant apoptosis in all the clones, indicating that there seemed to be no cross-resistance between TRAIL and radiation. Combined treatment of radiation with TRAIL synergistically enhanced killing of TRAIL-resistant cells, compared to TRAIL or radiation alone. Apoptosis induced by combined treatment of TRAIL and radiation in TRAIL-resistant cells was associated with cleavage of caspase-8 and the proapoptotic Bid protein, resulting in the activation of caspase-9 and caspase-3. No changes in the expressions of TRAIL receptors (DR4 and DR5) and Bcl-2 or Bax were found after treatment. The caspase inhibitor z-VAD-fmk completely counteracted the synergistic cell killing induced by combined treatment of TRAIL and gamma-radiation. These results demonstrated that ionizing radiation in combination with TRAIL could overcome resistance to TRAIL in TRAIL-resistant cells through TRAIL receptor-independent synergistic activation of the cascades of the caspase-8 pathway, suggesting a potential clinical application of combination treatment of TRAIL and ionizing radiation to TRAIL-resistant cancer cells.

Hypoxia-induced VEGF enhances tumor survivability via suppression of serum deprivation-induced apoptosis.

Low oxygen and nutrient depletion play critical roles in tumorigenesis, but little is known about how they interact to produce tumor survival and tumor malignancy. In the present study, we investigated the mechanism underlying hypoxia-modulated apoptosis of serum-deprived HepG2 cells. Our results showed that hypoxia blocked the apoptosis, which was accompanied with decreased Bax/Bcl-2 ratio, inhibited cytochrome c release, and reduced caspase-3 activity. More importantly, increased expressions of VEGF and its receptor-2 (KDR) under hypoxic/serum-deprived condition suggest that VEGF may act as a survival factor in a self-promoting manner. Data were further supported by results that recombinant human VEGF (rhVEGF) suppressed the serum deprivation-induced apoptosis, and anti-VEGF neutralizing antibody block anti-apoptotic activity of hypoxia. In addition, inhibitors of receptor tyrosine kinase blocked antiapoptosis of hypoxia. Our study further showed that rhVEGF or hypoxia induced ERK phosphorylation in serum-deprived cells, and that a specific inhibitor of MAPK/ERK, PD98059 eliminated the anti-apoptotic activity of rhVEGF or hypoxia by increasing Bax/Bcl-2 ratio and caspase-3 activity. Our data led us to conclude that induction of ERK phosphorylation and decrease of Bax/Bcl-2 ratio by rhVEGF implies that hypoxia-induced VEGF prevents apoptosis of serum-deprived cells by activating the MAPK/ERK pathway. Taken together, we propose that hypoxia enhances survival of nutrient-depleted tumor cells by reducing susceptibility to apoptosis, which consequently leads to tumor malignancy.

Senescence-like changes induced by hydroxyurea in human diploid fibroblasts.

Hydroxyurea was found to inhibit the growth of human diploid fibroblasts, which resulted in senescence-like changes both in morphology and replicative potential similar to the replicative senescence. SA-beta-gal activity, a typical characteristic of the replicative senescence was also induced through a long-term treatment of the presenescent cells with 400-800 microgM of hydroxyurea for about 3 weeks. In addition, we determined the levels of cyclin-dependent kinase inhibitors, p21(Waf1) and p16(INK4a), and the p53 tumor suppressor in order to monitor its effect on cell cycle and stress responses. We observed a great induction of both p53 and p21(Waf1), but not of p16(INK4a) in the premature senescent cells. UV-irradiation of the premature senescent cells showed a decreased level of DNA fragmentation presumably ascribed to the reduced activation of stress-activated protein kinases. These results suggest that a chronic hydroxyurea treatment induces the cellular senescence in association with the induction of p53 and p21(Waf1).

Apoptotic activity of ursolic acid may correlate with the inhibition of initiation of DNA replication.

Ursolic acid (UA), a pentacyclic triterpene acid, has been reported to exhibit anti-tumor activity. In this study, we investigated the pro-apoptotic effect of UA on HepG2 human hepatoblastoma cells. Treatment with UA decreased the viability of HepG2 cells in a concentration- and time-dependent manner. Furthermore, 30 microM of UA induced DNA fragmentation and subdiploid cells and enhanced the release of cytochrome c and the activation of caspase-3. These results suggest that UA induces cell death through apoptosis, which may be mediated by cytochrome c-dependent caspase-3 activation. In addition, cell-cycle analysis revealed that UA-treated cells were arrested predominantly in the G(0) and G(1) phases with a concomitant decrease in the cell population of S phase. Moreover, expression of p21(WAF1), a cell-cycle regulator, was increased by UA, indicating that p21(WAF1) might mediate UA-induced cell-cycle arrest. However, UA markedly inhibited SV40 DNA replication in the initiation stage in vitro and significantly reduced the DNA cleaving of topoisomerase I and the ssDNA binding activity of replication protein A. These results indicate that the inhibition of DNA replication by UA may result from blockade of the establishment of the replication fork during initiation stage, consequently contributing to UA-induced cell-cycle arrest. Taken together, we suggest that UA-induced cell-cycle arrest may be mediated by inhibition of DNA replication and the increase of p21(WAF1) expression, which induces the release of cytochrome c and the activation of caspase-3, leading to apoptosis of HepG2 cells.

A case of hemolytic uremic syndrome associated with Epstein-Barr virus infection.

The precise etiology of hemolytic uremic syndrome (HUS) is unknown. However, it has been associated with bacterial (Shigella, Salmonella, E. coli, S. pneumoniae), Bartonella, and viral (coxsackie, ECHO, influenza, varicella. Epstein-Barr) infections and with endotoxemia. Recently, we experienced a case of HUS in a 16-year-old boy who was in the acute phase of an Epstein-Barr virus (EBV) infection. He had typical manifestations of HUS and EBV infection. He also transiently presented disseminated intravascular coagulation. His renal dysfunction recovered by supportive care, including hemodialysis, plasmapheresis, antihypertensive medication and aspirin. We present this case with a review of the literature as the second report of HUS associated with EBV infection.